|Year : 2014 | Volume
| Issue : 2 | Page : 193-196
Prompt diagnosis and extraordinary survival from Naegleria fowleri meningitis: A rare case report
A Sood, S Chauhan, L Chandel, SC Jaryal
Department of Microbiology, Dr. Rajendra Prasad Government Medical College, Kangra at Tanda, Kangra, Himachal Pradesh, India
|Date of Submission||29-Mar-2013|
|Date of Acceptance||11-Nov-2013|
|Date of Web Publication||2-Apr-2014|
Department of Microbiology, Dr. Rajendra Prasad Government Medical College, Kangra at Tanda, Kangra, Himachal Pradesh
Source of Support: None, Conflict of Interest: None
Primary amoebic meningoencephalitis is a rare fatal meningitis caused by free living amoeba Naegleria fowleri, found in freshwater ponds and lakes. It infects children and young adults with exposure due to swimming or diving. We report a case of N. fowleri meningitis in a 6-year-old boy who presented with signs and symptoms of acute bacterial meningitis. No history of travelling or swimming was present. However, the boy frequently played with water stored from a "kuhl" (diversion channels of water). Wet mount of cerebrospinal fluid (CSF) revealed amoeboid and actively motile flagellate forms of trophozoites. CSF culture done on 1.5% non-nutrient agar plates with a lawn culture of Escherichia coli kept at 37°C for 15 days did not reveal any growth. The test of flagellation on passing CSF in distilled water was however positive in 3 h. Water of the "kuhl" from the stored tank also showed actively motile trophozoites similar to the forms obtained from the CSF. Based on our reports, the boy was immediately treated with amphotericin B, rifampicin and fluconazole for 21 days. Repeat CSF examination after 14 days did not reveal any trophozoites in wet mount and patient was discharged after 3 weeks of successful treatment.
Keywords: Meningoencephalitis, Naegleria fowleri, survival
|How to cite this article:|
Sood A, Chauhan S, Chandel L, Jaryal S C. Prompt diagnosis and extraordinary survival from Naegleria fowleri meningitis: A rare case report. Indian J Med Microbiol 2014;32:193-6
|How to cite this URL:|
Sood A, Chauhan S, Chandel L, Jaryal S C. Prompt diagnosis and extraordinary survival from Naegleria fowleri meningitis: A rare case report. Indian J Med Microbiol [serial online] 2014 [cited 2020 Jan 19];32:193-6. Available from: http://www.ijmm.org/text.asp?2014/32/2/193/129834
| ~ Introduction|| |
Primary amoebic meningoencephalitis (PAM) is a fatal type of meningitis caused by ubiquitous free living amoeba Naegleria fowleri. The amoeba is found in freshwater ponds and lakes. Most N. fowleri infections have occurred in children and young adults who have recent exposure to swimming or diving in warm fresh water.  Up to 440 cases have been documented world-wide, mostly from United states of America, Australia and Europe.  Hereby, we present a rare case of N. fowleri meningoencephalitis in a 6-year-old boy whose infection was promptly diagnosed and early treatment initiated, which ultimately saved his life. To the best of our knowledge in India, only nine cases of PAM due to Naegleria species have been reported.  These infections are uniformly fatal and mortality rate is estimated to be as high as 98%. 
| ~ Case Report|| |
This was a case report of a 6-year-old male child who was admitted to the Pediatrics Ward of Dr. Rajendra Prasad Government Medical College, Kangra, Himachal Pradesh, India. His chief complaints were fever, headache and altered sensorium. There was no prior history of travelling or swimming. However, the parents did give a history of the boy playing frequently with water stored in a cement tank used for varied purposes. On further probing it was found that this water was collected from a nearby diversion channel of water popularly called as "kuhl" in this area of Himachal Pradesh.
On general physical examination, the child was febrile (102°F), conscious, well-oriented and responding to verbal commands. Examination of central nervous system showed no involvement of cranial nerves, no focal deficits or seizures. On examination, neck rigidity was present and Kernig's and Brudzinki's signs could be illustrated. A provisional diagnosis of acute pyogenic meningitis was made and the patient started on ceftriaxone, mannitol and dexamethasone.
All laboratory investigations including complete hemogram and serum biochemistry were within limits except erythrocyte sedimentation rate, which was 70 mm in 1 st h. Rapid tests for human immunodeficiency virus 1 (HIV1) and HIV2 (Comb AIDS-RS, HIV 1+2 Immunoblot kit) were non-reactive. Weil felix test, Widal test and Mantoux test were also negative. Cerebrospinal fluid (CSF) was clear on gross examination, with cell count of 415 cells/mm 3 and predominance of neutrophils. Gram stain, Ziehl Neelsen and India ink staining did not reveal any significant findings. However, wet mount of CSF revealed amoeboid and flagellate forms of trophozoites. The size of amoeboid forms ranged from 20 to 40 μm in diameter with a single nucleus and a large, dense central nucleolus [Figure 1]. Few flagellate forms could also be seen, which were pear shaped and had two actively beating flagella [Figure 2]. The trophozoites showed active amoeboid motility and constantly changed shape and size. On Giemsa stain, both amoeboid and flagellate forms could be seen. The above findings were immediately conveyed to the pediatricians and diagnosis of PAM made and the boy started on revised treatment. Taking all aseptic precautions, the CSF was inoculated on 1.5% non-nutrient agar plates with a lawn culture of Escherichia coli. Plates were incubated at 37°C and checked microscopically daily (under × 10 and × 40) for clearing of the agar in thin tracks up to 15 days. However, no areas of clearing or plaques were obtained. A small portion of CSF was put in a tube containing 5ml of distilled water and incubated at 37°C. A wet preparation made from this after 3 h showed actively motile flagellate forms. Few drops of the remaining CSF were kept in a water bath at temperature of 42°C and trophozoites of Naegleria survived at this temperature. This differentiated pathogenic species from other non-pathogenic species of Naegleria. CSF culture for pyogenic organisms did not reveal any type of growth.
