Bacterial meningitis differential diagnosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S[2]


The differential diagnosis of bacterial meningitis includes two step approach. First is differentiating bacterial meningitis from other diseases which have similar clinical presentation as bacterial meningitis such as encephalitis, brain abscess, subarachnoid hemorrage, and brain tumour. Second step involves CSF examination and differentiating bacterial meningitis from viral, fungal and other causes of meningitis.[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]

Differential diagnosis

Bacterial meningitis may mimick other diseases in terms of clinical signs and symptoms. It is important to differentiate meningitis from other diseases with similar presentation. Once the diagnsis of meningitis is confirmed, the next step may be to differentiate different types of meningitis on the basis of CSF examnination:[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]

Differentiating bacterial meningitis from other diseases

Diseases Diagnostic tests Physical Examination Symptoms Past medical history Other Findings
Na+, K+, Ca2+ CT /MRI CSF Findings Gold standard test Neck stiffness Motor or Sensory deficit Papilledema Bulging fontanelle Cranial nerves Headache Fever Altered mental status
Brain tumour[2][3] Cancer cells[4] MRI Cachexia, gradual progression of symptoms
Delerium Tremens Clinical diagnosis Alcohal intake, sudden witdrawl or reduction in consumption Tachycardia, diaphoresis, hypertension, tremors, mydriasis, positional nystagmus, tachypnea
Subarachnoid hemorrhage[17] Xanthochromia[5] CT scan without contrast[7][8] Trauma/fall Confusion, dizziness, nausea, vomiting
Stroke Normal CT scan without contrast TIAs, hypertension, diabetes mellitus Speech difficulty, gait abnormality
Neurosyphilis[18][19] Leukocytes and protein CSF VDRL-specifc

CSF FTA-Ab -sensitive[20]

Unprotected sexual intercourse, STIs Blindness, confusion, depression,

Abnormal gait

Viral encephalitis Increased RBCS or xanthochromia, mononuclear lymphocytosis, high protein content, normal glucose Clinical assesment Tick bite/mosquito bite/ viral prodome for several days Extreme lethargy, rash hepatosplenomegaly, lymphadenopathy, behavioural changes
Herpes simplex encephalitis Clinical assesment History of hypertension Delirium, cortical blindness, cerebral edema, seizure
Wernicke’s encephalopathy Normal History of alcohal abuse Ophthalmoplegia, confusion
CNS abscess leukocytes >100,000/ul, glucose and protien, red blood cells, lactic acid >500mg Contrast enhanced MRI is more sensitive and specific,

Histopathological examination of brain tissue

History of drug abuse, endocarditis, immune status High grade fever, fatigue,nausea, vomiting
Drug toxicity Lithium, Sedatives, phenytoin, carbamazepine
Conversion disorder Diagnosis of exclusion Tremors, blindness, difficulty swallowing
Electrolyte disturbance or Depends on the cause Confusion, seizures
Febrile seizures Not performed in first simple febrile seizures Clinical diagnosis and EEG Family history of febrile seizures, viral illness or gastroenteritis Age > 1 month,
Subdural empyema Clinical assesment and MRI History of relapses and remissions Blurry vision, urinary incontinence, fatigue
Hypoglycemia ↓ or Serum blood glucose


History of diabetes Palpitations, sweating, dizziness, low serum, glucose

Differentiating bacterial meningitis from other causes of meningitis

Bacterial meningitis may be differntiated from other causes of meningitis by cerebrospinal fluid examination:[21][22][23][24][25]

