Azotemia
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| Azotemia Classification and external resources |
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| ICD-10 | R79.8 |
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| ICD-9 | 790.6 |
| DiseasesDB | 26060 |
| MeSH | D053099 |
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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[edit] 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.
Some 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). Most of these are prerenal causes, trauma may also be postrenal depending on location.
[edit] 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.
[edit] Signs and symptoms (prerenal azotemia)
- Decreased or absent urine output (oliguria or anuria).
- Fatigue
- Decreased alertness
- Confusion
- Pale skin color
- Tachycardia (rapid pulse)
- Dry mouth (xerostomia)
- Thirst, swelling (edema, anasarca)
- Orthostatic blood pressure (rises or falls, significantly depending on position)
- Uremic frost, a condition when urea and urea derivatives are secreted through the skin in sweat, which evaporates away to leave solid uric compounds, resembling a frost.
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.
In pre-renal and post-renal azotemias, elevation of the BUN exceeds that of the creatinine (i.e., BUN>12*creatinine). This is because BUN is readily absorbed while creatinine is not. In congestive heart failure (a cause of pre-renal azotemia) or any other condition that causes poor perfusion of kidneys, the sluggish flow of glomerular filtrate results in excessive absorption of BUN and elevation of its value in blood. Creatinine, however, is not absorbable and therefore does not rise significantly. Stasis of urine in post-renal azotemia has the same effect.
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.
[edit] See also
[edit] References
- ^ Kumar, V. & Abbas, A. (2005). Robbins and Cotran Pathologic Basis of Disease, 7th Edition, Philadelphia: Elsevier Saunders, pg. 960.
[edit] External Links
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