Muscular disorders are usual in hypothyroidism. Hypothyroid myopathy is most often limited to myalgias, muscle stiffness and cramps, with sometimes moderately elevated levels of muscle enzymes [1]. On the other hand, rhabdomyolysis due to hypothyroidism is very rare and only a few cases have been reported. We describe a patient with rhabdomyolysis due to hypothyroidism.
Case. A 31-year-old man presented with generalized body swelling and increasing stiffness. He had experienced severe aches and pains, lower limb weakness, polyuria, nocturia and polydipsia. He had no precipitating factor for rhabdomyolysis. On examination, he was pale and afebrile. He had periorbital puffiness, lip swelling, diffuse goitre and generalized non-pitting oedema. He had an athrophic plaque on his abdomen.
His laboratory findings were as follows: serum urea 32 mg/dl, creatinine 1.9 mg/dl, aspartate aminotransferase (AST) 122 IU/l, alanine aminotransferase (ALT) 66 IU/l, creatine kinase 2291 IU/l (normal <397), lactate dehydrogenase (LDH) 476 IU/l (normal 98192), free T3 0.41 pg/ml (normal 1.84.6), free T4 0.06 ng/dl (normal 0.72), thyroid-stimulating hormone (TSH) >100 mIU/ml (normal 0.264.2), anti-microsomal antibody >600 IU/ml (normal <34) and anti-thyroglobulin antibody >4000 IU/ml (normal <115). His creatinine clearance was 58%. Other laboratory tests were normal. Ultrasonography and needle biopsy of the thyroid were concordant with thyroiditis. The biopsy made from the atrophic lesion was concordant with morphea.
Findings were compatible with autoimmune thyroid disorder, primary hypothyroidism and rhabdomyolysis. He received thyroxine replacement. His symptoms and laboratory values were normalized after 4 weeks of thyroxine replacement. However, his creatinine was still high. For this reason, we performed needle biopsy of the kidney. Examination of kidney biopsy specimens revealed oedematous renal medullary tissue.
Discussion. Hypothyroidism, though rare, should be considered a definite and authentic cause of rhabdomyolysis. The exact cause of rhabdomyolysis in hypothyroidism remains unclear. Usually an aggravating factor such as use of lipid-lowering drugs, alcohol, exercise or chronic renal failure has been identified [2,3]. Rhabdomyolysis manifests with muscular symptoms (e.g. myalgia and weakness) and severely elevated serum levels of muscle enzymes. It can become a life-threatening disorder when complicated by acute renal failure [2]. Thyroid hormone replacement therapy improves thyroid and renal functions and reverses rhabdomyolysis.
Only a few cases of rhabdomyolysis due to hypothyroidism have been reported [46]. The present case describes a patient suffering from rhabdomyolysis due to hypothyroidism, with no additional precipitating factor.
As a result, hypothyroidism must be considered in patients presenting with acute renal failure and elevated muscle enzymes. As soon as the diagnosis is made, levothyroxin should be started.
Conflict of interest statement. None declared.
Department II of Internal Medicine Ankara Education and Research Hospital Ankara Turkey Email: altay_mustafa{at}hotmail.com
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