Severe proximal myopathy secondary to Hashimoto’s thyroiditis

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.

Hashimoto’s Thyroiditis Presenting As Non-specific Low Back Pain: A Case Report on Diagnostic Challenges and Management in Primary Care

“…Muscle weakness may occur as dysfunction of the nerve-mediated action of thyroid hormones on muscle fibres but myopathy presentations must be confirmed by further investigation [ 6 , 13 ]. Individuals with abnormal thyroid function can suffer from fatigue, poor sleep quality, and muscle pain.…”

“…Individuals with HT are initially asymptomatic but can progress to develop MSK manifestations such as joint stiffness and muscle weakness [ 4 , 6 , 7 ]. Severe or unmanaged hypothyroidism can cause significant proximal myopathy [ 6 ].…”

Autoantibodies to selenoprotein P in chronic fatigue syndrome suggest selenium transport impairment and acquired resistance to thyroid hormone

“…Patients with chronic fatigue syndrome (CFS) display several symptoms compatible with hypothyroidism, in particular physical and mental fatigue, depression, fibromyalgia (FM) and hypometabolism with low energy stores [ [11] , [12] , [13] ]. Accordingly, TH patterns in blood of patients with CFS have been analyzed and certain alterations with some resemblance to the clinical picture of critical illness with characteristically elevated rT3 and low T3 concentrations are reported, and described as a mild form of low-T3 syndrome [ 11 , 14 , 15 ]. In the case of FM, an association between FM diagnosis and thyroid autoimmunity has driven clinical trials with TH supplementation, albeit without clear general benefits [ 16 , 17 ].…”

Effect of Vitamin D Supplementation on Muscle Function in Patients With I131-Induced Hypothyroidism: A Pilot Randomized Trial

“…The mechanism involves the atrophy of type 2 (fast-twitching) muscle fibers and an increase in the number of type 1 (slow-twitching) muscle fibers [ 2 ]. After receiving thyroid hormone replacement, muscle symptoms often improve within 6 months to 1 year [ 3 ]. Nevertheless, significant functional impairment may persist in 40% of patients, even with adequate thyroid hormone treatment [ 4 ].…”