Paediatric Infectious Disease & Immunity

Question 1

A mother brings her 11-month-old son to the emergency department because she is concerned about a rash he has developed. On further questioning, the mother describes that the rash started 2 days ago, initially behind the ears but has since spread.

Prior to developing the rash, the infant was generally unwell with a cough and a fever. He is currently up to date with vaccines but the mother knows that he is supposed to have some more soon though she has not booked an appointment for these yet.

On examination you note that he is irritable, has white spots in his mouth and his eyes appear inflamed.

Given the most likely diagnosis, which of the following would he be most at risk of developing?

A. Aplastic crisis

B. Arthritis of the small joints

C. Deafness

D. Orchitis

E. Otitis media

Answer 1

E. Otitis media: The most common complication of measles is otitis media

Question 2

What are complications of measles?

Answer 2

otitis media: the most common complication
pneumonia: the most common cause of death
encephalitis: typically occurs 1-2 weeks following the onset of the illness)
subacute sclerosing panencephalitis: very rare, may present 5-10 years following the illness
febrile convulsions
keratoconjunctivitis, corneal ulceration
diarrhoea
increased incidence of appendicitis
myocarditis

Question 3

What is Parvovirus B19 also known as?

Answer 3

Erythrovirus

Question 4

what are common complications of mumps?

Answer 4

-orchitis - uncommon in pre-pubertal males but occurs in around 25-35% of post-pubertal males. Typically occurs four or five days after the start of parotitis
-hearing loss - usually unilateral and transient
-meningoencephalitis (aseptic CSF)
-pancreatitis

Question 5

What is the most common cause of late onset sepsis (>72 hours after birth)?

Answer 5

Staphylococcus aureus

Question 6

What is GBS also known as?

Answer 6

Streptococcus agalactiae

Question 7

What are some main organisms causing late onset neonatal sepsis?

Answer 7

-Staphylococcus aureus (commonest)
-Staph epidermidis
-E. coli
-Pseudomonas
-Klebsiella

Question 8

A 4 year old girl who recently started school is brought to her GP with a 24 hour history of feeling generally unwell, tiredness and headache. She has been eating and drinking but less than normal. Her mother states that she is usually happy and healthy but seems to have got gradually worse today. No one else in her class has been unwell. She has no past medical history and does not take any regular medications.

On examination the child looks unwell and appears quite withdrawn. Vital signs: pulse 100bpm, BP 110/70, respiratory rate 22/min, oxygen saturations 98%, temperature 38.5 degrees C. Systems examination is unremarkable. She has cold hands and feet and a non-blanching purpuric rash on her left upper thigh.

Her GP refers her to the nearest hospital. Which of the following treatments should her immediate family members receive? (class of Ab)

A. Meningococcal vaccine
B. Benzylpenicillin
C. Isoniazid
D. Ciprofloxacin
E. Paracetamol

Answer 8

D. Ciprofloxacin (fluoroquinolone; inhibits DNA synthesis)
-All household/close contacts should receive ciprofloxacin or rifampicin as prevention of spread of disease. A suitable alternative would be rifampicin (inhibits RNA synthesis)

Question 9

What are some complications of parvovirus B19?

Answer 9

-Red cell aplasia (aplastic anaemia)
Parvovirus infection also reduces erythropoiesis.
This is not significant for most patients; however, in vulnerable groups like those with conditions like sickle cell anaemia and hereditary spherocytosis that rely on erythropoiesis, infection can precipitate a severe anaemia, causing an aplastic crisis

-Infection in the first half of pregnancy can also cause severe foetal anaemia that can precipitate hydrops foetalis and subsequent miscarriage

-Cardiomyopathy

-arthralgia (adults)

Question 10

What are 3 other names for parvovirus B19?

Answer 10

-slapped cheek syndrome
-erythema infectiosum
-fifth disease

Question 11

what are 2 other names for roseola infantum?

Answer 11

Sixth disease (HHV6)
exanthum subitem

Question 12

How is measles diagnosed 3-14 days after onset of rash?

Answer 12

measles specific IgM and IgG serology (ELISA) is most sensitive 3-14 days after onset of the rash

Question 13

How is measles diagnosed 1-3 days after rash onset?

Answer 13

measles RNA detection by PCR best for swabs taken 1-3 days after rash onset

Question 14

What vaccine(s) happen at birth?

Answer 14

BCG vaccine if risk factors present (eg family have it within past 6 months)

Question 15

What vaccine(s) happen at 2 months?

