Infectious Disease Flashcards
What is the leading cause of acquired heart disease in children under 5 years of age in the US and other developed countries?
Kawasaki disease
What is Kawasaki disease and it’s aetiology?
Kawasaki disease (KD) is an acute, febrile, self-limiting, systemic vasculitis of unknown origin that almost exclusively affects young children. In an immunogenetically pre-disposed host, one or more infectious agents may play a role in triggering the clinical manifestations of the disease
How does Kawasaki disease present?
Acute febrile illness with vasculitis lasting 5 or more days.
5 cardinal areas; rash, mucosa, conjunctiva, extremities, lymph nodes.
Typical signs include fever, polymorphic rash – the rash of Kawasaki disease may be morbilliform (measles-like), maculopapular (red patches and bumps), erythematous (red skin) or target-like. Usually starts in perineum - nappy area.
injected eyes - red, conjunctivitis
Swelling and erythema of the hands and feet occur in the acute stage, followed by desquamation in the second week.
- Swollen, red palms and soles (erythematous and oedematous), may affect mobility/ability to use hands – progresses to desquamation/peeling ~2 weeks ± Beau lines (transverse grooves across nails)
- Erythema of oral/pharyngeal mucosa, strawberry tongue, cracked lips
Unilateral non-purulent cervical lymphadenopathy is present in about 40% of cases.
Coronary aneurysms develop in 20% to 25% of untreated patients.
Cracked lips
Other possibilities:
± pericarditis, CHF, joint pains, neuro (headaches, facial palsy), GI (abdo pain, D&V, obstructive jaundice), sterile pyuria, other derm
How do we ivx Kawasaki and what are the findings?
FBC: in acute phase – mild/mod normochromic anaemia, ↑WCC, in subacute phase (2nd week) - ↑plts
↑ESR, ↑CRP, ↑ferritin, ↑α1AT
Echo: evaluate for CAs (do a baseline at start, repeat week 2/3 of illness and at 2 months follow up)
Can consider: LFTs, urinalysis, CXR, ECG
Diagnosis is made on clinical findings
What are risk factors for Kawasaki?
Asian ancestry
age 3 months to 4 years
male sex
How do we manage acute Kawasaki? Prognosis?
Admit to hospital
presentation ≤10 days from onset; or presentation >10 days from onset with risk factors for complications
1st line: intravenous immunoglobulin (IVIG) - don’t give after 10 days
plus: high-dose aspirin
2nd line: corticosteroid
plus: high-dose aspirin
2nd line: infliximab - TNFa blocker
plus: high-dose aspirin
3rd line: other immunomodulatory drug or plasma exchange
plus: high-dose aspirin
Not acute:
presentation >10 days from onset without risk factors for complications
1st line: low-dose aspirin
- (as unlikely to now develop CAs)
After initial episode:
Stop aspirin
Unless there is aneurysm- in which case: start anti platelets eg clopidogrel
Follow up with echo essential to check for CAs at 2 months
Prognosis ; 2nd infection is rare
What is danger of aspirin in kids?
aspirin rarely used in children due to risk
of Reye syndrome (rapidly progressing
encephalopathy, liver failure, coma)
When is cardiovascular disease in Kawasaki likely to manifest? How do we monitor this?
From 3 weeks - 2 months post infection
Hence need for echo to monitor heart
May hear gallop rhythm / murmur
It’s not just the aneurysm that is the issue there can be pericarditis, myocarditis and sudden death
Measles, mumps, rubella are examples of?
Notifiable diseases
What is the aetiology and clinical presentation of mumps?
