Severe proximal myopathy secondary to Hashimoto's thyroiditis

BMJ Case Rep. 2019 Jul 27;12(7):e230427. doi: 10.1136/bcr-2019-230427.

Abstract

Muscular symptoms in hypothyroidism are common, including myalgia, fatigue and cramps; however, a significantly raised creatine kinase and muscle weakness are rare. Differential diagnosis of patients presenting with muscle weakness and a raised creatine kinase is wide, and hypothyroidism is rarely considered. We report this case of a 30-year-old female presenting with proximal muscle weakness as her primary symptom, hypothyroid symptoms of 3-month duration and a significantly raised creatine kinase. After ruling out other causes of a raised creatine kinase, thyroxine replacement was commenced, which led to complete resolution of her proximal weakness, myalgia and normalisation of creatine kinase level. This case illustrates severe proximal myopathy can be secondary to hypothyroidism, symptoms can resolve with thyroxine replacement and emphasises the importance of measuring thyroid function in patients with proximal weakness/myalgia and a significantly raised creatine kinase.

Keywords: muscle disease; thyroid disease.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Creatine Kinase / blood
  • Female
  • Hashimoto Disease / blood
  • Hashimoto Disease / complications*
  • Hashimoto Disease / physiopathology
  • Hormone Replacement Therapy
  • Humans
  • Muscle Weakness / blood
  • Muscle Weakness / drug therapy
  • Muscle Weakness / etiology*
  • Muscle Weakness / physiopathology
  • Thyroxine / blood
  • Thyroxine / therapeutic use*
  • Treatment Outcome

Substances

  • Creatine Kinase
  • Thyroxine