Answer 15

6 in 1: diptheria, tetanus, whooping cough, polio, Hib, Hep B
-Men B
-oral rotavirus
(8 vaccines)

Question 16

What vaccine(s) happen at 3 months?

Answer 16

6 in 1: diptheria, tetanus, whooping cough, polio, Hib, Hep B
-oral rotavirus
-PCV

Question 17

What vaccine(s) happen at 4 months?

Answer 17

-6 in 1: diptheria, tetanus, whooping cough, polio, Hib, Hep B
-Men B

Question 18

What vaccine(s) happen at 12-13months? (mnemonic)?

Answer 18

12-13=4 numbers= 4 vaccine groups
-Men B
-MMR
-Hib/Men C
-PCV

Question 19

What vaccine(s) happen at 2-8 yrs?

Answer 19

annual flu vaccine

Question 20

What vaccine(s) happen at 3-4 years?

Answer 20

-4 in 1 pre-school booster: whooping cough, polio, diptheria, tetanus
-MMR

Question 21

What vaccine(s) happen at 12-13 years?

Answer 21

Gardasil HPV vaccine

Question 22

What vaccine(s) happen at 13-18yrs?

Answer 22

-Men A, C W, Y
-“3 in 1” teenage booster: polio, diptheria, tetanus

Question 23

When do the Men B vaccines happen?

Answer 23

-2months
-4months
-12-13months

Question 24

When do the MMR vaccines happen?

Answer 24

-12-13months
-3-4 years

Question 25

When do the PCV vaccines happen? (mnemonic)?

Answer 25

PCV: 3 letters: 3 months & 13 months -3 months -12-13months

Question 26

When do the oral rotavirus vaccines happen?

Answer 26

-2months -3months

Question 27

when do the 6 in 1 vaccines happen (what are they)?

Answer 27

6 in 1: diptheria, tetanus, whooping cough, polio, Hib, Hep B -at 2 months -at 3 months -at 4 months

Question 28

An 8 year old girl is brought in by her mother having been unwell with a sore throat and runny nose for the past week. Her mother reports that for the past two nights she has been suffering from severe coughing fits which last up to a few minutes and is then gasping for breath. She has also vomited forcefully after a few of the coughing episodes. Her mother has noticed she appears very red in the face during the coughing fits. On further history taking her mother reveals that she has not received any vaccinations since birth as her mother was worried about the risk of developing autism. Given the likely cause of her symptoms which investigation would provide be most likely to provide a definitive diagnosis? A. Blood film B. Direct fluorescent antibody test C. Culture of organism on per-nasal swab D. PCR E. This would be the firstline investigation but is not the most sensitive. The sensitivity of the culture is dependent on the timing with swabs only swabs taken up to 3 weeks after onset usefulCulture of organism oral swab

Answer 28

D. PCR: PCR is the most sensitive investigation for the diagnosis of pertussis, with a sensitivity of 94% and a specificity of 97%. However, it should be noted a positive PCR result in the absence of cough is NOT diagnostic for whooping cough Not C: culture; This would be the firstline investigation but is not the most sensitive. The sensitivity of the culture is dependent on the timing with swabs only swabs taken up to 3 weeks after onset useful

Question 29

what are some features of congenital rubella (mnemonic)?

Answer 29

Congenital rubella syndrome (CCD): cataracts, cardiac defects (PDA), deafness (hearing, seeing and heart) 1. hearing impairment 2. Congenital heart defects – in particular, branch pulmonary artery stenosis and patent ductus arteriosus 3. Eye anomalies such as cataract(s), pigmentary retinopathy (salt and pepper type), chorioretinitis or congenital glaucoma

Question 30

An 8 month old baby is brought into A&E by his mother. Over the last 24 hours he has been febrile and irritable and now he has developed a rash. On examination there is widespread erythema and there are large fluid filled blisters across his body, many of which have ruptured. There are patches of desquamation and Nikolsky sign is positive. There is marked crusting and fissuring around his mouth, although his oral mucosa is unaffected. The boy has no relevant past medical history and is up to date with his vaccinations. Which of the following is the most likely diagnosis? A. Bullous pemphigoid B. Toxic epidermal necrolysis C. Kawasaki disease D. Staphylococcal scalded skin syndrome E. Pemphigus vulgaris

Answer 30

D. Staphylococcal scalded skin syndrome The age of this patient, the de-squamation, the positive Nikolsky sign and the sparing of the oral mucosa points towards staphylococcal scalded skin syndrome (SSSS)

Question 31

diffuse rose-pink macular rash with surrounding pale halos. His temperature is 40.0 degrees + seizure

Answer 31

HHV6

Question 32

when would you avoid the use of corticosteroids in suspected meningitis?

