It may be associated with hypocalcaemia and central nervous system infections.
Hypocalcaemia usually presents as sudden muscle contractions or strong shocks, and sometimes as localised muscle twitches.
Central nervous system infections, such as febrile convulsions, occur in children aged 6 months to 3 years and are characterised by sudden onset of unconsciousness, twitching and stiffness of the limbs, rolling of the eyes and purple lips at the beginning of the fever. Prompt medical examination and treatment is recommended.