Diagnosis and Treatment > Signs and Symptoms
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Summary
Familial hypomagnesemia with secondary hypocalcemia (FHSH) is a rare autosomal recessive disorder (OMIM# 602014) characterized by profound hypomagnesemia associated with hypocalcemia. It is caused by mutations in the gene encoding transient receptor potential cation channel member 6 (TRPM6). It usually presents with neurological symptoms in the first months of life. We report a case of a neonate presenting with recurrent seizures and severe hypomagnesemia. The genetic testing revealed a novel variant in the TRPM6 gene. The patient has been treated with high-dose magnesium supplementation, remaining asymptomatic and without neurological sequelae until adulthood. Early diagnosis and treatment are important to prevent irreversible neurological damage.
Learning points:
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Loss-of-function mutations of TRPM6 are associated with FHSH.
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FHSH should be considered in any child with refractory hypocalcemic seizures, especially in cases with serum magnesium levels as low as 0.2 mM.
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Normocalcemia and relief of clinical symptoms can be assured by administration of high doses of magnesium.
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Untreated, the disorder may be fatal or may result in irreversible neurological damage.
Search for other papers by Elizabeth M Madill in
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Department of Medicine (Alfred), Monash University, Melbourne, Victoria, Australia
Search for other papers by Leon A Bach in
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Summary
Thyrotoxicosis is an under-recognised but clinically important complication of parathyroidectomy. We report a case of a 37-year-old man with tertiary hyperparathyroidism who initially developed unexplained anxiety, diaphoresis, tachycardia, tremor and hyperreflexia one day after subtotal parathyroidectomy. Thyroid biochemistry revealed suppressed thyroid stimulating hormone and elevated serum free T4 and free T3 levels. Technetium-99m scintigraphy scan confirmed diffusely decreased radiotracer uptake consistent with thyroiditis. The patient was diagnosed with thyrotoxicosis resulting from palpation thyroiditis. Administration of oral beta-adrenergic antagonists alleviated his symptoms and there was biochemical evidence of resolution fourteen days later. This case illustrates the need to counsel patients about thyroiditis as one of the potential risks of parathyroid surgery. It also emphasises the need for biochemical surveillance in patients with unexplained symptoms in the post-operative period and may help to minimise further invasive investigations for diagnostic clarification.
Learning points
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Thyroiditis as a complication of parathyroidectomy surgery is uncommon but represents an under-recognised phenomenon.
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It is thought to occur due to mechanical damage of thyroid follicles by vigorous palpation.
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Palpation of the thyroid gland may impair the physical integrity of the follicular basement membrane, with consequent development of an inflammatory response.
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The majority of patients are asymptomatic, however clinically significant thyrotoxicosis occurs in a minority.
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Patients should be advised of thyroiditis/thyrotoxicosis as a potential complication of the procedure.
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Testing of thyroid function should be performed if clinically indicated, particularly if adrenergic symptoms occur post-operatively with no other cause identified.
