History

Fact Explanation
Fever Unlike in bacterial meningitis, where high fever and acute onset of neurological features are almost the hallmark features, [1] viral encephalitis might not have such a severe presentation. Some cases present as sub-acute fever and the other symptoms appearing gradually, [2] sometimes with acute fever. [3]
A history of gastroenteritis or respiratory tract infection Some patients present with a syndrome of acute watery diarrhea or following a mild upper respiratory tract infection. [4]
Headache Due to meningeal irritation. [5]
Vomiting One of the common manifestations, due to meningeal irritation. [5] [6] Viral encephalitis can present as a febrile vomiting illness. [7]
Seizures The presentation could be due to a acute seizure without other prominent symptoms. [8] [9] [10] [11] Due to increased intra-cranial pressure.
Rashes, and other multi-system complaints Due to disseminated adenoviral infection [12] [2] [13]
Features of increased intra-cranial pressure The infants may be drowsy through the examination, and when looking at the skull, the suture lines may be separated and the fontanels may be bulging and tensed. In older patients, diplopia, sun-setting eyes, behavior changes, and other neurological signs can be a feature of increased intracranial pressure. [14] [15] [16] [17]
Non-specific symptoms Lethargy, irritability poor feeding and anorexia are also common features, especially among infants. [2] [13] It also could be a presentation of cerebral edema, so one should be careful to assess. [4]
Risk factors for enteroviral meningitis Epidemics of enteroviral encephalitis In temperate climates are commonest during the summer and autumn months, and spread is predominantly through the fecal–oral route, with infections often commonly acquired in child-care facilities. The commonest infected group is school-aged children. [3] [18] [19]
References
  1. VAN DE BEEK D, DE GANS J, SPANJAARD L, WEISFELT M, REITSMA JB, VERMEULEN M. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med [online] 2004 Oct 28, 351(18):1849-59 [viewed 16 June 2014] Available from: doi:10.1056/NEJMoa040845
  2. STRAUSSBERG R, HAREL L, LEVY Y, AMIR J. A syndrome of transient encephalopathy associated with adenovirus infection. Pediatrics [online] 2001 May, 107(5):E69 [viewed 16 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/11331719
  3. CHADWICK D. R.. Viral meningitis. British Medical Bulletin [online] 2006 February, 75-76(1):1-14 [viewed 16 June 2014] Available from: doi:10.1093/bmb/ldh057
  4. CHATTERJEE N. K., SAMSONOFF W. A., BALASUBRAMANIAM N., WILSON K. R.-, SPARGO W., CHURCH T. M.. Isolation and Characterization of Adenovirus 5 from the Brain of an Infant with Fatal Cerebral Edema. Clinical Infectious Diseases [online] 2000 September, 31(3):830-833 [viewed 16 June 2014] Available from: doi:10.1086/314041
  5. CHAUDHURI A. Diagnosis and treatment of viral encephalitis. [online] 2002 October, 78(924):575-583 [viewed 16 June 2014] Available from: doi:10.1136/pmj.78.924.575
  6. Viral meningitis Paediatr Child Health [web] 1998, 3(6):433-436 [viewed 17 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851312
  7. MARKEY PG, DAVIS JS, HARNETT GB, WILLIAMS SH, SPEERS DJ. Meningitis and a Febrile Vomiting illness Caused by Echovirus Type 4, Northern Territory, Australia Emerg Infect Dis [online] 2010 Jan, 16(1):63-68 [viewed 26 June 2014] Available from: doi:10.3201/eid1601.081519
  8. GRANEROD JULIA, AMBROSE HELEN E, DAVIES NICHOLAS WS, CLEWLEY JONATHAN P, WALSH AMANDA L, MORGAN DILYS, CUNNINGHAM RICHARD, ZUCKERMAN MARK, MUTTON KEN J, SOLOMON TOM, WARD KATHERINE N, LUNN MICHAEL PT, IRANI SAROSH R, VINCENT ANGELA, BROWN DAVID WG, CROWCROFT NATASHA S. Causes of encephalitis and differences in their clinical presentations in England: a multicentre, population-based prospective study. The Lancet Infectious Diseases [online] 2010 December, 10(12):835-844 [viewed 26 June 2014] Available from: doi:10.1016/S1473-3099(10)70222-X
