When Severe Hypothyroidism Mimics Neuromuscular Diseases: A Case Supporting Outpatient Management in Modern Endocrinology

A 40-year-old man presented to the emergency department with postural instability, diplopia, myalgia, and elevated creatine kinase, initially suggesting a neuromuscular or acute neurological disorder. Laboratory tests revealed severe hypothyroidism (TSH >170 μU/mL, suppressed fT4). Despite the marked biochemical abnormalities, his clinical stability allowed safe outpatient management with levothyroxine and endocrinology follow-up. This case, which mimicked inflammatory myopathy or brainstem stroke, illustrates that hypothyroidism can manifest with neurological signs and emphasizes the need to consider endocrine causes in the differential diagnosis. It also supports the safety and effectiveness of structured outpatient pathways for clinically stable hypothyroid patients.