Meningitis & Encephalitis Flashcards
What are the causes of bacterial meningitis in different age groups?
Neo-3m: GRAM +VE = Group B Strep, E.Coli, Listeria
3m-6yr: N.Meningitidis, Strep Pneumoniae, HiB
>6yr: N.Meningitidis, Strep Pneumoniae
What are the causes of viral meningitis?
Enterovirus
HSV1&2
EBV
Adenovirus
How do young children present w/meningitis?
Poor feeding Irritable Fever Convulsions Vomiting URTI +/- respiratory distress
What are the Sx of meningism?
1) Photophobia
2) Neck stiffness
3) Headache
Kernig: Hips/knees flexed, knee extension = back pain
Brudzinski: Flex neck = flex knee & hip
What are the signs of ↑ICP?
Babies: Irritability & HIGH PITCHED cry
Drowsy & lethargic
↓GCS
Bulging fontanelle
I/L dilated pupil
Headache
Opisthotopos: Infant lying w/stiff arched back
How is meningitis investigated?
Bloods: FBC (↑Neut), ↑↑CRP, Glucose (for LP comparison), Coag Screen, cultures ABG LP Throat/nasal swab & culture Viral PCR Rapid antigen screen
How is meningitis treated?
GP: IM BenPen & URGENT TRANSFER
<3m OR >5yo: IV Cefotaxime (50mg/kg) + Amoxicillin
3m-5yo: IV Cefotaxime/ Ceftriaxone (80mg/kg)
>50yo: Ampicillin (Listeria cover) + Cefotaxime
Dexamethasone: 0.15mg/kg QDS for 4days for ALL bacterial meningitis >1yo
How are close contacts treated prophylactically in meningitis?
PO Ciprofloxacin
Group C meningococcal: Vaccination
How can meningitis cause ↑ICP?
Release of endotoxin by meningococcus
Leads to inflammatory mediated CSF response
Results in leakage of protein & fluid from cerebral vasculature
Causes cerebral oedema & vascular thrombosis
Produces ↑ICP = ↓cerebral perfusion
Potential for brain death
How does meningitis cause septicaemia?
Bacteraemia & endotoxin release = ↑ vascular permeability
Water & proteins from IVS to EVS
Leads to tissue hypoxia & ischaemia
What are the Sx of meningococcal septicaemia?
Fever Cold & painful peripheries Pallor Skin mottling → petechial rash Neck stiffness ↓ consciousness
How is meningococcal septicaemia investigated?
Whole blood real time PCR
LP = Contraindicated
What are the complications of meningitis?
Deafness: Inflammatory damage to cochlear hair cells
Cerebral abscess: Swinging pyrexia
Epilepsy
Mental developmental delay
What are the contraindications to an LP?
Signs of ↑ICP: Papilloedema, U/L pupil dilatation, Cushing's reflex Meningococcal septicaemia Local infection over LP site Coagulopathy Thrombocytopenia Seizure
What is Cushing’s reflex?
Physiological response to ↑ICP
Bradycardia + Hypertension + irregular breathing
What are the signs of a bacterial infection on a LP sample?
Cloudy
↓Glucose
↑Protein
Neutrophil polymorphs
What are the signs of a viral infection on a LP sample?
Clear
60-80% plasma glucose
Normal/↓ Protein
Lymphocytes
What are the signs of a TB infection on a LP sample?
Cloudy
↓Glucose
↑Protein
Lymphocytes +++
What is encephalitis?
Inflammation of the brain
What are the infective causes of encephalitis?
HSV 1- MOST COMMON CAUSE IN ADULTS
Viral: CMV, EBV, VZV, HIV, measles, mumps
Non-Viral: Bacterial meningitis, TB, Listeria, Legionella
What are the hallmarks of encephalitis?
Fever
Headache
Altered mental status
What are the Sx of viral encephalitis?
Meningism Cold sores (HSV) Fever Rash Lymphadenopathy Conjunctivitis ?Recent travel/animal bite
What are the investigations for encephalitis?
1) Bloods: Cultures, LFTs, Glucose (rule out DKA)
2) Contrast CT: HSV = focal B/L temporal lobe involvement
AFTER CT
3) LP: ↑↑Protein, ↑↑Lymphocytes, ↓Glucose, send for viral PCR
Other: Viral PCR (HSV)
Toxoplasma IgM titre
Malaria film, EEG
How is encephalitis treated?
IV Aciclovir: 10mg/kg TDS for 14days- start within 30mins of arrival
What are the different grades of hepatic encephalopathy?
1: ↓Awareness, impaired attention, altered sleep, euphoria/depression. Mild asterixis
2: Lethargy, disorientation, slurred speech, asterixis
3: Gross disorientation. Bizarre behavior, semi-stupor, asterixis absent.
4: Coma
What is the pathophysiology of hepatic encephalopathy?
Impaired clearance of ammonia
Leads to build up of ammonia
Affects neurotransmitters
How is hepatic encephalopathy treated?
Lactulose: 20-30g (approx 30ml) every 2hours until loose stools then titre so only 2-3 stools a day
