Articles on Medical Diseases and Conditions

Tag: cortisol

  • Female Hirsitism

    Female hirsutism is a relatively common problem in which the overriding concern of the physician is to rule out an ovarian or adrenal tumor. The type and distribution of hair can be used to differentiate physiologic hair growth from nonphysiologic growth (hirsutism). In females there are two types of hair: fine, thin, nonpigmented vellus hair and coarse, curly, pigmented terminal hair. Pubic and axillary terminal hair growth is induced by androgens in the physiologic range. Growth of such hair on the face (especially the chin), sternum area, and sacrum suggests male distribution and therefore excess androgens. Virilization goes one step further and is associated with definite hirsutism, acne, deepening of the voice, and hypertrophy of the clitoris.

    The major etiologies of hirsutism are listed in the box. Hirsutism with or without other evidence of virilization may occur before or after puberty. When onset is prepubertal, the etiology is more often congenital adrenal hyperplasia or tumor. After puberty, PCO disease, Cushing’s syndrome, late-onset congenital adrenal hyperplasia, and idiopathic causes are more frequent. Findings suggestive of tumor are relatively sudden onset; progressive hirsutism, especially if rapidly progressive; and signs of virilization.

    Laboratory tests

    There is considerable disagreement among endocrinologists regarding which tests are most useful in hirsutism. The tests most often used are urine 17-KS, serum testosterone (total or free testosterone), DHEA-S, serum androstenedione, serum dihydrotestosterone, urine 3-a-androstanediol glucuronide, serum LH and FSH, serum prolactin, serum 17-OH-P, urine free cortisol, an ACTH stimulation (“Cortrosyn”) test, and the low-dose overnight dexamethasone suppression test. Each of these tests is used either to screen for one or more etiologies of hirsutism or to differentiate between several possible sources of abnormality. There is considerable disagreement concerning which tests to use for initial screening purposes, with some endocrinologists ordering only two or three tests and others using a panel of five to seven tests. Therefore, it may be worthwhile to briefly discuss what information each test can provide.

    Some Conditions That Produce Hirsutism
    Ovary
    PCO disease
    (Hyperthecosis)
    Ovarian tumor
    Adrenal
    Congenital adrenal hyperplasia (CAH)
    Cushing’s syndrome (nontumor)
    Adrenal tumor
    Testis
    Leydig cell tumor
    Other
    Idiopathic hirsutism
    Hyperprolactinemia
    Starvation
    Acromegaly (rare)
    Hypothyroidism (rare)
    Porphyria (rare)
    Medications
    Phenytoin (Dilantin)
    Diazoxide (Hyperstat)
    Minoxidil(Loniten)
    Androgenic steroids
    Glucocorticosteroids
    Streptomycin

    Urine 17-KS was one of the first tests in hirsutism or virilization. Elevated urine 17-KS levels suggest abnormality centered in the adrenal, usually congenital adrenal hyperplasia (CAH) or adrenal tumor. Ovarian tumors, PCO disease, or Cushing’s syndrome due to pituitary adenoma usually do not produce elevated urine 17-KS levels (although some exceptions occur). However, some cases of CAH fail to demonstrate elevated 17-KS levels (more often in the early pediatric age group and in late-onset CAH). Serum 17-OH-P in neonatal or early childhood CAH and 17-OH-P after ACTH stimulation in late-onset CAH are considered more reliable diagnostic tests. Also, a significant minority (16% in one series) of patients with adrenal carcinoma and about 50% of patients with adrenal adenomas fail to show elevated 17-KS levels. In addition, 17-KS values from adrenal adenoma and carcinoma overlap, although carcinoma values in general are higher than adenoma values. The overnight low-dose dexamethasone test is more reliable to screen for Cushing’s syndrome of any etiology (including tumor) than are urine 17-KS levels, and the 24-hour urine free cortisol assay is a little more reliable than the overnight dexamethasone test (see Chapter 30). At present most endocrinologists do not routinely obtain 17-KS levels.

    Serum testosterone was discussed earlier. Testosterone levels are elevated (usually to mild degree) in more than one half of the patients with PCO disease and in patients with Leydig cell tumors or ovarian testosterone-producing tumors. Elevated serum testosterone suggests a problem of ovarian origin because the ovaries normally produce 15%-30% of circulating testosterone; and in addition, the ovary produces about one half of circulating androstenedione from adrenal DHEA and this androstenedione is converted to testosterone in peripheral tissues. On the other hand, testosterone is produced in peripheral tissues and even in the adrenal as well as in the ovary. Serum testosterone levels therefore may be elevated in some patients with nonovarian conditions such as idiopathic hirsutism. These multiple origins make serum testosterone the current best single screening test in patients with hirsutism. Several investigators have found that serum free testosterone levels are more frequently elevated than serum total testosterone levels in patients with hirsutism, although a lesser number favor total testosterone. Possible false results in total testosterone values due to changes in testosterone-binding protein is another point in favor of free testosterone. Some investigators have reported that serum androstenedione and DHEA-S levels are elevated in some patients with free testosterone values within reference range and that a test panel (e.g., free testosterone, androstenedione, dihydrotestosterone, and DHEA-S) is the most sensitive means of detecting the presence of excess androgens (reportedly with a sensitivity of 80%-90%).

    Dehydroepiandrosterone-sulfate (DHEA-S) is produced entirely in the adrenal from adrenal DHEA. Therefore, elevated DHEA-S levels suggest that at least some excess androgen is coming from the adrenal. The DHEA-S test is also more sensitive for adrenal androgen excess than the urine 17-KS test. A minor difficulty is that a certain number of patients with PCO disease (in which the ovary is supposed to be the source of excess androgen production) and also certain patients with idiopathic hirsutism have some DHEA-S evidence of adrenal androgen production. For example, one third of PCO disease patients in one series were found to have increased DHEA-S levels. Although this was interpreted to mean that some adrenal factor was present as well as the ovarian component, it tends to confuse the diagnosis. Another difficulty is that some infertile women without hirsutism have been reported to have elevated DHEA-S levels. Androstenedione, as noted previously, is a metabolite of adrenal DHEA that is produced about equally in the adrenal and in the ovaries but then reaches peripheral tissues where some is converted to testosterone. Therefore, elevated serum androstenedione levels indicate abnormality without localizing the source. Dihydrotestosterone (DHT) is a metabolite of testosterone and is formed mainly in peripheral tissues. Therefore, elevated DHT levels suggest origin from tissues other than the ovaries or adrenals. Androstanediol glucuronide is a metabolite of DHT and has the same significance. Some investigators report that it is elevated more frequently than DHT. Serum prolactin levels are usually elevated in prolactin-producing pituitary tumors (prolactinoma). These tumors are said to be associated with hirsutism in about 20% of cases. The mechanism is thought to be enhancement of ACTH effect on formation of DHEA. However, it has also been reported that up to 30% of patients with PCO disease have mildly elevated serum prolactin levels (elevated < 1.5 times the upper limit of the reference range). Prolactinomas are more likely in patients with irregular menstrual periods.