Cerebrospinal fluid level Normal level Bacterial meningitis[24] Viral meningitis[24] Fungal meningitis Tuberculous meningitis[26] Malignant meningitis[21]
Cells/ul < 5 >300 10-1000 10-500 50-500 >4
Cells Lymphos:Monos 7:3 Gran. > Lymph Lymph. > Gran. Lympho.>Gran Lymphocytes Lymphocytes
Total protein (mg/dl) 45-60 Typically 100-500 Normal or slightly high High Typically 100-200 >50
Glucose ratio (CSF/plasma)[22] > 0.5 < 0.3 > 0.6 <0.3 < 0.5 <0.5
Lactate (mmols/l)[23] < 2.1 > 2.1 < 2.1 >3.2 > 2.1 >2.1
Others ICP:6-12 (cm H2O) CSF gram stain, CSF culture, CSF bacterial antigen PCR of HSV-DNA, VZV CSF gram stain, CSF india ink PCR of TBC-DNA CSF tumour markers such as alpha fetoproteins, CEA


  1. 1.0 1.1 Stern TA, Celano CM, Gross AF, Huffman JC, Freudenreich O, Kontos N; et al. (2010). "The assessment and management of agitation and delirium in the general hospital". Prim Care Companion J Clin Psychiatry. 12 (1): PCC.09r00938. doi:10.4088/PCC.09r00938yel. PMC 2882819. PMID 20582303.
  2. 2.0 2.1 2.2 Soffer D (1976) Brain tumors simulating purulent meningitis. Eur Neurol 14 (3):192-7. PMID: 1278192
  3. 3.0 3.1 3.2 Terheggen HG (1985) [CNS tumors with the clinical picture of meningitis.] Monatsschr Kinderheilkd 133 (1):13-9. PMID: 3883130
  4. 4.0 4.1 4.2 Weston CL, Glantz MJ, Connor JR (2011). "Detection of cancer cells in the cerebrospinal fluid: current methods and future directions". Fluids Barriers CNS. 8 (1): 14. doi:10.1186/2045-8118-8-14. PMC 3059292. PMID 21371327.
  5. 5.0 5.1 5.2 Lee MC, Heaney LM, Jacobson RL, Klassen AC (1975). "Cerebrospinal fluid in cerebral hemorrhage and infarction". Stroke. 6 (6): 638–41. PMID 1198628.
  6. 6.0 6.1 Han JH, Wilber ST (2013). "Altered mental status in older patients in the emergency department". Clin Geriatr Med. 29 (1): 101–36. doi:10.1016/j.cger.2012.09.005. PMC 3614410. PMID 23177603.
  7. 7.0 7.1 7.2 Birenbaum D, Bancroft LW, Felsberg GJ (2011). "Imaging in acute stroke". West J Emerg Med. 12 (1): 67–76. PMC 3088377. PMID 21694755.
  8. 8.0 8.1 8.2 DeLaPaz RL, Wippold FJ, Cornelius RS, Amin-Hanjani S, Angtuaco EJ, Broderick DF; et al. (2011). "ACR Appropriateness Criteria® on cerebrovascular disease". J Am Coll Radiol. 8 (8): 532–8. doi:10.1016/j.jacr.2011.05.010. PMID 21807345.
  9. 9.0 9.1 Stein MT, Trauner D (1982). "The child with a stiff neck". Clin Pediatr (Phila). 21 (9): 559–63. PMID 7105615.
  10. 10.0 10.1 De Cauwer HG, Eykens L, Hellinckx J, Mortelmans LJ (2007). "Differential diagnosis between viral and bacterial meningitis in children". Eur J Emerg Med. 14 (6): 343–7. doi:10.1097/MEJ.0b013e328270366b. PMID 17968200.
  11. 11.0 11.1 Spanos A, Harrell FE, Durack DT (1989). "Differential diagnosis of acute meningitis. An analysis of the predictive value of initial observations". JAMA. 262 (19): 2700–7. PMID 2810603.
  12. 12.0 12.1 Lindquist L, Linné T, Hansson LO, Kalin M, Axelsson G (1988). "Value of cerebrospinal fluid analysis in the differential diagnosis of meningitis: a study in 710 patients with suspected central nervous system infection". Eur J Clin Microbiol Infect Dis. 7 (3): 374–80. PMID 3137038.
