Differential diagnosis of meningitis involves distinguishing between various causes of inflammation of the meninges, the protective membranes surrounding the brain and spinal cord. Here's a brief overview:
1. Bacterial meningitis:
- Caused by bacterial pathogens such as Streptococcus pneumoniae, Neisseria meningitidis, or Haemophilus influenzae type b.
- Symptoms include sudden onset of fever, severe headache, stiff neck (nuchal rigidity), altered mental status, photophobia (sensitivity to light), and nausea/vomiting.
- Diagnosis is confirmed by cerebrospinal fluid (CSF) analysis, which typically shows elevated white blood cell count, elevated protein levels, and decreased glucose levels.
- Prompt treatment with antibiotics is essential to prevent serious complications and reduce mortality.
2. Viral meningitis (aseptic meningitis):
- Caused by various viruses, including enteroviruses (most common), herpesviruses, and others.
- Symptoms are similar to bacterial meningitis but tend to be less severe.
- CSF analysis typically shows lymphocytic pleocytosis (elevated lymphocytes), normal glucose levels, and mildly elevated protein levels.
- Treatment is supportive, as viral meningitis is usually self-limiting and resolves on its own.
3. Tuberculous meningitis:
- Caused by Mycobacterium tuberculosis, typically affecting individuals with underlying tuberculosis infection.
- Symptoms include subacute onset of fever, headache, altered mental status, and focal neurological deficits.
- CSF analysis may show lymphocytic pleocytosis, elevated protein levels, and decreased glucose levels, although findings can be variable.
- Treatment involves prolonged courses of antituberculous medications.
4. Fungal meningitis:
- Caused by fungal pathogens such as Cryptococcus neoformans, Histoplasma capsulatum, or Candida species.
- Symptoms are similar to bacterial meningitis but may develop more insidiously.
- CSF analysis may show lymphocytic pleocytosis, elevated protein levels, and decreased glucose levels.
- Treatment involves antifungal medications, often requiring prolonged courses.
5. Non-infectious causes:
- Meningitis-like symptoms can also be caused by non-infectious etiologies such as autoimmune conditions (e.g., lupus, vasculitis), drug reactions, or malignancies.
- Diagnosis requires careful clinical evaluation, including a detailed medical history, physical examination, and appropriate laboratory and imaging studies.
2. Introduction
Meningitis is the inflammation of the meninges ( membranes surrounding the
CNS) , more specifically the leptomeninges ( subarachnoid and piameter )
4. Serous V/S Purulent Meningitis
PURULENT MENINGITIS
( aka pyogenic
meningitis ) is the
inflammation of
leptomeninges caused
by a bacterial infection,
leading to a more
severe, and potentially
life threatening
condition.
SEROUS MENINGITIS ( aka
aseptic meningitis ) refers
to inflammation of the
meninges that is typically
caused by viruses ( can be
fungal, protozoal ). It usually
presents with mild
symptoms and has a better
prognosis as compared to
purulent meningitis.
5. PURULENT MENINGITIS
Streptococcus pneumoniae,
Neisseria meningitis, Hemophilus
influenza, Group B streptococcus,
Listeria monocytogenes,
Staphylococcus aureus, Klebsiella,
Pseudomonas, E coli,
Mycobacterium tuberculosis,
Diphtheroids, Propionibacterium
acnes, Serratia marcescens,
Salmonella species, Brucella ,
Francisella tularensis,
Streptococcus suis, Ehrlichia
chaffeensis
SEROUS MENINGITIS
Enterovirus, HSV 1 & 2, Arbovirus,
Influenza virus, Herpes
zoster,Human Herpes Virus 6,
Epstein barr virus (EBV),
Lymphocytic choriomeningitis virus,
Mumps, Cytomegalo virus (CMV),
Human immunodeficiency virus
(HIV), West nile virus, Human T cell
lymphotrophic virus I and II,
Varicella zoster virus, SARS-CoV-2
virus (corona virus).
6. SYMPTOMS
CLASSIC TRIAD - Fever, headache, nuchal rigidity.
Photophobia
Phonophobia
Irritability
Altered mental status & Seizures ( in meningoencephalitis )
Symptoms are almost similar in both which could be mild
in serous and severe in purulent meningitis.
7. Physical examination
It include bradycardia, disorientation, pappilledema,
neck stiffness, positive kernig’s and brudzinski’s sign.
In children, petechial
rash, bulging
fontanelle, jaundice
and convulsions can
also be seen.
10. SEROUS MENINGITIS
Cells >10-1000
Color- clear or slightly cloudy
Lymphocyte > Leukocytes
Protein- Normal or slightly high
Glucose ratio > 0.6
PCR of viral RNA, HSV-DNA, VZV.
PURULENT MENINGITIS
Cells >300
Color- presence of pus, cloudy
Lymphocyte < Leukocytes
Protein- typically 100- 500
Glucose ratio < 0.3
CSF gram stain, culture, bacterial
antigen.
Other methods: electroencephalogram (allows you to clarify the presence of structural changes in the
brain by its bioelectric activity); computed tomography, which allows to detect with encephalitis a
decrease in the density of brain tissue (foci of low density without clear boundaries), with tumors foci of
uneven density; with an abscess of the brain the formation of a round shape with a zone of low density
inside, but with a high density of the contours of the capsule; nuclear magnetic resonance imaging.
11. SEROUS MENINGITIS
Antiherpetic (nucleoside analogues acyclovir, valaciclovir,
pencyclovir, phamcyclovir);
anticytomegalovirus (gancyclovir, phospharnet, cidophavir);
anti-influenza (Ozeltamivir, Zanamivir, Amanthadin, Remathaddin).
The disadvantage of antiherpetic drugs is the lack of effect on latent
viruses.
Treatment
12. PURULENT MENINGITIS
Broad-spectrum antibiotics: ampicillin, carbepicillins, cephalosporins,
aminoglycosides, chloramphenicol, tetracycline, macrolides,
carbapenems.
Drugs acting on gram-positive bacteria and cocci: oxacillin,
vancomycin, fusidine, etc.
Antibiotics active against gram-negative bacteria: polymyxins.
Tuberculosis antibiotics: streptomycin, rifampicin, florimycin.
Treatment
13. IV Lasix 40mg ( not faster than 1-2 min)
Mannitol solution ( 10%, 15%, 20%) at rate of 1g/kg IV for 60 min.
In severe cases, Glucocorticoids ( prednisone, hydrocortisone,
dexamethasone) in small dose. Eg. 1-2mg / kg prednisone.
Oxygen in required.
Drugs to improve micro circulation - pentoxifylline ( 100mg in 250ml
saline IV , drip over 90 - 180min.
Drugs to normalise brain tissue metabolism - piracetam ( 2 capsules,
thrice a day for 6 wks ), nootropil , cerebrolysin ( 40mg-1ml IM )
OTHER in rehabilitation at 4th-5th week - adaptogenic drugs eg,
Eleutherococcus 30 drops twice for 3 weeks.
Treatment
