Learning objectives: 1) The importance of re-evaluation of a diagnosis when clinical response to treatment is unexpected 2) Recognition that incorrect diagnoses can carry “inertia” that impedes subsequent objective assessments (anchoring)
Case information: A 50-year-old man initially presented to his PMD after developing a painful rash and weakness one week after exposure to fumes from an industrial-strength drain cleaner. Initial diagnosis was a chemical steam burn. His symptoms did not respond to oral steroids and he was referred to an academic burn center, where he underwent multiple outpatient burn treatments without significant improvement. Five weeks after exposure, he developed dysphagia and odynophagia. He was admitted to the burn service and underwent laryngoscopy and evaluation for possible angioedema. All evaluations were unrevealing and he was discharged. After 4 days at home, he returned to the ED with new shortness of breath, worsened dysphagia and continued painful rash. Admission vitals: BP 130/52, T-97.2, pulse 100 and 97% RA. His lungs were clear. His rash was confluent, erythematous and weeping with extension across the shoulders, chest, waist-line and mid-back. His blood work revealed an ANA titer >1:640 and CPK of >5000. He was admitted to the internal medicine service and diagnosed with dermatomyositis. With guidance from rheumatology, he was started on IV solumedrol with IVIG and added rituximab due to further deterioration. With aggressive treatment, his swallowing and proximal muscle weakness have minimally improved. He continues physical therapy and swallowing training.
Discussion: After an initial diagnosis of chemical steam burn, the "inertia" of this explanation was difficult to dislodge despite the fact that many of his symptoms and findings, as well as his response to treatment, were not consistent with this diagnosis. Dermatomyositis and its associated symptoms (proximal weakness, rash, dysphagia) can have a gradual onset, leading to difficulty in diagnosis.
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