Level 2 - Infections

Question 1

Definition of chicken pox?

Answer 1

• Highly infectious disease caused by herpes virus transmitted by air droplets
• VZV infection between 1-6yrs commonly —winter/spring
• Varicella is very infectious

Question 2

Transmission of chicken pox? Infectious period?

Answer 2

• Transmission is by personal contact or droplet spread, with an incubation period (the time from becoming infected until symptoms appear) of 1-3 weeks
• Chickenpox is infectious from 1-2 days before the rash appears until the vesicles are dry or have crusted over, usually 5 days after the onset of the rash

Question 3

What is Herpes Zoster?

Answer 3

• Herpes Zoster (shingles)
  o a reactivation of the latent infection may occur -> vesicular lesions in the distribution of the sensory nerve. Increased risk in immunosuppressed

Question 4

Epidemiology of chicken pox?

Answer 4

• Incidence is highest before 10 years of age
• > 90% of people older than 15 years of age UK are immune
• Peak incidence from March-May

Question 5

Causes of chicken pox? Name a risk factor?

Answer 5

• Caused by varicella-zoster virus (VZV)

- Immunocompromised

Question 6

Prodrome of chicken pox?

Answer 6

• Infection begins 2 days before vesicles appear

- Infection ends when last vesicle crusts over

Question 7

Rash in chicken pox?

Answer 7

• Head and trunk rest of body.
• Red macules papulevesiclepustulecrusting
• Completely heal in 2wks

Question 8

Other symptoms in chicken pox?

Answer 8

headache, anorexia, URTI (sore throat, coryza, cough), fever and itching

Question 9

Investigations (when needed) for chicken pox?

Answer 9

Ex: Characteristic rash, its distribution and progression
Other: Serology (VZV IgM), vesicle fluid or electron microscopy

Question 10

Management of chicken pox?

Answer 10

Usually self-limiting, symptomatic: Paracetamol, calamine lotion and chlorphenamine
School exclusion: 5 days from start of skin eruption
Antivirals: Acyclovir if severe, in babies and immunosuppressed
Human varicella zoster Ig recommended for high risk immunocompromised

Question 11

Complications of chicken pox in pregnancy?

Answer 11

• Varicella in pregnancy can result in severe chickenpox

- Infection during 1st 28 weeks of pregnancy can lead to intrauterine infection and foetal varicella syndrome

Question 12

Other complications in chicken pox?

Answer 12

• Secondary bacterial infection
  o Due to staphylococcal/streptococcal leading to toxic shock syndrome or necrotising fasciitis
• Encephalitis
  o Cerebellitis, meningitis
• Purpura fulminans
  o Vasculitis in the skin due to cross-reactivity of antiviral antibodies
• Immunocompromised can disseminate causing pneumonitis/DIC – fatal 20%

Question 13

Define conjunctivitis? Classification?

Answer 13

• Redness and inflammation of conjunctiva (thin layer that covers front of eye)
• Hyperaemic vessels may be moved to sclera by pressure on globe
• Classified as infectious or non-infectious, and as acute (<4 weeks), chronic, or recurrent

Question 14

What is allergic conjunctivitis?

Answer 14

o Associated with IgE antibodies or non-atopic

o Can be acute/chronic or seasonal (hayfever)

Question 15

What is infectious conjunctivitis?

Answer 15

o Hyper-acute conjunctivitis is a rapidly developing severe conjunctivitis typically caused by infection with chlamydia
o Ophthalmia neonatorum (ON) is conjunctivitis occurring within the first four weeks of life
 Can be infectious or non-infectious
 Can be caused by Chlamydia trachomatis or Neisseria gonorrhoeae

Question 16

Epidemiology of allergic conjunctivitis?

Answer 16

o 15-40% of children

Question 17

Infectious aetiologies of conjunctivitis?

Answer 17

o Viral
 Most common 80% adenoviruses
 HSV, VZV, EBV, Coxsackie
o Bacterial
 Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae
 Moraxella catarrhalis, Chlamydia trachomatis, and Neisseria gonorrhoea

Question 18

Non-infectious causes of conunctivitis?

