Introduction:
Rhabdomyolysis is rarely seen with Creatinine Kinase (CK) elevation exceeding 1 million U/L. We report severe rhabdomyolysis and acute kidney injury with coexisting influenza infection. It shows the need for detailed investigation of its etiologies, management options for its renal complications and the paucity of data to support them.
Methods:
The patient is a 45-year-old male with past medical history of hypertension. He presented to the ER with fevers and was diagnosed with Influenza B infection. There were no reports of recent trauma or herbal/supplement use. The patient did endorse using alcohol occasionally but denied any binge drinking. Other illicit drug screening was negative. Admission labs showed initial creatinine of 2.2 mg/dL, with a baseline of 0.9 mg/dL. Urinalysis showed large blood with no significant RBCs. Initial CK testing showed results greater than 8000 U/L. He was started on isotonic volume expansion. However, the patient soon became anuric with worsening volume overload. His creatinine had risen to 4.5 mg/dL with severe hypocalcemia of 4.5 mg/dL, hyperkalemia of 5.5 mmol/L, metabolic acidosis with CO2 of 14 mmol/L, and severe hyperphosphatemia up to 14 mg/dL. Repeat CK screening showed results greater than 1 million U/L. Thus, he was started on emergent Continuous Renal Replacement Therapy (CRRT) with Continuous Veno-Venous Hemodiafiltration (CVVHDF) using a high flux AN69 filter. He was maintained with such therapy for 7 days after which his CK value began to down-trend to less than 200,000 U/L. He remained anuric however and continued to require intermittent hemodialysis for 1 month as outpatient, after which time he recovered to near normal kidney function. Due to his unprecedented level of CK elevation, work-up was done and negative for HCV/HBV, HIV, TSH, ANCA, anti-Jo, sick cell disease, other hemoglobinopathies and paraproteinemia. There was no suspicion for compartment syndrome and CT abdomen/pelvis was unremarkable.
Results:
Severe Rhabdomyolysis with CK elevation greater than 1 million U/L is exceedingly rare. This case illustrates this rare phenomenon due to Influenza B infection, as all other work-up was unremarkable. Beyond that however, it shows the clinical conundrum of its management in acute renal failure. The renal pathophysiology of severe rhabdomyolysis involves direct tubular nephrotoxicity of myoglobin as it deposits and obstructs the proximal tubule. Management of renal failure initially involves high dose isotonic volume expansion; but when such therapy is refractory, little is known about the best dialysis modality to utilize when renal replacement is needed. Although intermittent hemodialysis often is preferred for rapid correction of electrolyte derangements, CRRT using a high flux filter has been shown to more effectively dialyze myoglobin with sustained level reduction and less rebound. Despite this, there is paucity of data to guide nephrologists as to if CRRT results in better renal outcomes than intermittent hemodialysis.
Conclusions:
Severe rhabdomyolysis with CK exceeding 1 million U/L has not been well reported and even less so due to Influenza B infection. This case reports such a novel finding and demonstrates the need for data to guide renal replacement therapy in such circumstances.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.