Clinical Cost-Saving Clues: A Case of Diagnosing a Rare Hypothyroid Myopathy

Severe hypothyroidism left untreated can lead to the progression of a distinct hypothyroid myopathy. This unique thyroid myopathy is characterized by weakness of the proximal limb muscles with an increase in muscle mass, muscle stiffness, and cramps. There is no consistent concept or guidelines for diagnostic work-up with the typical findings of this specific myopathy. While muscle biopsy can provide additional clinical information, the majority of cases can be diagnosed clinically by the hallmark signs of muscular weakness and pseudohypertrophy of muscles in combination with elevated creatine kinase (CK) and thyroid-stimulating hormone (TSH) levels. We present a patient who developed the hallmark findings of this rare hypothyroid myopathy, in which physical exam and laboratory data provided the diagnosis. Magnetic resonance imaging or muscle biopsy could have been performed to confirm the presence of muscular pseudohypertrophy, but the cost of testing would not have altered the treatment course. Therefore, the diagnosis can be cost-effectively made without invasive diagnostic and radiologic measures.