Answer 18

o Allergic, mechanical/irritative/toxic, immune-mediated and neoplastic

Question 19

Symptoms of conjunctivitis?

Answer 19

• Eyes itch, burn, ‘gritty feeling’ and lacrimate

- Often bilateral with discharge sticking lids together

Question 20

Explain different discharges in conjunctivitis?

Answer 20

• Discharge can be watery, mucoid, purulent depending on cause
  o Bacterial purulent with sticking lids, may have lymphadenopathy
  o Viral watery discharge and less, URTI

Question 21

What happens to eye function?

Answer 21

• Acuity, pupillary responses, corneal lustre are unaffected

Question 22

DDx of conjunctivitis?

Answer 22

• Acute glaucoma, Scleritis, Episcleritis, Keratitis, Uvitis, Iritis, Corneal ulcer, abrasion or foreign body
• Nasolacrimal duct obstruction
• Dry Eye
• Blepharitis

Question 23

Investigations of conjunctivitis?

Answer 23

• Slit lamp examination if needed

- Gram staining and culture if gonococcal suspected

Question 24

When is sticky eyes common? Management?

Answer 24

• Sticky eyes common in first few days of life
  o Clean with saline
  o Eye drops lubricating

Question 25

Management of conjunctivitis? Bacterial? Allergic? Neonates? Opthalmia neonatorum?

Answer 25

- Usually self-limiting and rarely causes loss of vision (resolves within 5-10 days) - Bacterial Conjunctivitis o Chloramphenicol topical drops (or fusidic acid drops) - Allergic Conjunctivitis o Topical antihistamines o Topical corticosteroids o Cromoglycate eye drops - Neonates o Treat with neomycin - Ophthalmia Neonatorum o Gonococcal infection should be cultured and treated with 3rd generation cephalosporin given o If chlamydia infection then treated with oral erythromycin

Question 26

Complications of conjunctivitis?

Answer 26

- Keratoconjunctivitis - Keratitis - ON o Corneal scarring, ulceration, visual impairment

Question 27

What is a food allergy? Type of reactions?

Answer 27

- Immediate IgE-antibody allergic reaction to specific food antigens - 70% have FHx of atopy - Immunological reactions - both IgE (acute, often rapid, onset) and non-IgE-mediated (delayed and non-acute reactions) - Food Intolerance – non-immunological hypersensitivity to specific food

Question 28

Epidemiology of food allergy?

Answer 28

- Affects 5% of young people - Incidence are rising - Around 2% have cow’s milk protein allergy

Question 29

Most common food allergens?

Answer 29

o Cow’s milk, egg, peanut, tree nut, fish, shellfish, wheat and soya

Question 30

Questions to ask about the allergic reaction?

Answer 30

- Why they suspect an allergy? - What foods do they feel are implicated? - Symptoms that occur after eating? - At what age and how much food is eaten to cause symptoms? - How long do symptoms last? - Worst reaction to ever happen? - Family history of allergy?

Question 31

Features of IgE mediated allergy?

Answer 31

Occurs 10-15 minutes after Acute urticaria – localised or generalised Acute angio-oedema Oral itching, nausea, vomiting Colicky abdominal pain Nasal itching, sneezing, rhinorrhoea, allergic conjunctivitis Cough, shortness of breath, wheezing and bronchospasm Other signs of anaphylaxis, stridor, feeling of impending doom, cardiovascular collapse Pruritis, erythema, diarrhoea and abdominal pain are common to both types

Question 32

Features of Non-IgE Mediated allergy?