  9. MICHAEL BENEDICT D., SOLOMON TOM. Seizures and encephalitis: Clinical features, management, and potential pathophysiologic mechanisms. [online] December, 53:63-71 [viewed 26 June 2014] Available from: doi:10.1111/j.1528-1167.2012.03615.x
  10. MISRA USHA KANT, TAN CHONG TIN, KALITA JAYANTEE. Viral encephalitis and epilepsy. [online] 2008 August, 49:13-18 [viewed 26 June 2014] Available from: doi:10.1111/j.1528-1167.2008.01751.x
  11. KIM M. A., PARK K. M., KIM S. E., OH M. K.. Acute symptomatic seizures in CNS infection. Eur J Neurol [online] 2007 November, 0(0):071116221701002-??? [viewed 26 June 2014] Available from: doi:10.1111/j.1468-1331.2007.01996.x
  12. RIEGER-FACKELDEY E., AUMEIER S., GENZEL-BOROVICZéNY O.. Disseminated Adenoverus Infection in Two Premature Infants. Infection [online] 2000 August, 28(4):237-239 [viewed 17 June 2014] Available from: doi:10.1007/s150100070044
  13. OOI MONG HOW, WONG SEE CHANG, CLEAR DANIELA, PERERA DAVID, KRISHNAN SHEKHAR, PRESTON TERESA, TIO PHAIK HOOI, WILLISON HUGH J., TEDMAN BRIAN, KNEEN RACHEL, CARDOSA MARY JANE, SOLOMON TOM. Adenovirus Type 21–Associated Acute Flaccid Paralysis during an Outbreak of Hand‐Foot‐and‐Mouth Disease in Sarawak, Malaysia. CLIN INFECT DIS [online] 2003 March, 36(5):550-559 [viewed 17 June 2014] Available from: doi:10.1086/367648
  14. KUMAR GYANENDRA, KALITA JAYANTEE, MISRA USHA KANT. Raised intracranial pressure in acute viral encephalitis. Clinical Neurology and Neurosurgery [online] 2009 June, 111(5):399-406 [viewed 26 June 2014] Available from: doi:10.1016/j.clineuro.2009.03.004
  15. GOITEIN KJ, AMIT Y, MUSSAFFI H. Intracranial pressure in central nervous system infections and cerebral ischaemia of infancy. Arch Dis Child [online] 1983 Mar, 58(3):184-186 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1627839
  16. KENNEDY P G E. VIRAL ENCEPHALITIS: CAUSES, DIFFERENTIAL DIAGNOSIS, AND MANAGEMENT. Journal of Neurology, Neurosurgery & Psychiatry [online] 2004 March, 75(90001):10i-15 [viewed 26 June 2014] Available from: doi:10.1136/jnnp.2003.034280
  17. SOLOMON T.. Seizures and raised intracranial pressure in Vietnamese patients with Japanese encephalitis. [online] 2002 May, 125(5):1084-1093 [viewed 26 June 2014] Available from: doi:10.1093/brain/awf116
  18. KHETSURIANI NINO, TONG SUXIANG, LU XIAOYAN, REED SHANNON, ERDMAN DEAN, CAMPBELL ANGELA, SUPAWAT KRONGKAEW, LIAMSUWAN SAHAS, JOTHIKUMAR NARAYANAN, OLSEN SONJA. Systemic Infection with Enteric Adenovirus in Immunocompetent Child with Disease . Emerg. Infect. Dis. [online] 2009 February, 15(2):355-357 [viewed 17 June 2014] Available from: doi:10.3201/eid1502.081066
  19. GRAY GC, MCCARTHY T, LEBECK MG, SCHNURR DP, RUSSELL KL, KAJON AE, LANDRY ML, LELAND DS, STORCH GA, GINOCCHIO CC, ROBINSON CC, DEMMLER GJ, SAUBOLLE MA, KEHL SC, SELVARANGAN R, MILLER MB, CHAPPELL JD, ZERR DM, KISKA DL, HALSTEAD DC, CAPUANO AW, SETTERQUIST SF, CHORAZY ML, DAWSON JD, ERDMAN DD. Genotype Prevalence and Risk Factors for Severe Clinical Adenovirus Infection, United States 2004-2006 Clin Infect Dis [online] 2007 Nov 1, 45(9):1120-1131 [viewed 17 June 2014] Available from: doi:10.1086/522188

Examination

Fact Explanation
Altered behaviour In viral encephalitis, more than 50% of the patients present with a change in behavior and personality. Some patients can be easily irritated (especially children) or disoriented. [1] [2] [3] Cognition should be examined since it's common to have a cognitive impairment. [4] Depending on the damage to the brain, some changes might be long-standing. [5]
Fever Due to the inflammatory reaction. Fever can be mild to high in severity. [6] [7]
Skin rash Even though not a very common feature, maculo-papular skin rashes can be present with adenoviral CNS infections. [8] But other infections should be taken into account when a rash is characteristic or prominent. [7]
