| Interstitial nephritis is an inflammation of the tubules and the spaces between the tubules and the glomeruli in the kidney. The condition may be a temporary lesion, or it may be chronic and progressive. Acute interstitial nephritis is most often caused by an allergic reaction to a drug or as a side effect of medications. Drugs that are risk factors for development of this condition include antibiotics, diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs). The condition may occur two or more weeks after exposure to the medication. This condition can also be caused by chronic exposure to heavy metals, including lead, cadmium, and mercury.
Interstitial nephritis causes reduction in kidney function, ranging from mild impairment to acute kidney failure. Signs of acute renal failure, such as decreased urine output, may occur in about half of interstitial nephritis cases. The kidney may fail to concentrate the urine when water intake is reduced and cause an alteration of the acid/base levels in the body. Failure to excrete appropriate acid in the urine may cause metabolic acidosis to occur. The disorder may progress to chronic renal failure or end-stage renal disease.Risk: Individuals who take certain medications are at higher risk for development of this condition. The medications include antibiotics, diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs). Incidence and Prevalence: The acute type of interstitial nephritis is common, accounting for an estimated 15% of cases of acute kidney failure in the US (Agha). |
Source: Medical Disability Advisor
| History: The individual may report increased or decreased urine output, nausea, vomiting, swelling of the body (any area), weight gain (from fluid retention), and drowsiness or confusion. There may be fever, a rash, and blood in the urine. Physical exam: The physical exam may reveal edema, or fluid overload, or signs of volume depletion, with abnormal sounds heard when examining with a stethoscope. There may be blood in the urine, fever, nausea, and mental changes, ranging from drowsiness to confusion to coma. Blood pressure is often high. Tests: Urinalysis may reveal blood (hematuria), increased protein (proteinuria), renal tubular cells, and other abnormalities. A complete blood count (CBC) may reveal eosinophilia (higher than normal esosinophil count). A failure to concentrate urine even when water intake is restricted may be revealed with urine specific gravity and osmolality tests. Urine pH may show a failure to acidify urine properly. Arterial gases and blood chemistry may reveal metabolic acidosis. BUN (blood urea nitrogen) and creatine levels are measured to assess the level of kidney functioning. Urinalysis to determine the presence of red blood cells in the urine (RBC urine) may indicate kidney disease if positive.
The diagnosis of interstitial nephritis and degree of damage to the kidney may be confirmed with a kidney biopsy. |
Source: Medical Disability Advisor
| If the acute interstitial nephritis is caused by a specific drug, the drug may be discontinued or changed or the dosage modified. Corticosteroids or anti-inflammatory medications may help in some cases. A restriction of protein in the diet may be needed to control azotemia (accumulation of nitrogenous waste products in the blood) associated with acute renal failure.
Dialysis may be required for a short time. |
Source: Medical Disability Advisor
| The outcome depends on the cause or type of the nephritis. Most individuals with acute interstitial nephritis recover completely. Individuals with prolonged and severe acute interstitial nephritis may progress to renal failure.
Although most individuals with chronic interstitial nephritis will recover some function with treatment, a few individuals will progress to chronic renal failure. |
Source: Medical Disability Advisor
| An exercise rehabilitation program under the direction of a physician may benefit individuals who are receiving dialysis treatment. |
Source: Medical Disability Advisor
| Complications include acute and chronic renal failure. |
Source: Medical Disability Advisor
| An extended leave of absence may be required. Upon returning to work, the individual may need to work part-time hours for a short period, and periodic rest breaks will need to be scheduled. Individuals receiving dialysis may need to be reassigned to sedentary duties on the days of treatment. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Did individual have a recent bacterial or viral infection? Did individual have any skin symptoms?
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Did individual have flank pain or blood in the urine?
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Has individual abused analgesics?
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Is individual on prolonged immunosuppressant therapy?
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Was individual exposed to lead or cadmium?
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Did individual receive appropriate testing to confirm the diagnosis?
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Were conditions such as tumors, diabetes, renal tuberculosis, and chronic obstructive uropathy ruled out?
Regarding treatment:
- What was the underlying cause? Was it corrected?
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Did individual require dialysis?
Regarding prognosis:
- Can individual's employer accommodate part-time work?
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Does individual have any conditions such as lupus nephritis, Sjögren's syndrome, mixed cryoglobulinemia, crescentic glomerulonephritis, IgA nephropathy, Wegener's granulomatosis, congestive heart failure, hypertension, systemic lupus erythematosus, diabetes mellitus, or thyrotoxicosis?
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Did individual have any complications such as acute or chronic renal failure?
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Source: Medical Disability Advisor
| Agha, Irfan A. "Interstitial Nephritis." MedlinePlus. National Library of Medicine. 3 Nov. 2004 <http://www.nlm.nih.gov/medlineplus/ency/article/000464.htm>. |
Source: Medical Disability Advisor