Answer 32

If child <3months

Question 33

what are common meningitis organisms at Neonatal-3 months

Answer 33

Group B streptococcus , E.coli , Listeria monocytogenes

Question 34

what are common meningitis organisms at 1 month-6 years

Answer 34

Neisseria meningitidis , Streptococcus pneumoniae , Haemophilus influenzae

Question 35

What Abs would be given >3months meningitis:

Answer 35

IV ceftriaxone

Question 36

GP medication for meningitis

Answer 36

IM benzylpenicillin -Cefotaxime as an alternative if penicillin allergic

Question 37

what Abs would be given <3months meningitis:

Answer 37

IV ampicillin/amoxicillin (listeria coverage) +cefotaxime (as ceftriaxone causes biliary stasis)

Question 38

supportive therapy for bacterial meningitis:

Answer 38

1. Analgesia and antipyretics 2.Oxygen: reservoir rebreathing mask, unless intubation required 3. Anticonvulsant therapy if needed 4. IV fluids: 0.9%NaCl+5% dextrose 5.Vasopressors if hypotensive despite fluid resuscitation

Question 39

what are common meningitis organisms at >6 years

Answer 39

Neisseria meningitidis , Streptococcus pneumoniae

Question 40

An 18-year-old primigravida is booked for induction at 38 weeks due to intrauterine growth restriction. After a short labour, a baby girl is delivered by vaginal delivery. The baby has a low birth weight. On examination, she is noted to have microcephaly, moderate hepatosplenomegaly and a petechial rash. Shortly after admission to the neonatal intensive care unit, she has a seizure. The mother was well throughout pregnancy, has no past medical history, takes no medications and has had all of her vaccinations. What infection has the baby likely been exposed to in-utero? A. Cytomegalovirus B. Herpes Simplex C. Parvovirus B19 D. Rubella E. Varicella Zoster

Answer 40

A. Cytomegalovirus Congenital CMV manifests with hearing loss, low birth weight, petechial rash, microcephaly and seizures

Question 41

Congenital CMV mnemonic:

Answer 41

-Low birth weight -Purpuric skin lesions -Sensorineural deafness -Microcephaly Other features: -Visual impairment -Learning disability -Encephalitis/seizures -Pneumonitis -Hepatosplenomegaly -Anaemia -Jaundice Cerebral palsy

Question 42

Congenital rubella features (mnemonic):

Answer 42

(CCD): cataracts, cardiac defects (eg PDA), deafness

Question 43

congenital toxoplasmosis features (mnemonic):

Answer 43

Pentad of Cs: 1. chorioretinitis, 2. intracranial calcifications, 3. hydrocephalus, 4. convulsions 5. cerebral palsy

Question 44

When should exclusion happen? A 6-year-old boy presents with a 3-day history of fever, mild coryzal symptoms, rash and cervical lymphadenopathy. He has an erythematous, maculopapular rash on his face and neck that has started spreading down his body. He has not received any routine childhood immunisations

Answer 44

5 days from onset of rash is correct. The most likely diagnosis is rubella based on his clinical presentation of fever, mild coryza, a characteristic rash and lymphadenopathy. In addition, due to his vaccination status, he is at higher risk of rubella. Rubella requires exclusion from school for 5 days from the onset of the rash.

Question 45

When should exclusion happen? An 8-year-old girl presents with a 2-day history of fever, lethargy and a sore throat. Over the last few hours, she has developed a pinpoint, sandpaper-like blanching rash that initially appeared on her trunk before spreading to the rest of the body. The area around her mouth is noted to be spared. Her pharynx is inflamed with petechiae noted on the hard and soft palate. Cervical lymphadenopathy is palpable.

Answer 45

24 hours after commencing antibiotics The most likely diagnosis is scarlet fever given the history of acute fever and sore throat before the development of a characteristic rash (with circumoral pallor), cervical lymphadenopathy and 'Forchheimer spots'. A 'strawberry tongue' may also be seen on clinical examination. Scarlet fever results from a reaction to toxins produced by group A haemolytic streptococci. It is highly contagious and requires exclusion from school for 24 hours after commencing antibiotics (first-line phenoxymethylpenicillin if not penicillin allergic).