Features of increased intracranial pressure The infants may be drowsy through the examination, and when looking at the skull, the suture lines may be separated and the fontanels may be bulging and tensed. In older patients, diplopia, sun-setting eyes, behavior changes, and other neurological signs can be a feature of increased intracranial pressure. [9] [10] [11] [12]
Focal neurological deficits Almost 30% of the patients with viral encephalitis suffer focal neurological signs. The commonly experienced features are focal seizures, hemiparesis and cranial nerve dysfunction. The neurological features can be diffuse too. Some neurological syndromes prevail even after the original infection resolves. [6] [7] [13] [14] [15] [16] [17]
References
  1. GRANEROD JULIA, AMBROSE HELEN E, DAVIES NICHOLAS WS, CLEWLEY JONATHAN P, WALSH AMANDA L, MORGAN DILYS, CUNNINGHAM RICHARD, ZUCKERMAN MARK, MUTTON KEN J, SOLOMON TOM, WARD KATHERINE N, LUNN MICHAEL PT, IRANI SAROSH R, VINCENT ANGELA, BROWN DAVID WG, CROWCROFT NATASHA S. Causes of encephalitis and differences in their clinical presentations in England: a multicentre, population-based prospective study. The Lancet Infectious Diseases [online] 2010 December, 10(12):835-844 [viewed 26 June 2014] Available from: doi:10.1016/S1473-3099(10)70222-X
  2. DE SOUSA ALINE ANDRADE, REIS RENATA, BENTO-TORRES JOãO, TRéVIA NONATA, LINS NARA ALVES DE ALMEIDA, PASSOS ALINE, SANTOS ZAIRE, DINIZ JOSé ANTONIO PICANçO, VASCONCELOS PEDRO FERNANDO DA COSTA, CUNNINGHAM COLM, PERRY VICTOR HUGH, PICANçO DINIZ CRISTOVAM WANDERLEY, MOSLEY R. LEE. Influence of Enriched Environment on Viral Encephalitis Outcomes: Behavioral and Neuropathological Changes in Albino Swiss Mice. PLoS ONE [online] 2011 January [viewed 26 June 2014] Available from: doi:10.1371/journal.pone.0015597
  3. BERG A.-L., GAVIER-WIDEN D., NILSSON K., WIDEN F., BERG M., GREGORIUS S., AGREN E., ERLANDSSON M., MORNER T.. Necrotizing Encephalitis of Unknown Cause in Fennoscandian Arctic Foxes (Alopex Lagopus). Journal of Veterinary Diagnostic Investigation [online] 2007 January, 19(1):113-117 [viewed 26 June 2014] Available from: doi:10.1177/104063870701900121
  4. HOKKANEN L, POUTIAINEN E, VALANNE L, SALONEN O, IIVANAINEN M, LAUNES J. Cognitive impairment after acute encephalitis: comparison of herpes simplex and other aetiologies.. Journal of Neurology, Neurosurgery & Psychiatry [online] 1996 November, 61(5):478-484 [viewed 26 June 2014] Available from: doi:10.1136/jnnp.61.5.478
  5. DEKA K, BHUYAN D, CHAUDHURY PK. Conduct disorder--A sequelae of viral encephalitis Indian J Psychiatry [online] 2006, 48(4):258-259 [viewed 26 June 2014] Available from: doi:10.4103/0019-5545.31560
  6. STRAUSSBERG R., HAREL L., LEVY Y., AMIR J.. A Syndrome of Transient Encephalopathy Associated With Adenovirus Infection. PEDIATRICS [online] 2001 May, 107(5):e69-e69 [viewed 26 June 2014] Available from: doi:10.1542/peds.107.5.e69
  7. CHAUDHURI A. Diagnosis and treatment of viral encephalitis. [online] 2002 October, 78(924):575-583 [viewed 26 June 2014] Available from: doi:10.1136/pmj.78.924.575
  8. CHATTERJEE N. K., SAMSONOFF W. A., BALASUBRAMANIAM N., WILSON K. R.-, SPARGO W., CHURCH T. M.. Isolation and Characterization of Adenovirus 5 from the Brain of an Infant with Fatal Cerebral Edema. Clinical Infectious Diseases [online] 2000 September, 31(3):830-833 [viewed 26 June 2014] Available from: doi:10.1086/314041
  9. KUMAR GYANENDRA, KALITA JAYANTEE, MISRA USHA KANT. Raised intracranial pressure in acute viral encephalitis. Clinical Neurology and Neurosurgery [online] 2009 June, 111(5):399-406 [viewed 26 June 2014] Available from: doi:10.1016/j.clineuro.2009.03.004
  10. GOITEIN KJ, AMIT Y, MUSSAFFI H. Intracranial pressure in central nervous system infections and cerebral ischaemia of infancy. Arch Dis Child [online] 1983 Mar, 58(3):184-186 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1627839
  11. KENNEDY P G E. VIRAL ENCEPHALITIS: CAUSES, DIFFERENTIAL DIAGNOSIS, AND MANAGEMENT. Journal of Neurology, Neurosurgery & Psychiatry [online] 2004 March, 75(90001):10i-15 [viewed 26 June 2014] Available from: doi:10.1136/jnnp.2003.034280
