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OJHAS Vol. 10, Issue 1:
(Jan-Mar 2011) |
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Primary Amoebic (Naegleria fowleri) Meningoencephalitis Presenting as Status Epilepticus |
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A Sharma, Professor,
R Raina, Associate
professor,
P Jaret, Assistant professor,
V Bharti, Senior
resident,
G Gargi, Junior
resident,
P Panda, Junior
resident,
Dept. of
Medicine, Indira Gandhi Medical College, Shimla, INDIA. |
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Address for Correspondence |
Junior
Resident,
Department of Medicine,
Indira Gandhi Medical College,
Shimla, INDIA.
E-mail:
prashantpanda85@gmail.com |
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Sharma A, Raina R, Jaret P, Bharti V, Gargi
G, Panda P. Primary Amoebic (Naegleria fowleri) Meningoencephalitis Presenting as Status Epilepticus. Online J Health Allied Scs.
2011;10(1):22 |
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Submitted: Jan 22,
2011; Accepted: March 31, 2011; Published:
April 15, 2011 |
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| Abstract: |
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Primary
amebic meningoencephalitis (PAM) is a rare entity. Usual presenting features
are fever, headache and seizures with meningeal signs and this
disease carries high mortality rate. We present a case report of PAM
presenting as status epilepticus.
Key Words:
Primary
amebic meningoencephalitis; Naegleria fowleri; Status epilepticus
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N. fowleri is the only species of Naegleria genus that is pathogenic
to humans. It is ubiquitous in natural fresh water lakes and
ponds (especially warm water). It causes extremely rare and sporadic
CNS infections. Typically, N. fowleri produces primary amebic
meningoencephalitis (PAM), which is clinically indistinguishable from
acute bacterial meningitis.1
A 21 years female
residing at district Bilaspur of Himachal Pradesh, presented with fever,
headache and vomiting for 1 week and seizures for 1 day. Fever was
high grade (up to 103°F), intermittent, associated with chills
and rigors. Headache was diffuse dull aching to start with, present all
over the head, and later on it increased in severity. She also had vomiting
7-8 episodes per day, mainly consisting of undigested food particles, non bilious, not containing any blood, mucus.
There was also history of 7-8 episodes
of generalised tonic clonic seizures without regaining consciousness. General physical examination was unremarkable. Neurological examination
revealed unconscious state with neck rigidity and positive Kernig’s
sign. The rest of the systemic examination was normal. Complete haemogram,
LFT’s , RFT’s, and blood culture were normal. CSF examination
revealed proteins 55 mg%, sugar 30 mg%, cytology 7 WBCs, mostly
lymphocytes. Wet mount specimen of CSF revealed motile flagellate forms
of Naegleria fowleri. CSF was repeated twice which revealed similar
form on microscopy. MRI brain was done which was normal. Retrospectively
history revealed that she had taken a bath at a local pond. On the day
1, patient was initially started empirically on ceftriaxone, vancomycin,
acyclovir and steroid on the lines of acute bacterial meningitis and
acute viral encephalitis and also patient was dilantinised for status
epilepticus. On day 2 after CSF report, patient was started on injection amphotericin. Despite this, patient deteriorated and she expired on 5th
day of admission.
Primary amebic meningoencephalitis
is caused by free living amebas of genera Naegleria fowleri, Acanthamoeba
and Balamuthia mandrillaris formerly known as leptomyxid amoeba. These
are free living, amephizoic and opportunistic protozoa that are ubiquitous
in nature. These amebas are found in soil, water, air samples from all
over world. Man gets infected from inhalation of trophozoites or cysts
on exposure to polluted water in ponds, swimming pools and manmade lakes.
Nageleria fowleri is a thermophilic amoeba that grows well in tropical
and subtropical climates and raised temperatures during hot summer
months or warm water from power plants facilitates its growth. Human
infection involves brain, lung, skin and eyes and has increased
significantly since last 10 years. The portal of entry to CNS is
through olfactory neuroepithelium. CNS infection occurs in two forms:
a) Primary amebic meningoencephalitis,
(PAME) caused by Naegleria fowleri
b) Granulomatous amebic
encephalitis, (GAE) caused by species of Acanthamoeba and Balamuthia
mandrillaris.
Incubation period for
N. fowleri is 3 to 7 days and that for acanthamoeba is unknown but perhaps
more than 10 days. PAME produced by N. fowleri is characterized by acute
fulminant meningoencephalitis with severe headache, high grade fever,
nausea, vomiting, altered consciousness with signs of meningeal irritation.
Cranial nerve palsies, seizures, confusion, agitation, and coma may follow and death occurs
within a week if not treated early. Most patients die, usually
by the seventh day.2-5
Recognition of
primary
amoebic meningoencephalitis depends on clinical suspicion based on patient
history. A spinal tap usually reveals an elevated white blood
cell count (>100 cells/mm3) with a high percentage of polymorphonuclear
leukocytes (>70%), a depressed glucose level (<50 mg/dL), and
an elevated protein level (>60 mg/dL), mimicking those of bacterial
meningitis. Occasionally, amebae can be observed on Gram-stained smears. In CSF, both amoeboid and
flagellate forms have been reported. If primary amoebic meningoencephalitis
is suspected, a fresh-centrifuged specimen of CSF should be inspected
by wet-mount preparation and fixation and staining. Special culture
media are required for culture of amoeba. Serological tests performed
are indirect Immunofluorescence assay (IIA), dot immunobinding assay
(DIBA) and enzyme linked immunotransfer blot technique (EITB). Neuroimaging
findings nonspecific brain edema suggestive of meningitis, favouring N. fowleri, and punctuate enhancing lesions due to acanthamoeba.6-8
A few patients have been successfully treated using a combination of
miconazole, oral rifampin and high dose of injection amphotericin.1,9
The risk of infection from water containing N.
fowleri is unknown but probably small, since thousands of people
swim in lakes, ponds and hot springs known to contain these organisms,
and yet cases of PAM are extremely rare. This case is peculiar because
we found flagellate form in CSF in contrast to amoeboid form reported
in other case reports although both are known to cause PAM. PAM
is known to cause seizures, but presentation as status epilepticus is
rare. To the nest of our knowledge, no case of PAM has been reported from the Sub-Himalayan
region. PAM should be suspected in patients with acute meningitis who do not respond to conventional treatment and who have fulminant
course.
- Brown
RL. Successful treatment of primary amebic meningoencephalitis (PAM).
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S, Modi M, Bhatia R, Sehgal R. Naegleria
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S, Momen A. A Primary Amebic Meningoencephalitis. Pak J Med Sci
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GF, Cepero NF, Ibarra SE, Garcia OJ. Primary
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- Jain R, Prabhakar S, Modi M,
Bhatia R, Sehgal R. Naegleria meningitis: a rare Survival. Neurol India
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- Singh SN, Patwari AK, Dutta
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