In a patient with long-term analgesic use, such as naproxen, painless hematuria is likely a result of analgesic nephropathy - a condition resulting from chronic tubulointerstitial damage from papillary ischemia induced by analgesic-mediated vasoconstriction of the vasa recta.
Analgesic nephropathy is commonly caused by long-standing use of analgesics and is the most common cause of drug-induced renal failure. It may occur as a result of drugs that contain phenacetin, acetaminophen, NSAIDs, or aspirin. Overuse may eventually lead to acute or chronic renal failure. Progression is insidious. Also use this vignette to recall the cardinal signs of osteoarthritis. Patients complain of swollen, hard, and painful joints, especially in the fingers at the PIP and DIP joints. The cause is mechanical wear and tear leading to destruction of articular cartilage. Age and obesity are two key risk factors.
Thaller and Wang discuss the evaluation of asymptomatic microscopic hematuria in adults. Routine screening for hematuria is not indicated; however, once discovered, its cause should be investigated beginning with a medical history and review of medications. Laboratory and imaging studies, such as intravenous pyelography, renal ultrasonography or retrograde pyelography, may be required to determine the degree and location of the associated disease process.
Kean et al. discuss management of chronic musculoskeletal pain in the elderly. Pain control in the elderly includes the use of non-steroidal anti-inflammatory drugs, acetaminophen, and various narcotics. Each has drawbacks and toxicities. Non-steroidals may cause adverse gastro-intestinal events and have renal toxicity. COX-2 inhibitors have cardiovascular effects. Narcotics may lead to cognitive decline and sedation in the elderly.
Illustration A depicts the mechanism of action of NSAIDs (COX 1/2 inhibitors).
Answer 2: Naproxen does cause analgesic nephropathy, but not via the described mechanism. Segmental sclerosis and hyalinosis are signs of focal segmental glomerulosclerosis.
Answer 3: Naproxin does cause analgesic nephropathy, but not via the described mechanism. Wire looping of capillaries is found in diffuse proliferative glomerulonephritis.
Answer 4: Acyclovir may cause crystalline nephropathy, in which polarizing microscopy shows birefringent needle-shaped crystals within leukocytes; renal biopsy may show foci of interstitial inflammation without tubular necrosis. Antibodies to the glomerular basement membrane are found in Goodpasture syndrome.
Answer 5: Acyclovir may cause crystalline nephropathy, in which polarizing microscopy shows birefringent needle-shaped crystals within leukocytes; renal biopsy may show foci of interstitial inflammation without tubular necrosis. A split basement membrane is found in Alport syndrome.
Thaller TR, Wang LP. Evaluation of asymptomatic microscopic hematuria in adults. Am Fam Physician. 1999 Sep 15;60(4):1143-52, 1154.
PMID:10507744 (Link to Abstract)
Kean WF, Rainsford KD, Kean IR. Management of chronic musculoskeletal pain in the elderly: opinions on oral medication use. Inflammopharmacology. 2008 Apr;16(2):53-75. doi: 10.1007/s10787-008-1623-7.
PMID:18389178 (Link to Abstract)