  12. SOLOMON T.. Seizures and raised intracranial pressure in Vietnamese patients with Japanese encephalitis. [online] 2002 May, 125(5):1084-1093 [viewed 26 June 2014] Available from: doi:10.1093/brain/awf116
  13. KELLY TARA A., O’LORCAIN PIARAS, MORAN JOANNE, GARVEY PATRICIA, MCKEOWN PAUL, CONNELL JEFF, COTTER SUZANNE. Underreporting of Viral Encephalitis and Viral Meningitis, Ireland, 2005–2008. Emerg. Infect. Dis. [online] 2013 September, 19(9):1428-1436 [viewed 26 June 2014] Available from: doi:10.3201/eid1909.130201
  14. LOGAN S. A E, MACMAHON E.. Viral meningitis. BMJ [online] 2008 January, 336(7634):36-40 [viewed 26 June 2014] Available from: doi:10.1136/bmj.39409.673657.AE
  15. MICHAELI O., KASSIS I., SHACHOR-MEYOUHAS Y., SHAHAR E., RAVID S.. Long-term Motor and Cognitive Outcome of Acute Encephalitis. PEDIATRICS [online] December, 133(3):e546-e552 [viewed 26 June 2014] Available from: doi:10.1542/peds.2013-3010
  16. BIG C., REINECK L. A., ARONOFF D. M.. Viral Infections of the Central Nervous System: A Case-Based Review. Clinical Medicine & Research [online] December, 7(4):142-146 [viewed 26 June 2014] Available from: doi:10.3121/cmr.2009.864
  17. AYGUN A. D.. Long-term Neurological Outcome of Acute Encephalitis. Journal of Tropical Pediatrics [online] 2001 August, 47(4):243-247 [viewed 26 June 2014] Available from: doi:10.1093/tropej/47.4.243

Differential Diagnoses

Fact Explanation
Encephalitis due to other viruses Similar symptoms could be presentations of other viral encephalitis. But there are characteristic features of certain viral infections of the central nervous system. i.e. Herpes simplex encephalitis. They could be evaluated in history and examination before proceeding into investigations, which are diagnostic. [1] [2] [3] [4]
Partially treated bacterial CNS infection In this era of widely available antibiotics, cases with pyogenic meningitis often presents partially treated and the clinical appearance could be deceiving. The dilemma is that the cerebrospinal fluid analysis also can be altered. Where there is a doubt, it's always useful to manage as pyogenic meningitis and investigate thoroughly with PCR or serology. [5] [6] [7] [8] [9] [10] [11]
Seizure disorders without an infective cause Seizures are a common manifestation in all encephalitis types. Whereas encephalitis especially poorly resolved ones increase the tendency to have seizures in future, seizure disorders can mimic encephalitis also. [12] [13] [14] [15] [16]
Migraine The usual presentation of migraine is a unilateral throbbing kind of headache, associated with photophobia and/or phonophobia. But migraine presentation can be so diverse that arriving at a diagnosis can be a bit of a work. The complex kind of migraines, i.e. hemiphlegic migraine, acute confusional migraine, can easily mimic an infective cause in the central nervous system. [17] [18] [19] [20] [21] [22] [23] [24] [25] [26]
Febrile seizure It'a more common differential for fever and fits. Febrile fits usually follow high fever, follow an identifiable focus of infection, and has a good prognosis. Most of the time do not require antiepileptics unless in a status, and do not require long term follow up or drugs. Usually febrile seizures can be excluded in initial checkup of the patient but when in doubt, always should be managed as encephalitis as the latter could be a life-threatening condition. [27] [28] [29] [30] [31] [32] [33]
References
  1. BIG C., REINECK L. A., ARONOFF D. M.. Viral Infections of the Central Nervous System: A Case-Based Review. Clinical Medicine & Research [online] December, 7(4):142-146 [viewed 26 June 2014] Available from: doi:10.3121/cmr.2009.864
  2. KELLY TARA A., O’LORCAIN PIARAS, MORAN JOANNE, GARVEY PATRICIA, MCKEOWN PAUL, CONNELL JEFF, COTTER SUZANNE. Underreporting of Viral Encephalitis and Viral Meningitis, Ireland, 2005–2008. Emerg. Infect. Dis. [online] 2013 September, 19(9):1428-1436 [viewed 26 June 2014] Available from: doi:10.3201/eid1909.130201
