Managing infections in an Intensive Care Unit have always been a challenge for the intensivist, especially central nervous system related infections, which have significant morbidity and mortality; it often requires extensive intensive care management.
Amebic meningoencphalitis is a rare entity, but when it occurs it can be lethal. It is of two types’ primary amebic meningoencephalitis (PAM) and granulomatus amebic encephalitis (GAE). PAM is caused be Naegleria fowleri (brain-eater), which is a free living ameba, and may lead to acute fulminant meningoencephalitis leading to death 3-7 days after exposure1. Naegleria is a thermophile protozoon; survives in waterways contaminated by thermal discharge from power plants, warm fresh water like swimming pool, but rarely lead to disease. In the United State 33 cases were reported in a 10 year period from 1998-2007 and all with fatal outcome2. Infection commonly occurs from July to August. The common route of entry is through nose; water containing organism moves in the nose, then migrates to brain through cribriform plate along olfactory nerves1. Symptoms are usually nonspecific similar to bacterial meningitis2. There is no rapid detection test for this organism. Diagnostic test involves CSF study with direct visualization of naegleria under light microscope which are actively motile. Indirect hemagglutination, ELISA etc. are other methods of diagnosis. MRI is usually suggestive of cerebral edema. As it has a very rapid clinical course, the patient dies with ambiguous clinical diagnoses; treatment is usually late they and the disease enters into non-responsive stage. The drugs of choice are amphotericin-B, rifampicin and tetracycline; some clinicians use fluconazole as well for better results3. Surgical intervention has only supportive role.
During the recent years, we have an incidence of total eight patients with meningoencepalitis who had a short history of headache, fever and neck rigidity. Most of these patients were young and active with no any previous illness. They came from different parts of Karachi city. All were admitted to intensive care unit after placement of endotracheal tube due to low GCS and the need for mechanical ventilation. They developed brain death within 24 to 48 hours. There CSF wet mount showed the presence of Naegleria infestation. CT scan showed gross dilatation of ventricles and midline shift. One patient had coning as well. Unfortunately, the incidence of this infection is increasing, and in 2009 we came across four patients in a single month.
This is a rare but fatal disease and requires a high degree of suspicion for its quick diagnosis. Awareness can lead early detection and early start of treatment which might save the lives. After six patients were reported in the US in 2007, CDC with coordination of Council of State formed ‘Naegleria Workgroup’ to determine the causes and plan for future action. Other countries also need to make special committees of concerned authorities to highlight this issue and produce awareness in the people as well as healthcare staff. Swimming pools should be surveyed for the infection as prevention is better than cure. Water related activities should be avoided in warm fresh water during periods of high water temperature and low water levels. Whenever there is a suspicion of mixing of sewerage water with drinking water, it should not be used. Role of health related NGO’s is important for public awareness program. In the hospitals a detailed history with suspicion of meningitis will help in diagnosis. We need to formulate some guidelines for correct diagnosis and early treatment. CSF cytology of wet mount should be considered. Prophylactic use of amphotericin-B may help to improve survival.
REFERENCES
1- Jain R, Prabhakar S, Modi M, Bhatia R, Sehgal R. Naegleria meningitis: a rare survival. Neurol India. 2002; 50(4):470-2.
2- Naegleria Infection. Parasitic disease information. On line, sited 2009 June. Available from: URL: http://www. cdc.gov/ncidod/dpd/parasites/naegleria/
3- Vargas-Zepeda J, Gómez-Alcalá AV, Vásquez-Morales JA, Licea-Amaya L, De Jonckheere JF, Lares-Villa F. Successful treatment of Naegleria fowleri meningoencephalitis by using intravenous amphotericin B, fluconazole and Rifampicin. Arch Med Res. 2005; 36(1):83-6.
Citation: Khan MF, Saleemullah H. Naegleria meningitis: an emergingchallenge (letter to editor). Anaesth Pain & Intensive Care 2009;13(2):83
Muhammad Faisal Khan & Hameedullah Saleemullah
Dept. of Anesthesia, Agha Khan University, Stadium Road, PO Box 3500, Karachi (Pakistan); Phone: (92) 21 34864624; E-mail: mohammad.khan@aku.edu
