Hypothyroidism and high CK an association or a coincidence?

Lubna Etbinah; Rabia Mahmoud; Mustafa alsinan; Agne Jovaisate; Godwin Simon; Lina El-tayeb; Bashir Mahmoud; Ayan Mohammed; Edel Casey; Audrey Limbe; Belayet Hossain; Ali Akram; Mariana Dram; Furhana Hussain; Cathriene Cheung; Gideon Mlawa

doi:10.1530/endoabs.99.EP583

Introduction: Hypothyroidism presentation can be variable. Some patients are asymptomatic whilst other present with general lethargy and cold intolerance. Depending on the degree of hormone deficiency, patient can also present with by skeletal muscle involvement characterized by muscle aches and weakness (proximal myopathy). In some cases, patients with hypothyroidism will have elevated CK but this usually less that 5000

Cases: 1. 46 years old was referred under the medical team directly from GP with a history of 6-8 months history of muscle aches. He also reported feeling cold and lethargic with weight gain. He was found to be severely hypothyroid with high CK. He was cycling to work daily and that might have contributed to high CK. Elevated TSH 57.4, FT4 0.5, FT3 0.6, Cortisol 332, with High CPK levels. CK 8723, Creatinine, He was started on levothyroxine and discharged home. He improved clinically and after 4 weeks blood test showed CK 1043, FT10.4, TSH 22, FT3 3.8 2. 33 year old male presented with few months’ history of tiredness, muscle weakness, weight gain, and being sleepy most of the time. His blood test showed evidence of severe hypothyroidism and high CK4157, cortisol 135, FT4 0.5, TSH>100, and creatine 130. He was treated with IV fluids and started on Levothyroxine 1 mg once daily. The short synacthen test was normal.

Discussion: Hypothyroidism is a common endocrine disorder which is encountered in non-acute settings. It can be associated with tiredness, weight gain, and cold intolerance as well as proximal muscle weakness (myopathy). Elevated CK (rhabdomyolysis) may be associated with severe hypothyroidism. Heavy exercise, statins, or excessive alcohol intake are some of the factors which may contribute to elevated CK in patients with hypothyroidism. The cause of CK elevation in hyporthyroid patients remains unknown, but is thought to be due to interference or defective mitochondrial oxidative metabolism, insulin resistance. Thyroxine plays a key role in the energy metabolism. Thyroid hormone deficiency leads to impaired metabolism of glycogen (glycogenolysis), triglyceride turnover, and mitochondrial oxidative metabolism which in turn impair muscle function.

Conclusion: Severe hypothyroidism can be associated with high CK (rhabdomyolysis), proximal myopathy and muscle aches. Blood tests including CK and cortisol should be checked in patients with new diagnosis of hypothyroidism. Patients with elevated CK and hypothyroidism should be advised to avoid any precipitating factors rhabdomyolysis such heavy exercise, statins and alcohol.

Endocrine Abstracts

EP583