Question 46

When should exclusion occur? A 5-year-old girl presents with a 2-day history of fever, reduced appetite, abdominal discomfort and a sore mouth. She has scattered ulcerative lesions in her mouth and an erythematous maculopapular rash on the sides of her fingers, dorsum of her hands and margins of her heels.

Answer 46

No exclusion. The most likely diagnosis is hand, foot and mouth given the characteristic nature of her rash. It is typically self-limiting, does not require exclusion from school and is managed conservatively with analgesia and encouraging oral fluid intake. It is most commonly caused by the Coxsackie A16 virus.

Question 47

When should exclusion for whooping cough happen?

Answer 47

2 days after commencing antibiotics (or 21 days from onset of symptoms if no antibiotics)

Question 48

When should exclusion for measles happen?

Answer 48

4 days from onset of rash

Question 49

When should exclusion for chickenpox happen?

Answer 49

after all lesions crusted over

Question 50

When should exclusion for impetigo happen?

Answer 50

Until lesions are crusted and healed, or 48 hours after commencing antibiotic treatment

Question 51

When should exclusion from mumps occur?

Answer 51

5 days from onset of rash

Question 52

When should exclusion from rubella occur?

Answer 52

5 days from onset of swollen glands

Question 53

When should exclusion from scabies occur?

Answer 53

until treated (permethrin 5% is first-line malathion 0.5% is second-line, malathion also used for headlice)

Question 54

When should exclusion from influenza occur?

Answer 54

until recovered

Question 55

what organism causes threadworms?

Answer 55

Enterobius vermicularis (threadworms)

Question 56

treatment for threadworms:

Answer 56

-CKS recommend a combination of anthelmintic with hygiene measures for all members of the household -mebendazole is used first-line for children > 6 months old. A single dose is given unless infestation persists

Question 57

Impetigo common organisms:

Answer 57

Group A Streptococcus or staphylococcus aureus

Question 58

clinical features of impetigo

Answer 58

1. It classically presents as a pruritic rash with discrete patches that have a golden crusting 2. Patients may also be febrile 3. It commonly occurs in infants and school-age children

Question 59

Management of impetigo:

Answer 59

-In most circumstances it can be managed in primary care with topical treatments such as fusidic acid. Oral flucloxacillin may also help. -It is highly infectious. Patients should not share towels and should not attend school or work until they have completed 48 hours of antibiotic treatment.

Question 60

what is the most common intrauterine infection?

Answer 60

CMV (cytomegalovirus)

Question 61

CMV symptoms (mnemonic)

Answer 61

-seizures -hepatosplenomegaly -learning difficulties

Question 62

Common causes of meningitis in neonates:

Answer 62

Gp B Strep, E Coli, Listeria, Pneumococcus, Staph aureus.

Question 63

Common causes of meningitis in babies >1month & children:

Answer 63

Meningococcus, Pneumococcus and Haemophilus influenzae B (Haemophilus, a coccobacilli, was previously more common until it was included in the childhood vaccination programme; it now much less commonly seen).

Question 64

what is the most common cause of meningitis in children:

Answer 64

Neisseria meningitides is the most common cause of meningitis in children. 5% of survivors have neurological sequelae (not all of them) and there is a 10% mortality

Question 65

when is Meningococcal Gp C vaccine routinely given?

Answer 65

at 12 months of age and at 14 years, as part of the MenACWY vaccine.

Question 66

when is Men Gp B vaccine usually given?

Answer 66

at 8 and 16 weeks, followed by a booster at 1 year

Question 67

what meningitis vaccine is given to travellers?

Answer 67

. Gp A strains are seen in other parts of the world and a Gp A+C travel vaccine is available.

Question 68

sepsis vs shock definitions:

Answer 68

Severe sepsis develops when the infection causes organ damage. Sepsis= a life-threatening reaction to an infection Septic shock is the most severe form in which the infection causes low blood pressure, resulting in damage to multiple organs.

Question 69

What Abs would be given >3months meningitis:

Answer 69

IV ceftriaxone

Question 70

what antibiotic would be added for recent foreign travel if meningitis suspected?

Answer 70

Vancomycin

Question 71

when should dexamethasone be given in the context of meningitis:

Answer 71

Dexamethasone may be given if >3 months old and presents with these in CSF analysis: o Frankly purulent CSF o CSF WBC>1000/μL oRaised CSF WBC+protein concentration>1g/L o Bacteria on Gram stain steroids should not be used in meningococcal septicaemia

Question 72

Infection with which virus in the first 20 weeks of pregnancy causes hydrops fetalis?

