Meningococcemia overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Ammu Susheela, M.D. [3]
Overview
Meningococcemia is the presence of Neisseria meningitidis (also known as meningococcus), a severe bacterical infection, in the blood stream. It is demonstrated by blood culture. The disease is hard to identify as it can appear in several different forms, depending on which part of the body the bacteria invade. Neisseria meningitides is a gram-negative diplococcus. The bacteria is known to cause meningitis, septicaemia, pneumonia, and even rarely urethritis. Early recognition and treatment of anyone exposed to meningococcus is extremely important to prevent serious illness or death.
Historical Perspective
The historical reports indicate that meningococci was first reported in 1805. SInce then for more than 2 hundred years, meningococcus have been causing a high degree of morbidity and mortality. It usually appear as sporadic but reports of outbreak have been reported from different parts of the world especially Sub Saharan African belt. Outbreak usually happens in close communities like schools, colleges and prisons.
Classification
13 serotypes of meningococci have been isolated based on their polysaccharide capsule out of which five of them causes clinically severe diseases. They are also classified according to outer membrane protein.
Pathophysiology
Meningococcal infection is caused by Neisseria meningitidis and they spread through respiratory and throat secretions. Once it get absorbed by endocytosis into the body, it get seeded in skin , meninges and other organs and cause a variety of clinical manifestation from meningitis to septicemic shock. The meningococcal lipopolysachride is an important factor in the infection and host factors like Toll like receptor (TLR) and inflammatory cytokines play an important role in the pathogenesis of the disease.
Causes
Meningococcemia is caused by a bacteria called Neisseria meningitidis. The bacteria frequently lives in a person'supper respiratory tract without causing visible signs of illness. The bacteria can be spread from person to person through respiratory droplets -- for example, you may become infected if you are around someone with the condition when they sneeze or cough. Family members and those closely exposed to someone with the condition are at increased risk. The infection occurs more frequently in winter and early spring.
Differential Diagnosis
Meningococcemia must be differentiated from other diseases that cause neurological symptoms, such as brain abscess, encephalitis, delirium tremens, brain tumor, and subarachnoid hemorrhage. The rash component of meningococcemia must be differentiated from other illnesses causing skin rash, such as chickenpox, herpes zoster, erythema multiforme, among others.
Epidemiology and Demographics
Meningococcus occurs through out the year, however the incidence is highest in late winter and early spring. It is the second most common community acquired bacterial infections. The highest incidence worldwide is in a place called sub Saharan Africa called meningitis belt. Children are mostly affected by this disease.
Risk Factors
Risk factors of meningococcemia include age group of infants or old age, closed communities, seasons of winter and early spring, complement deficiency, asplenia and travel to endemic regions especially sub-Saharan African meningitis belt.
Screening
Routine screening is not recommended for meningococcemia.
Natural History, Complications and Prognosis
Neisseria meningitidis bacteria can cause meningitis to fatal septicemia. The symptoms of meningitis appear within 3-7 days of exposure and presents with fever and signs of bacterial meningitis. If it causes septicemia, it can be very fatal where the patient dies in few hours. In non fatal conditions they develop disabilities like arthritis, gangrene, Disseminated intravascular coagulopathy and cutaneous vasculitis. The outcome is uncertain in septicemic patients but prognosis is good in non septicemic patients with early intervention and treatment.
History and Symptoms
Every child with purpuric rash and high fever should be treated as meningococcemia until proven otherwise. The history suggest patient with high fever, rash, headache, myalgia and stiff neck.
Physical Examination
Physical examination may shows fever, hypotension, petechial rash, conjuctival congestion, nuchal rigidity, seizures, edema, hepatosplenomegaly, dyspnea and rales.
Laboratory findings
Meningococci is usually identified from blood or CSF analysis. Aspiration or skin biopsy of the rash yield meningococci. CSF analysis usually shows increased protein, low glucose and increased number of neutrophils.
Medical Therapy
Meningococcemia is a medical emergency. Breathing support, fluid resucitation, antibiotics like cephalosporin and wound care are the major aspects of treatment.
Primary Prevention
Primary prevention of meningococcemia includes vaccination and chemo prophylaxis. There are mainly 2 different types of vaccine namely polysacchride and conjugate vaccine. Chemoprophylaxis is mainly with rifampin, ceftriaxone, ciprofloxacin and azithromycin.
Cost-effectiveness of Therapy
Cost effective analysis study has indicated that a 2-dose series at ages 11 years and 16 years has a similar cost-effectiveness compared with moving the single dose to age 15 years or maintaining the single dose at 11 years.
Future or Investigational Therapies
Future investigational therapies are showing promising results where 2 new vaccines were being developed against serogroup B and 3 new types of antigen have been found to be useful in making vaccines more potent.