Snapshot A 60-year-old man presents to the emergency room with a 1-day history of fever and a new skin rash. He is taking methicillin for a soft tissue infection. On physical exam, he has costovetebral tenderness, and a diffuse maculopapular rash over his trunk. His serum creatinine is elevated at 3 mg/dL. Urinalysis reveals white blood cells. Further testing with Wright stain is positive for eosinophils in the urine. Introduction Clinical definition acute interstitial nephritis (AIN), also known as tubulointerstitial nephritis, is an acute immune-mediated interstitial inflammation of the kidneys Epidemiology demographics middle-aged adults Etiology drug-induced hypersensitivity (majority of cases) typically developed between 1 week to 9 months 5 Ps Pee (diuretics, especially sulfa ones) Pain-free (NSAIDs) Penicillins and cephalosporins Proton pump inhibitors rifamPin systemic infections autoimmune diseases systemic lupus erythematosus sarcoidosis Pathogenesis type IV hypersensitivity reaction T-cell-mediated attack on tubular cells Prognosis typically resolves after withdrawal of inciting agent Presentation Symptoms primary symptoms fever hematuria arthralgia can be asymptomatic Physical exam rash maculopapular flank/costovertebral angle tenderness Studies Labs serum eosinophilia elevated serum creatinine Urinalysis with microscopy and sediment analysis white blood cell casts hematuria eosinophiluria seen with Hansel or Wright stain Renal biopsy not usually indicated Histology severe tubular damage interstitial edema T-cell and eosinophilic infiltration Diagnostic criteria elevated creatinine urinalysis with white cell casts and eosinophiluria Differential Acute tubular necrosis from NSAIDs no rash or eosinophils Renal atheroemboli also presents with eosinophiluria, eosinophilia, and skin rash rash is typically livedo reticularis with digital infarcts and not maculopapular Treatment Conservative discontinue inciting drug indications for all drug-induced hypersensitivity cases Medical glucocorticoids indications if creatinine continues to rise after stopping drugs Complications Renal failure requiring dialysis
QUESTIONS 1 of 5 1 2 3 4 5 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.RL.13.65) A 60-year-old man with a history of osteoarthritis has been awaiting hip replacement surgery for 3 years. During his annual physical, he reports that he has been taking over the counter pain medications, but that no amount of analgesics can relieve his constant pain. Laboratory results reveal that his renal function has deteriorated when compared to his last office visit 2 years ago. Serum creatinine is 2.0 mg/dL, and urinalysis shows 1+ proteinuria. There are no abnormalities seen on microscopy of the urine. A renal biopsy shows eosinophilic infiltration and diffuse parenchymal inflammation. What is the most likely explanation for this patient's deterioration in renal function? QID: 101019 Type & Select Correct Answer 1 Focal segmental glomerulosclerosis 5% (6/114) 2 Ischemic acute tubular necrosis 2% (2/114) 3 Nephrotoxic acute tubular necrosis 19% (22/114) 4 Toxic tubulointerstitial nephritis 63% (72/114) 5 Rapidly progressive glomerulonephritis 7% (8/114) M 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (M1.RL.12.50) A 26-year-old male currently undergoing standard therapy for a recently diagnosed active tuberculosis infection develops sudden onset of fever and oliguria. Laboratory evaluations demonstrate high levels of eosinophils in both the blood and urine. Which of the following is most likely responsible for the patient’s symptoms: QID: 101268 Type & Select Correct Answer 1 Rifampin 63% (62/98) 2 Isoniazid 20% (20/98) 3 Pyrazinamide 8% (8/98) 4 Ethambutol 2% (2/98) 5 Return of active tuberculosis symptoms secondary to patient non-compliance with anti-TB regimen 4% (4/98) M 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic
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