1. Aseptic Meningitis Assistant Prof./ Tamer Ata
MD, PhD MEDICAL MICRIBIOLIOGY AND IMMUNOLOGY
FACULTY OF MEDICINE
AL-MAAREFA COLLEGES

2. CSF analysis in different types of meningitis
Bact. Meningitis
Viral Meningitis
Fungal Meningitis
Tuberculous Meningitis
WBCs
> 1000 cmm
< 1000 cmm
Variable
Predominant differential cell
PMN
Lymphocyte
Protein
↑↑↑
Normal or ↑ ↑
Glucose
(better CSF / serum ratio) ↓
Normal

3. Viral meningitis
Viral meningitis is the most common type of meningitis.
It is often less severe than bacterial meningitis.
Most people usually cure without treatment.
Viruses that can cause meningitis spread in different way.
People at Risk
Infant < 1 month & children < 5 years old,
immunocompromised by diseases, medications (such as chemotherapy), and recent organ or bone marrow transplantations

4. Causes of viral meningitis
DNA viruses
RNA viruses
Herpes viruses (contact & droplet)
HSV
VZV
Polio-enteroviruses
Non polio-enteroviruses (food born) → the commonest
# Coxsackie
#ECHO
Measles and Mumps (contact & droplet)
Influenza (droplet & contact)
ArBo viruses (insect bite mainly mosquito as West Nile virus)
Lymphocytic choriomeningitis virus (Rodent born)

5. Diagnosis of viral meningitis
Clinically viral meningitis are similar to those for septic meningitis. However, bacterial meningitis is usually severe and can cause serious complications
Diagnosis
specimens → CSF (clear & mild ↑ protein & normal glucose & lymphocyte), naso-oropharyngeal swabs, rectal swabs, stool, blood → detect viral particle by EM or nucleic acid by PCR
Serological : detect specific antibodies
in patient serum especially IgM

6. Treatment
Infants and immunocompromised patients with severe illness may need to be hospitalized.
Most people who get viral meningitis completely recover within 7 to 10 days.
Meningitis caused by certain viruses can be treated:
Herpesvirus (HSV-1 & VZV) → acyclovir antiviral drug
influenza, → amantadine and oseltamivir (tamiflue).

7. Prevention
no vaccines to protect against non-polio enteroviruses, which are the most common cause of viral meningitis.
Available vaccines for other viruses as MMR, varicella, polio (Sabine & Salk) and influenza vaccines.
General precautions as hand hygiene, patient respiratory isolation, use PPE as Mask, disinfection of surfaces.

8. Fungal meningitis
Spores of fungi in the soil (Cryptococcus in excreta of pigeon).
Transmitted by inhalation → pulmonary lesion → fungemia → CNS
Not contagious i.e. no human to human transmission
Causative agents:
Opportunistic (immuno-comprommised)
Endemic in USA & America (soil)
Cryptococcus neoformans
(one of the most common causes of adult meningitis in Africa)
Blastomyces
Histoplasma

9. Fungal meningitis High risk group Immunocompromised as
HIV , organ transplantation, or anti-TNF medications (for treatment of rheumatoid arthritis) patients.
Oncology patients with neutropenia or bone marrow inhibition.
Long term steroid therapy
Clinically: similar with bacterial meningitis but tend to be subacute to chronic in the course

10. Diagnosis of Cryptococcus
Sample: CSF
Direct microscopic examination by India ink stain: capsulated yeast
Culture: on Sabouraud’s dextrose agar → creamy mucoid colonies → biochemical reaction = urease positive.
Serological: direct detection of capsule antigen in CSF using latex agglutination test.

12. Treatment Amphotricin B parenteral
Fluconazole (water soluble and cross BBB) parenteral

13. Tuberculous meningitis
Mycobacterium tuberculosis spread in the blood from any site (pulmonary) to reach CNS and meninges → small tubercles on meninges → rupture into CSF.
Most cases are adult
Diagnosis of TB meningitis is more difficult than bacterial meningitis (no classic C/P).
Chronic course, 1st vague, non-specific symptoms of headache, low-grade fever, irritable, insomnia and gradually worsening headache.   → obvious symptoms of meningitis.

14. Diagnosis of T. meningitis
Sample: CSF …….
Direct smear stained by Z-N stain: acid fast bacilli
Culture: on Lowenstein-Jenssen Media or Dorset egg media (2 weeks-2months)
-- Bac-Tec radiometry culture → early detection within 9 days
PCR: rapidly detect TB nucleic acid in CSF.

16. Parasitic meningitis (1ry amoebic meningoencephalitis)
Cause: Naegleria fowleri
Epidemiology: a very rare fatal form of parasitic meningitis (death within 2 weeks)
Not contagious (no human to human transmission)
Risk Factors
found in warm freshwater as lakes and rivers.
Geothermal (naturally hot) water, such as hot springs
Swimming pools that are poorly maintained, minimally-chlorinated, and/or un-chlorinated
Water heaters.  can survive for short periods at higher temperatures (46°C).

17. 1ry amoebic meningoencephalitis
Transmission
swimming or diving in warm freshwater places, like lakes and rivers.
Pathogenesis :
entering the body through the nose
→ travels olfactory nerve →
Subarachnoid space (Meningitis)
→ the brain →
destroy the brain tissue.

18. 1ry amoebic meningoencephalitis
Clinically:
In its early stages, may be similar to of bacterial meningitis 1 to 7 days after infection
headache, fever, nausea, vomiting, stiff neck and disturbance in smell.
Later, confusion, loss of balance, seizures, and hallucinations.
the disease progresses rapidly and usually causes death (within 12 days or 2 weeks).

19. 1ry amoebic meningoencephalitis
Diagnosis:
Direct smear: motile amoeba in CSF
Antigen detection: in CSF by IF or IHC
PCR: detect nucleic acid in CSF
Culture: non nutrient agar media covered with E. coli (food source)
Treatment: amphotricin B or
miltefosine

20. Other parasites with CNS infection in immunocompromised patients
Acanthamoeba (in water and soil):
Involve the eyes (contact lens use)
skin wounds or cuts
inhaled into the lungs
2. Toxoplasma in late stage of HIV patients