  3. CHAUDHURI A. Diagnosis and treatment of viral encephalitis. [online] 2002 October, 78(924):575-583 [viewed 26 June 2014] Available from: doi:10.1136/pmj.78.924.575
  4. LOGAN S. A E, MACMAHON E.. Viral meningitis. BMJ [online] 2008 January, 336(7634):36-40 [viewed 26 June 2014] Available from: doi:10.1136/bmj.39409.673657.AE
  5. FERGUSON R.. The effect of antibiotic therapy before admission to hospital on recognition of the causative organism in acute bacterial meningitis. Journal of Infection [online] 1986 November, 13(3):241-244 [viewed 26 June 2014] Available from: doi:10.1016/S0163-4453(86)91157-6
  6. PANDIT L.. Diagnosis of partially treated culture-negative bacterial meningitis using 16S rRNA universal primers and restriction endonuclease digestion. Journal of Medical Microbiology [online] 2005 June, 54(6):539-542 [viewed 26 June 2014] Available from: doi:10.1099/jmm.0.45599-0
  7. Partly treated pyogenic meningitis. Br Med J [online] 1977 Feb 5, 1(6057):340 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1604482
  8. KATNIK R. A persistent biochemical marker for partially treated meningitis/ventriculitis. J Child Neurol [online] 1995 Mar, 10(2):93-9 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/7782615
  9. HOFFMAN O, WEBER RJ. Pathophysiology and Treatment of Bacterial Meningitis Ther Adv Neurol Disord [online] 2009 Nov, 2(6):1-7 [viewed 26 June 2014] Available from: doi:10.1177/1756285609337975
  10. BASMACI R, MARIANI P, DELACROIX G, AZIB S, FAYE A, TAHA MK, BINGEN E, BONACORSI S. Enteroviral Meningitis Does Not Exclude Concurrent Bacterial Meningitis J Clin Microbiol [online] 2011 Sep, 49(9):3442-3443 [viewed 26 June 2014] Available from: doi:10.1128/JCM.01015-11
  11. LANNIGAN R, MACDONALD MA, MARRIE TJ, HALDANE EV. Evaluation of cerebrospinal fluid lactic acid levels as an aid in differential diagnosis of bacterial and viral meningitis in adults. J Clin Microbiol [online] 1980 Apr, 11(4):324-327 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC273397
  12. MISRA USHA KANT, TAN CHONG TIN, KALITA JAYANTEE. Viral encephalitis and epilepsy. [online] 2008 August, 49:13-18 [viewed 26 June 2014] Available from: doi:10.1111/j.1528-1167.2008.01751.x
  13. KIM M. A., PARK K. M., KIM S. E., OH M. K.. Acute symptomatic seizures in CNS infection. Eur J Neurol [online] 2007 November, 0(0):071116221701002-??? [viewed 26 June 2014] Available from: doi:10.1111/j.1468-1331.2007.01996.x
  14. LAROCHE SUZETTE. Seizures and Encephalopathy. Semin Neurol [online] December, 31(02):194-201 [viewed 26 June 2014] Available from: doi:10.1055/s-0031-1277987
  15. CAPLAN JASON P., BINIUS TRACY, LENNON VANDA A., PITTOCK SEAN J., RAO MURALI S.. Pseudopseudoseizures: Conditions That May Mimic Psychogenic Non-Epileptic Seizures. Psychosomatics [online] 2011 November, 52(6):501-506 [viewed 26 June 2014] Available from: doi:10.1016/j.psym.2011.08.004
  16. PUOTI GIANFRANCO, ELEFANTE ANDREA, SARACINO DARIO, CAPASSO ANTONELLA, COTRUFO ROBERTO, BELLUOMO ANELLO CLARA. New-Onset Refractory Status Epilepticus Mimicking Herpes Virus Encephalitis. Case Rep Neurol [online] 2013 December, 5(3):162-167 [viewed 26 June 2014] Available from: doi:10.1159/000355273
  17. BENATAR M and DRISLANE FW. Imitators of Epilepsy. 2nd edition: Chapter 14Encephalopathy as a Mimic of Seizures. [web] [viewed June 26 2014] Available at http://www.ncbi.nlm.nih.gov/books/NBK7338/
  18. KIENBACHER C, WöBER C, ZESCH HE, HAFFERL-GATTERMAYER A, POSCH M, KARWAUTZ A, ZORMANN A, BERGER G, ZEBENHOLZER K, KONRAD A, WöBER-BINGöL . Clinical features, classification and prognosis of migraine and tension-type headache in children and adolescents: a long-term follow-up study. [online] 2006 July, 26(7):820-830 [viewed 26 June 2014] Available from: doi:10.1111/j.1468-2982.2006.01108.x
  19. EVANS RANDOLPH W., GLADSTEIN JACK. Confusional Migraine or Photoepilepsy?. Headache [online] 2003 May, 43(5):506-508 [viewed 26 June 2014] Available from: doi:10.1046/j.1526-4610.2003.03099.x