|Figure 1: Amoeboid trophozoites as seen in the cerebrospinal fluid (×40)|
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Subsequently, water of the "kuhl" from the stored tank was collected and transported to our laboratory. The water was centrifuged and its wet mount preparation showed actively motile trophozoites similar to the forms obtained from the CSF. Culture of this water sample on 1.5% nutrient agar was again not successful.
Based on the clinical profile and microbiological investigations an aggressive management for PAM was started. The boy was started on intravenous amphotericin B (1 mg/kg body weight), intravenous fluconazole (8 mg/kg) and oral rifampicin (10 mg/kg) for a period of 21 days with strict monitoring of his renal functions. He started responding to treatment after 5 days. The repeat CSF examination done after 14 days did not show any trophozoites in wet mount. The patient was discharged after 3 weeks of treatment and follow-up examination did not show any signs and symptoms.
| ~ Discussion|| |
Free living amoebae of the genera Naegleria, Acanthamoeba and Balamuthia are ubiquitous in nature and produce serious infections of the central nervous system and eye. The first case of human infection with free living amoebae was described by Fowler and Carter in 1965.  PAM caused by N. fowleri usually occurs in previously healthy young individuals who have exposure to warm fresh water by swimming or otherwise. The portal of entry is through the olfactory mucosa and then passing through the cribriform plate leading to fulminant and fatal meningoencephalitis within a week. Clinically, it is difficult to differentiate PAM from acute bacterial meningitis. This needs help of a microbiologist, without which patient will be treated unnecessarily with antibiotics of no use. The correct and prompt diagnosis of PAM is a diagnostic challenge as there is limited awareness to this disease amongst clinicians and microbiologists.
Until date, only 440 cases have been documented world-wide mostly from the United States, Australia and Europe and only 9 cases from India.  This high disparity is mainly due to greater awareness amongst the diagnostic staff and clinicians in the developed countries. The majority of cases get infection by swimming in warm freshwater lakes or ponds, but there are only few reports of infection being acquired through household water or well water.  In our case also, there was history of exposure to stored water from "kuhl." "Kuhls" are a traditional irrigation system widely present in the state of Himachal Pradesh and the water of "kuhls" is used widely by people for varied purposes. This is the first case of PAM in which N. fowleri infection has been acquired from stored water and that too while playing with water. In our part of the state, the temperature of water is quite high when compared to other regions, which might have led to the proliferation of N. fowleri in kuhl water.
There is a high mortality rate probably exceeding 98% patients in patients with PAM.  A wide range of pharmacologic agents have been evaluated against N. fowleri, but most of these agents have shown limited activity against it. Amphotericin B is the only agent with established clinical efficacy for PAM and can be used either systemically or intrathecally. Apart from other side effects, nephrotoxicity caused by amphotericin B is a limiting factor in many cases. It has been used alone and in combination with drugs such as rifampin, fluconazole, sulfadiazine, miconazole, sulfisoxazole, ketoconazole, dexamethasone, ornidazole and chloramphenicol to successfully treat PAM.  Azithromycin has been used successfully in experimental mice.  Triple drug regime of intravenous amphotericin B, fluconazole and oral rifampicin has reported to be successful in few PAM patients. 
Only eight reports of cured cases have been documented in the medical literature so far.  In India only four patients have survived until date. Most of the survivors noted until date were treated with amphotericin B in varying combinations with other drugs such as, rifampicin, sulphadiazine, dexamethasone, phenobarbitone, and streptomycin. ,, Our patient was lucky to survive as his infection was diagnosed promptly and early effective treatment was initiated.
In patients with purulent CSF indices and no bacteria demonstrated on gram stain a strong suspicion of PAM should be aroused and it is advisable that a wet mount preparation of each CSF sample should always be made. In our case, we were able to reach to the diagnosis, only through accurate laboratory interpretation of wet mount preparation of CSF, although the amoeba could not be cultured despite repeated attempts. The exact cause for getting culture negative is not known to us but Jain et al. also could not get a positive culture in their patient.  In case of a negative culture result the presence of free living amoebae should not be ruled out.  Furthermore, our case report highlights the importance of accurate diagnosis as initiation of early treatment can save precious life of the patient. An attempt to increase awareness amongst people in prevention of diseases is also required as chlorination of water at 2 ppm can kill the trophozoites of N. fowleri. 
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[Figure 1], [Figure 2]
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