Match each patient's clinical presentation with the most likely diagnosis for their acute kidney injury.
- A 65-year-old man with a history of urinary hesitancy and nocturia presents with lower abdominal fullness and inability to void for 12 hours. Examination shows suprapubic dullness to percussion, and an ultrasound reveals bilateral hydronephrosis.Postrenal acute kidney injury
- A 54-year-old woman with known portal hypertension and refractory ascites is admitted for oliguria. Her serum creatinine has risen from 1.1 to 2.8 mg/dL over three days. Volume expansion with albumin yields no improvement. Urinalysis shows 5-10 hyaline casts per low-power field but no cells.Hepatorenal syndrome
- A 72-year-old man hospitalized with severe pneumonia and transient hypotension develops oliguria on hospital day 4. His fractional excretion of sodium is 2.5%. Urine microscopy demonstrates pigmented granular casts and renal tubular epithelial cells.Acute tubular necrosis
- A 42-year-old woman presents with arthralgias, a low-grade fever, and a pruritic rash two weeks after initiating ibuprofen therapy. Her serum creatinine is 2.2 mg/dL. Urinalysis reveals sterile pyuria and white blood cell casts without significant bacteriuria.Acute interstitial nephritis
Answer
The presentations map as follows: the man with hydronephrosis has Postrenal acute kidney injury; the woman with portal hypertension has Hepatorenal syndrome; the man with transient hypotension has Acute tubular necrosis; the woman with a rash and NSAID use has Acute interstitial nephritis.
Each clinical vignette contains specific history, physical, or laboratory findings that distinguish it from other causes of acute kidney injury. Pigmented granular casts point to Acute tubular necrosis, bland sediment with lack of response to fluid expansion points to Hepatorenal syndrome, white blood cell casts with fever and rash point to Acute interstitial nephritis, and hydronephrosis with urinary retention points to Postrenal obstruction.
Step-by-Step Solution
Key Concept
Formulating a differential diagnosis for acute kidney injury based on history, physical examination, and urinalysis.