  20. SHAABAT ALI. Confusional migraine in childhood. Pediatric Neurology [online] 1996 July, 15(1):23-25 [viewed 26 June 2014] Available from: doi:10.1016/0887-8994(96)00089-6
  21. CEVOLI S., PIERANGELI G., MONARI L., VALENTINO M. L., BERNARDONI P., MOCHI M., CORTELLI P., MONTAGNA P.. Familial hemiplegic migraine: clinical features and probable linkage to chromosome 1 in an Italian family. Neurol Sci [online] December, 23(1):7-10 [viewed 26 June 2014] Available from: doi:10.1007/s100720200016
  22. BHATIA ROHIT, DESAI SOAHAM, TRIPATHI MANJARI, GARG AJAY, PADMA M. V., PRASAD KAMESHWAR, SINGH MAMTA B.. Sporadic hemiplegic migraine: report of a case with clinical and radiological features. J Headache Pain [online] December, 9(6):385-388 [viewed 26 June 2014] Available from: doi:10.1007/s10194-008-0067-1
  23. THOMSEN LL, OLESEN J. Sporadic hemiplegic migraine. Cephalalgia [online] 2004 December, 24(12):1016-1023 [viewed 26 June 2014] Available from: doi:10.1111/j.1468-2982.2004.00788.x
  24. HUETE ADOLFO JIMENEZ, SANCHEZ-DEL-RIO MARGARITA, FRANCH ORIOL. Hashimoto's Encephalopathy Mimicking Migraine With Aura. Headache [online] 2007 January [viewed 26 June 2014] Available from: doi:10.1111/j.1526-4610.2006.00660.x
  25. NG CL. Diagnostic challenge--is this really a stroke? Aust Fam Physician [online] 2006 Oct, 35(10):805-8 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17019457
  26. HEDNA VISHNUMURTHY, STEAD LATHA, BIDARI SHARATHCHANDRA, PATEL AKHIL, GOTTIPATI AMARESHWARI, FAVILLA CHRISTOPHER G, SALARDINI ARASH, KHAKU AUNALI, MORA DIANA, PANDEY AJAY, PATEL HET, WATERS MICHAEL F. Posterior reversible encephalopathy syndrome (PRES) and CT perfusion changes. Array [online] 2012 December [viewed 26 June 2014] Available from: doi:10.1186/1865-1380-5-12
  27. BERG AT, SHINNAR S, HAUSER WA, ALEMANY M, SHAPIRO ED, SALOMON ME, CRAIN EF. A prospective study of recurrent febrile seizures. N Engl J Med [online] 1992 Oct 15, 327(16):1122-7 [viewed 26 June 2014] Available from: doi:10.1056/NEJM199210153271603
  28. SRINIVASAN J, WALLACE KA, SCHEFFER IE. Febrile seizures. Aust Fam Physician [online] 2005 Dec, 34(12):1021-5 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16333484
  29. GRAVES RC, OEHLER K, TINGLE LE. Febrile seizures: risks, evaluation, and prognosis. Am Fam Physician [online] 2012 Jan 15, 85(2):149-53 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22335215
  30. ESMAILI GOURABI H, BIDABADI E, CHERAGHALIPOUR F, AARABI Y, SALAMAT F. Febrile Seizure: Demographic Features and Causative Factors Iran J Child Neurol [online] 2012, 6(4):33-37 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943022
  31. ONOE SACHIKO, NISHIGAKI TOSHINORI. A clinical study of febrile myoclonus in children. Brain and Development [online] 2004 August, 26(5):321-325 [viewed 26 June 2014] Available from: doi:10.1016/j.braindev.2003.09.003
  32. LAI NM, TAN ML, QUAH SY, TAN EL, FOONG KW. Over-investigated and under-treated: children with febrile convulsion in a Malaysian district hospital. Singapore Med J [online] 2010 Sep, 51(9):724-9 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/20938614
  33. MOHAMMADI M. Febrile Seizures: Four Steps Algorithmic Clinical Approach Iran J Pediatr [online] 2010 Mar, 20(1):5-15 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445995

Investigations - for Diagnosis

Fact Explanation
Lumbar puncture Lumbar puncture should always be carefully assessed before performing since it's extremely necessary to exclude increased intracranial pressure. The anatomical skills should be practiced by the physician since it's a blind procedure. The cerebrospinal fluid analysis should be sent for routine investigations, and when in need, some specific investigations as mentioned next. [1] [2] [3] [4] [5] [6] [7] [8] [9] In difficult conditions, lumbar puncture can be performed under CT-guidance. [9]
