Endocrine Abstracts

Introduction: Hypothyroidism and hyperthyroidism are commonly encountered medical disorders that can be associated with neurologic and neuromuscular dysfunction. Muscle involvement is a common manifestation of both clinical and subclinical hypothyroidism, although this may not always be clinically appreciated. Hypothyroid associated myopathy can cause weakness, cramps, aching and painful muscles, sluggish movements and Severe myopathy secondary to hypothyroidism leading to Rhabdomyolysis and renal failure has also previously been reported.

Case: Here we present a case of a 49 year old male patient with known Type 1 Diabetes and hypothyroidism diagnosed in 2012 with associated raised anti TPO antibody levels of 279 IU/ml (reference range: <34 IU/ml). There was a previous described history of poor compliance with his Levothyroxine. His regular medications were Levothyroxine 150 mg OD, Novorapid and Lantus. He was admitted with 3 days history of bilateral feet swelling and bilateral foot droop. His admission blood tests demonstrated a combination of an acute kidney injury, rhabdomyolysis and severe hypothyroidism. These were his initial admission investigations: TSH >100 mU/l (0.27-4.20 mU/l), Free T4: 0.7 pmol/l (11-25 pmol/l), 9 am Cortisol 490 nmol/l (>420 nmol/l) and Creatine Kinase: 56600 U/l (40-320 U/l). Subsequent test was negative for hepatitis. His MRI spine reported degenerative changes of the L4/l5 intervertebral disc with impingement of L4 nerve root bilaterally. However, there was no evidence of significant cord compression. Vasculitis screening (ANA, ANCA, DsDNA, Anti-GBM) were also negative. Nerve conduction studies indicated peroneal nerve paresis, secondary to anterior compartment syndrome felt to be a results of acute swelling of his lower legs due to severe hypothyroidism which in turn led the development of rhabdomyolysis and renal failure. With Levothyroxine dosed at 200 mg once daily and improved compliance his thyroid function improved rapidly. His TSH was normal within three months, with some improvement of his foot drop. However, his peroneal nerve palsies has not fully resolved.

Conclusion: Anterior compartment syndrome associated with rhabdomyolysis and foot drop is a rare complication of severe hypothyroidism. Anterior compartment syndrome is most commonly unilateral. However, bilateral presentations should trigger the search for metabolic explanations.

References: 1. Duyff RF, Van den Bosch J, Laman DM, van Loon BJ, Linssen WH. Neuromuscular findings in thyroid dysfunction: A prospective clinical and electrodiagnostic study. 2. Kung AW, Ma JT, Yu YL, Wang CC, Woo EK, Lam KS, et al. Myopathy in acute hypothyroidism.