    Luteinizing hormone and FSH are useful in diagnosis of PCO disease, which typically (although not always) shows elevated LH levels, with or without elevated FSH levels.

    Urine free cortisol or low-dose overnight dexamethasone test are both standard tests used for diagnosis of Cushing’s syndrome, which is another possible cause of hirsutism.

    Serum 17-OH-P is used to diagnose CAH. Levels of the 17-OH-P specimens drawn between 7 A.M. and 9 A.M. are elevated in nearly all patients with CAH who have symptoms in the neonatal period or in early childhood. However, in late-onset CAH that becomes clinically evident in adolescence or adulthood, 17-OH-P levels may or may not be elevated. The most noticeable symptom of late-onset CAH is hirsutism. Reports indicate that about 5%-10% (range, 1.5%-30%) of patients with hirsutism have late-onset CAH. The most effective test for diagnosis of late-onset CAH is an ACTH (Cortrosyn) stimulation test. A baseline 17-OH-P blood specimen is followed by injection of 25 units of synthetic ACTH, and a postdose specimen is drawn 30 minutes after IV injection or 60 minutes after intramuscular injection. Exact criteria for interpretation are not frequently stated. However, comparison of test results in the literature suggests that an abnormal response to ACTH consists of 17-OH-P values more than 1.6 times the upper limit of the normal 17-OH-P range before ACTH. An “exaggerated” response appears to be more than 3 times the upper limit of the pre-ACTH normal range. In homozygous late-onset CAH there is an exaggerated 17-OH-P response to ACTH. CAH heterozygotes may have a normal response to ACTH or may have an abnormal response to ACTH that falls between a normal response and an exaggerated response.

    Suppression tests, such as a modified dexamethasone suppression test with suppression extended to 7-14 days, have been advocated in the past to differentiate between androgens of adrenal and ovarian origin. Dexamethasone theoretically should suppress nontumor androgen originating in the adrenal. However, studies have shown that the extended dexamethasone suppression test may be positive (i.e., may suppress androgen levels to < 50% of baseline) in some patients with PCO disease, and the test is no longer considered sufficiently dependable to localize the origin of increased androgen to either the adrenal or the ovary alone.

    Radiologic visualization of abdominal organs is helpful if PCO disease, ovarian tumor, or adrenal tumor is suspected. Ultrasound examination of the ovaries and CT of the adrenals are able to detect some degree of abnormality in most (but not all) patients.

    Polycystic ovary (PCO) disease

    PCO disease is considered by some to be the most common cause of female postpubertal hirsutism. It is also an important cause of amenorrhea, oligomenorrhea, and female sterility. PCO disease is defined both clinically and by histopathology. The classic findings at operation are bilaterally enlarged ovaries (about 65%-76% of cases), which on pathologic examination have a thickened capsule and numerous small cysts (representing cystic follicles) beneath the capsule. However, PCO disease is considered to have a spectrum of changes in which there is decreasing ovarian size and a decreasing number of cysts until the ovaries are normal in size (about 25%-35% of cases) with few, if any, cysts but with an increased amount of subcapsular and interstitial stroma. There is also a condition called “hyperthecosis” in which the thecal cells of the stroma are considerably increased and have a luteinized appearance. Some consider hyperthecosis a separate entity; some include it in PCO disease but consider it the opposite end of the spectrum from the polycystic ovary type; and some combine PCO disease and hyperthecosis together under a new name, “sclerocystic ovary syndrome.”

    Clinically, there is considerable variety in signs and symptoms. The classic findings were described by Stein and Leventhal, and the appellation Stein-Leventhal syndrome can be used to distinguish patients with classic findings from patients with other variants of PCO disease. The Stein-Leventhal subgroup consists of women who have bilaterally enlarged polycystic ovaries and who are obese, are hirsute without virilization, have amenorrhea, and have normal urine 17-KS levels. Other patients with PCO disease may lack one or more of these characteristics. For example, only about 70% of patients have evidence of hirsutism (literature range, 17%-95%). Some patients with PCO disease have hypertension, and some have abnormalities in glucose tolerance. A few have virilization, which is said to be more common in those with hyperthecosis.

    Laboratory tests. Laboratory findings in PCO disease are variable, as are the clinical findings. In classic Stein-Leventhal cases, serum testosterone levels are mildly or moderately elevated in about 50% of patients, and other androgen levels are elevated in many patients whose serum testosterone level remains within reference range. Free testosterone levels are elevated more frequently than total testosterone levels. Higher testosterone values tend to occur in hyperthecosis. Most investigators consider the increased androgen values to be derived mainly from the ovary, although an adrenal component has been found in some patients. Although urine 17-KS levels are usually normal, they may occasionally be mildly increased. The most characteristic finding in PCO is an elevated serum LH level with FSH levels that are normal or even mildly decreased. However, not all patients with PCO show this gonadotropin pattern.

    Summary of tests in hirsutism

    Most endocrinologists begin the laboratory investigation of hirsutism with a serum testosterone assay. Many prefer free testosterone rather than total testosterone. The number and choice of additional tests is controversial. Additional frequently ordered screening tests include serum DHEA-S, serum DHT, and the ACTH-stimulated 17-OH-P test. If abnormality is detected in one or more of these tests, additional procedures can help to find which organ and disease is responsible.

  • Addison’s Disease

    Addison’s disease is primary adrenocortical insufficiency from bilateral adrenal cortex destruction. Tuberculosis used to be the most frequent etiology but now is second to autoimmune disease atrophy. Long-term steroid therapy causes adrenal cortex atrophy from disuse, and if steroids are abruptly withdrawn, symptoms of adrenal failure may develop rapidly. This is now the most common cause of addisonian-type crisis. Less common etiologies of Addison’s disease are infection, idiopathic hemorrhage, and replacement by metastatic carcinoma. The most frequent metastatic tumor is from the lung, and it is interesting that there often can be nearly complete replacement without any symptoms.

