Endocrine Abstracts

Introduction: Hypothyroidism is not a common cause of renal failure which remains under-appreciated. Herein we report a case of acute renal failure in a patient with a severe primary hypothyroidism in whom hormone replacement therapy with Levothyroxine has significantly improved renal function.

Observation: A 72-year-old man was referred to our department for primary hypothyroidism. His past medical history included a coronary heart disease with a heart failure.Four weeks ago, he was diagnosed with a renal failure. He presented to our department with generalized weakness, constipation, hearing loss and night snoring. On examination, he had a myxoedema with a puffy face, a macroglossia and a peripheral non-pitting edema, a psychomotor slowdown, a bradycardia, a dry skin and slow relaxing reflexes. The thyroid gland was not palpable. The diagnosis of hypothyroidism was confirmed by the thyroid function tests showing increased thyroid-stimulating hormone (TSH)>100 mUI/l (0.35–4.95) and decreased Free T4 at 0.75 pmol/l (N:9–20). Routine blood tests disclosed a moderate renal failure with a serum creatinine at 18 mg/l (the clearance of creatinine was estimated at 39 ml/mn), normal natremia and kalemia levels, an elevated lactate dehydrogenase (LDH) level at 554 U/l (N: 125–245), a normal creatine phosphokinase (CPK) level and hepatic cytolysis. The patient received Levothyroxine replacement with initiation dose of 12.5 μg per day then we increased the dose gradually by 12.5 μg every 7 to 10 days. After one month of treatement, the control of serum creatinine was at 11 mg/l with a significant improvement in creatinine clearance to 70 ml/min.

Discussion and conclusion: In our patient, thyroid hormone replacement therapy resulted in renal function improvement which confirms the relationship between hypothyroidism and renal failure. Although the physiopathology of this association remains poorly understood, the decreased cardiac output and renal blood flow leading to a reduction in glomerular filtration rate represents the main mechanism. Other factors have been implicated such as rhabdomyolysis and hydro-retention. Since treatment of hypothyroidism can improve renal function, evaluation of thyroid function in patient with unexplained kidney failure is recommended.