Meningitis

Question 1

Define:

Answer 1

Inflammation of the leptomenningeal (pia and arachnoid mater) coverings of the brain usually due to an infection.

Question 2

Why is there cerebral oedema and what are the consequences?

Answer 2

The immune reaction to the infection leads to cerebral oedema and a raised intracranial pressure.

This leads to:

• herniation
• Raised ICP + systemic hypotension reduces cerebral perfusion

Question 3

Bacterial causes in neonates:

Answer 3

Group B streptoccoci
E.coli
Listeria Monocytogens

Question 4

Bacterial causes in children:

Answer 4

Strep Pneumoniae
Neisseria meningitidis
Hemophalous influenzae

Question 5

Bacterial causes in adults:

Answer 5

Neisseria meningitidis
Strep pneumoniae
TB

Question 6

Bacterial causes in the elderly:

Answer 6

Listeria monocytogens

Strep pneumoniae

Question 7

Viral causes:

Answer 7

HIV
Herpes simplex virus 
Varicella Zoster virus 
Mumps 
Enteroviruses

Question 8

Fungal causes:

Answer 8

cryptococcus (associated with HIV meningitis)

Question 9

Other causes:

Answer 9

o Aseptic meningitis (not due to microbes)

o Mollaret’s meningitis (recurrent benign lymphocytic meningitis

Question 10

Risk factors:

Answer 10

Sickle cell anaemia 
Alcoholism 
Close communities (university halls)
Splenectomy 
Ear infections 
For bacterial <5 and greater than 60
Mastoiditis 
Sinusitis 
Immunodeficiency 
Intracranial surgery

Question 11

Epidemiology:

Answer 11

2500 cases reported in the UK a year

More common in the elderly or 15-30 year olds

Question 12

Symptoms:

Answer 12

Severe headache
Neck stiffness 
Photo/phonophobia 
Leg pain 
Cold hands and feet 
Abnormal skin 
Fever
Irritability/ altered mental state 
Reduced consciousness
Vomiting 
Petechical rash - non-blanching (glass test the rash will stay)
Children - high pitched cry, fits and hypothermia

Question 13

Signs:

Answer 13

Pyrexia 
Tachycardia 
Hypotension 
Neck stiffness 
Photophobia 
Skin rash 
Altered mental state

Kernig’s sign - the knee is flexed to 90 degrees when it is further flexed there is back pain

Brudzinski’s Sign - flexion of the hips when the neck is flexed

Question 14

Investigations:

Answer 14

Bloods - FBC, U+Es, glucose, LFTs and coagulation

Blood cultures, throat and rectal swabs

CT scan to exclude a lesion or raised ICP

THEN LP - if the GCS is above 15 and no signs of raised ICP then straight to LP

CSF is sent for MC&S, gram stain, glucose, protein, virology and lactate.

CXR to check for TB (bilateral hilar lymphadenopathy)

Question 15

What would you find if the CSF indicated a bacterial meningitis:

Answer 15

• Cloudy CSF
• High neutrophils
• High protein
• Low glucose

Question 16

What would you find if the CSF indicated a viral meningitis:

Answer 16

• Clear CSF
• High lymphocytes
• High protein
• Normal glucose

Question 17

What would you find if the CSF indicated fungal meningitis:

Answer 17

• Fibrinous CSF
• High lymphocytes
• High protein
• Low glucose

Question 18

Management:

Answer 18

Before LP IV antibiotics straight away:
Cephalosporin (1st line e.g..g. cefotaxime or ceftriaxone)
If >55 yrs give ampicillin too (for the listeria)
Blind: GIVE IM BENZYLPENICILLIN IF IN GP. If allergic to this: ceftriaxone

Then give Iv Dexamethasone (reduces risks of complications)

Then LP if there is no signs of raised ICP

• Resuscitation
o Manage in ITU
o Notify public health services

Question 19

Complications:

Answer 19

DIC
Shock
Sepsis
Renal failure
Cerebral oedema 
Cranial nerve lesions
Seizures 
Peripheral gangrene
Hydrocephalous 
Waterhouse-Friderichsen Syndrome (bilateral adrenal haemorrhage caused by severe meningococcal infection)
Cerebral venous thrombosis

Question 20

Prognosis:

Answer 20

Bacterial = 10-40% mortality if associated with sepsis

Viral is self-limiting