    The salt-wasting forms of congenital adrenal hyperplasia—due to congenital deficiency of certain enzymes necessary for adrenal cortex hormone synthesis—might also be included as a variant of Addison’s disease.

    Weakness and fatigability are early manifestations of Addison’s disease, often preceded by infection or stress. Other signs and symptoms of the classic syndrome are hypotension of varying degree, weight loss, a small heart, and sometimes skin pigmentation. Anorexia, nausea, and vomiting occur frequently in adrenal crisis. The most common symptoms of adrenal crisis are hypotension and nausea.

    General laboratory tests

    Serum sodium is decreased in 50%-88% of patients with primary Addison’s disease, and serum potassium is mildly elevated in 50%-64% of cases (due to concurrent aldosterone deficiency). One investigator reported hypercalcemia in 6% of patients. There occasionally may be a mild hypoglycemia, although hypoglycemia is more common in secondary adrenal insufficiency. Serum thyroxine is low normal or mildly decreased and TSH is upper normal or mildly increased. Plasma aldosterone is usually decreased and plasma renin is elevated. There often is a normochromic-normocytic mild anemia and relative lymphocytosis with a decreased neutrophil count. Total eosinophil count is usually (although not always) close to normal.

    In primary adrenal insufficiency, a morning serum cortisol value is typically decreased and the plasma ACTH value is increased. Arginine vasopressin (AVP or ADH) is usually elevated.

    Diagnostic tests in Addison’s disease

    Screening tests. A single random serum cortisol specimen has been used as a screening procedure, since theoretically the value should be very low in Addison’s disease and normal in other conditions. Unfortunately, there are sufficient interfering factors so that its usefulness is very limited. Because serum cortisol normally has a circadian rhythm with its peak about 6-8 A.M., the specimen must be drawn about 6-8 A.M. in order not to misinterpret a lower value drawn later in the day. Stress increases plasma cortisol levels, although the increase is proportionately much less in Addison’s disease than in normal persons. The classic patient with Addison’s disease in crisis has an early morning cortisol level of less than 5 µg 100 ml (138 nmol/L), and a level of 5-10 µg/100 ml (138-276 nmol/L) is suspicious for Addison’s disease, especially if the patient is under stress. Patients with milder degrees of illness or borderline deficiency of cortisol may have a morning cortisol value of more than 10 µg/100 ml. It is often difficult to determine whether mild elevation of more than 10 µg/100 ml is due to stress or is a normal level. An early morning cortisol level of more than 20 µg/100 ml (550 mmol/L) is substantial evidence against Addison’s disease. Many endocrinologists do not consider a single random cortisol level to be reliable in screening for Addison’s disease. In spite of this it is usually worthwhile to obtain a serum specimen early for cortisol assay for diagnostic purposes (if it excludes Addison’s disease) or as a baseline (if it does not). A plasma sample should be obtained at the same time (EDTH anticoagulant) and frozen in case ACTH assay is needed later. As noted previously, serum sodium (and also chloride) is often low in classic cases, and if so would be suggestive of Addison’s disease if it were associated with a normal or elevated urine sodium and chloride level. However, as noted previously, serum sodium can be within population reference range in 12%-50% of patients.

    Rapid ACTH screening (“Cortrosyn”). Most investigators now prefer a rapid ACTH stimulation test rather than the single cortisol assay, since the rapid test can serve as a screening test unless the patient is extremely ill and in some patients may provide the same information as a confirmatory test. After a baseline serum cortisol specimen is obtained, 25 units of ACTH or 0.25 mg of corsyntropin (Cortrosyn or Synacthen, a synthetic ACTH preparation) is administered. There is variation in technique among the descriptions in the literature. Most measure plasma cortisol response after administration of corsyntropin but a few assay urinary 17-OHCS. Some inject corsyntropin intramuscularly and others intravenously. Intravenous (IV) administration is preferred but not required under ordinary circumstances. If the patient is severely ill or is hypotensive, IV is recommended to avoid problems in corsyntropin absorption. Some obtain a serum cortisol specimen 30 minutes after giving corsyntropin, whereas others do so at 60 or 120 minutes. Some obtain samples at two intervals instead of one. The majority appear to obtain one sample at 60 minutes. Some also obtain a sample at 30 minutes; this helps confirm the 60-minute value and avoids technical problems. However, the 30-minute specimen is not considered to be as reliable as the 60-minute specimen, especially if intramuscular (IM) injection was used. Theoretically, patients with primary adrenal insufficiency should demonstrate little response, whereas patients with pituitary insufficiency or normal persons should have stimulated cortisol levels that exceed 20 µg/100 ml (550 mmol/L). Some endocrinologists require an increment of at least 7 µg above baseline in addition to a peak value of 20 µg or more, especially when baseline cortisol is over 10µg/100 ml (225 mmol/L). However, increments less than or greater than 7µg are not as reproducible (on repeat corsyntropin tests) as the 20-µg peak cutoff value. Some patients with pituitary insufficiency demonstrate normal response to corsyntropin and some have a subnormal response. Because corsyntropin test results are not uniform in patients with pituitary insufficiency, it has been suggested that aldosterone should be measured as well as cortisol. Aldosterone levels should increase in pituitary hypofunction but should not rise significantly in primary adrenal failure. The metyrapone test is also useful to diagnose pituitary insufficiency.

    Some patients may have equivocal rapid test results, and others may have been treated with substantial doses of steroids for considerable periods of time before definitive tests for etiology of Addison’s disease are attempted. Under long-term steroid suppression, a normal adrenal cortex may be unable to respond immediately to stimulation. A definitive diagnosis of Addison’s disease is possible using prolonged ACTH stimulation. The classic procedure is the 8-hour infusion test. If biologic rather than synthetic ACTH is used, many recommend giving 0.5 mg of dexamethasone orally before starting the test to prevent allergic reactions. A 24-hour urine specimen is taken the day before the test. Twenty-five units of ACTH in 500 ml of saline is given intravenously during an 8-hour period while another 24-hour urine specimen is obtained. In normal persons, there will be at least a twofold to fourfold increase in cortisol or 17-OHCS levels. In Addison’s disease, there is practically no response. If pituitary deficiency is suspected, the test should be repeated the next day, in which case there will be a gradual, although relatively small, response. If exogenous steroids have been given over long periods, especially in large doses, the test period the classic approach is to repeat the 8-hour ACTH infusion procedure daily for 5-7 days. Patients with primary Addison’s disease should display little daily increment in cortisol values; those with secondary Addison’s disease should eventually produce a stepwise increase in cortisol values. Some have used a continuous ACTH infusion for 48 hours or depot IM synthetic ACTH preparations once daily instead of IV infusions or standard IM injections twice daily. If the patient has symptoms of adrenal insufficiency, both the rapid ACTH test and the prolonged ACTH test can be performed while the patient is taking 0.5-1.0 mg of dexamethasone per day, as long as therapy has not extended more than 5-6 days before starting the tests. Dexamethasone can be used because at these low doses it will not be a significant part of either serum or urine cortisol assays. Long periods of glucocorticoid therapy will interfere with the pituitary-adrenal feedback response necessary for rapid cortisol response to ACTH and will require longer periods of ACTH stimulation in the prolonged ACTH stimulation test.

