Publication:

Diphtheria pertussis tetanus vaccine induced convulsion: is hypocalcemia a triggering factor?

Background Active pertussis toxin in diphtheria pertussis tetanus (DPT) vaccine has been proposed to cause severe reactions. A convulsion following DPT vaccine is a known adverse reaction but hypocalcemia as a triggering factor is not reported. The aim of the study was to find the association between serum calcium and DPT vaccine induced convulsions and to study the clinical profile.

Methods Retrospective observational and descriptive study was done at emergency ward of a tertiary care teaching hospital. 20 infants of DPT induced convulsions with previous normal neurodevelopment were included in the study. Main outcome measures were association between DPT vaccine induced convulsions and serum calcium levels.

Results Out of 20 infants included in the study, male to female ratio was 1.8:1, all of them were less than 6 months of age, 17 (85% ) were exclusively breast fed, hypocalcemia was seen in 17 cases (85%), 11 (55%) had fever. 16 (80%) had convulsions following third dose of DPT vaccine.

Conclusions There is a significant association between hypocalcemia and DPT vaccine induced convulsion. Hence there is need for Calcium and Vitamin D3 supplementation in pregnant and lactating mothers and early detection and adequate treatment of rickets in infants.