77-year-old male with HTN & recent TIA has AKI & hyperkalemia

freecme000
Published on Feb 20, 2022
CC- 77-year-old Caucasian man Presents with AKI (11.2 mg/dL, baseline creat was 1.3 mg/dL) and hyperkalemia (6.2 mmol/L).

HPI - He had a recent TIA 2 weeks ago for which has started on warfarin treatment and had a CT angiogram at that time which showed carotid stenosis - he was discharged with creatine of 1.3 mg/dl on day 3 after TIA eval completed. 2 weeks later presents with worsening uremic symptoms including fatigue, nausea, anorexia, metallic taste and decreased urine output past few days.

ROS - He denied any skin rash or discoloration, leg pain, leg swelling, hematuria, abdominal pain and any neurologic symptoms.
PMH - hypertension, hyperlipidemia, paroxysmal atrial fibrillation, 3.2 cm infrarenal AAA, transient ischemic attack (TIA) two weeks prior. non-smoker
MEDS- warfarin (started after TIA diagnosis), amlodipine, atenolol and lisinopril, lipitor
EXAM - blood pressure of 150/74 mmHg. There was no skin rash on lower extremities.
LABS - Laboratory data revealed blood urea nitrogen (126 mg/dL), serum creatinine (11.2 mg/dL), potassium (6.9 mmol/L), bicarbonate (14 mmol/L),, INR 4.0, eosinophilia (19%), elevated sedimentation rate (76 mm/hr), and C- reactive protein (29 mg/L), with normal complement levels. Urinalysis showed a bland urine sediment, no RBC, and non-nephrotic range proteinuria (382 mg/24 hr).
IMAGING - Renal ultrasound showed normal size kidneys with bilateral cortical thinning, and no hydronephrosis. Patient was started on dialysis and a percutaneous renal biopsy was performed after correction of INR.
His Renal Biopsy shows focal interstitial infiltrate consisting of lymphocytes, plasma cells, and eosinophils, intimal fibrosis noticed in interlobular arteries. (SEE IMAGE ABOVE)
He was started on trial of prednisone for 8 weeks and his creatinine improved to 1.7 range and dialysis discontinued.

MOST LIKELY CAUSE FOR ACUTE RENAL FAILURE WAS

1) Renal Atheroembolic disease
2) Warfarin induced nephropathy
3) ATN from contrast exposure
4) Warfarin induced allergic interstitial nephritis

CLICK ON LINK BELOW FOR ANSWER
https://renal.medcase.com/free_cme/238858/
tweet your reply/comments @kidneytube