    Thorn Test. If steroid measurements are not available, the Thorn test could be substituted, although it is not as accurate. First, a count of total circulating eosinophils is done. Then the patient is given 25 units of ACTH, either intravenously in the same way as in the ACTH test just described or intramuscularly in the form of long-acting ACTH gel. Eight hours after ACTH administration is started, another total circulating eosinophil count is made. Normally, cortisone causes depression of eosinophil production. Therefore a normal cortisol response to ACTH stimulation would be a drop of total circulating eosinophils to less than 50% of baseline values. A drop of less than 50% is considered suspicious for adrenal insufficiency. False positive responses (less than a 50% drop) may occur in any condition that itself produces eosinophilia (e.g., acute episodes of allergy).

    Adrenocorticotropic hormone (ACTH) assay. Plasma ACTH measurement has been used to help confirm the diagnosis of Addison’s disease and to differentiate primary from secondary adrenal failure. In primary adrenal failure, the ACTH value should be high and cortisol levels should be low. In hypothalamic or pituitary insufficiency, both ACTH and cortisol values theoretically should be low. Unfortunately, a considerable number of patients have cortisol or ACTH values within reference range. A specimen for plasma ACTH determination can be drawn at the same time as the specimen for baseline cortisol before stimulation tests and can be frozen for availability if needed.

    Antiadrenal antibodies. In primary Addison’s disease, antiadrenal antibodies have been detected in 60%-70% of patients. This test would have to be performed in large reference laboratories or certain university medical centers. Currently, this test is not being used as a primary diagnostic procedure.

  • Cushing’s Syndrome. Part 2

    48-hour dexamethasone suppression test.

    The 48-hour DST is the most widely used confirmatory procedure. Dexamethasone (Decadron) is a synthetic steroid with cortisone-like actions but is approximately 30 times more potent than cortisone, so that amounts too small for laboratory measurement may be given to suppress pituitary ACTH production. The test is preceded by two consecutive 24-hour urine collections as a baseline. If low doses (2 mg/day) are used, patients with normal adrenal function usually have at least a 50% decrease (suppression) in their 24-hour urine 17-OHCS values compared to baseline, whereas those with Cushing’s syndrome from any etiology have little if any change. This test result is usually normal in those patients whose low-dose overnight DST is abnormal (nonsuppressed) only because of obesity. If larger doses (8 mg/day) are used, about 85% (range, 42%-98%) of those with adrenal cortex hyperplasia due to pituitary oversecretion of ACTH have at least a 50% decrease (suppression) of their 24-hour urine 17-OHCS values. Adrenal cortisol-producing adenomas or carcinoma rarely decrease their urine 17-OHCS levels. Patients with the ectopic ACTH syndrome due to bronchial or thymus carcinoids have been reported to produce false positive test results (decrease in urine 17-OHCS levels) in up to 40% of patients. Patients with the ectopic ACTH syndrome from lung small cell carcinoma or other tumors rarely change urine 17-OHCS levels. Since the test takes a total of 4 days (48 hours at baseline and 48 hours of test duration) and requires 24-hour urine collections, and since there are a significant number of exceptions to the general rules, plasma ACTH assay is supplementing or replacing the high-dose DST for differentiation of the various etiologies of Cushing’s syndrome. Some investigators report that the metyrapone test (discussed later) is better than the 48-hour high-dose DST in differentiating pituitary oversecretion of ACTH from adrenal tumor.

    A single-dose overnight version of the high-dose DST has been reported, similar to the low-dose overnight test. A baseline serum cortisol specimen is drawn fasting at 8 A.M.; 8 mg of dexamethasone is given at 11 P.M.; and a second serum cortisol specimen is drawn fasting at 8 A.M. the next day. Normal persons and patients with pituitary ACTH syndrome have 50% or more cortisol decrease from baseline. Cortisol-producing adrenal tumors and ectopic ACTH patients have little change. Limited evaluation of this test reported similar results to the standard high-dose dexamethasone procedure.

    Metyrapone test. Metyrapone (Metopirone) blocks conversion of compound S to cortisol. This normally induces the pituitary to secrete more ACTH to increase cortisol production. Although production of cortisol is decreased, the compound S level is increased as it accumulates proximal to the metyrapone block, and 17-OHCS or radioassay CPB methods for cortisol in either serum or urine demonstrate sharply increased apparent cortisol values (due to compound S) in normal persons and those with pituitary-induced adrenal cortex hyperplasia. Fluorescent assay or RIA for cortisol do not include compound S and therefore yield decreased cortisol values. Adrenal tumors are not significantly affected by metyrapone. Some authorities recommend measuring both cortisol and compound S. An increase in compound S verifies that lowering of the plasma cortisol level was accompanied by an increase in ACTH secretion. This maneuver also improves the ability of the test to indicate the status of pituitary reserve capacity, and the test is sometimes used for that purpose rather than investigation of Cushing’s disease. To obtain both measurements, one must select a test method for cortisol that does not also measure compound S. Compound S can be measured by a specific RIA method. Phenytoin or estrogen administration interferes with the metyrapone test.

    Adrenocorticotropic hormone stimulation test. Injection of ACTH directly stimulates the adrenal cortex. Patients with cortex hyperplasia and some adenomas display increased plasma cortisol and 17-OHCS levels. If urine collection is used, a 24-hour specimen taken the day of ACTH administration should demonstrate a considerable increase from preinfusion baseline values, which persists in a 24-hour specimen collected the day after ACTH injection. Normal persons should have increased hormone excretion the day ACTH is given but should return to normal in the next 24 hours. Carcinoma is not affected. The ACTH stimulation test at present does not seem to be used very frequently.

