Question

Meningococcal meningitis

Answer 1

MENINGIOCOCCAL MENINGITIS

INTRODUCTION : Meningococcal meningitis is a bacterial form of meningitis . Meninges are the thin lining that surrounds the brain and spinal cord. It is a vaccine preventable disease.The occurrences of this although is throughout the world but the highest burden is in Sub Saharan Africa known as meningitis belt. Around 30000 cases are still reported every year from that area.

HOST: This disease can affect anyone of any age but mainly its seen among babies, preschool and young people.

AGENT : The disease causing agent is Neisseria Meningitidis. It is a gram negative bacteria. Twelve type of N.Meningitidis is been identified called serotypes, six of which (A,B,C,W,X and Y) can cause epidemics.

PATHOPHYSIOLOGY: The bacteria attack the lining between the brain and the skull called meninges and infected fluid from meninges passes to the spinal cord. This results in inflammation and irritation of meninges thereby developing symptoms. N.Meningitidis bacteria has a slimy outer coat that contains disease causing endotoxin which is very virulent. These endotoxins when released into blood stream causes septicemia . These endotoxins affects the heart reducing its ability to circulate blood and increases pressure in blood vessels. Thus causing hemorrhage resulting in rapid shut down of vital organs.

TRANSMISSION: The agent can infect only humans and have no animal reservoir. It is transmitted from person to person through droplets of respiratory and throat infections from carriers. Other factors that promote the spread of infection are:

• Smoking
• Kissing, sneezing or coughing on some one
• Living in close quarters with the carriers
• Overcrowded housings
• Mass gatherings

CLINICAL FEATURES: The average incubation period is four days but can range from two to ten days. the most common symptoms are:

• Stiff neck (Nuchal rigidity)
• Positive Kernig's Sign
• high fever
• sensitivity to light ( Photophobia)
• confusion
• seizures
• headache
• vomiting
• In infants, bulging fontanels and ragdoll appearance
• In severe cases, hemorrhagic rashes and circulatory collapse

DIAGNOSIS: Initially disease can be diagnosed by lumber puncture showing purulent spinal fluid. The confirmation is done by agglutination test or Polymerase chain reaction(PCR) test of the spinal fluid. The identification of serotype and the culture of the fluid is done to find the adequate antibiotic.

TREATMENT: Meningococcal Meningitis is a medical emergency. The person should be admitted. There no need for isolation but only droplet precaution is needed. The antibiotic should be started immediately as soon as possible but after lumber puncture. Else it will be difficulty to culture the organism for examination if spinal fluid is taken after starting antibiotics. The most commonly used antibiotics are Penicillin, Ampicillin, Ceftriaxone.

PREVENTION:

Vaccination : Universal vaccine against meningococcal meningitis is not available but many licensed vaccines are used. These vaccine are serogroup specific. There are three types of vaccines:

• Polysaccharide vaccine: It is used when there is an outbreak of epidemic mainly in Africa. This drug is not effective for children below 2 years. It gives 3 year protection but do not induce herd immunity.
• Conjugate Vaccine: These vaccines are used for routine immunization. Its immunity lasts for long term and it offers herd immunity. It can be safely used for children from one year of age.
• Protein based vaccine: its mainly used in N.Meningitidis B. Its also used in routine immunization.

Prophylactic Treatment: Antibiotic are given prophylactically to those people who are living in close contacts like in Africa. Its given to close contacts in household and in non-epidemic times. Ciprofloxacin is antibiotic of choice and Ceftriaxone an alternative.

PROGNOSIS: The prognosis of the disease if untreated is fatal. Appropriate surveillance, Vaccination in risk prone area and risk age groups can reduce the incidences and spread of disease.