Meningococcal Disease

Question 1

What is the causative agent?

Answer 1

Neisseria meningitidis (serogroup A, B, C, W135, Y). Most infections are due to serogroup B.

Question 2

What is the incubation period?

Answer 2

4 days (range 2 to 10 days)

Question 3

How is it transmitted?

Answer 3

Respiratory droplets and direct salivary contact with an infected person.

Human upper respiratory tract is the main reservoir of carriage and site of meningococcal dissemination

Question 4

What is the clinical features?

Answer 4

Three main forms of the disease:

1) Meningeal syndrome - presents with stiff neck, high fever, sensitivity to light, confusion, headaches and vomiting.
2) Septic form - is less common but a more severe (often fatal) form of meningococcal disease, which is characterized by a haemorrhagic rash and rapid circulatory collapse
3) Pneumonia

The onset of symptoms is sudden and death can follow within hours. In as many as 10-15% of survivors, there are persistent neurological defects, including hearing loss, speech disorders, mental retardation and paralysis.

Question 5

What are the investigations required for meningococcal disease?

Answer 5

• Lumbar puncture shows a purulent spinal fluid
• Gram stain and culture from CSF and blood.
• PCR assay helpful for culture-negative cases and identification of serogroup during outbreaks.
• Acute and convalescent phase serology if highly suspicious for meningococcal disease but culture and PCR negative.

Question 6

What is the management of meningococcal disease?

Answer 6

• Medical emergency
• Admission to a hospital is necessary
• initiate IV empirical antimicrobial therapy with adjunctive dexamethasone as soon as possible after blood c/S
• Ceftriaxone IV 2 – 4 gm daily x 10-14 days; or
• Penicillin G 300,000 U/kg/day IV (up to 24 million U/day)

Add adjunctive IV dexamethasone prior to/at time of administration of empiric antimicrobials (to prevent neurological complications of bacterial meningitis)

• If Gram stain or c/s grows Strep pneumoniae 🡪 continue Q6h x4/7
• If Gram stain or c/s grows others (not Strep pneumoniae) 🡪 stop IV dexamethasone thereafter

Question 7

someone is exposed to a patient with meningococcal disease. how to post exposure prophylaxis

Answer 7

• Rifampicin 600mg 12 hourly x two days (adults); children (> 1 month) 10mg/kg for 2 days; or
• Ciprofloxacin 500mg oral single dose; or
• IM ceftriaxone 250 mg single dose (adults); children <15years, 125mg single IM dose