A rare reason for hospital admission with muscle weakness in the Covid-19 rra: CPT-2 deficiency

INTRODUCTION: Carnitine Palmitoyl Transferase-2 (CPT-2) is a mitochondrial enzyme involved in the pathway of long chain fatty acids. CPT-2 deficiency is a rare autosomal recessive disease. Except for neonatal and severe infantile hepatocardiomuscular forms, the myopathic form diagnosed at later ages often presents with attacks of muscle weakness and recurrent rhabdomyolysis attacks. CLINICAL CASE: A 27-year-old male patient who applied to the emergency department with complaints of pain all over the body, muscle weakness, nausea, vomiting, headache and decreased urine output in the last 2 days. He was consulted because of LDH: 456 U/L (0–248 U/L), CK: 5567 U/L (0–190 U/L), AST: 382 U/L (10–37), ALT: 89.8 U/L (10–40 U/L), creatinine: 1.23 mg/dL (0–1,2 mg/dL). He was interned with the prediagnosis of acute kidney injury secondary to rhabdomyolysis. It was learned that he had been fasting for 2 days and working at an intense physical pace. There were intensive care hospitalizations due to rhabdomyolysis at the age of 16 and 24 years and Reye's syndrome at the age of 15. It was not diagnosed at that time. His mother's cousin when he was 15 had sudden cardiac death. On physical examination, he was conscious and his general condition was poor. Blood pressure: 141/100mmHg, pulse: 76/min, and fever: 37.4. There were 4/5 muscle weakness in bilateral lower extremity proximal muscles 3/5, distal muscles 4/5, upper extremity proximal and distal muscles 4/5. Pre-diagnoses of very long chain fatty acid dehydration deficiency, CPT-2 deficiency, glutaric acidemia type-2 were considered, IV hydration and riboflavin 3×100mg, coenzyme-Q 2×100mg, carnitine 2×1gr mitochondrial cocktail were started. Tandem Mass and urine amino acid levels were requested from the patient who was in the attack period. During his hospitalization, he had increases of acute phase reactants and respiratory symptoms, Covid PCR+ was detected. Liver function tests increased under favipravir treatment. In the follow-up, the values of CK, creatinine and liver function tests ​​decreased with hydration. Homozygous c.338C>T(p.Ser113Leu) mutation was detected in the CPT-2 gene. CONCLUSION: CPT-2 deficiency should be kept in mind as a rare cause of increased muscle weakness after fasting, intense exercise, and all infections, especially Covid and other upper respiratory tract infections. Intense hydration and mitochondrial cocktail therapy should be added to the patient until the diagnosis is clarified.