A non blanching petechial rash is an ominous signs of meningococcaemia in an unwell patient
- Serious cause of Meningitis and Septicaemia
- Those with complement C8 and C9 deficiency are more susceptible
- Over 13 serogroups - commonest are A,B,C W-135 and Y.
- In the UK mainly types B and C
- Affects either infant under 5 years or teenagers aged 15-19
- Found in the nasopharynx of asymptomatic carriers
- N. meningitidis is a gram-negative Capsulated diplococcus
- The gram-negative cell wall contains lipopolysaccharide which is overproduced resulting in early DIC and petechiae and bruising
- The meningococcus can use both glucose and maltose
- Can produce a polysaccharide capsule that blocks phagocytosis
- Lipopolysaccharide stimulates macrophages to release Cytokines
- Increased cytokines lead to septic shock ( e.g. TNF-Alpha, IL-1, IFN-gamma)
- Meningococcal bacteria adhere to epithelium using pili. Also IgA protease
- The Bacteria have a rapid doubling time of the bacterium
- This causes the release of large amounts of endotoxin by a process known as blebbing.
- Meningitis +/- accompanying meningococcal septicaemia
- Meningococcal septicaemia alone without evidence of meningitis.
- Adrenal haemorrhage (Waterhouse-Friderichsen syndrome).
- Multiorgan failure
- Disseminated intravascular coagulation
- Acute respiratory distress syndrome
- Purpura fulminans - cutaneous bleeding
- Gram stain of CSF will show typical kidney-shaped gram-negative cocci within polymorphs
- Tests for meningococcal capsular antigen
- Oxidase positive
- Culture on chocolate agar with 5% CO2
- Also use Thayer Martin media
- Carbohydrate fermentation - ferments glucose and maltose
- Polymerase chain reaction to detect meningococci in blood or CSF
- Penicillin, Cefotaxime, Rifampicin, Ciprofloxacin
- Prevention with a vaccine which covers the Y, W135, C and A serotype
- Antibiotic choice are
- Ceftriaxone 2 g BD
- Cefotaxime 2 g 6 hourly
- Benzylpenicillin 2.4 g 4 hourly
- Vasopressor and aggressive fluid replacement
- Glucocorticoid therapy may be indicated e.g. adrenal haemorrhage (Waterhouse-Friderichsen syndrome).
- ? recombinant human activated protein C in sepsis
- Rifampicin for close contacts