Meningitis

Question 1

What is meningitis?

Answer 1

Meningitis is infection of the meninges.

Pathogens reach the meninges either by direct extension from the ears, nasopharynx, cranial injury or congenital meningeal defect

OR

Via bloodstream spread.

Question 2

What are the infective causes meningitis?

Answer 2

Infective cause

1. Bacteria : 
=> Neisseria meningitides (meningococcus) 
=> Streptococcus pneumoniae (pneumococcus)
=> Listeria monocytogenes
=> Staph. aureus
=> Streptococcus group B
=> Mycobacterium tuberculosis
=> Gram -ve bacilli e.g. E.coli

2. Viruses:
=> Enterovirus i.e. Coxsackie 
=> Mumps
=> Herpes simplex
=> HIV
=> Epstein-Barr virus

3. Fungi
   => Cryptococcus neoformans
   => Candida albican

Question 3

What are the non-infective causes of meningitis?

Answer 3

Malignant meningitis

Intrathecal drugs

Blood from subarachnoid haemorrhage

Question 4

Prompt action saves lives!

What should you do in a case of suspected meningitis in primary care?

Answer 4

Urgent transfer to secondary care

If non-blanching rash present, give benzylpenicilin 1.2g IM/IV before admitting

Question 5

What are the early signs of meningitis?

Answer 5

Headache

Fever

Leg pains

Cold hands & feet

Abnormal skin colour

Question 6

What are the later signs of meningitis?

Answer 6

Meningism triad:
=> Neck stiffness
=> Headache
=> Fever / rigors

=> Photophobia

=> Vomiting

=> Kernig’s sign - pain and resistance on passive knee extension with hip flexed

=> Non-blanching petechial rash

=> Low GCS / coma

=> Seizures ± focal CNS signs

=> Shock, prolonged cap refill, hypotension, disseminated intravascular coagulation (DIC)

Question 7

What is the clinical picture in acute bacterial meningitis?

Answer 7

Sudden onset with intense malaise, fever, rigors, severe headache, photophobia, vomiting => within hours or minutes

Patient is irritable and prefers to lie still, neck stiffness and a +ve Kernig’s sign => within hours

Petechial rash associated with meningococcal septicaemia

Acute septicaemic shock may develop in bacterial meningitis

Question 8

What is the clinical picture in viral meningitis?

Answer 8

Viral meningitis is less severe ; fewer obvious signs/ symptoms

Benign ; self limiting

Lasts 4-10 days

Question 9

What are the differential diagnosis for meningitis?

Answer 9

Subarachnoid haemorrhage

Encephalitis

Septicaemia

Malaria

Dengue

Tetanus

=> Difficult to differentiate between the sudden headache of meningitis and subarachnoid haemorrhage

=> Meningitis always considered in anyone with fever, sudden headache ± neck stiffness

=> Chronic meningitis can resemble intracranial mass lesions with headache, epilepsy and focal signs

=> Cerebral malaria can mimic bacterial meningitis

Question 10

How do you manage suspected meningitis without shock?

Answer 10

Intravenous infusion, fluid resus. Check & correct blood glucose

=> Take blood cultures

If signs of high intracranial pressure/shift of brain i.e. papilloedema, uncontrolled seizures, focal neurology, GCS <12 present

=> Get ICU help
=> IV antibiotics 
=> Dexamethasone 10mg IV
=> Airway support
=> Fluid resus
=> Delay lumbar puncture till stable 

If above signs not present

=> Get senior help
=> Perform lumbar puncture <1h
=> IV antibiotics
=> Dexamethasone 10mg IV

Question 11

How do you manage suspected septicaemia e.g. shock, prolonged cap refill, cold hands & feet, hypotension, evolving rash?

Answer 11

Get ICU help

=> Blood cultures
=> IV antibiotics
=> Airway support
=> Fluid resus
=> Delay lumbar puncture until stable

Question 12

Careful monitoring is needed once patient stable

Antibiotic therapy based on organism and sensitivity

Maintain normovolaemia with IV infusions

Isolate for first 24h - inform public health

Answer 12

INFO CARD

Question 13

What investigations should be carried out?

Answer 13

Blood cultures first

Then lumbar puncture prior to antibiotics:

=> Only in patients with no evidence of shock, petechial rash or raised intracranial pressure

=> Where possible to obtain lumbar puncture <1h

Bloods: 
U&E, 
FBC (low WCC in immunocompromised - get help), 
LFT, 
Glucose, 
Coagulation 

Throat swab - 1 for bacteria ; 1 for virus

Chest X-ray

HIV / TB tests if suspected

Question 14

How do you treat meningitis?

Answer 14

Initiate antibiotics early

Features of meningitis present => dexamethasone 10mg IV

Question 15

What prophylaxis is available for meningitis?

Answer 15

Meningococcal infection has to be notified to Public Health
=> advice for immunisation and prophylaxis antibiotics of contacts

=> MenC vaccine is given in the UK

=> Meningococcal B vaccine for infants and in outbreaks

=> Combined meningococcal A & B vaccines used prior to travel

=> Pneumococcal conjugated vaccine given to infants in many countries

=> Pneumococcal polysaccharides vaccine offered to older adults or people with immunodeficiency

=> HiB (haemophilus influenza) vaccine given in childhood in UK => removed common cause of fatal meningitis

Question 16

What is the most common cause of meningitis in the UK?

Answer 16

Meningococcal

Question 17

What causes chronic meningitis?

Answer 17

Tuberculosis meningitis and cryptococcal meningitis

=> start with vague headache, anorexia, vomiting
=> meningitis signs take weeks to develop
=> Drowsiness, focal signs e.g. diplopia, papilloedema, hemiparesis, and seizures are common

Question 18

What are the investigations and treatment for chronic meningitis caused by TB?

Answer 18

Tuberculosis meningitis:

=> Brain imaging i.e. MRI - meningitis, hydrocephalus and tuberculomas

=> Repeated CSF exam necessary

=> Anti-tb drugs i.e. rifampicin, isoniazid

Question 19

What is malignant meningitis?

Answer 19

Malignant cells can cause subacute or chronic, non-infective meningitis

=> meningitis symptoms, cranial nerve lesions, paraparesis and root lesions common