Azotemia

Azotemia is a medical condition characterized by abnormal levels of nitrogen-containing compounds, such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds in the blood.

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Causes

The cause is usually insufficient filtering of the blood by the kidneys. ^[1]

Azotemia can be classified according to its cause.

• In prerenal azotemia the blood supply to the kidneys is inadequate.
• In postrenal azotemia the urinary outflow tract is obstructed.

Other forms of azotemia are caused by diseases of the kidneys themselves.

Other causes of azotemia include congestive heart failure, shock, severe burns, prolonged vomiting or diarrhea, some antiviral medications, liver failure, or trauma to the kidney(s).

Uremia

Uremia is a broader term referring to the pathological manifestations of severe azotemia. Azotemia is one of many clinical characteristics of uremia, which is a syndrome characteristic of renal disease. Uremia includes azotemia, as well as acidosis, hyperkalemia, hypertension, anemia and hypocalcemia along with other findings.

Signs and symptoms (prerenal azotemia)

• Decreased or absent urine output
• Fatigue
• Decreased alertness
• Confusion
• Pale skin color
• Rapid pulse
• Dry mouth
• Thirst, swelling (edema, anasarca)
• Orthostatic blood pressure (rises or falls, significantly depending on position)

A urinalysis will typically show a decreased urine sodium level, a high urine creatinine-to- serum creatinine ratio, a high urine urea-to-serum urea ratio, and concentrated urine (determined by osmolality and specific gravity). None of these is particularly useful in diagnosis.

Prompt treatment of some causes of azotemia can result in restoration of kidney function; delayed treatment may result in permanent loss of renal function. Treatment may include hemodialysis or peritoneal dialysis, medications to increase cardiac output and increase blood pressure, and the treatment of the condition that caused the azotemia to begin with.

See also

• Kidney failure
• Uremia
• Nephrology

References