    Serum adrenocorticotropic hormone. Serum ACTH measurement by immunoassay is available in many reference laboratories. At present, the assay techniques are too difficult for the average laboratory to perform in a reliable fashion, and even reference laboratories still have problems with accuracy.

    There is a diurnal variation in serum ACTH levels corresponding to cortisol secretion, with highest values at 8-10 A.M. and lowest values near midnight. Stress and other factors that affect cortisol diurnal variation may blunt or eliminate the ACTH diurnal variation. Serum ACTH data in adrenal disease are summarized in Table 30-1.

    Plasma adrenocorticotropic hormone in adrenal diseases

    Table 30-1 Plasma adrenocorticotropic hormone in adrenal diseases

    In Cushing’s syndrome due to adrenal tumor or micronodular hyperplasia, pituitary activity is suppressed by adrenal-produced cortisol, so the serum ACTH level is very low. In ectopic ACTH syndrome, the serum ACTH level is typically very high (4-5 times the upper preference limit) due to production of cross-reacting ACTH-like material by the tumor. However, some patients with the ectopic ACTH syndrome have serum levels that are not this high. In bilateral adrenal hyperplasia due to pituitary overactivity, serum ACTH levels can either be normal or mildly to moderately elevated (typically less than the degree of elevation associated with the ectopic ACTH syndrome). However, there is a substantial degree of overlap between pituitary tumor ACTH values and ectopic ACTH syndrome values. It has been suggested that ACTH specimens obtained at 10-12 P.M. provide better separation of normal from pituitary hypersecretion than do specimens drawn in the morning. Another study found that specimens drawn between 9:00 and 9:30 A.M. provided much better separation of normal from pituitary hypersecretion than specimens drawn at any other time in the morning. In summary, adrenal tumor (low ACTH levels) can usually be separated from pituitary-induced adrenal cortex hyperplasia (normal or increased ACTH levels) and from ectopic ACTH (increased ACTH levels). Pituitary-induced adrenal cortex hyperplasia has ACTH values that overlap with the upper range of normal persons and with the lower range of the ectopic ACTH syndrome. The time of day that the specimen is drawn may improve separation of normal persons from those with Cushing’s disease.

    Corticotropin-releasing hormone test. About 85% of Cushing’s disease is due to pituitary hyperplasia or tumor, and about 15% is due to ectopic ACTH from a nonpituitary tumor. Corticotropin-releasing hormone (CRH) from the hypothalamus stimulates the pituitary to release ACTH (corticotropin). Ovine CRH is now available, and investigators have administered this hormone in attempts to differentiate adrenal tumor and the ectopic ACTH syndrome from pituitary overproduction of ACTH. Initial studies reported that after CRH administration, pituitary ACTH-producing tumors increased plasma cortisol levels at least 20% over baseline and increased their ACTH level at least 50% over baseline. Normal persons also increase their ACTH and plasma cortisol levels in response to CRH, and there is substantial overlap between normal response and pituitary tumor response. Primary adrenal tumors and the ectopic ACTH syndrome either did not increase cortisol levels or increased ACTH less than 50% and plasma cortisol levels less than 20%. However, several studies found that about 10% of pituitary ACTH-producing tumors failed to increase plasma ACTH or cortisol to expected levels. This is similar to the rate that pituitary tumors fail to suppress cortisol production as much as expected in the high-dose 48-hour DST. About 15% of patients with the ectopic ACTH syndrome overlap with pituitary ACTH tumors using the ACTH criteria already mentioned, and about 10% overlap using the plasma cortisol criteria. Therefore, differentiation of the etiologies of Cushing’s syndrome by the CRH test alone is not as clear-cut as theoretically would be expected. To prevent false results, the patients should not be under therapy for Cushing’s syndrome when the test is administered.

    The CRH test has also been advocated to evaluate the status of pituitary function in patients on long-term, relatively high-dose corticosteroid therapy.

    To summarize, the expected results from the CRH test after injection of CRH are (1) for a diagnosis of Cushing’s disease, an exaggerated response from adenoma of pituitary; (2) for Cushing’s syndrome of adrenal origin or ectopic ACTH syndrome, no significant increase in ACTH; (3) for the differential diagnosis of increased ACTH from pituitary microadenoma versus ectopic ACTH syndrome, inconsistent results. The CRH test is not completely reliable in differentiating primary pituitary disease from hypothalamic deficiency disease.

    Cushing’s disease versus ectopic ACTH syndrome. The intracerebral inferior venous petrosal sinuses receive the venous blood from the pituitary containing pituitary-produced hormones; the right inferior petrosal sinus mostly from the right half of the pituitary and the left sinus from the left half. Several studies have suggested that catheterization of both inferior petrosal sinuses can differentiate ectopic ACTH production from the pituitary ACTH overproduction of Cushing’s disease in patients who do not show a pituitary tumor on computerized tomography (CT) scan or when the diagnosis is in question for other reasons. The most commonly used method is comparison of the ACTH level in the inferior petrosal sinuses with peripheral venous blood (IPS/P ratio) 3 minutes after pituitary stimulation by ovine CRH. Although several criteria have been proposed, it appears that an IPS/P ratio greater than 2.0 without CRH stimulation or a ratio of 3.3 or more in one of the inferior petrosal sinuses 3 minutes after CRH stimulation is over 95% sensitive and specific for Cushing’s disease versus ectopic ACTH syndrome (if technical problems are avoided). However, apparently this procedure is not as good in differentiating Cushing’s disease from pseudo-Cushing’s disease, since there is about 20% overlap with results from patients with some clinical or laboratory findings suggestive of Cushing’s disease (such as some patients with psychiatric depression) but without proof of pituitary hyperplasia or adenoma. In one study the same overlap was seen with clinically normal persons.

    Computerized tomography

    CT can frequently differentiate between unilateral adrenal enlargement (adrenal adenoma or carcinoma) and bilateral enlargement (pituitary hyperactivity or ectopic ACTH syndrome). However, it has been reported that nonfunctioning adrenal cortex nodules may occur in 1%-8% of normal persons, and one of these nodules could be present coincidentally with pituitary Cushing’s syndrome or ectopic ACTH. CT is very useful, better than pituitary sella x-ray films, in verifying the presence of a pituitary adenoma. Even so, third- and fourth-generation CT detects only about 45% (range, 30%-60%) of pituitary adenomas. In addition, it has been reported that 10%-25% of normal persons have a pituitary microadenoma, and some of these nonfunctioning nodules may be seen on CT and lead to a misdiagnosis of Cushing’s disease.

