2. Infections - systemic

Question 1

How do bacterial and viral meningitis differ in their pathophysiology?

Answer 1

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

Question 2

What are the different causative organisms of meningitis at different ages?

Answer 2

NEONATES
-E coli
-Group B strep
-Listeris
INFANTS / CHILDREN
-Viral
-Hib
-N. Meningitides
-Strep pneumoniae
ADOLESCENTS
-N. Meningitides
-Strep pneumoniae

Question 3

How does meningitis present in neonates?

Answer 3

-Fever
-Irritable
-Seizures
-Poor feeding
-Respiratory distress
-Coma

Question 4

How does meningitis present in infants / children?

Answer 4

-Fever
-N+V
-Cold peripheries
-Lethargy
-Unsettled
-Refusing food

Question 5

How does meningitis present in adolescents?

Answer 5

-Unwell
-Headache
-Photophobia
-Muscle aches
-Neck stiffness
-N+V

Question 6

What signs does meningitis have?

Answer 6

-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)

Question 7

What are the contraindications for doing a LP for suspected meningitis?

Answer 7

-Focal neurological signs / seizures
-Raised ICP
-Shock
-Respiratory insufficiency
-Abnormal clotting
-Extensive purpura

Question 8

If you suspect meningococcal meningitis in the community, what should you give before transferring to hospital?

Answer 8

IM benzylpenicillin single dose
-<10yrs - 1g
-1-9yrs - 600mg
-<1yr - 300mg

Question 9

If you suspect bacterial meningitis in hospital, how should you manage it empirically?

Answer 9

-<3 months - IV gentamicin + benzylpenicillin
->3 months - IV ceftriaxone

Question 10

What antibiotics treat which type of bacterial meningitis?

Answer 10

-Meningococcal –> IV benpen / cefotaxime
-Pneumococcal –> IV cefotaxime
-H. influenzae –> IV cefotaxime
-Listeria –> IV amoxicillin + gentamicin
+DEXAMETHASONE to reduce risk of complications

Question 11

What are the immediate and delayed complications of meningitis?

Answer 11

IMMEDIATE
-Shock (fluids)
-Seizures (IV aciclovir)
-DIC
-Cerebral oedema
-SIADH
DELAYED
-Hearing loss
-Focal paralysis
-Seizures
-Cerebral palsy

Question 12

What is meningococcal septicaemia and how does it present?

Answer 12

-Acute infection of the bloodstream and subsequent vasculitis
-N meningitidis bacteria
-Fever, mottling, leg pain, cold peripheries, breathing difficulties, rapidly spreading purpuric rash (>12h)

Question 13

What causes infectious mononucleosis?

Answer 13

-EBV (90%) or CMV
-Source is oropharyngeal secretions
-Virus infects B lymphocytes in pharyngeal lymphoid tissue –> lymph system spread

Question 14

How does the prodrome of IM present and how long is the incubation period?

Answer 14

-Flu-like illness for 3 days (headache, fever, chills)
-Incubation = 4-6 weeks

Question 15

How does IM present (after prodrome)?

Answer 15

-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

Question 16

How is IM diagnosed?

Answer 16

-Positive serology for EBV
->10% atypical lymphocytes
-Mono spot test but has v low sensitivity (false +ves)
-Raised LFTs, IgM and IgG
-Mild thrombocytopenia

Question 17

How should IM be managed?

Answer 17

-Supportive care - simple analgesia, fluids
-Patients with splenomegaly should avoid contact sports for 1 month and adolescents should avoid alcohol

Question 18

What is Kawasaki disease?

Answer 18

-Systemic vasculitis with coronary arteritis –> coronary artery aneurysms

Question 19

How does Kawasaki disease present?

Answer 19

-Irritability
-Prolonged fever (>38.5 for >5 days)

Question 20

How is Kawasaki disease diagnosed?

Answer 20

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

Question 21

What are the differential diagnoses for Kawasaki disease?

Answer 21

-Measles
-Scarlet fever
-Rubella
-Drug reactions

Question 22

What associated features might Kawasaki disease have?

Answer 22

-Urethritis and sterile pyuria
-Arthralgia
-Arthritis
-Aseptic meningitis
-D+V
-Myocarditis, pericardial effusion, arrhythmias, mitral insufficiency, acute MI, coronary aneurysms

Question 23

How would you manage Kawasaki disease?

Answer 23

-High dose IV Ig (2g/kg over 12h)
-High dose aspirin 30-50mg/kg/day - lower dose once fever has resolved

Question 24

How would you investigate Kawasaki disease?

Answer 24

-FBC, ESR, CRP, LFTs, U+Es
-Coagulation
-Urinalysis
-Urine culture
-Immunology
-ECG
-Throat swab
-Platelets - rise in 2nd week of infection
-Echo

Question 25

How does vertical transmission of HIV occur?

Answer 25

-Infants may become infected during labour and the post-natal period
-Effective prophylaxis reduces risk to <1%
–Antiretrovirals
–Elective C-section
–Avoidance of breast feeding

Question 26

How does paediatric HIV present?

Answer 26

-Chronic diarrhoea
-Failure to thrive, delayed development
-Cerebral palsy
-Recurrent bacterial and viral infections
-Lymphadenopathy, hepatosplenomegaly
-Respiratory distress
-Treat with antiretroviral therapy and avoid live vaccines
-NB an unaffected infant of a positive mother can test positive for 12-18 months

Question 27

How does rubella present?

Answer 27

-Maculopapular rash starting on face –> whole body
-Lymphadenopathy (sub-occipital, post-auricular)
-Caused by rotavirus

Question 28

What are red flags for serious illness in children <5 according to the NICE traffic light system?

Answer 28

COLOUR
-Pale / mottled / ashen / blue
ACTIVITY
-No response to social cues
-Appears ill to HCP
-Does not wake / stay awake
-Weak, high-pitched or continuous cry
BREATHING
-Grunting
-RR >60
-Modearte/severe chest indrawing
CIRCULATION
-Reduced skin turgor
OTHER
-T >38 if <3 months
-Non-blanching rash
-Bulging fontanelle
-Neck stiffness
-Status epilepticus
-Focal neurological signs
-Focal seizures

Question 29

How is a fever defined and how is it best measured + managed?

Answer 29

->38
(>38 in infant <3months = red flag, >39 in 3-6months = amber flag)
-Measured using axillary (or tympanic) electronic thermometer
-Keep hydrated and give anti-pyretics if distressed / clinically unwell

Question 30

How do CSF results change in normal cases vs bacterial meningitis vs viral meningitis?

Answer 30

NORMAL
-Neut = 0
-Lymph = <5 (<11 in neonates)
-Protein = <0.4 (<1.0 in neonates)
-Glucose (CSF:blood ratio) = >0.6
BACTERIAL
-Neut = 100-10,000
-Lymph = <100
-Protein = >1.0
-Glu = <0.4
VIRAL
-Neut = <100
-Lymph = 10-1000
-Protein = 0.4-1
-Glu = usually normal