Endocrine Abstracts

Background: Infants born to mothers who are deficient in vitamin D are at risk of developing vitamin D deficiency and hypocalcaemia.We present a case report on infantile hypocalcemic seizures secondary to vitamin D deficiency followed by persistent hypomagnesemia.

Case description: A 4-week-old term male baby born by uncomplicated pregnancy was brought due to acute onset seizures which terminated with IV lorazepam. He was exclusively breast fed since birth. Examination was unremarkable. His electrolytes test showed low magnesium (0.3 mmol/l) and calcium levels (1.51 mmol/l)which required multiple IV calcium and magnesium replacement initially. Blood pH was normal. Vitamin D level were low (21 nmol/l), high PTH level (31 pmol/l), Ca: Creatinine <0.9. Maternal Vitamin D and Magnesium levels were (10 nmol/l and 0.63 mmol/l). Both mum and child received oral Calcium, Vitamin D and Magnesium supplementation on discharge. Although the calcium levels normalised on follow ups, the infant’s magnesium levels remained subnormal even with high doses of oral magnesium supplementation. His development was up to date at the time of his recent 8 month follow up.

Discussion: Vitamin D deficiency continues to be a problem in developed countries. Maternal vitamin D deficiency is one of the major risk factors for early infantile vitamin D deficiency followed by hypomagnesemia due to infantile hypocalcaemia. It was of interest to note that in our patient, therapy with calcium as well as with magnesium resulted in clinical improvement and caused elevation of serum calcium but not rise in magnesium levels. He remains under follow up with Endocrine team and further plan is to carry out urinary magnesium studies and genetic testing to rule out familial hypomagnesemia.

Conclusion: Our case illustrates the importance of checking both calcium and magnesium levels in early infants who presents with seizures. It is worthwhile to check both child and maternal vitamin D status in infantile hypocalcemia as this is an easily correctable condition. Persisting hypomagnesemia in this infant warrants further evaluation to rule out familial hypomagnesemia.