Preceding infection as a risk factor of stroke in the young

The cause of stroke in the young remains unknown in 20-50% of the patients. Infections preceding stroke have been recently recognised to be an independent risk factor of stroke.

Sixty consecutive patients aged 40 years or less presenting with ischaemic completed stroke are taken up for the study. Patients with neurological deficit of less than 24 hours, evidence of haemorrhage on CT scan, infection occurring after the onset of stroke were excluded. Controls consisted of age and sex matched persons residing in the same area. Both the groups were enquired about preceding fever and infections and were examined for evidence of infections. Serum was examined for antibodies against measles, herpes simplex, and Japanese B encephalitis viruses. Cultures were put up from appropriate samples and CSF examined in patients only.

Evidence of infection was noted in 26 (43.3%) of patients and 6 controls (p < 0.001). History of fever was elicited in 23 patients and 3 controls while 15 patients were febrile on examination at admission. Signs of local infection was observed in 14 patients and one control. The commonest site of infection was respiratory tract. Cultures were positive in 11 patients, commonest being beta haemolytic streptococci in six from throat. Conventional risk factors were identical in both groups of patients with and without evidence of preceding infection. Smoking and alcoholism were significantly higher in patients with preceding infection.

Preceding infection is an important risk factor of stroke in the young. Smoking and alcoholism are more frequent in patients with preceding infection. Whether they predispose the individual for infection or infection increases the stroke risk in them needs to be examined.