Differential Diagnosis
The patient presents with a 2-week history of muscle weakness and pain, proximal muscle tenderness and weakness, and elevated CK and ALT levels. The following differential diagnoses are considered:
- Single Most Likely Diagnosis
- Polymyositis: The patient's symptoms of proximal muscle weakness, muscle pain, and elevated CK levels are consistent with polymyositis. The absence of skin rash makes dermatomyositis less likely, but the presence of occasional purpuric spots on hands and mouth could be indicative of an overlap syndrome.
- Other Likely Diagnoses
- Rhabdomyolysis: The high CK level and muscle weakness suggest rhabdomyolysis, which could be caused by various factors such as trauma, infection, or medication.
- Viral Myositis: The patient's symptoms and elevated CK levels could also be consistent with viral myositis, which is often caused by influenza or coxsackievirus.
- Sickle Cell Crisis: Although the patient has no family history of sickle cell disease, the patient's Nigerian descent and cyanosed right big toe suggest the possibility of sickle cell disease, which could be presenting with a crisis.
- Do Not Miss Diagnoses
- Septic Arthritis or Osteomyelitis: The patient's muscle weakness and pain could be masking an underlying septic arthritis or osteomyelitis, which would require prompt antibiotic treatment.
- Neuromuscular Junction Disorder: Conditions such as myasthenia gravis or botulism could present with muscle weakness and should be considered, especially given the patient's difficulty getting up.
- Cardiac Ischemia: The patient's chest pain and elevated CK levels could also be indicative of cardiac ischemia, which would require immediate attention.
- Rare Diagnoses
- Glycogen Storage Disease: The patient's muscle weakness and elevated CK levels could be consistent with a glycogen storage disease, such as McArdle's disease.
- Mitochondrial Myopathy: The patient's symptoms and elevated CK levels could also be consistent with a mitochondrial myopathy, such as Kearns-Sayre syndrome.
- Eosinophilic Myositis: The patient's muscle weakness and elevated CK levels, combined with the presence of purpuric spots, could suggest eosinophilic myositis, a rare condition characterized by eosinophilic infiltration of the muscles.