Mumps virus - RNA Paramyxovirus, transmission by resp droplets
Systemic infection - not just resp
Clinically:
• Headache, fever,
Painful Parotid swelling
• +/- pancreatitis, neuritis, arthritis, mastitis, nephritis, thyroiditis, pericarditis
Meninges involvement, gonads, pancreas ( causing mumps orchitis, encephalitis, aseptic meningitis and deafness)
Risk factors for mumps?
unvaccinated status international traveller immunosuppression healthcare worker close-contact living (college students, prisoners, military) vaccine failure
How do we ivx mumps? Treatment? Prognosis?
salivary mumps IgM
Can do serology- Elisa
FBC - leukocytes is
Believe it’s clinical
Can ivx for complications eg serum Amylase for pancreatitis
Treatment:
No cure, supportive Tx with analgesia, fluids, infection should pass 1-2 weeks
• Prognosis – mumps is rarely fatal, but complications include infertility (oophoritis, orchitis), aseptic meningitis, deafness
Describe the measles virus? what is the mode of spread?
Is of the Paramyxoviridae family, genus morbilivirus
-> name: rubeola virus
spread through resp secretions
• One of the most highly communicable diseases
• Spending more than 15 mins in direct contact is enough to transmit
• 7-18 day incubation, period of infectivity from 4 days before and 4 days after rash
How does measles present?
High fever, coryxa, conjunctivitis
Koplik spots, small red spots with white centres clustered inside mouth/buccal mucosa - “grains of salt on a reddish background” :
- are prodromic of measles and manifest 2-3 days before the measles rash itself.
• maculopapular Rash - craniocaudal spread (appears around hairline first) then on face/neck, spreads to hands and feet
How do we ivx measles?
measles-specific IgM and IgG serology (ELISA)
How do we manage measles? Complications?
Rest and supportive treatment – fluids (maintaining good hydration), antipyretics
Vitamin A supplements - to boost antibody response
- Secondary bacterial infections – treat with ABX
- Complications – otitis media, pneumonia, convulsions, encephalitis, haerring loss
Describe the rubella virus?
RUBELLA
• German measles, Togavirus, spread through sneezing/coughing
• Infective period 1 week before symptoms to 4 days after
How does rubella present? Mx? Complications?
Clinically: • Rose-pink skin rash; - maculopapular - confluent: come together to form big blotches - craniocaudal spread
Enanthema: petechiae on palate
Symmetrical lymphadenopathy,
Fever, coryza, arthralgia, conjunctivitis, serious risks in pregnancy
Management:
• No specific treatment – pass within 7-10 days, supportive – fluids, antipyretics
• Complications – haemorrhagic complications due to thrombocytopenia
How do we ivx rubella?
Serology - igm / igg (Elisa)
FBC - thrombocytopaenia
What is the pathogenesis of parvovirus B19?
Fifth disease/slapped cheek syndrome
- Transmission via respiratory secretions, vertical transmission, transfusions
- Infects erythroblastoid RC precursors in BM
- Infectious period – 7-10 days before rash, 1 day after it develops
How does parvovirus present?
Can be asymptomatic
1 • Erythema infectiousum (most common) –
viraemic phase of fever, malaise, headache, myalgia with red rash on face (slapped cheek), progresses to maculopapular (lace) like rash in trunk and limbs;
reticular spread on extensor surfaces
Arthritis -
Typically involves the small joints of the hands, wrists, knees or ankles and is self-limited.
2 • Aplastic crisis – most serious consequence, occurs in children with chronic haemolytic anaemia (sickle cell, thalassaemia) or immunodeficient (infection persists 3wks+)
3 • Fetal disease – maternal transmission – leads to fetal hydrops, death due to severe anaemia
What is management for parvovirus?
usually self-limiting, supportive tx – fluids, analgesia
- Give paracetamol for the fever and arthralgia
- May need to add some NSAID; ibuprofen for the arthritis
- If Aplastic crisis : RBC transfusion
- If immunosuppressed - IVIG
How does ROSEOLA INFANTUM /Sixth disease present?
Very infectious
Caused by HHV6B sometimes HHV7
- High fever (eg 40C) for 3-4 days
- Rash AFTER fever stops
Discrete small rose-pink maculopapular rash/spots
starts on body/trunk and spread to arms, lasting 1-2 days
• Sore throat, lymphadenopathy
May have febrile seizures
Mx and complications of 6th disease?
