Neuroinfluenza: evaluation of seasonal influenza associated severe neurological complications in children (a multicenter study)

Although influenza primarily affects the respiratory system, in some cases, it can cause severe neurological complications. Younger children are especially at risk. Pediatric literature is limited on the diagnosis, treatment, and prognosis of influenza-related neurological complications. The aim of the study was to evaluate children who suffered severe neurological manifestation as a result of seasonal influenza infection.

The medical records of 14 patients from six hospitals in different regions of the country were evaluated. All of the children had a severe neurological manifestations related to laboratory-confirmed influenza infection.

Median age of the patients was 59 months (6 months—15.5 years) and nine (64.3%) were male. Only 4 (28.6%) of the 14 patients had a comorbid disease. Two patients were admitted to hospital with influenza-related late complications, and the remainder had acute complication. The most frequent complaints at admission were fever, altered mental status, vomiting, and seizure, respectively. Cerebrospinal fluid (CSF) analysis was performed in 11 cases, and pleocytosis was found in only two cases. Neuroradiological imaging was performed in 13 patients. The most frequent affected regions of nervous system were as follows: cerebellum, brainstem, thalamus, basal ganglions, periventricular white matter, and spinal cords. Nine (64.3%) patients suffered epileptic seizures. Two patients had focal seizure, and the rest had generalized seizures. Two patients developed status epilepticus. Most frequent diagnoses of patients were encephalopathy (n = 4), encephalitis (n = 3), and meningitis (n = 3), respectively. The rate of recovery without sequelae from was found to be 50%. At discharge, three (21.4%) patients had mild symptoms, another three (21.4%) had severe neurological sequelae. One (7.1%) patient died. The clinical findings were more severe and outcome was worse in patients <5 years old than patients >5 years old and in patients with comorbid disease than previously healthy group.

Seasonal influenza infection may cause severe neurological complications, especially in children. Healthy children are also at risk such as patients with comorbid conditions. All children who are admitted with neurological findings, especially during the influenza season, should be evaluated for influenza-related neurological complications even if their respiratory complaints are mild or nonexistent.