    Summary of tests in Cushing’s syndrome

    Currently, the most frequently utilized tests to screen for Cushing’s syndrome are the overnight low-dose DST and the test to detect abolishment of serum cortisol diurnal variation. Urine free-cortisol determination would provide more accurate information than the diurnal variation test. Confirmatory tests (if necessary) and tests to differentiate adrenal from nonadrenal etiology that are most often used are the 48-hour DST or the metyrapone test, serum ACTH assay, and CT visualization of the adrenals.

    Conditions that affect the screening and confirmatory tests should be kept in mind. In particular, alcoholism (especially with recent drinking) and psychiatric depression can closely mimic the test results that suggest Cushing’s syndrome. Finally, there are some patients in each category of Cushing’s syndrome etiology who do not produce the theoretically expected response to screening or confirmatory tests.

  • Cushing’s Syndrome. Part 1

    Cushing’s syndrome is caused by excessive body levels of adrenal glucocorticoids such as cortisol, either from (primary) adrenal cortex overproduction or from (secondary) therapeutic administration. This discussion will consider only the primary type due to excess adrenal production of cortisol. About 70% of cases (range 50%-80%) of Cushing’s syndrome due to adrenal overproduction of cortisol are caused by pituitary hypersecretion of ACTH leading to bilateral adrenal cortex hyperplasia. About 10% of cases are due to adrenal cortex adenoma, about 10% to adrenal cortex carcinoma, and about 10% to “ectopic” ACTH production by tumors outside the adrenal or pituitary glands, most commonly lung bronchial carcinoids (28%-38% of ectopic tumor cases) with the next most frequent being lung small cell carcinomas. A few cases are caused by thymus carcinoids, pancreatic islet cell tumors, pheochromocytomas, and various adenocarcinomas. One additional category is the uncommon syndrome of micronodular cortical hyperplasia, which biochemically behaves in a similar manner to adrenal cortex adenoma. Adrenal tumor is the most frequent etiology in patients younger than 10 years, and pituitary hyperactivity is the most common cause in patients older than 10. Cushing’s syndrome must be differentiated from Cushing’s disease, which is the category of Cushing’s syndrome due to pituitary hypersecretion of ACTH (usually due to a basophilic cell pituitary adenoma or microadenoma). The highest incidence of Cushing’s syndrome is found in adults, with women affected 4 times more often than men. Major symptoms and signs include puffy, obese-looking (“moon”) appearance of the face, body trunk obesity, “buffalo hump” fat deposit on the back of the neck, abdominal striae, osteoporosis, and a tendency to diabetes, hirsutism, easy bruising, and hypertension.

    Standard test abnormalities

    General laboratory findings include impairment of glucose tolerance in about 85% of patients (literature range, 57%-94%) that is severe enough to be classified as diabetes mellitus in about 25%. There is lymphocytopenia (usually mild) in about 80%, but most patients have an overall mild leukocytosis. Hemoglobin tends to be in the upper half of the reference range, with polycythemia in about 10% of affected persons. About 20%-25% have a mild hypokalemic alkalosis. The serum sodium level is usually normal but is slightly increased in about 5%. Total circulating eosinophils are usually decreased.

    Screening tests

    Urine 17-Ketosteroid assay. The urine 17-KS assay was one of the first tests used for diagnosis of Cushing’s syndrome. However, urine 17-KS values are increased in only about 50%-55% of patients with Cushing’s syndrome, and the test yields about 10% false positive results. Thus, 17-KS assay is no longer used to screen for Cushing’s syndrome. The 17-KS values may be useful in patients who are already known to have Cushing’s syndrome. About 45% of patients with adrenal adenoma and about 80%-85% (range 67%-91%) of patients with adrenal carcinoma have elevated urine 17-KS values. Patients with adrenal carcinoma tend to have higher urine 17-KS values than patients with Cushing’s syndrome from other etiologies, so that very high urine 17-KS values of adrenal origin suggest adrenal carcinoma.

    Single-specimen serum cortisol assay. Laboratory diagnosis of Cushing’s syndrome requires proof of cortisol hypersecretion. For some time, assay of 17-OHCS in a 24-hour urine specimen or a single-specimen plasma 17-OHCS assay by the Porter-Silber method was the mainstay of diagnosis. However, in Cushing’s syndrome this technique yields about 15% false negative and 15% false positive results. The 17-OHCS values in urine are increased in some patients by obesity, acute alcoholism, or hyperthyroidism, whereas the 17-OHCS values in plasma are increased in many patients by stress, obesity, or an increase in cortisol-binding protein due to estrogen increase (oral contraceptive medication or pregnancy). Therefore, urine 17-OHCS assay and single determinations of plasma 17-OHCS are no longer considered reliable enough to screen for Cushing’s syndrome. Plasma or urine 17-OHCS assay was also used to measure adrenal response in stimulation or suppression tests. However, it has been replaced for this purpose by serum cortisol assay, which is technically easier to do and avoids the many problems of 24-hour urine specimen collections.

    Single determinations of plasma cortisol, either in the morning or in the afternoon or evening, have the same disadvantages as plasma 17-OHCS and are not considered reliable for screening of Cushing’s syndrome. For example, single morning specimens detect about 65% of patients with Cushing’s syndrome (range, 40%-83%) and produce false positive results in about 30% of cases (range, 7%-60%). One report indicates that 11 P.M. or midnight specimens provide better separation of normal persons from those with Cushing’s syndrome.

    Plasma cortisol diurnal variation. If plasma cortisol assay is available, a better screening test for Cushing’s syndrome than a single determination consists of assay of two plasma specimens, one drawn at 8 A.M. and the other at 8 P.M. Normally there is a diurnal variation in plasma levels (not urine levels), with the highest values found between 6 and 10 A.M. and the lowest near midnight. The evening specimen ordinarily is less than 50% of the morning value. In Cushing’s syndrome, diurnal variation is absent in about 90% of patients (literature range, 70%-100%). False positive results are obtained in about 20% of patients (range, 18%-25%). Therefore, significant alteration of the diurnal pattern is not specific for Cushing’s syndrome, since it is found occasionally in patients with a wide variety of conditions. Some of the conditions that may decrease or abolish the normal drop in the evening cortisol level in some persons are listed in the box on this page. Therefore, a normal result (normal circadian rhythm) is probably more significant than an abnormal result (although, as already noted normal plasma cortisol circadian rhythm may be present in about 10% of patients with Cushing’s syndrome).

