A boy is suffering from acute pyelonephritis. Most specific urinary finding will be?
Correct Answer: WBC casts
Description: Ans. a. WBC casts (Ref: Robbins 9/e p932, Harrison 19/e p861, 18/e p2390; Smith 17/e p51; Campbell 10/e p96)Most specific urinary finding in acute pyelonephritis is WBC casts."When acute pyelonephritis is clinically apparent, the onset is usually sudden, with pain at the costovertebral angle and systemic evidence of infection, such as fever and malaise. There are usually indications of bladder and urethral irritation, such as dysuria. frequency, and urgency. The urine contains many leukocytes (pyuria) derived from the inflammatory infiltrate, but pyuria does not differentiate upper from lower urinary tract infection. The finding of leukocyte casts, typically rich in neutrophils (pus casts), indicates renal involvement, because casts are formed only in tubules. The diagnosis of infection is established by quantitative urine culture.''- Robbins 9/e p932Clinical significance of different castsHyaline casts* A normal constituentQ of urine and has no attached significanceQ* Tom Horsfall proteinQ is protein secreted by epithelial cells of loop of henle. This protein may be excreted as Hyaline castQRBC cast* Are suggestive of glomerular injuryQ or acute glomerulonephritisWBC casts* Are suggestive of interstitial injury and may be seen in interstitial nephritisQ* WBC cast with bacteria indicate pyelonephritisQBrood granular casts* Are seen in CRFQ and suggests interstitial fibrosis and dilatation of tubules.Pigmented muddy brown granular casts* Are suggestive of ischemic or nephrotoxic injuryQ (Tubular Necrosis)Acute PyelonephritisAcute suppurative inflammation of the kidney caused by bacterial and sometimes viral (e.g. polyoma virus) infection.Hematogenous, induced by septicemic spread or ascending infectionAssociated with vesicoureteral reflux.Morphology:Hallmarks of acute pyelonephritis: Patchy interstitial suppurative inflammation, intratubular aggregates of neutrophils and tubular necrosisQ.Complications of Acute PyelonephritisPapillary necrosis is seen mainly in diabetics and in those with urinary tract obstruction; usually bilateralQPyonephrosis: In cases of total or almost complete obstruction, particularly when it is high in the urinary tract.Perinephric abscessThe neutrophilic infiltrate is replaced by one that is predominantly composed of macrophages, plasma cells, and (later) lymphocytesQ.The inflammatory foci are eventually replaced by irregular scarsQ that can be seen on the cortical surface as fibrous depressionsPredisposing Factors:Urinary tract obstruction, instrumentation of the urinary tract (catheterization), vesicoureteral refluxQPregnancyQDiabetes mellitusQImmunosuppression and immunodeficiencyQInvestigation:Urine contains many leukocytes (pyuria) derived from the inflammatory infiltrate, but pyuria does not differentiate upper from lower urinary tract infection.The finding of leukocyte casts, typically rich in neutrophils (pus casts), indicates renal involvement, because casts are formed only in tubulesQ.Leukocyte casts are present in the urine of some patients, and the detection of these casts is pathognomonic for acute pyelonephritisQ
Category:
Medicine
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now