Encephalitis-associated pandemic A (H1N1) 2009 in a Kuwaiti girl

Neurological events related to influenza A (H1N1) pdm09

OBJECTIVES

To review neurological complications after the influenza A (H1N1) pdm09, highlighting the clinical differences between patients with post-vaccine or viral infection.

DESIGN

A search on Medline, Ovid, EMBASE, and PubMed databases using the keywords “neurological complications of Influenza AH1N1” or “post-vaccine Influenza AH1N1.”

SETTING

Only papers written in English, Spanish, German, French, Portuguese, and Italian published from March 2009 to December 2012 were included.

SAMPLE

We included 104 articles presenting a total of 1636 patient cases. In addition, two cases of influenza vaccine-related neurological events from our neurological care center, arising during the period of study, were also included.

MAIN OUTCOME MEASURES

Demographic data and clinical diagnosis of neurological complications and outcomes: death, neurological sequelae or recovery after influenza A (H1N1) pdm09 vaccine or infection.

RESULTS

The retrieved cases were divided into two groups: the postvaccination group, with 287 patients, and the viral infection group, with 1349 patients. Most patients in the first group were adults. The main neurological complications were Guillain-Barre syndrome (GBS) or polyneuropathy (125), and seizures (23). All patients survived. Pediatric patients were predominant in the viral infection group. In this group, 60 patients (4.7%) died and 52 (30.1%) developed permanent sequelae. A wide spectrum of neurological complications was observed.

CONCLUSIONS

Fatal cases and severe, permanent, neurological sequelae were observed in the infection group only. Clinical outcome was more favorable in the post-vaccination group. In this context, the relevance of an accurate neurological evaluation is demonstrated for all suspicious cases, as well as the need of an appropriate long-term clinical and imaging follow-up of infection and post-vaccination events related to influenza A (H1N1) pdm09, to clearly estimate the magnitude of neurological complications leading to permanent disability.

Cortical vision loss as a prominent feature of H1N1 encephalopathy

A 20-year-old woman infected with the 2009 H1N1 strain of influenza A developed bilateral visual loss. Brain MRI showed restricted diffusion of the parietal and occipital lobes, and her spinal fluid did not contain inflammatory cells. This report describes an unusual case of H1N1 influenza A virus infection primarily affecting the posterior visual pathways.

Neurologic complications of influenza A(H1N1)pdm09: surveillance in 6 pediatric hospitals

OBJECTIVE

We sought to determine the range and extent of neurologic complications due to pandemic influenza A (H1N1) 2009 infection (pH1N1'09) in children hospitalized with influenza.

METHODS

Active hospital-based surveillance in 6 Australian tertiary pediatric referral centers between June 1 and September 30, 2009, for children aged <15 years with laboratory-confirmed pH1N1'09.

RESULTS

A total of 506 children with pH1N1'09 were hospitalized, of whom 49 (9.7%) had neurologic complications; median age 4.8 years (range 0.5-12.6 years) compared with 3.7 years (0.01-14.9 years) in those without complications. Approximately one-half (55.1%) of the children with neurologic complications had preexisting medical conditions, and 42.8% had preexisting neurologic conditions. On presentation, only 36.7% had the triad of cough, fever, and coryza/runny nose, whereas 38.7% had only 1 or no respiratory symptoms. Seizure was the most common neurologic complication (7.5%). Others included encephalitis/encephalopathy (1.4%), confusion/disorientation (1.0%), loss of consciousness (1.0%), and paralysis/Guillain-Barré syndrome (0.4%). A total of 30.6% needed intensive care unit (ICU) admission, 24.5% required mechanical ventilation, and 2 (4.1%) died. The mean length of stay in hospital was 6.5 days (median 3 days) and mean ICU stay was 4.4 days (median 1.5 days).

CONCLUSIONS

Neurologic complications are relatively common among children admitted with influenza, and can be life-threatening. The lack of specific treatment for influenza-related neurologic complications underlines the importance of early diagnosis, use of antivirals, and universal influenza vaccination in children. Clinicians should consider influenza in children with neurologic symptoms even with a paucity of respiratory symptoms.

Pulmonary manifestation of novel swine-origin influenza A (H1N1) virus (S-OIV) infection in immunocompromised patients: initial findings with multidetector computed tomography

OBJECTIVE

To describe initial multidetector computed tomographic (MDCT) findings of novel swine-origin influenza A (H1N1) virus (S-OIV) infection in immunocompromised patients and to evaluate whether or not identification of certain abnormalities can help predict patients who are at risk for a severe clinical course.

SUBJECTS AND METHODS

This retrospective study included 13 patients with confirmed S-OIV infection suffering from an underlying immunodeficiency or who were receiving immunosuppressive therapy. All patients underwent MDCT of the thorax due to respiratory distress. All data were read by two independent radiologists who described the type and pattern of opacities, distribution and extent of the abnormalities observed. Adverse outcome measures were defined as acute respiratory distress syndrome with the need for mechanical ventilation, extracorporeal membrane oxygenation or death.

RESULTS

MDCT revealed pulmonary manifestations in 12 (92%) of 13 individuals. Six (50%) patients showed an adverse outcome with development of acute respiratory distress syndrome, 4 of these died. The most common findings were ground-glass opacities (10/12; 83%) and pulmonary consolidation (7/12; 58%) predominantly with a bilateral distribution. Reticular pattern and a tree-in-bud appearance were found in 3/12 (25%), respectively. Bilateral opacities with extensive involvement of the lung parenchyma were most predictive of a severe clinical course.

CONCLUSION

The MDCT scan in immunocompromised patients with confirmed S-OIV infection frequently revealed pulmonary abnormalities, which included ground-glass opacities and consolidations. Therefore, prediction of an adverse clinical outcome could be made in patients with MDCT findings demonstrating bilateral extensive consolidations, often combined with ground-glass opacities.

Epidemiology and clinical presentation of pandemic influenza A (H1N1) among hospitalized children in Kuwait

OBJECTIVE

To describe the epidemiological and clinical characteristics of children hospitalized for the 2009 influenza A H1N1 infection in Kuwait.

MATERIALS AND METHODS

A retrospective chart review of hospitalized children with laboratory-confirmed influenza A H1N1 infection in two hospitals in Kuwait was conducted. Epidemiological characteristics, clinical features, risk factors for severe disease, complications and mortality were analyzed.

RESULTS

The medical records of 197 children hospitalized for the 2009 pandemic H1N1 infection from August 2009 to January 2010 were reviewed. The majority of the children (104; 52.8%) were admitted during the month of October. The median age was 2 years. Most of the admitted children were in two age categories: 64 infants ≤1 year (32%) and 62 schoolchildren >5 years (31%). The most frequent presentations were fever in 193 (98%), cough in 155 (79%) and runny nose in 105 (53%) cases. The majority of the admitted children (109; 55%) had been previously healthy. All children received an antiviral agent (oseltamivir), and antibiotics were administered to 147 (75%). Bacterial co-infections occurred in 3 (1.5%) of all hospitalized children. Six (3%) children were admitted to the intensive care unit, of whom 4 (66%) required artificial ventilation. There was only 1 mortality.

CONCLUSIONS

The pandemic H1N1 infection was associated with a wide spectrum of clinical manifestations. The majority of hospitalized children had previously been healthy. Most of the admitted children had an uncomplicated clinical course.