    Urine free cortisol. About 1% of plasma cortisol is excreted by the kidney in the original free or unconjugated state; the remainder appears in urine as conjugated metabolites. Original Porter-Silber chromogenic techniques could not measure free cortisol selectively. Fluorescent methods or immunoassay can quantitate free cortisol, either alone or with compound S, depending on the method. Immunoassay is becoming the most frequently used technique. Urine free-cortisol values in 24-hour collections are reported to be elevated in about 95% of patients with Cushing’s syndrome (literature range, 90%-100%) and to produce false positive elevation in about 6% of patients without Cushing’s syndrome (literature range, 0%-8%).

    Urine free-cortisol levels may be elevated in some patients by some of the factors that affect blood cortisol, including severe stress, acute alcoholism, psychiatric depression, and occasionally patients with obesity. In cortisol-binding protein changes such as an increase produced by estrogens, most reports indicate that urine free-cortisol secretion levels are usually normal. Renal insufficiency may elevate plasma cortisol levels and decrease urine free-cortisol levels. Hepatic disease may increase plasma cortisol levels but usually does not affect urine free-cortisol levels significantly. The major difficulty with the test involves accurate collection of the 24-hour specimen. Also, the test is not performed in most ordinary laboratories and would have to be sent to a medical center or reference laboratory.

    Some Conditions That Affect Serum Cortisol Diurnal Variation

    Severe stress
    Severe nonadrenal illness
    Obesity
    Psychiatric depression
    Alcoholism (especially with recent intake)
    Change in sleep habits
    Encephalitis
    Blindness
    Certain medications (prolonged steroids, phenothiazines, reserpine, phenytoin, amphetamines)

    Single-dose dexamethasone suppression test. The most simple reasonably accurate screening procedure is a rapid overnight dexamethasone suppression test (DST). Oral administration of 1 mg of dexamethasone at 11 P.M. suppresses pituitary ACTH production, so that the normal 8 A.M. peak of plasma cortisol fails to develop. After 11 P.M. dexamethasone, normal persons and the majority of obese persons have 8 A.M. plasma cortisol values less than 50% of baseline (predexamethasone) levels. Many endocrinologists require suppression to 5 µg/100 ml (138 nmol/L) or less. The consensus is that about 95% of Cushing’s syndrome patients exhibit abnormal test response (failure to suppress), although there is a range in the literature of 70%-98%). There is an average of less than 5% false positive results in normal control persons (range, 1%-10%).

    There is controversy in the literature regarding certain aspects of this test. Some investigators found substantial numbers of patients with a Cushingoid type of obesity, but without demonstrable Cushing’s syndrome, who failed to suppress adequately (falsely suggesting Cushing’s syndrome) after the overnight DST. This involved 10% of Cushingoid obese patients in one series and 53% in another. Unfortunately, there are not many reports in the literature that differentiate lean from obese persons in control series. Another controversial point is the degree that the 8 A.M. cortisol specimen must be suppressed from baseline value to separate normal persons from those with Cushing’s syndrome. Some have found the standard of a 50% decrease from baseline values to be insufficiently sensitive, missing up to 30% of Cushing’s syndrome patients. These investigators suggest a fixed 8 A.M. plasma cortisol value (after dexamethasone) of 5 or 7 µg/100 ml. However, establishment of such a fixed value is complicated by the variations in cortisol reference ranges found in different methods and kits. Another problem are conditions that may produce false results (failure to suppress normally). Some of these are listed in the box on this page.

    Phenytoin and phenobarbital affect cortisol by affecting the microsomal metabolic pathway of the liver. Estrogen increases cortisol-binding protein values, which, in turn, increases total plasma cortisol values. This may affect the DST when a fixed 5 µg/100 ml cutoff limit is used, since the already increased cortisol level must be suppressed even more than usual to reach that value. Spironolactone is a fluorescent compound and interferes with the Mattingly fluorescent assay technique. Immunoassay is not affected. Additional evidence to support abnormal screening test results may be obtained by using the standard DST.

    Some Conditions That Interfere With the Low-Dose Overnight Dexamethasone Suppression Test

    Conditions producing false normal test results*
    Drug-induced interference (phenytoin, phenobarbital, estrogens, possibly spironolactone)
    Conditions producing false abnormal test results†
    Acute alcoholism
    Psychiatric depression
    Severe stress
    Severe nonadrenal illness
    Malnutrition
    Obesity (some patients)
    Renal failure
    _____________________________________________________________
    * Apparent suppression of 8 A.M. cortisol in patients with Cushing’s syndrome.
    † Failure to suppress 8 A.M. cortisol in patients without Cushing’s syndrome.

    The single-dose DST and diurnal variation test may be combined. Plasma cortisol specimens are drawn at 8 A.M. and 8 P.M. Dexamethasone is administered at 11 P.M., followed by a plasma cortisol specimen at 8 A.M. the next day.

    Confirmatory tests

    Confirmation of the diagnosis depends mainly on tests that involve either stimulation or suppression of adrenal hormone production. It is often possible with the same tests to differentiate the various etiologies of primary hyperadrenalism. Normally, increased pituitary ACTH production increases adrenal corticosteroid release. Increased plasma corticosteroid levels normally inhibit pituitary release of ACTH and therefore suppress additional adrenal steroid production. Adrenal tumors, as a rule, produce their hormones without being much affected by suppression tests; on the other hand, they tend to give little response to stimulation, as though they behaved independently of the usual hormone control mechanism. Also, if urinary 17-KS values are markedly increased (more than twice normal), this strongly suggests carcinoma. However, hyperplasia, adenoma, and carcinoma values overlap, and 17-KS levels may be normal with any of the three etiologies.

  • Adrenal Cortex Hormones

    This chapter will begin with adrenal cortex hormones and conclude with adrenal medulla hormones. The adrenal medulla produces epinephrine and norepinephrine. The relationships of the principal adrenal cortex hormones, their actions, and their metabolites are shown in Fig. 30-1. The adrenal cortex is divided into three areas. A narrow outer (subcapsular) region is known as the “zona glomerulosa”. It is thought to produce aldosterone. The cortex middle zone, called the “zona fasciculata”, mainly secretes 17-hydroxycortisone, also known as “hydrocortisone” or “cortisol”. This is the principal agent of the cortisone group. A thin inner zone, called the “zona reticularis”, manufactures compounds with androgenic or estrogenic effects. Pathways of synthesis for adrenal cortex hormones are outlined in Fig. 30-2. Production of cortisol is controlled by pituitary secretion of adrenal cortex-stimulating hormone, or adrenocorticotropic hormone (corticotropin; ACTH). The pituitary, in turn, is regulated by a feedback mechanism involving blood levels of cortisol. If the plasma cortisol level is too high, pituitary action is inhibited and ACTH production is decreased. If more cortisol is needed, the pituitary increases ACTH production.

