Definitions for Renal and Lung Cases

Acrocyanosis

This refers to cyanosis of the fingers. It indicates poor peripheral oxygenation and can occur when oxygen tension in the blood is low or when peripheral perfusion is poor.

Atelectasis

Lung collapse with loss of internal air. This can happen when the vacuum between the lung and chest wall is broken, allowing the lung to collapse within the chest ( e.g., pneumothorax), when the lung is compressed by masses in the chest, or when an airway is blocked, leading to slow absorption of the distal air into the blood without replentishment.

BUN

BUN stands for Blood Urea Nitrogen and refers to the urea concentration in the blood. Urea is the end product of protein nitrogen metabolism and is freely filtered at the glomerulus. About 40-60% of filtered urea is reabsorbed in the renal tubules, depending on the urine flow rate in the tubules. When BUN is elevated, it may indicate decreased glomerular filtration, but it may also indicate decreased urine flow (such as occurs in dehydration), allowing increased reabsorption, or an increased urea production rate (such as occurs in catabolism or tissue destruction, or digestion of high protein meals). The normal ratio of BUN to creatinine is less than 15. If BUN is increased without a corresponding increase in creatinine (e.g., the BUN/creatinine ration exceeds 15), then at least part of the the elevation in BUN is probably caused by non-renal mechanisms. These may include decreased urine flow rate in dehydration, leading to increased urea reabsorption, or increased urea production in catabolic states or high protein diets. Elevation of BUN is termed "azotemia," and an elevation of BUN without a corresponding elevation in creatinine is called "prerenal azotemia."

Dyspnea

Difficulty breathing. Mild dyspnea has been described as "an uncomfortable awareness of one's own breathing."

Intercostal retractions

Sagging of the chest wall between the ribs inward during inspiration. This happens during heavy (stressed) breathing and when chest expansion is inhibited by excess internal material that is not elastic (fluid or solid tissue). It is classically seen in infants with respiratory distress syndrome (the lungs are poorly elastic in that setting because pulmonary surfactant is lacking and alveolar fluid surface tension is excessive), but may occur in a number of other situations.

Orthostatic hypotension

Decreased blood pressure when standing with normal blood pressure when lying down. May lead to fainting on standing or getting up from lying or seated positions.

Polydipsia

Increased volume of (voluntary) fluid intake; usually accompanied by increased thirst.

Polyuria

Increased urine volume.

Renal insufficiency and renal failure

Decreased ability of the kidney to rid the body of waste products, usually due to decreased glomerular filtration rate. Generally indicated by mild-to- moderate increases in serum creatinine. If renal function declines further, renal insufficiency becomes renal failure.