Immunity & Infectious Disease Part II

1. Immunity & Infectious Disease Part II Dr. D Barry

2. Previously covered… Immunity Vaccinations Vaccine Preventable disease

3. This lecture; 1) Assessment of Febrile Child 2) Common Childhood Infections 3) Antibiotic choices 4) Immunocompromised Patient

4. 1; Clinical Assessment of febrile child

5. Fever Find a source!!!!! Is it benign viral? Does it require anti-biotic cover? Who needs a septic work-up? Is it one of the critical illnesses? (sepsis, meningitis, pneumonia, septic arthritis, UTI) Best tool; thorough history & examination Infections evolve & change… advise parents Other – PUO, complicated fevers, etc.

6. History; symptoms Generalised; irritability (?intermittent, on handling, consolable), feeding, intake, drowsy, sleeping, sweating, etc. Resp; cough, wheeze, rapid beathing etc. GIT/GU; diarrhoea, vomiting, abdo pain, pulling up legs, foul urine, etc. ENT; coryza, pulling at ears, sore throat CNS; headache, photophobia, seizure Other; rash, tender/swollen joints etc.

7. Other questions • ID contacts (creche, family, school) • Special ID questions; • travel, pets/animals, contacts, activities • Vaccination history • Antibiotic hx; allergies, how often on a/b, previous admissions etc. • Previous illnesses

8. On examination Tips; Observe firstly General inspection; C.H.A.N.D.L.E.R. Vitals (?sepsis) HR, BP, CRT +/- ABC Chest exam; CVS & respiratory (do early if settled) Fontanelle, Neck stiffness, Kernigs, Brudinski’s Skin – expose & examine all areas Lymph nodes Joints Ears & throat (at end; children don’t like this!) Urine dipstick (never omit this)

9. Septic work-up • FBC, CRP • Blood culture • Urine c + s • Swabs (wounds, throat, etc) • CXR • LP • Other (depends on clinical indication • eg. skin scrapings, sputum C+S

10. Important questions to consider… Have you found the source? Is it benign childhood illness? Does it require anti-biotic cover? +/- f/u? Does this child need a septic work-up? Does this child need admission? Is this child critical? (sepsis, meningitis, pneumonia, septic arthritis, UTI) Notifiable dx? Trace contacts? Isolation? Choice of antibiotic…

11. Take Home Message Wide spectrum of infective disease Your job to find out which (source of fever) Thorough History & Exam!!!! +/- septic work-up

12. 2; Common Childhood Infections The Classic Exanthemas

13. Describing a Rash 1) What’s the primary lesion? • Macule / papule / vesicle / bullae / haemorrhagic 2) Surrounding skin? (eg erythematous / indurated etc.) 3) Pattern? (eg. confluent? discrete? isolated? etc) 4) What’s the distribution? (eg face/scalp? trunkal? Peripheral? Exposed areas etc.) 5) Other features? (eg. Itchy? Oozing? Tender? etc) 6) How did it evolve (time)? [ask from history]

14. 1: Fever & rash High fever Miserable Cough Runny nose Day 6; rash face & spread down trunk

15. Description… macular papular confluent ‘morbilliform’ extensive spread downwards.

16. Measles (rubeola) • Contact & spread; airborne/droplet • Incubation; 10-14 days • Clinical; Prodrome; high fever, harsh cough, coryza, conjunctivitis, • Rash; ‘morbilliform’, maculo-papular • Begins d3-6 from hairline, down face to trunk • Lasts up to 10/7 • Koplik’s spots

17. The science bit… measles (Rubeola) RNA Paramyxovirus Clinical diagnosis Salivary swab measles IgM Treatment Supportive Ribavirin if patient Immunocompromised ?Contacts Prevention: HNIG within 6/7 if imunocompromised contact Complications; Otitis, pneumonia, croup Encephalitis 1/5000 within a week of rash 15% Mortality 20-40% Neuro sequelae Late complication; SSPE (subacute sclerosing panencephalitis) 1/100,000

18. Measles Live vaccine (1960s) Mini-measles can occur 6 -10 days after immunisation Mild pyrexia and erythematous rash Pre-vaccine; >500,000 cases/yr with 500 mortalities Measles outbreak (when vaccine uptake ↓) Immunise all susceptible individuals within 72 hrs Contraindications; Pregnancy Untreated malignancy Immunodeficiency states (except HIV) Immunosuppressive therapy History of anaphylaxis to a previous dose

19. 2; Fever & rash Erythematous Coarse / sand-paper Began on neck d2 Extensive Spread Esp. marked in folds (axilla, groin etc.) but doesn’t blanch here [Pastia lines] Palms, soles often involved

20. White strawberry tongue Red strawberry tongue (prominent papillae) Circum-oral pallor Flushed face Desquamates d5-7

21. Scarlet Fever Spread via droplets [school-age children] Strep pharyngitis 2-5 day incubation; Sudden fever, sore throat, malaise, +/- headache, vomiting etc. lymphadenopathy Rash from day 2; (as described) Rash fades day 5-7 & desquamates

22. The science bit… Group A (β-haemolytic) strep “strep Pyogenes” Erythrogenic toxin Complications; Rheumatic fever Acute Glomerulonephritis Tests; throat swab +/- ASOT titre Tx; Penicillin (phenoxymethylpenicillin) x10/7

23. Skin infections Impetigo, erysipelas, cellulitis, URTI Sinusitis, otitis, tonsillitis Invasive Sepsis, shock, nectrotizing fascitis Complications; Scarlet fever Rheumatic fever Glomerulonephritis ASOT; Up to ~200 Normal Rises x 4/52 Plateau x 3-6/12 Normal after 6-12/12 Streptococcus Pyogenes

