Meningitis Flashcards
What is meningitis?
Inflammation of the membranes covering the brain and spinal chord (meninges)
What can cause meningitis?
Infective causes:
Bacteria (greatest level of mortality)
Viruses e.g., Herpes
Fungi
Non infective causes:
Trauma (brain injury)
Drugs
Which bacteria causes meningitis?
Most common = neiserria meningitis (gram negative diplococci)
13 types characterised by surfaces structures in the capsule and outer cell membrane
6 responsible for majority of cases -
A, B, C, X, Y and W-135
Others:
- S. Pneumoniae (gram positive cocci)
- H. Influenzae type B (gram negative rods)
How is neiserria meningitis transmitted?
- Inhabits human nasopharynx
- Transmitted by droplets/secretions from upper respiratory tract
- Spread through close contact
How are other organisms transmitted?
Infections of the skin, urinary tract and GI tract may be transmitted via the bloodstream
What is the pathophysiology of meningitis?
- Bacteria invade subarachnoid space
- Causes inflammation and decreases CSF resorption
- BBB disrupted
- Inflammation of brain parenchyma
- Leads to oedema or ischaemia
What are risk factors of meningitis?
Infants and young children
Community settings (increased close contact)
Asplenia
People with compromised immune system
People exposed to active/passive tobacco smoke
Elderly
Pregnancy
Working with animals (increased risk of listeria bacteria meningitis)
What are symptoms of meningitis?
Fever Headache Photophobia Neck stiffness Petechial rash
How does meningitis present in young children?
Fever Nausea, vomiting, poor feeding Irritability, drowsiness, confusion Muscle and joint ache Cold extremities Symptoms of increased intracranial pressure e.g. irregular breathing Petechial rash
What are Kernig’s sign in meningitis?
Severe stiffness of hamstring causes inability to straighten leg when hip is flexed to 90^
What is Brudzinski’s sign of meningitis?
Severe stiffness in neck causes patients hips and knees to flex
How can meningitis be presented?
Bacterial meningitis
Septicaemia
Both
How to diagnose meningitis?
History Physical examination Blood tests (FBC, CRP, culture) Imaging (CT) Microbiological testing of cerebral fluid
What are the characteristics of the antibiotics used to treat meningitis?
Bactericidal
Broad spectrum
Cross the BBB therefore lipophilic
Rapid treatment (IV)
Which antibiotics are used to treat meningitis?
Ceftriaxone (bactericidal, broad spectrum, moderately lipophilic)
OR
Cefotaxime
use Chloramphenicol if unable to take cephlasporins due to hypersensitivity
What is administered in early treatment of meningitis?
Single stat dose of benzylpenicillin (IV)
Urgent referral to hospital and supportive care e.g oxygen and IV fluids
What are supportive therapies for meningitis?
Respiratory support IV fluids Corticosteroids Anticonvulsant therapy Management of complications of septicaemia and shock –Correction of metabolic disturbances –Vasoactive therapies –Renal replacement therapies if required
What are long term complications of meningitis?
Fatigue
Emotional changes
Hearing loss, visual disturbances, neurological problems
Septicaemia -> renal failure, orthopaedic and skin complications
Who is chemoprophylaxis treatment indicated for?
Those in prolonged close contact (same household during 7 days prior to presentation)
Those in transient close contact (direct exposure to large particle droplets/secretions from respiratory tract of pt around time if hospital admission)
The patient! Given as soon as able to take oral meds unless treated with ceftriaxone
Who is chemoprophylaxis NOT indicated for?
Staff and children attending same nursery/school
Residents of nursing homes
Food or drink sharing or similar low level of salivary contact
Travelling in next seat on same public transport
When is chemoprophylaxis given? And what type of antibiotics are prescribed?
As soon as possible after diagnosis
- Ciprofloxacin (all ages and pregnancy, single dose)
- Rifampicin (all patients, given twice daily for 2 days but many interactions)
- Ceftriaxone (via injection so used when other options unsuitable)
Which abx are given for infants younger than 3 months
Cefotaxime + ampicillin OR amoxicillin