- Supportive, antipyretics, fluids
* Complications – high fever may cause febrile convulsions
How does chicken pox present and what is the Mx?
characterise rash
Pyrexia, headache, abdo pain, malaise
• Crops of vesicles appear over 3-5 days – head, neck, trunk (sparse on limbs) – itchy
• Macular -> Papular → vesicle → crust – several stages at once
Management:
• Supportive, fluids, minimise scratching, analgesia
• Antihistamines, emollients for pruritis
• Acyclovir if immunocompromised or severe
Isolate/no school from 5 days from onset of rash OR till lesions gone/crrusted over
Aetiology, presentation and Mx of HAND, FOOT, MOUTH DISEASE?
- Most commonly due to Coxsackie A16 virus
- Painful vesicular lesions on hands, foot, mouth, tongue, buttocks
- Mild systemic features – fever, sore throat,spots in mouth → develop into ulcers
- Disease subsides in a few days with fluids and analgesia
do not need time off school (or isolation) - unless unwell
What are the causes of meningitis?
Viral are most common – most are self resolving
• Bacterial may have severe consequences
• Non-infectious causes: malignancy, AI disease
How does meningitis present?
• Lethargy, loss of interest, drowsiness, coma, seizures, muscle pains, resp symptoms,
- Headache, photophobia, neck stiffness, +ve Kernig sign
- Non-blanching purpuric rash - meningococcal rash (doesnt necessarily mean meningitis is yet present)
↑cap refill (>2)
- ↑ICP: ↓consciousness, abnormal pupillary response, abnormal posturing
- Late signs – papilloedema, bulging fontanelle in infants, opisthotonus (hyperextension of head and back)
How do we ivx meningitis?
Basic obs - HR, RR, O2 sats, BP, temp, AVPU
Bacterial meningitis workup a lot more
- FBC (often ↑WCC)
- Blood glucose and blood gas (acidosis)
- Coagulation, CRP, U&Es, LFTs (check for CMV, EBV, Coxiella)
- Blood culture, throat swab, urine, stool culture, nasopharyngeal aspirate if resp symptoms
- Rapid antigen test for organisms (on blood, CSF or urine)
- LP for CSF (full workup; glucose, protein, cultre, gram stain) - if viral, most important test
- PCR of blood and CSF (for N meningitides)
- CXR as part of febrile work up
- Consider CT (if focal neuro signs or ↓ consciousness)
Treat as bacterial if → ↑CRP, ↑WCC, abnormal CSF
What are the contraindications of LP?
Contraindications for LP: signs of ↑ICP (fluctuating consciousness, bradycardia, focal neuro signs, abnormal posturing, unequal pupils, papilloedema
How do we manage meningitis?
Admit
Bloods for culture then Empirical abx - based on age:
• Immediate IV Ceftriaxone if > 3 months old
• Use cefotaxime + amoxicillin/ampicillin if < 3 months old
(abx is given to cover listeria)
• Add vancomycin if recent travel outside the UK
If signs of shock:
Immediate fluid bolus of 20ml/kg saline over 5-10 mins If signs of shock persist, give a second bolus
If signs persist after second bolus:
• Give a first fluid bolus of 20ml/kg saline
• Call for anaesthetic assistance for intubation
and mechanical ventilation
• Give vasoactive drugs: IV adrenaline or NA
• Discuss with paediatric intensivist, consider more boluses
Add 15 litre face mask O2 via reservoir breathing mask
If > 3 months: give dexamethasone if suspected bacteria
How do we treat meningitis upon return of blood cultures?
Once cultures return:
• Treat Hib with IV ceftriaxone for 10 days
• Treat S pneumoniae with IV ceftriaxone for 14 days
- Group B Strep with IV cefotaxime for > 14 days
- L monocytogenes with IV amoxicillin/ampicillin (21), + gent (7)
- G-ve bacilli with IV cefotaxime for 21 days
What further ivx should be done in meningitis? Why?
Offer a formal audiological assessment asap
-Inflamm damage to cochlear
Test for complement deficiency if: >1 episode of meningococcal disease, or meningococcal disease caused by serogroups other than B, or any serogroup plus a history of other recurrent or serious bacterial infections
