Articles on Medical Diseases and Conditions

Entries for September, 2009

Metabolic Alkalosis

Alkalosis may also be divided into metabolic and respiratory types. In metabolic alkalosis, three relatively common situations should be discussed. Alkali administration. Alkali administration most commonly occurs when sodium bicarbonate is taken in large quantities for the treatment of peptic ulcer symptoms. If this happens, excess HCO–3 is absorbed above the amount needed to neutralize […]

Respiratory Acidosis

The second major category of acidosis is that called respiratory acidosis. This may be due to any condition that causes pulmonary CO2 retention. These conditions include the respiratory muscle paralysis of poliomyelitis, the respiratory brain center depression sometimes seen in encephalitis or with large doses of such drugs as morphine, primary lung disease (e.g., pulmonary […]

Metabolic Acidosis

This type of acidosis has at least three main causes. Acid-gaining acidosis. Hydrogen ions not included in the CO2 system are added to the blood. The common situations are: 1. Direct administration, such as treatment with ammonium chloride, or the late effects of salicylate poisoning. Ammonium chloride (NH4Cl) releases H+ ions and Cl– ions as […]

Clinical Disturbances of pH

With this background, one may proceed to the various clinical disturbances of pH. These have been clinically termed “acidosis,” when the pH is decreased toward the acid side of normal and alkalosis, when the pH is elevated toward the alkaline side of normal. Acidosis, in turn, is usually subdivided into metabolic and respiratory etiology, and […]

Acid-Base Test Specimens

In the early days, acid-base studies were performed on venous blood. Venous specimens are nearly as accurate as arterial blood for pH and HCO3 (or PCO2) measurements if blood is obtained anaerobically from a motionless hand or arm before the tourniquet is released. Nevertheless, arterial specimens have mostly replaced venous ones because venous blood provides […]

Carbon Dioxide of pH and Carbon Dioxide

This section describes the laboratory tests used in pH abnormalities, which, incidentally, are often called “acid-base problems” because of the importance of the bicarbonate and carbonic acid changes involved. Carbon dioxide combining power. Venous blood is drawn aerobically with an ordinary syringe and the serum is then equilibrated to normal alveolar levels of 40 mm […]

Blood pH: The Bicarbonate-Carbonic Acid System

The term pH comes from the French puissance hydrogen, meaning the strength or power of hydrogen. The hydrogen ion concentration of blood expressed in gram molecular weights of hydrogen per liter (moles/L) is so much less than 1 (e.g., 0.0000001) that it is easier to communicate this information in terms of logarithms; thus, 0.0000001 becomes […]

Acid-Base and pH Measurements

Fluid and electrolyte problems are common in hospitalized patients. Most of these problems are secondary to other diseases or are undesirable side effects of therapy. There are a few diseases regularly associated with certain pH or electrolyte alterations that can help suggest the diagnosis and can be used to monitor therapy. Fluid and electrolytes in […]

Radionuclide Bone Scanning

Certain disorders affecting bone are discussed elsewhere (hyperparathyroidism, metastatic tumor in bone). The commonest diagnostic problems involve fractures, osteomyelitis, and metastatic tumor. The nonradiologic procedures most frequently used in bone disease are serum alkaline phosphatase and bone scanning. Strontium 85 was the first agent to be widely used in bone scanning. Its relatively high patient […]

Radionuclide Joint Scanning

Besides synovial fluid examination, radionuclide joint scanning is a procedure that may offer useful information. For screening purposes, the scan could be performed with one of the isotope-labeled phosphate compounds used for bone scanning. These scans reveal abnormality in most joints that have a significant degree of inflammation, even when subclinical. Joint scanning permits a […]