Answer 32

``` Atopic Eczema GORD Infantile colic Diarrhoea/Dysentery Pallor Faltered growth Pruritis, erythema, diarrhoea and abdominal pain are common to both types ```

Question 33

What is cow's milk protein allergy? Symptoms? Management in breast/bottle fed babies?

Answer 33

- Separate to colic and is either IgE or non-IgE mediated - Causes colic symptoms, GORD, blood/mucus in stools, faltering growth - In breastfed babies, completely exclude cows’ milk protein from diet - In formula-fed babies, change to hypoallergenic extensively hydrolysed or amino acid formula

Question 34

DDx of food allergy?

Answer 34

Cow's milk protein, IBD, IBS

Question 35

Investigations to identify food allergy?

Answer 35

Food Diary If IgE mediated: - Skin prick tests - RAST or ELISA test (measures specific IgE antibodies) Non-IgE allergies can be deduced from history and examination - May need endoscopy and biopsy which will have eosinophilic infiltrates - Exclusion of food under supervision of dietician

Question 36

Management of food allergy?

Answer 36

``` Dietary - Avoid foods from diet Drug - Mild Reactions o Antihistamines - Anaphylaxis o Adrenaline (via auto-injector, Epipen) Cows’ milk protein allergy usually resolves during childhood ```

Question 37

Definition of Epstein-Barr virus? Transmission? Pathology?

Answer 37

- Glandular fever is an infectious, usually self-limiting disease - Virus has tropism for B lymphocytes and epithelial cells of pharynx - Transmission via oral contact and majority of infections are subclinical - EBV infection leads to a lifelong latent carrier state

Question 38

Epidemiology of EBV?

Answer 38

- 50% of children will have detectable EBV antibodies by 5 years of age - 90% of people will have antibodies by 25 years of age

Question 39

Causative organism of EBV?

Answer 39

- Caused by the Epstein-Barr virus (EBV), a member of the human herpes virus family (hHV4)

Question 40

Features of EBV?

Answer 40

- Long incubation period - Most people are asymptomatic - In most people, the disease is self-limiting and lasts 2–3 weeks

Question 41

Symptoms of EBV?

Answer 41

``` o Fever o Malaise, myalgia, rigors, anorexia o Lymphadenopathy o Tonsillopharyngitis o Palatal petechiae o Hepatosplenomegaly o Maculopapular rash o Jaundice ```

Question 42

DDx of EBV?

Answer 42

``` Streptococcal throat infection Leukaemia Cytomegalovirus Toxoplasmosis Acute viral hepatitis ```

Question 43

Investigations of EBV?

Answer 43

- Blood film shows atypical lymphocytes - FBC, lymphocytosis, heterophile antibody (Monospot) test - Viral serology for IgM EBV - LFTs

Question 44

Management of EBV?

Answer 44

- Supportive o Pain relief and paracetamol - If airway compromised, then corticosteroids could be used - AVOID AMPICILLIN/AMOXICILLIN AS CAUSES MACULOPAPULAR RASH IN CHILDREN AFFECTED WITH EBV

Question 45

Prognosis of EBV?

Answer 45

- Risk factor for Burkitt’s lymphoma, Hodgkin’s lymphoma, B-cell lymphoma and other cancers

Question 46

Definition Kawasaki Disease?

Answer 46

Affects children <5 Known as mucocutaneous lymph node syndrome Systemic vasculitis disease with coronary arteritis coronary artery aneurysms= most important complication (20-30%)

Question 47

Epidemiology of kawasaki disease?

Answer 47

Commonest cause of acquired heart disease in children

Question 48

Features of Phase 1: Acute (weeks 1-2)??

Answer 48

1) High temp (>38) lasting for >5days 2) Polymorphous rash (red-raised spots) @genital area trunk, arms, legs, face 3) Swollen glands in the neck 4) Dry, cracked lips and swollen tongue (strawberry) 5) Red fingers or toes – tender to touch 6) Red eyes- 94% conjunctival infection – non purulent

Question 49

Features of Phase 2: Sub-Acute (weeks 4-6)??

Answer 49

1) Peeling skin from fingers and toes 2) Abdo pain, D&V, jaundice 3) Pus in urine 4) Drowsy, lethargic & headache 6) Joint pain and swollen

Question 50

Classical features to make diagnosis of Kawasaki's disease?