    30-1

    Fig. 30-1 Derivation of principal urinary steroids.

    30-2

    Fig. 30-2 Adrenal cortex steroid synthesis. Important classic alternate pathways are depicted in parentheses, and certain alternate pathways are omitted. Dotted lines indicate pathway that normally continues in another organ, although adrenal capability exists.

    Excess or deficiency of any one of adrenal cortex hormones leads to several well-recognized diseases which are diagnosed by assay of the hormone or its metabolites. In diseases of cortisol production, three assay techniques form the backbone of laboratory diagnosis: 17-hydroxycorti-costeroids (17-OHCS), 17-ketosteroids (17-KS), and direct measurement of cortisol. Before the use of these steroid tests in various syndromes is discussed, it is helpful to consider what actually is being measured.

    17-Hydroxycorticosteroids

    These are C21 compounds that possess a dihydroxyacetone group on carbon number 17 of the steroid nucleus (Fig. 30-3). In the blood, the principal 17-OHCS is hydrocortisone. In urine, the predominating 17-OHCS are tetrahydro metabolites (breakdown products) of hydrocortisone and cortisone. Therefore, measurement of 17-OHCS levels can be used to estimate the level of cortisone and hydrocortisone production. Estrogen therapy (including oral contraceptives) will elevate plasma 17-OHCS values, although degradation of these compounds is delayed and urine 17-OHCS levels are decreased.

    Adrenal cortex steroid nomenclature.

    Fig. 30-3 Adrenal cortex steroid nomenclature. A, basic 17-OHCS nucleus with standard numerical nomenclature of the carbon atoms. B, configuration of hydrocortisone at the C-17 carbon atom. C, configuration of the 17-KS at the C-17 carbon atom.

    17-Ketosteroids

    These are C19 compounds with a ketone group on carbon number 17 of the steroid nucleus (see Fig. 30-3). They are measured in urine only. In males, about 25% of 17-KS are composed of metabolites of testosterone. The remainder of 17-KS in males and nearly all 17-KS in females is derived from androgens other than testosterone, although lesser amounts come from early steroid precursors and a small percentage from hydrocortisone breakdown products. Testosterone itself is not a 17-KS. The principal urinary 17-KS is a compound known as dehydroisoandrosterone (dehydroepiandrosterone; DHEA). This compound is formed in the adrenal gland and has a weak androgenic effect. It is not a metabolite of cortisone or hydrocortisone, and therefore 17-KS cannot be expected to mirror or predict levels of hydrocortisone production.

    In adrenogenital or virilization syndromes, high levels of 17-KS usually mean congenital adrenal hyperplasia in infants and adrenal tumor in older children and adults. In both conditions, steroid synthesis is abnormally shifted away from cortisone formation toward androgen production. High 17-KS levels are occasionally found in testicular tumors if the tumor produces androgens greatly in excess of normal testicular output. In Cushing’s syndrome, 17-KS production is variable, but adrenal hyperplasia is often associated with mild to moderate elevation, whereas adrenal carcinoma frequently produces moderate or marked elevation in urinary values. In adrenal tumor, most of the increase is due to DHEA.

    Low levels of 17-KS are not very important because of normal fluctuation and the degree of inaccuracy in assay. Low levels are usually due to a decrease in DHEA. This may be caused by many factors, but the most important is stress of any type (e.g., trauma, burns, or chronic disease). Therefore, normal 17-KS levels are indirectly a sign of health.

    Plasma cortisol

    Plasma cortisol, like thyroxine, exists in two forms, bound and unbound. About 75% is bound to an alpha-1 globulin called “transcortin,” about 15% is bound to albumin, and about 10% is unbound (“free”). The bound cortisol is not physiologically active. Increased estrogens (pregnancy or estrogenic oral contraceptives) or hyperthyroidism elevates transcortin (raising total serum cortisol values without affecting free cortisol), whereas increased androgens or hypothyroidism decreases transcortin. In addition, pregnancy increases free cortisol. A marked decrease in serum albumin level can also lower total serum cortisol levels. There is a diurnal variation in cortisol secretion, with values in the evening being about one half those in the morning. Lowest values are found about 11 P.M.

    Cortisol test methods. All current widely used assays for serum cortisol measure total cortisol (bound plus free). There are three basic assay techniques: Porter-Silber colorimetric, Mattingly fluorescent, and immunoassay. The Porter-Silber was the most widely used of the older chemical methods. It measures cortisol, cortisone, and compound S (see Fig. 30-2), plus their metabolites. Ketosis and various drugs may interfere. The Mattingly fluorescent procedure is based on fluorescence of certain compounds in acid media at ultraviolet wavelengths. It is more sensitive than the Porter-Silber technique, faster, requires less blood, and measures cortisol and compound B but not compound S. Certain drugs that fluoresce may interfere. Immunoassay has two subgroups, competitive protein binding (CPB) and radioimmunoassay (RIA) or enzyme immunoassay (EIA). The CPB technique is the older of the two. It is based on competition of patient cortisol-like compounds with isotope-labeled cortisol for space on cortisol-binding protein. CPB measures cortisol, cortisone, compound S, and compound B. Advantages are small specimen requirement and less interference by drugs. RIA or EIA is based on competition of patient cortisol with labeled cortisol for anticortisol antibody. The method is nearly specific for cortisol, with less than 20% cross-reaction with compound S. In certain clinical situations, such as congenital adrenal hyperplasia or the metyrapone test, it is important to know what “cortisol” procedure is being performed to interpret the results correctly.

    All techniques measure total blood cortisol, so that all will give falsely increased values if increases in cortisol-binding protein levels occur due to estrogens in pregnancy or from birth control pills. Stress, obesity, and severe hepatic or renal disease may falsely increase plasma levels. Androgens and phenytoin (Dilantin) may decrease cortisol-binding protein levels. In situations where cortisol-binding protein levels are increased, urine 17-OHCS or, better, urine free cortisol assay may be helpful, since urine reflects blood levels of active rather than total hormone.