12511 Rhabdomyolysis Related Acute Kidney Injury Presenting as First Manifestation of Autoimmune Hypothyroidism: A Case Report

Abstract Disclosure: A. Tiwari: None. S. Mantravadi: None. N. Doshi: None. A. Dabaja: None. C. Saad: None. Introduction: Autoimmune thyroiditis is the predominant cause of primary hypothyroidism, with an incidence of estimated 0.3-1.5 cases per 1000 people, with female to male predominance of 7-10[1]. Hypothyroid myopathy affects 79 % of the affected population. Its common presentation is fatigue and cramp but in rare instances rhabdomyolysis can occur with trivial triggers like alcohol, exercise2, Case Presentation: A 32-year-old male with no significant medical history, presented with generalized weakness, myalgia, and facial puffiness for last three months. The patient engaged in regular-intensity workouts and reported consuming 12 beers several times a week for past 5 years. Physical examination revealed facial puffiness and proximal muscle weakness. Initial Laboratory findings showed elevated creatinine (1.68 mg/dL, baseline 1.0 mg/dL in April 2020), CK (8113 U/L), AST (260 U/L), ALT (129 U/L). Urinalysis revealed hematuria and mild proteinuria. Serum electrolytes were unremarkable. Abdominal ultrasound showed diffuse hepatic steatosis with normal kidney appearance. This could not explain the reason for the Acute Kidney Injury and further workup showed TSH (>150 mIU/L) and TPO antibodies (197.9 U/mL). Autoimmune panel was unremarkable. Thyroid ultrasound done subsequently revealed a markedly heterogeneous gland. Treatment included parenteral crystalloids, low-dose prednisone which was empirically added for suspected autoimmune myositis and was later discontinued once the autoimmune panel was negative, and Levothyroxine at the recommended dose. At the time of discharge, his creatinine was reduced to 1.33 mg/dL and CK to 2,298 U/L. Discussion: Severe rhabdomyolysis is a rare but significant complication of autoimmune thyroiditis, potentially leading to acute kidney injury (AKI) if not promptly diagnosed and treated. Resident physicians often attribute symptoms like myalgia and generalized weakness in males to clear evident rhabdomyolysis if they find a cause like alcohol consumption and exercise, potentially overlooking the actual etiology. We recommend thyroid workup in such patients to promptly detect and manage underlying etiology predisposing to muscle damage and subsequent kidney injury. Our patient never had any Physician encounter as his prior medical history was unremarkable, however we suggest thorough family history and thyroid profile should be a part of outpatient workup as well for patients who show other risk factors for rhabdomyolysis like daily alcohol consumption, vigorous workout, consume medications like HMG CoA inhibitors, antipsychotics etc. Presentation: 6/3/2024