Answer 50

To make diagnosis: Fever for 5 days + 4 out of 5 of the following: 1) Conjunctivitis without pus 2) Cervical lymphadenopathy 3) Extremity changes – swelling of hands/feet and desquamation 4) Rash 5) Lips- red, cracking or strawberry tongue

Question 51

Diagnosis of Kawasaki Disease?

Answer 51

Diagnosis can be made clinically Bloods - FBC - increased WCC, thrombocytosis, CRP and ESR raised Urine - MSU dipstick - pus Lumbar puncture- CSF ECG and echo to rule out CV comlications and aneurysm

Question 52

Management of Kawasaki's disease?

Answer 52

High dose IV immunoglobuilin 2g/kg within 10 days Aspirin 30-50mg continued for at least 6 weeks Corticosteroids - prednisolone -if IV-ImmunoGlobulin ineffective

Question 53

Complications of Kawasaki's disease?

Answer 53

- Coronary artery aneurysm can develop (20-30%) - MI risk in 1st year - Thrombosis

Question 54

What virus causes measles?

Answer 54

- RNA paramyoxyviridae virus | - Highly infectious

Question 55

Transmission of measles? Incubation and infectious period?

Answer 55

- Transmitted by droplets / direct contact - Incubation period: 7-14 days - Infectious 2d before symptoms and 4d after onset of rash

Question 56

Epidemiology of measles?

Answer 56

- Peak age= <1 year (before immunisation) or older children that are not immunised - Occurs typically in preschool children - peak in winter/spring - Commonest in developing countries - Rare due to MMR vaccine

Question 57

Risk factors of measles?

Answer 57

- Not immunised, immunocompromised, contact!

Question 58

Prodromal symptoms of measles? Rash?

Answer 58

- Prodrome of: o Fever o Conjunctivitis, coryza, cough, lymphadenopathy o Koplik’s spots (grain like spots opposite lower molars and buccal mucosa) - Rash appears 3-4 days later usually behind ear and spreads to whole body - Initially maculopapular but then blotchy and conflueunt, may desquamate in 2’ wk.

Question 59

Investigations of measles?

Answer 59

- Clinical diagnosis confirmed by serology &/ or viral culture - Blood Film o Leucopenia, lymphopenia

Question 60

Management of measles?

Answer 60

- Isolation - Supportive – Antipyretics - Notifiable disease to Health Board - Immunocompromised o Ribavirin - Immunised in MMR vaccine to prevent disease

Question 61

Complications of measles?

Answer 61

o Otitis Media o Pneumonia o Diarrhoea o Subacute sclerosing panencephalitis

Question 62

Rare complications of measles?

Answer 62

o Encephalitis | o Subacute Sclerosing Panencephalitis

Question 63

What is periorbital cellulitis?

Answer 63

- Infection of soft tissues anterior to orbital septum

Question 64

Where is periorbital cellulitis more common?

Answer 64

- Common in young children

Question 65

Causes of periorbital cellulitis? When is it more common?

Answer 65

- Commonly caused by sinusitis, facial insect bites, trauma, dental infections - Most common pathogenic organisms are S. aureus, S. epidermidis, streptococci and anaerobe - Unimmunised children can be due to H.influenzae type b - Both conditions occur more commonly in the winter months

Question 66

Symptoms of periorbital cellulitis?

Answer 66

- Fever - Almost always unilateral - Erythema - Tenderness - Oedema of the eyelid - Absence of painful eye movements, diplopia and visual impairments distinguish from orbital cellulitis

Question 67

DDx of periorbital cellulitis?

Answer 67

Orbital cellulitis Conjunctivitis Episcleritis Scleritis

Question 68

Management of periorbital cellulitis? How would you manage orbital cellulitis?

Answer 68

- Periorbital cellulitis - oral co-amoxiclav | - If orbital cellulitis - admit and need to do CT and LP to assess extent and exclude meningitis – IV Abx needed