Chest pain, weakness, and elevated cardiac enzymes: How would you treat?
You repeat parts of your physical exam and confirm that his proximal upper extremity muscles are much weaker than his distal muscles.
In practice settings where specialty consultation is not always immediately available, your diagnostic skills may be challenged by uncommon presentations of disease. In this case, the challenge is “chest pain and positive cardiac enzymes” in a patient who does not appear to have a primary cardiac problem.
A: ____________________________________________________________ ______________________________________________________________
DTaP approach
When confronted with a difficult clinical problem, you may find it useful to organize the management plan according to the acronym “DTaP,” which for this patient would include:
- Diagnostic plan: serial ECGs and cardiac enzymes: an echocardiogram
- Therapeutic plan: pain control; antibiotics for possible pneumonia; consider steroids
- Assistance from consultants (who are you going to ask for help?): physiatrist consult for electromyography (EMG); cardiology consult; neurology consult
- Patient education (explain to the patient and his family the current diagnostic possibilities and your management plan)
- Provider education (learn more about myopathies!).
You request specialty consultations:
Neurology: possible polymyositis; recommends rheumatology consultation, multiple labs (most of which are sent out to a reference lab and return only several days later)
Cardiology: ECG normal; cardiologist does not see evidence for congestive heart failure or coronary artery disease
Physical medicine and rehabilitation: EMG performed; findings consistent with inflammatory myopathy
Rheumatology: recommends proceeding with muscle biopsy to differentiate polymyositis and inclusion-body myositis
Surgery: performs muscle biopsy which is sent to a regional neuropathologist; reveals inflammatory myopathy with prominent perivascular lymphocytic inflammation strongly suggestive of dermatomyositis.
Further case management and resolution
You administer solumedrol intravenously 1 g/d for 3 days, then change to prednisone orally 1 mg/kg/d.
The patient improves steadily with 3 months of oral steroid therapy. He tests positive for anti-Jo antibodies but his pulmonary symptoms resolve. He undergoes an outpatient evaluation for cancer screening. Colonoscopy, esophogastroduodenoscopy and chest/abdominal/pelvic computed tomography scans are negative for evidence of malignancy.
This case illustrates the importance of not letting dramatic laboratory abnormalities—for this patient, an elevated CK enzyme level—unduly influence your investigative focus. The patient’s history and physical exam findings provided a larger context in which the diagnosis of acute coronary insufficiency became unlikely. Balanced consideration of the patient’s muscle pain and weakness and elevated CK level narrowed the diagnostic possibilities appropriately.
Other ways in which you may encounter inflammatory myopathies
Dermatomyositis usually causes a characteristic rash that facilitates early diagnosis (though it did not appear in this case). As shown in FIGURES 1 AND 2, patients may have either a heliotrope rash (blue-purple to dusky erythematous discoloration on the upper eyelids, with or without edema), or Gottron’s papules (slightly raised violaceous papules and plaques overlying bony prominences, particularly the joints in the fingers and the knuckles).10
A variety of less specific skin and nail changes can occur. Dermatomyositis may present with skin lesions alone (dermatomyositis sine myositis) or rarely with myopathy alone (dermatomyositis sine dermatitis). In our case, multiple examiners failed to detect any classic dermatologic abnormalities, though the pinkish skin changes over the extensor aspect of the MCP joints were, in retrospect, suggestive of dermatomyositis. The weakness associated with this disease may be mild, moderate, or severe enough to result in quadriparesis. Dermatomyositis usually occurs alone but may be present with scleroderma and mixed connective tissue disease.
The main categories of idiopathic acquired inflammatory myopathy are polymyositis, dermatomyositis, and inclusion-body myositis. They cause moderate-to-severe weakness and inflammation of muscles.6 The prevalence of these disorders is unclear because diagnosis has not consistently been based on uniform, reliable criteria. But the incidence is believed to be 1 per 100,000 of the general population, with dermatomyositis being the most common and polymyositis the least common of these myopathies.9 Inclusion-body myositis is the most common form of inflammatory myopathy in patients older than 50 years. Polymyositis is generally seen after the second decade of life. Both children and adults may be affected by dermatomyositis. There have been rare familial occurrences.
Inclusion-body myositis is often misdiagnosed as polymyositis or dermatomyositis until identified by muscle biopsy findings (see How inflammatory myopathies develop), although suspicion is raised with a poor response to steroid therapy.9 Some patients report falling as a result of quadriceps weakness. On occasion the weakness can be asymmetric or distal (rare with dermatomyositis or polymyositis). Diagnosis is always made by muscle biopsy. Disease progression is slow but steady and most patients end up requiring a walker or assistive device.