Cerebrospinal fluid analysis The usual components of CSF full report should be assessed. As in all viral encephalitis, the expected findings are mildly to moderately elevated protein (60-80 mg/dL), normal glucose level and a moderate leucocytosis (up to 1000 leukocytes/µL). Mononuclear cells usually predominate, but in early stages polymorphonuclear leukocytes might predominate. [10] [11]
Antigen detection Cerebrospinal fluid is usually used. The commonly detected antigens are the viral nucleic acids, in polymerase chain reaction. (PCR) This offers the definitive diagnosis. [12] [13] [14] [15] [16] [17] [18]
Viral culture Viral cultures have been successfully performed in cerebrospinal fluid samples. [11] [14] [19] [20] [21]
References
  1. SINCLAIR GE. Lumbar Puncture Technique Can Med Assoc J [online] 1962 Apr 28, 86(17):789 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1849125
  2. SEMPERE AP, BERENGUER-RUIZ L, LEZCANO-RODAS M, MIRA-BERENGUER F, WAEZ M. [Lumbar puncture: its indications, contraindications, complications and technique]. Rev Neurol [online] 2007 Oct 1-15, 45(7):433-6 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17918111
  3. ROOS LK. Lumbar Puncture. Semin Neurol [online] 2003 December, 23(1):105-114 [viewed 27 June 2014] Available from: doi:10.1055/s-2003-40758
  4. MACDONALD RL, BERNSTEIN M. Emergency Lumbar Puncture in Adults Can Fam Physician [online] 1989 May:1183-1186 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2280348
  5. DUFFY GP. Lumbar Puncture in the Presence of Raised Intracranial Pressure Br Med J [online] 1969 Feb 15, 1(5641):407-409 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1981862
  6. DUFFY GP. Lumbar puncture in the presence of raised intracranial pressure. Br Med J [online] 1969 Feb 15, 1(5641):407-9 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/5763958
  7. FESSLER RD, SOBEL J, GUYOT L, CRANE L, VAZQUEZ J, SZUBA MJ, DIAZ FG. Management of elevated intracranial pressure in patients with Cryptococcal meningitis. J Acquir Immune Defic Syndr Hum Retrovirol [online] 1998 Feb 1, 17(2):137-42 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/9473014
  8. BOON J.M., ABRAHAMS P.H., MEIRING J.H., WELCH T.. Lumbar puncture: Anatomical review of a clinical skill. Clin. Anat. [online] December, 17(7):544-553 [viewed 27 June 2014] Available from: doi:10.1002/ca.10250
  9. DE CAMPO J, VILLANUEVA EV. Diagnostic Imaging Clinical Effectiveness fact sheet: Suspected meningitis - role of lumbar puncture and computed tomography. Australas Radiol [online] 2005 June, 49(3):252-253 [viewed 27 June 2014] Available from: doi:10.1111/j.1440-1673.2005.01450.x
  10. AGAMANOLIS DP. Neuropathology: Chapter 5; Infections of the Nervous System. [web] [viewed 27 June 2014] Available on http://neuropathology-web.org/chapter5/chapter5dViruses.html.
  11. CHAUDHURI A. Diagnosis and treatment of viral encephalitis. [online] 2002 October, 78(924):575-583 [viewed 27 June 2014] Available from: doi:10.1136/pmj.78.924.575
  12. STEININGER CHRISTOPH, POPOW‐KRAUPP THERESIA, LAFERL HERMANN, SEISER ANDREAS, GODL IRENE, DJAMSHIDIAN SCHIVA, PUCHHAMMER‐STOCKL ELISABETH. Acute Encephalopathy Associated with Influenza A Virus Infection. CLIN INFECT DIS [online] 2003 March, 36(5):567-574 [viewed 27 June 2014] Available from: doi:10.1086/367623
  13. FRANGE P., PEFFAULT DE LATOUR R., ARNAUD C., BODDAERT N., OUALHA M., AVETTAND-FENOEL V., BERNAUDIN F., AGUILAR C., BARNERIAS C., LERUEZ-VILLE M., TOUZOT F., LORTHOLARY O., FISCHER A., BLANCHE S.. Adenoviral Infection Presenting as an Isolated Central Nervous System Disease without Detectable Viremia in Two Children after Stem Cell Transplantation. Journal of Clinical Microbiology [online] December, 49(6):2361-2364 [viewed 27 June 2014] Available from: doi:10.1128/JCM.00080-11
  14. KIDD AH, JONSSON M, GARWICZ D, KAJON AE, WERMENBOL AG, VERWEIJ MW, DE JONG JC. Rapid subgenus identification of human adenovirus isolates by a general PCR. J Clin Microbiol [online] 1996 Mar, 34(3):622-627 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC228858
