clinical features of febrile convulsions

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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).
  • fever
    • 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) 
  • seizures
    • 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)


Last reviewed 01/2022