Infectious causes of encephalitis and meningoencephalitis in Thailand, 2003-2005.

Acute encephalitis is a severe neurologic syndrome. Determining etiology from among ≈100 possible agents is difficult. To identify infectious etiologies of encephalitis in Thailand, we conducted surveillance in 7 hospitals during July 2003-August 2005 and selected patients with acute onset of brain dysfunction with fever or hypothermia and with abnormalities seen on neuroimages or electroencephalograms or with cerebrospinal fluid pleocytosis. Blood and cerebrospinal fluid were tested for >30 pathogens. Among 149 case-patients, median age was 12 (range 0-83) years, 84 (56%) were male, and 15 (10%) died. Etiology was confirmed or probable for 54 (36%) and possible or unknown for 95 (64%). Among confirmed or probable etiologies, the leading pathogens were Japanese encephalitis virus, enteroviruses, and Orientia tsutsugamushi. No samples were positive for chikungunya, Nipah, or West Nile viruses; Bartonella henselae; or malaria parasites. Although a broad range of infectious agents was identified, the etiology of most cases remains unknown.

Correlation between serum and salivary phenytoin concentrations in Thai epileptic children.

OBJECTIVE: To study the correlation between serum and salivary phenytoin concentration in Thai epileptic children. MATERIAL AND METHOD: Children aged 5 to 12 years with diagnosed epilepsy who received phenytoin monotherapy seen in the neurological clinic at Queen Sirikit National Institute of Child Health were studied. The recruited patients were required to have good compliance, normal albumin level, and no evidence of cancer, HIV infection, hepatic, renal and salivary glands disease. Blood and saliva samples were collected and measured phenytoin level by fluorescence-polarization immunoassay technique. RESULTS: Thirty patients, 19 males and 11 females, were studied. The average (mean +/- SD) age and weight were 8.24 +/- 2.09 years and 27.76 +/- 9.86 Kilograms. Both serum and salivary phenytoin levels correlated with phenytoin doses as exponential type (R2 = 0.4188, 0.3682, respectively). Equations for describing serum and salivary phenytoin levels by phenytoin dose were y = 0.7403e(0.3952x) and y = 0.1431e(0.3072x) respectively. Serum and salivary phenytoin levels were closely correlated as linear type (R = 0.880, R2 = 0.967). The obtained equation of this relationship was y = 10.165x, where y = serum phenytoin level and x = salivary phenytoin level. Adverse drug reactions were found in 5 patients (6.6%), horizontal nystagmus 2 cases, hirsutism 2 cases and gingival hyperplasia 1 case. CONCLUSION: High correlation between serum and salivary phenytoin levels supported the use of saliva instead of blood for phenytoin monitoring in Thai children which were difficult in blood collection and had psychological trauma. The obtained equations in the present study could be applied for adjusting the dosage regimen and monitoring by using salivary phenytoin level in clinical practice.

Japanese encephalitis virus remains an important cause of encephalitis in Thailand.

BACKGROUND: Japanese encephalitis virus (JEV) is endemic in Thailand and prevention strategies include vaccination, vector control, and health education. METHODS: Between July 2003 and August 2005, we conducted hospital-based surveillance for encephalitis at seven hospitals in Bangkok and Hat Yai. Serum and cerebrospinal (CSF) specimens were tested for evidence of recent JEV infection by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and a plaque reduction neutralization test (PRNT). RESULTS: Of the 147 patients enrolled and tested, 24 (16%) had evidence of acute flavivirus infection: 22 (15%) with JEV and two (1%) with dengue virus. Of the 22 Japanese encephalitis (JE) cases, 10 (46%) were aged ≤ 15 years. The median length of hospital stay was 13 days; one 13-year-old child died. Ten percent of encephalitis patients enrolled in Bangkok hospitals were found to have JEV infection compared to 28% of patients enrolled in hospitals in southern Thailand (p < 0.01). Four (40%) of the 10 children with JE were reported as being vaccinated. CONCLUSIONS: JEV remains an important cause of encephalitis among hospitalized patients in Thailand. The high proportion of JE among encephalitis cases is concerning and additional public health prevention efforts or expanded vaccination may be needed.