  15. KHETSURIANI N, TONG S, LU X, REED S, ERDMAN D, CAMPBELL A, SUPAWAT K, LIAMSUWAN S, JOTHIKUMAR N, OLSEN S. Systemic Infection with Enteric Adenovirus in Immunocompetent Child with Haemophilus influenzae Disease Emerg Infect Dis [online] 2009 Feb, 15(2):355-357 [viewed 27 June 2014] Available from: doi:10.3201/eid1502.081066
  16. READ SJ, JEFFERY KJ, BANGHAM CR. Aseptic meningitis and encephalitis: the role of PCR in the diagnostic laboratory. J Clin Microbiol [online] 1997 Mar, 35(3):691-696 [viewed 27 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC229652
  17. CHESKY MARISA, SCALCO ROSANA, FAILACE LUCIANE, READ STEVEN, JOBIM LUIZ FERNANDO. Polymerase chain reaction for the laboratory diagnosis of aseptic meningitis and encephalitis. Arq. Neuro-Psiquiatr. [online] 2000 September, 58(3B):836-842 [viewed 27 June 2014] Available from: doi:10.1590/S0004-282X2000000500008
  18. DEBIASI RL, TYLER KL. Molecular Methods for Diagnosis of Viral Encephalitis Clin Microbiol Rev [online] 2004 Oct, 17(4):903-925 [viewed 27 June 2014] Available from: doi:10.1128/CMR.17.4.903-925.2004
  19. CHATTERJEE N. K., SAMSONOFF W. A., BALASUBRAMANIAM N., WILSON K. R.-, SPARGO W., CHURCH T. M.. Isolation and Characterization of Adenovirus 5 from the Brain of an Infant with Fatal Cerebral Edema. Clinical Infectious Diseases [online] 2000 September, 31(3):830-833 [viewed 27 June 2014] Available from: doi:10.1086/314041
  20. STRAUSSBERG R., HAREL L., LEVY Y., AMIR J.. A Syndrome of Transient Encephalopathy Associated With Adenovirus Infection. PEDIATRICS [online] 2001 May, 107(5):e69-e69 [viewed 27 June 2014] Available from: doi:10.1542/peds.107.5.e69
  21. BERG A.-L., GAVIER-WIDEN D., NILSSON K., WIDEN F., BERG M., GREGORIUS S., AGREN E., ERLANDSSON M., MORNER T.. Necrotizing Encephalitis of Unknown Cause in Fennoscandian Arctic Foxes (Alopex Lagopus). Journal of Veterinary Diagnostic Investigation [online] 2007 January, 19(1):113-117 [viewed 27 June 2014] Available from: doi:10.1177/104063870701900121

Investigations - Fitness for Management

Fact Explanation
Complete blood count May show a lymphocytic leukocytosis or leukopenia, but unhelpful to arrive at a diagnosis. [1] [2] [3] [4] [5]
References
  1. Viral meningitis Paediatr Child Health [online] 1998, 3(6):433-436 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851312
  2. DEBIASI RL, TYLER KL. Molecular Methods for Diagnosis of Viral Encephalitis Clin Microbiol Rev [online] 2004 Oct, 17(4):903-925 [viewed 26 June 2014] Available from: doi:10.1128/CMR.17.4.903-925.2004
  3. CHADWICK D. R.. Viral meningitis. British Medical Bulletin [online] 2006 February, 75-76(1):1-14 [viewed 26 June 2014] Available from: doi:10.1093/bmb/ldh057
  4. CHADWICK D. R.. Viral meningitis. British Medical Bulletin [online] 2006 February, 75-76(1):1-14 [viewed 26 June 2014] Available from: doi:10.1093/bmb/ldh057
  5. KUMAR R, MATHUR A, KUMAR A, SETHI GD, SHARMA S, CHATURVEDI UC. Virological investigations of acute encephalopathy in India. Arch Dis Child [online] 1990 Nov, 65(11):1227-30 [viewed 26 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/2174227

Management - Specific Treatments

Fact Explanation
Antiviral therapy Cidofovir treatment has been proved beneficial in some cases. [1] [2] The other agents that are used are: ribavirin, ganciclovir, acyclovir, and vidarabine.
References
  1. FRANGE P., PEFFAULT DE LATOUR R., ARNAUD C., BODDAERT N., OUALHA M., AVETTAND-FENOEL V., BERNAUDIN F., AGUILAR C., BARNERIAS C., LERUEZ-VILLE M., TOUZOT F., LORTHOLARY O., FISCHER A., BLANCHE S.. Adenoviral Infection Presenting as an Isolated Central Nervous System Disease without Detectable Viremia in Two Children after Stem Cell Transplantation. Journal of Clinical Microbiology [online] December, 49(6):2361-2364 [viewed 27 June 2014] Available from: doi:10.1128/JCM.00080-11
  2. BORDIGONI P., CARRET A.-S., VENARD V., WITZ F., LE FAOU A.. Treatment of Adenovirus Infections in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation. Clinical Infectious Diseases [online] 2001 May, 32(9):1290-1297 [viewed 27 June 2014] Available from: doi:10.1086/319984