Abstract: FR-PO008

Recurrent Exercise Associated AKI: An Unusual Presentation of Malignant Hyperthermia

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Joshi, Megha Raj, Walter Reed, Bethesda, Maryland, United States
  • Gordon, Sarah M., WRNMMC, Rockville, Maryland, United States
Background

We present a healthy soldier with recurrent exercise associated acute kidney injury (AKI) and hematuria. After extensive testing, muscle biopsy was diagnostic of malignant hyperthermia (MH). This case suggests myopathic disorders should be discussed in exercise-associated AKI.

Methods

A thirty-five year old white male was referred for recurrent painless dark urine after running. He had no medical or surgical history, and no family history of renal disease. He denied new medications, substance or supplement use. There was no history of nephrolithiasis or urinary tract infection.

Results

He was normotensive with an unremarkable physical exam. Pre-exercise renal function, proteinuria quantification, urine dipstick and microscopy, sickle cell screen, drug screen, and creatinine kinase (CK) were normal. Serum creatinine was 0.9 mg/dL. Post exercise serum creatinine rose to 1.5mg/dL. Testing demonstrated elevated serum and urine myoglobin (111ng/mL and 29ng/mL respectively) and mildly elevated CK (309 U/L). Repeat urine sediment showed muddy brown casts consistent with acute tubular necrosis (ATN) and 20 isomorphic red cells per field. Labs normalized within one week of rest. He was evaluated by Hematology and Rheumatology for muscular and red blood cell abnormalities; no etiology was identified. Cystoscopy and contrasted tomography urogram were normal. Pre- and post-exercise renal artery dopplers were normal. He was referred to a neuromuscular specialist, and a muscle biopsy was diagnostic for malignant hyperthermia. We recommended avoidance of strenuous exercise and anesthetic agents. Renal function is normal without symptom recurrence following de-escalation of his exercise regimen.

Conclusion

The classic presentation of MH is characterized by acute hyperthermia, muscle rigidity, and rhabdomyolysis with AKI. There are also case reports of subclinical rhabdomyolysis in MH, however none document evidence of ATN. Exercise-induced AKI is a rare clinical presentation of MH, and should be considered in the differential. Avoidance of AKI precipitants is important, as the risk for CKD among individuals with recurrent AKI is well documented.