  13. 13.0 13.1 Naganuma M, Fujioka S, Inatomi Y, Yonehara T, Hashimoto Y, Hirano T; et al. (2008). "Clinical characteristics of subarachnoid hemorrhage with or without headache". J Stroke Cerebrovasc Dis. 17 (6): 334–9. doi:10.1016/j.jstrokecerebrovasdis.2008.04.009. PMID 18984423.
  14. 14.0 14.1 Rajnik M, Ottolini MG (2000). "Serious infections of the central nervous system: encephalitis, meningitis, and brain abscess". Adolesc Med. 11 (2): 401–25. PMID 10916131.
  15. 15.0 15.1 Tyler KL (2004). "Herpes simplex virus infections of the central nervous system: encephalitis and meningitis, including Mollaret's". Herpes. 11 Suppl 2: 57A–64A. PMID 15319091.
  16. 16.0 16.1 Kennedy PG (2004). "Viral encephalitis: causes, differential diagnosis, and management". J Neurol Neurosurg Psychiatry. 75 Suppl 1: i10–5. PMC 1765650. PMID 14978145.
  17. Yeh ST, Lee WJ, Lin HJ, Chen CY, Te AL, Lin HJ (2003) Nonaneurysmal subarachnoid hemorrhage secondary to tuberculous meningitis: report of two cases. J Emerg Med 25 (3):265-70. PMID: 14585453
  18. Liu LL, Zheng WH, Tong ML, Liu GL, Zhang HL, Fu ZG; et al. (2012). "Ischemic stroke as a primary symptom of neurosyphilis among HIV-negative emergency patients". J Neurol Sci. 317 (1–2): 35–9. doi:10.1016/j.jns.2012.03.003. PMID 22482824.
  19. Berger JR, Dean D (2014). "Neurosyphilis". Handb Clin Neurol. 121: 1461–72. doi:10.1016/B978-0-7020-4088-7.00098-5. PMID 24365430.
  20. Ho EL, Marra CM (2012). "Treponemal tests for neurosyphilis--less accurate than what we thought?". Sex Transm Dis. 39 (4): 298–9. doi:10.1097/OLQ.0b013e31824ee574. PMC 3746559. PMID 22421697.
  21. 21.0 21.1 Le Rhun E, Taillibert S, Chamberlain MC (2013). "Carcinomatous meningitis: Leptomeningeal metastases in solid tumors". Surg Neurol Int. 4 (Suppl 4): S265–88. doi:10.4103/2152-7806.111304. PMC 3656567. PMID 23717798.
  22. 22.0 22.1 Chow E, Troy SB (2014). "The differential diagnosis of hypoglycorrhachia in adult patients". Am J Med Sci. 348 (3): 186–90. doi:10.1097/MAJ.0000000000000217. PMC 4065645. PMID 24326618.
  23. 23.0 23.1 Leen WG, Willemsen MA, Wevers RA, Verbeek MM (2012). "Cerebrospinal fluid glucose and lactate: age-specific reference values and implications for clinical practice". PLoS One. 7 (8): e42745. doi:10.1371/journal.pone.0042745. PMC 3412827. PMID 22880096.
  24. 24.0 24.1 24.2 Negrini B, Kelleher KJ, Wald ER (2000). "Cerebrospinal fluid findings in aseptic versus bacterial meningitis". Pediatrics. 105 (2): 316–9. PMID 10654948.
  25. Brouwer MC, Tunkel AR, van de Beek D (2010). "Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis". Clin Microbiol Rev. 23 (3): 467–92. doi:10.1128/CMR.00070-09. PMC 2901656. PMID 20610819.
  26. Caudie C, Tholance Y, Quadrio I, Peysson S (2010). "[Contribution of CSF analysis to diagnosis and follow-up of tuberculous meningitis]". Ann Biol Clin (Paris). 68 (1): 107–11. doi:10.1684/abc.2010.0407. PMID 20146981.

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