Meningitis

Question 1

Routes of Transmission

Answer 1

Microorganisms reach either by Aural, Pharyngeal,
Cranial injury, Congenital Meningeal Defect, or by Bloodstream; Immunosuppressed patients
at higher risk of atypical organisms
o If there is compromise to Subarachnoid space, likely recurrent Meningitis; Typically, due to Pneumococcus

Question 2

Non infective causes

Answer 2

Malignant Meningitis,

Intrathecal Drugs and SAH

Question 3

Acute Bacterial Meningitis

Answer 3

Leptomeninges congested with Polymorphonuclear cells; Purulent formation leads to formation of Adhesions which may cause CN palsies and Hydrocephalus; Cerebral
Oedema occurs in any bacterial meningitis

Question 4

Chronic Infections

Answer 4

(e.g. CNS TB) – Brain is covered in viscous grey-green Exudate with numerous Meningeal Tubercles; Adhesions always present

Question 5

Viral Meningitis

Answer 5

Predominantly Lymphocytic CSF reaction without Purulent formation,
Polymorphs or Adhesions; Little or no Cerebral
Oedema unless Encephalitis occurs

Question 6

Ddx of Acute Meningitis

Answer 6

Sudden onset headache might be like the one seen
in SAH and Migraine; Meningitis must be suspected
in anyone with Headache and Fever

Question 7

Ddx of Chronic Meningitis

Answer 7

Chronic Meningitis resembles Intracranial Mass

lesion (Headache, Epilepsy, Focal signs)

Question 8

Mimic of Bacterial Meningitis

Answer 8

Cerebral Malaria can mimic Bacterial Meningitis

Question 9

Presentation of Meningitis

Answer 9

• Triad of Headache, Neck Stiffness and Fever; Photophobia and Vomiting often present
• Patients irritable; Often prefers to lie still; Neck Stiffness and Positive Kernig’s sign (Pain on
Knee extension while Hip flexed and Calf parallel to ground) within hours

Question 10

Presentation of Less Severe Cases

Answer 10

(e.g. Viral causes) – Less prominent presentation; Consciousness remains
intact (uncomplicated), although fever might result in delirium; Viral Meningitis is usually benign, self-limiting lasting 4-10 days; Headache may follow for some months; No severe sequelae unless
Encephalitis occurs

Question 11

Which signs indicate complications

Answer 11

Progressive Drowsiness, Lateralising signs and CN
palsies indicates complications (e.g. Venous Sinus Thrombosis, Severe Cerebral Oedema,
Hydrocephalus) or differential diagnoses e.g. Cerebral Abscess, Encephalitis

Question 12

Presentation of Acute Bacterial Meningitis

Answer 12

Malaise, Fever, Rigors,
Severe Headache, Photophobia, vomiting which
evolves rapidly;

Question 13

Presentation of Meningococcal Meningitis

Answer 13

Petechial or other
rash, Acute Septicaemia shock can develop in any
Bacterial Meningitis

Question 14

How should meningococcal meningitis be managed?

Answer 14

Meningococcal Meningitis should be a clinical diagnosis based on presence of Petechial Rash; Immediate IV/IM antibiotics before blood cultures taken
o LP performed only for other causes of Meningitis if no mass lesion suspected
o CT scan (to ensure no raised ICP and hence low risk of Cerebellar Tonsillar
Herniation), INR might be appropriate before LP in some patients

Question 15

When to use dexamethasone

Answer 15

Dexamethasone is indicated for patients with Pneumococcal Meningitis before initial antibiotics for reduce Cerebral Oedema

Question 16

How to manage local infection?

Answer 16

Local infection (e.g. Paranasal Sinuses) must be treated surgically if necessary; Repair
of Skull Fracture and Dural tears

Question 17

What investigations should be done?

Answer 17

• CSF pressure is usually elevated; Blood taken for Cultures, Glucose, FBC; CXR/Head XR
o Gram staining, ZN staining (TB), Indian ink for Fungus
o Microbiology opinion important – Specific tests e.g. PCR, VDRL

Question 18

What follow up should be done?

Answer 18

Notification to Public Health Authorities; Advice for Immunisation and Prophylaxis of close
contacts (e.g. Rifampicin, Ciprofloxacin)
o MenC, Quadrivalent ACWY, MenB, Polyvalent Pneumococcus (PCV13 or PPV23), HiB

Question 19

Antibiotics in acute bacterial meningitis: Unknown pyogenic

Answer 19

Cefotaxime

alt. Benzylpenicillin

Question 20

Antibiotics in acute bacterial meningitis: Meningococcus

Answer 20

Benzylpenicillin

alt. Cefotaxime

Question 21

Antibiotics in acute bacterial meningitis: Pneumococcus

Answer 21

Cefotaxime

Alt. Penicillin

Question 22

Antibiotics in acute bacterial meningitis: Haemophilus

Answer 22

Cefotaxime

Alt. chloramphenicol

Question 23

Normal CSF Values

Answer 23

Crystal clear appearance
<5mm MN cells
Nil polymorph cells
0.2-0.4 Protein 
2/3-1/2 blood glucose

Question 24

Viral CSF Values

Answer 24

Clear/turbid 
MNC: 10-100
PMN: Nil
Protein: 0.4-0.8
Glucose: >0.5

Question 25

Pyogenic CSF Values

Answer 25

Turbid/purulent 
MNC: <50
PMC: 200-300
Protein: 0.5-2.0
Glucose: <0.5 glucose (low)

Question 26

Tuberculosis

Answer 26

Turbid/viscous
MNC: 100-300
PMC: 0-200
Low glucose

Question 27

Chronic Meningitis

Answer 27

TB and Cryptococcal Meningitis present as vague Headaches, Fatigue, Anorexia and Vomiting;

Question 28

Acute on Chronic Meningitis

Answer 28

unusual; Meningism takes week to develop

o Drowsiness, Focal signs (Diplopia, Papilloedema, Hemiparesis) and Seizures

Question 29

Other causes of chronic meningitis

Answer 29

Syphilis, Sarcoidosis and Behçet’s Disease can also cause Chronic Meningitis

Question 30

What is seen on MRI in chronic meningitis

Answer 30

Meningeal Enhancements, Hydrocephalus and Tuberculomas on MRI Head;

Question 31

Management of Chronic Meningitis

Answer 31

Treatment with
standard Antituberculosis drugs (except Ethambutol due to eye complications)
• Adjuvant Corticosteroids (Prednisolone) recommended
• Relapses and complications are common; Mortality >60% even with treatment