2. Infections - systemic Flashcards
How do bacterial and viral meningitis differ in their pathophysiology?
Viral = mucus membrane infection –> lymph node involvement –> organ involvement
Bacterial = nasopharyngeal epithelium colonisation –> invasion of blood –> meninges –> cerebral oedema (inflammation + extravasation) –> altered cerebral blood flow and metabolism
What are the different causative organisms of meningitis at different ages?
NEONATES
-E coli
-Group B strep
-Listeris
INFANTS / CHILDREN
-Viral
-Hib
-N. Meningitides
-Strep pneumoniae
ADOLESCENTS
-N. Meningitides
-Strep pneumoniae
How does meningitis present in neonates?
-Fever
-Irritable
-Seizures
-Poor feeding
-Respiratory distress
-Coma
How does meningitis present in infants / children?
-Fever
-N+V
-Cold peripheries
-Lethargy
-Unsettled
-Refusing food
How does meningitis present in adolescents?
-Unwell
-Headache
-Photophobia
-Muscle aches
-Neck stiffness
-N+V
What signs does meningitis have?
-Papilloedema
-Bulging fontanelle
-Bradycardia
-HTN
-Kernig sign (=pain on knee extension when hip is flexed)
-Brudzinski sign = flexion of head –> flexion of hips (due to neck stiffness)
What are the contraindications for doing a LP for suspected meningitis?
-Focal neurological signs / seizures
-Raised ICP
-Shock
-Respiratory insufficiency
-Abnormal clotting
-Extensive purpura
If you suspect meningococcal meningitis in the community, what should you give before transferring to hospital?
IM benzylpenicillin single dose
-<10yrs - 1g
-1-9yrs - 600mg
-<1yr - 300mg
If you suspect bacterial meningitis in hospital, how should you manage it empirically?
-<3 months - IV gentamicin + benzylpenicillin
->3 months - IV ceftriaxone
What antibiotics treat which type of bacterial meningitis?
-Meningococcal –> IV benpen / cefotaxime
-Pneumococcal –> IV cefotaxime
-H. influenzae –> IV cefotaxime
-Listeria –> IV amoxicillin + gentamicin
+DEXAMETHASONE to reduce risk of complications
What are the immediate and delayed complications of meningitis?
IMMEDIATE
-Shock (fluids)
-Seizures (IV aciclovir)
-DIC
-Cerebral oedema
-SIADH
DELAYED
-Hearing loss
-Focal paralysis
-Seizures
-Cerebral palsy
What is meningococcal septicaemia and how does it present?
-Acute infection of the bloodstream and subsequent vasculitis
-N meningitidis bacteria
-Fever, mottling, leg pain, cold peripheries, breathing difficulties, rapidly spreading purpuric rash (>12h)
What causes infectious mononucleosis?
-EBV (90%) or CMV
-Source is oropharyngeal secretions
-Virus infects B lymphocytes in pharyngeal lymphoid tissue –> lymph system spread
How does the prodrome of IM present and how long is the incubation period?
-Flu-like illness for 3 days (headache, fever, chills)
-Incubation = 4-6 weeks
How does IM present (after prodrome)?
-Triad = sore throat + lymphadenopathy + pyrexia
-Exudative pharyngitis
-Generalised, tender lymphadenopathy
–NB tonsillitis typically only causes anterior cervical chain lymphadenopathy
-Hepatosplenomegaly
-Widespread erythematous macular rash
-Lethargy, anorexia, headache
How is IM diagnosed?
-Positive serology for EBV
->10% atypical lymphocytes
-Mono spot test but has v low sensitivity (false +ves)
-Raised LFTs, IgM and IgG
-Mild thrombocytopenia
How should IM be managed?
-Supportive care - simple analgesia, fluids
-Patients with splenomegaly should avoid contact sports for 1 month and adolescents should avoid alcohol
What is Kawasaki disease?
-Systemic vasculitis with coronary arteritis –> coronary artery aneurysms
How does Kawasaki disease present?
-Irritability
-Prolonged fever (>38.5 for >5 days)
How is Kawasaki disease diagnosed?
Fever + 4/5 of the following:
1.Bilateral non-purulent conjunctivitis
2.Lips / oral cavity changes eg dryness, erythema, fissuring of lips, strawberry tongue, pharyngeal redness
3.Extremities changes eg erythema of palms / soles, indurative oedema, peeling of fingers / toes
4.Rash
5. Cervical lymphadenopathy
What are the differential diagnoses for Kawasaki disease?
-Measles
-Scarlet fever
-Rubella
-Drug reactions
What associated features might Kawasaki disease have?
-Urethritis and sterile pyuria
-Arthralgia
-Arthritis
-Aseptic meningitis
-D+V
-Myocarditis, pericardial effusion, arrhythmias, mitral insufficiency, acute MI, coronary aneurysms
How would you manage Kawasaki disease?
-High dose IV Ig (2g/kg over 12h)
-High dose aspirin 30-50mg/kg/day - lower dose once fever has resolved
How would you investigate Kawasaki disease?
-FBC, ESR, CRP, LFTs, U+Es
-Coagulation
-Urinalysis
-Urine culture
-Immunology
-ECG
-Throat swab
-Platelets - rise in 2nd week of infection
-Echo