Question 73

what are absolute contraindications to primary immunisations?

Answer 73

1. Severe allergic reaction (anaphylaxis) to a previous dose of the vaccine or a vaccine component 2. Known severe immunodeficiency (e.g. congenital immunodeficiency, HIV infection with severe immune suppression, malignancy with chemotherapy, transplantation with immunosuppressive therapy) 3. Current moderate to severe acute illness with or without fever, until the illness has resolved.

Question 74

contraindications to MMR vaccine:

Answer 74

1. Immunosuppression 2. Neomycin allergy (aminoglycoside antibiotic) 3. Other live vaccine <4w prior 4. IVIG <3months prior 5. Avoid pregnancy 1 month following vaccination

Question 75

6 in 1 vaccine mnemonic:

Answer 75

o Parents Polio o Will Whooping cough (Pertussis) o Immunise Influenzae (HiB) o Toddlers Tetanus o Because B (Hepatitis) o Death Diphtheria

Question 76

Which four are most likely differential diagnoses?

Answer 76

1. Pyelonephritis 2. Sepsis 3. Pneumonia (can present in babies even if chest is clear) 4. Meningitis A 6-month-old coming with high fever indicates a high probability of sepsis. In such babies, the focus of sepsis may be difficult to identify. In our baby, the high fever cannot be explained by just the diarrhoea and the diarrhoea is not severe enough to cause the tachypnoea and tachycardia, exclusing gastroenteritis as a differential. The foul smelling urine gives a clue, and meningitis is a serious infection that can present in babies without any localizing signs.

Question 77

A 6-year-old child was briefly admitted two weeks ago to an open paediatric ward with an undiagnosed rash. His 1-year-old brother is now in paediatric ED and has been diagnosed with measles by the paediatric registrar who has now gone off to attend to an emergency. What do you do? (3 options) Advise that it is fine for the patient to be in an open 6 bed area Ensure the patient is being managed in a side-room with respiratory precautions Ensure the patient is being managed in a side-room with gloves and aprons Ensure the patient is being managed in a negative-pressure room Inform the local Health Protection Consultant by phone even if out of hours Notify the Health Protection Consultant in office hours/through a notification form Inform the hospital infection control team

Answer 77

1. Ensure the patient is being managed in a side-room with respiratory precautions 2. Inform the local Health Protection Consultant by phone even if out of hours 3. Inform the hospital infection control team

Question 78

what is kawasaki disease also known as?

Answer 78

IgA vasculitis -mucocutaneous lymph node syndrome.

Question 79

Answer 79

Gamma globulin (vs penicillin) as 5 days of fever suggests Kawasaki (no recent unwell contacts as well so points against scarlet fever)

Question 80

what's the definition of fever?

Answer 80

A fever is usually when your body temperature is 37.8°C or higher

Question 81

A 3 year old girl is seen at GP with a pruritic rash covering her body, including her scalp, face and limbs (pictured). It developed 3 days ago. Her dad is also concerned that his other child, who a four year boy, will also catch this. He has sent his son to stay with his mother in the meanwhile. At present his son is asymptomatic. He asks how long about if he needs to wait to see if his son will get the rash.

Answer 81

Given the most likely diagnosis, what is the most appropriate response for the GP to give when advising about the incubation period concerning the son? A. Up to 14 days B. It is non-contagious C. Up to 21 days D. Up to 3 days E. Up to 7 days

Question 82

A 3 year old girl is seen at GP with a pruritic rash covering her body, including her scalp, face and limbs (pictured). It developed 3 days ago. Her dad is also concerned that his other child, who a four year boy, will also catch this. He has sent his son to stay with his mother in the meanwhile. At present his son is asymptomatic. He asks how long about if he needs to wait to see if his son will get the rash. Given the most likely diagnosis, what is the most appropriate response for the GP to give when advising about the incubation period concerning the son? A. Up to 14 days B. It is non-contagious C. Up to 21 days D. Up to 3 days E. Up to 7 days

Answer 82

C. Up to 21 days The incubation period for chickenpox is up to 21 days

Question 83

Conservative management of chickenpox (advice):

Answer 83

Management of chickenpox is conservative as the condition is self-limiting. Simple measures include 1. keeping fingernails short 2. wearing long sleeved clothing to prevent scratching 3. use of oatmeal baths to reduce itching.