Endocrine Abstracts

Renal impairment and electrolyte disorders in hypothyroidism are frequently subtle and rarely observed in clinical practice. Case reports have noted the association but it is rarely found in textbooks. We describe a case of new onset renal dysfunction secondary to hypothyroidism. A 54-year-old male was referred to renal clinic with new renal failure. He described a 3 weeks history of sudden onset peri-orbital, facial and generalised leg swelling and associated muscle ache and pains. He had no significant past medical history and was on no regular medication. On clinical examination he was overweight with marked peri-orbital oedema and facial swelling. Additionally there was bilateral peripheral oedema to the knees. Laboratory results revealed new acute renal failure (ur 10, Creat 200, eGFR 30 ml/min), full blood count and coagulation screen were normal. Bedside urinalysis showed no evidence of blood or protein. Creatine kinase was elevated at 3322 U/l (0–170) with a normal MB fraction and normal electrocardiogram. Cholesterol was elevated at 7, with a normal autoimmune screen and complement level. Renal ultrasonography showed normal kidneys and no abnormalities. Thyroid function tests revealed a TSH of 211.2 and Free T4 of <0.3. TPO antibodies were strongly positive (>600 (0–70)). A diagnosis of autoimmune thyroiditis was made. The patient was commenced on thyroxine replacement, which resulted in resolution of his symptoms and correction of renal function.

The cause of the renal failure in hypothyroidism is due to two mechanisms, decreased renal plasma flow due to a hypodynamic state in hypothyroidism and in severe cases, renal failure can be secondary to rhabdomyolysis. Knowledge of the association between thyroid dysfunction and renal impairment is important for the clinician. We suggest that thyroid function testing should form part of the first line blood investigations for patients with impaired renal function.