Severe proximal myopathy secondary to Hashimoto's thyroiditis

Area of Science:

• Endocrinology
• Neurology
• Clinical Medicine

Background:

• Muscular symptoms like myalgia and fatigue are common in hypothyroidism.
• Significant muscle weakness and elevated creatine kinase (CK) are rare presentations of hypothyroidism.
• Hypothyroidism is often overlooked in the differential diagnosis of myopathy with elevated CK.

Observation:

• A 30-year-old female presented with proximal muscle weakness and hypothyroid symptoms.
• She had a significantly elevated creatine kinase level.
• Other causes for elevated CK were systematically excluded.

Findings:

• Thyroxine replacement therapy led to complete resolution of her proximal weakness and myalgia.
• Creatine kinase levels normalized following treatment.
• This case highlights a severe proximal myopathy secondary to hypothyroidism.

Implications:

• Severe proximal myopathy can be an unusual manifestation of hypothyroidism.
• Thyroid function testing should be considered in patients with unexplained proximal weakness and elevated CK.
• Early diagnosis and treatment with thyroxine can reverse hypothyroid myopathy.