clinical features of febrile convulsions
The usual presentation is of a child who is unwell with high temperature and then has a major seizure lasting a few minutes.
- febrile seizures usually occur in the first 24 hours of illness (1,2).
- may be present at any time (at times after seizures)
- seizures which occur 3 or more days after the onset of fever is unlikely to be febrile seizures (2)
- if the fever is less than 380 C, consider an alternative diagnosis (3)
- they are predominantly brief, generalised tonic-clonic seizures. There may be cyanosis or incontinence
- duration of the febrile seizure is less than 10 minutes in majority of cases
- after the fit the child may sleep for some time
- it is important to establish that there are no features of a complex seizure - ie that there were no focal features, there are no residual deficits(1,3)
- febrile myoclonic seizures have also been reported in some cases (3)
- presence of post-ictal symptoms (except for drowsiness) should raise suspicion of another diagnosis or a more serious cause (4)
- (1) Patel N et al. Febrile seizures. BMJ. 2015 ;351:h4240
- (2) Patterson JL et al. Febrile seizures. Pediatr Ann. 2013;42(12):249-54
- (3) Sadleir LG, Scheffer IE. Febrile seizures. BMJ. 2007; 334(7588): 307–311.
- (4) Deakin K. Clinical Review – Febrile seizures. GPonline 2011
Last reviewed 01/2022