Invasive Meningococcal Disease Flashcards
what is meningitis?
Meningitis describes inflammation of the meninges (membranes) which cover the brain and spinal cord
what are the three layers of meninges?
dura mater
arachnoid mater
pia mater
what are the infectious causes of meningitis?
Bacteria e.g. meningococcus, pneumococcus
Viruses e.g. coxsackievirus, echovirus, herpes virus, mumps virus, influenza, HIV etc
Less common infective causes include fungi, protozoa, and other parasites
what are the non infectious causes of meningitis?
Medications e.g. antibiotics (amoxicillin, trimethoprim/sulfamethoxazole), carbamazepine, lamotrigine, NSAIDs, ranitidine
Cancers e.g. melanoma, lung cancer, breast cancer, lymphoma, leukaemia
Autoimmune disease e.g. Systemic lupus erythematosus (SLE), Behçet’s syndrome.
what are the causes of meningitis?
infectious - usually this is the cause
non infectious - rarer
why can diagnosing meningitis be difficult?
Diagnosis of acute bacterial meningitis can be challenging, as it can present with common, non-specific clinical features
what differential diagnosis could meningitis be confused with?
Viral meningitis
Fungal meningitis
TB meningitis
Drug-induced meningitis
Sepsis from other causes
Encephalitis – inflammation of the brain
Brain abscess – collection of pus in the brain
Subarachnoid haemorrhage
Brain tumour
HIV infection
what is invasive meningococcal disease?
-Infection with Neisseria meningitidis
Gram-negative diplococci
Carried by 10-24% of the population
Humans are only known reservoir
how is invasive meningococcal disease transmitted?
Transmission by respiratory droplets/ naso-pharyngeal secretions
Transmitted by aerosol, droplets, or direct contact with secretions from the upper respiratory tract. Transmission usually requires either frequent or prolonged close contact
what is the incubation period of invasive meningococcal disease?
Incubation period 2-10 days, usually 3-4 days
what are the two main manifestations of invasive meningococcal disease?
- Meningitis: a localised infection of the meninges, with “local” symptoms
- Septicaemia : a systemic infection with widespread signs, and generalised organ damage
describe neisseria meningitides
12 serogroups based on the capsular polysaccharide
who does invasive meningococcal disease affect ?
-Commonly affects extremes of age (<2 months and >60 years) because of impaired or waning immunity.
- Another spike in incidence is also seen in adolescence and early adulthood (due to close contact/ social mixing?)
what are the risk factors for invasive meningococcal disease ?
Extremes of age
Immunocompromised (e.g. HIV) or immunosuppressed (e.g. chemotherapy)
Asplenia/hyposplenia
Cancer – people with leukaemia and lymphoma
Sickle cell disease
Organ dysfunction – e.g. liver or kidney disease
Cranial anatomical defects
Cochlear implants
Contiguous infection - e.g. otitis media, sinusitis, mastoiditis, pneumonia
Smokers
Living in overcrowded households, college dormitories or military barracks
People who have had contact with a case
Travellers abroad to high risk area - increased risk of encountering the pathogen
what are the symptoms of meningococcal meningitis?
fever
confusion
stiff neck
headache
increased sensitivity to light
nausea and vomiting
what group of individuals may not have the usual symptoms of Meningococcal meningitis?
babies
what are the symptoms babies experience with meningococcal meningitis?
They may be:
-slow or inactive
-irritable
-vomiting
-feeding poorly
-or have a bulging anterior fontanelle (the soft spot of the skull)
what Is a sign of Meningococcal meningitis in babies that drs can observe ?
brudzinkis neck sign
(google pic)
what are the Meningococcal septicaemia symptoms?
Fever and chills
Fatigue
Vomiting
Cold hands and feet
Severe aches or pain in the muscles, joints, chest, or abdomen
Rapid breathing
Diarrhoea
Non blanching rash (petechiae)
In the later stages, a dark purple rash (purpura)
how does Meningococcal septicaemia work?
The bacteria enter the bloodstream and multiply, damaging the walls of the blood vessels, causing bleeding into the skin and organs.
what is a sign observed on the skin for Meningococcal septicaemia?
petechiae
a rash that when you pressed down on it, it doesn’t diseappear- can be hard to see on black or brown skin
what can sepsis cause?
Sepsis can cause Disseminated Intravascular Coagulation (DIC)
These clots can cause arterial occlusions leading to gangrene of extremities & auto-amputations (spontaneous detachment of an appendage from the body)
what is disseminated intravascular coagulation?
the activation of coagulation pathways that results in formation of intravascular thrombi (clots) and depletion of platelets and coagulation factors.
what can disseminated intravascular coagulation cause
These clots can cause arterial occlusions leading to gangrene of extremities & auto-amputations (spontaneous detachment of an appendage from the body)
