Summary:The

Background: Estimated glomerular filtration rate (eGFR) is now routinely reported by most National Health Service laboratories. There are many limitations when interpreting eGFR: thyroid dysfunction is not widely recognized as being one of these. Methods: We extracted from the pathology computer system results of all patients with hypothyroidism and hyperthyroidism who also had serum creatinine measured. We also extracted creatinine data on euthyroid patients. eGFR was calculated using the simplified Modification of Diet in Renal Disease Study equation. Results: The median eGFRs of the hypothyroid, euthyroid and hyperthyroid patients were 64, 77 and 107 mL/min/1.73 m 2 , respectively; all groups were significantly different from each other (P , 0.001). Conclusion: Thyroid dysfunction is associated with significant alterations in eGFR and actual GFR.

A 73 year old white man presented with life threatening hypokalaemic paralysis requiring admission to an intensive care unit. Biochemical investigations showed severe hypokalaemia with hyperchloraemic metabolic acidosis, a spot urine pH of 6.5, and a positive urinary anion gap, establishing the diagnosis of distal renal tubular acidosis. Autoimmune tests revealed Sjögren syndrome as the underlying cause of the distal renal tubular acidosis. Full recovery followed potassium and alkali replacement. This dramatic presentation of Sjögren syndrome has not previously been reported in an elderly man. (J Clin Pathol 1999;52:157-158) Keywords: hypokalaemic paralysis; renal tubular acidosis; Sjögren syndrome Sjögren syndrome, an autoimmune exocrinopathy, can occur as an entity on its own (primary Sjögren syndrome) or in association with other autoimmune rheumatic disorders, most often rheumatoid arthritis, systemic lupus erythematosus, and scleroderma (secondary Sjö-gren syndrome). Overt or latent renal tubular acidosis, caused by autoimmune tubulointerstitial nephropathy, is a common extraglandular manifestation occurring in 33% of Sjögren syndrome patients. 1 Hypokalaemic paralysis is a well known, albeit rare, complication of severe distal renal tubular acidosis from any cause.2 3 Cases of Sjögren syndrome manifesting for the first time as hypokalaemic paralysis caused by severe distal renal tubular acidosis have been reported from various parts of the world. [4][5][6] As far as we are aware, this presentation of Sjögren syndrome has not been reported from the United Kingdom. We therefore report such a case to increase awareness of this dramatic presentation of the syndrome. Case reportA 73 year old white man presented with weakness of both legs of five days' duration. He had suVered previously from joint pains, but was usually mobile and self dependant. He gave a history of polyuria and polydipsia for the last four months. Five days before admission, he was unable to get up and felt worse in the morning, with improvement by the end of the day. On the day of admission, he was found lying on the floor by his sister.There was no history of dizziness, chest pain, cough, or dyspnoea. He smoked 10 cigarettes a day and drank 14 units of alcohol a week.On examination, he was conscious, oriented, and did not smell of alcohol, though he looked very frail and dehydrated. Recumbent blood pressure was 165/70 mm Hg, pulse rate was 98 beats/min and regular, jugular venous pressure was not raised, lung fields were clear, and heart sounds were normal. Abdominal examination showed no abnormality.On CNS examination, the cranial nerves were intact. There was proximal muscle weakness and wasting, more prominent in the legs than in the arms, with no evident muscle tenderness. Reflexes were normal apart from bilateral diminished ankle jerks. A straight leg raising test showed no abnormality, and there were no sensory deficits. An ECG showed sinus rhythm with obvious flattening of the T waves in all leads. A chest radiograph showe...

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