24. EBV Incubation 1-2 months Fever (prolonged) Lymphadenopathy (generalised) Pharyngitis, tonsilitis with exudates Palatal petechiae, Swollen uvula Splenomegaly (sometimes tender) Hepatomegaly +/- hepatitis Thrombocytopenia Rash (‘rubelliform’) 10% (↑with amoxicillin)

25. Tests; • FBC – Lymphocytes (atypical) • Monospot (Paul Bunnel); (heterophile a/b) • Wk l 38% +, • Wk 2 60% +, • Wk 3 80% + (false + : Hepatitis/Rubella/Hodgkins) • Serology antibody titres

26. Complications Haemolytic anaemia Pneumonitis Post-infectious malaise Lymphoma (Burkitts) / lymphoproliferation

27. 3; fever & rash Mild fever & prodrome Rash (d1-3) Begins on face spreads downwards generalised erythematous maculo papular Last 3-5/7

28. Rubella Rubella – difficult to diagnose Fever <38.5, LN + (esp Post Triangle) May have splenomegaly, palatal petechiae Mild self limited disease in children – 25 -50% subclinical Incubation 2 – 3 weeks Infectious (droplets) for <1wk from rash onset Buccal swab, urine, rising antibody titre Rare complications: Polyarthralgia / Polyarthritis Thrombocytopenia Encephalitis (1 in 6000)

29. 5; fever & rash Fever Lethargic Poor intake ? Sore Rash; Erythematous cheeks

30. Erythema Infectiosum / 5th disease / Parvovirus B19 20% asymptomatic Outbreaks esp. Spring [4-15 yr olds] Biphasic; Flu-like prodrome, 1 week later; Rash! Erythematous over cheeks; ‘Slapped-cheek’ Macular over body (central clearing) ‘lacy’ May Recur

31. Complications; Arthritis (transient) Congenital infection; severe! Intra-uterine death Hydrops Neonatal thrombocytopenia Pts with haemolytic anaemia; Aplastic crisis (attacks red cell precursors)

32. 6: Fever then rash! High fever (40oC) x 3/7, Otherwise well Fever settles abruptly; thenrash; Extensive, Maculo-papular Lasts only 1-2 days

33. Roseola / 6th disease / exanthem Subitum HHV6 High fever +/- febrile convulsion (10%) Rash appears afterwards +/- red papules on palate / uvula (Nagayama) Very common; 100% a/b + by 2 yrs age Herpes family ? reactivation in Immunocompromised host?

34. Common childhood infections; The skin

35. Hand, Foot & Mouth disease Coxsackie virus A & B, enterovirus Mild, self-limiting (1 wk) disease Fever & m/p rash to vesicles Spread by direct contact, droplet, faeco-oral

36. Fever & Rash (vesicular) Vesicles Varying stages Extensive Itchy

37. Varicella Zoster Primary (chicken-pox). Reactivation (zoster) Both are infectious – spreading Varicella! Chicken Pox Incub 10-21 (14-16) Fever / malaise rash (usually simultaneous with Symptoms) Maculae - papule - vesicle - pustule [at different stages] Trunk/face - extremities Typically 3 crops over 3-5 days Infectious 24-48 hours pre-rash until last lesion is crusted over

38. Complications: Cellulitis / lymphadenitis Encephalitis (1:1000), Hepatitis Post infectious cerebellar ataxia Pneumonia (adults & immunocompromised) Haemorrhagic progressive VZV / thrompbocytopenia / purpura fulminans (↓ protein C) Reyes syndrome (ASA ingestion) VZV - Reactivation - Zoster

39. Treatment Symptomatic Vaccine Available Immunocompromised Contact; VZIG within 72 o of exposure Infected; Acyclovir within 24 o of rash

40. HSV-1 Primary infection; herpetic gingivostomatitis Can cause acute vulvo-vaginitis Localised infection; herpetic whitlow Fever 2-3/7 Ulceration Heal in < 1 week Age 1-4 year olds Dormant in trigeminal ganglion Recurrence

41. Complications Herpetic Keratoconjunctivitis Herpes encephalitis Neonatal herpes Treat complications (above) with HD acyclovir Monitor U&E

42. Staphlococcus • Skin Flora, Nasal Colonies • Folliculitis / Furnacles / Carbuncles • Impetigo (+ Bullous Impetigo) • Staph Scalded Skin • Surgical wounds (nb. ? MRSA) • Other- cellulitis, LN, osteomyelitis, septic arthritis

43. Staphlococcus! Impetigo; Skin flora; Staplococcal*/streptococcal Honey-crusted crusts Very Contageous Often superinfection of skin lesions; eczema / VZV / scabies etc… Tx.; Fluclox +/- BzPen

44. Bullous Impetigo Disrcete Bullae Toxin mediated Same treatment; Fluclox / BzPen Skin care

45. Staphlococcal Scalded Skin • SSSS • Toxin mediated • Systemically unwell; ? sepsis • malaise / fever / irritable / dehydration • pain +++ • Peeling off of sheets of epidermis Nikolsky’s sign

46. Treatment of SSSS IV antibiotics; Fluclox +/- BzPen Skin care; emollients Prevention of 2ary infection Fluid & electrolyte balance

47. Common Childhood Illnesses Other

48. Describe this….What might this child have?

49. Kawasaki Syndrome Clinical features Fever >5days 1. Maculo-papular rash generalised 2. Conjunctival injection Bilat, non-purulent 3. Extremity change Induration hands/feet, erythematous palms/soles, periungal desquatamion 4. Oral mucosa change; erythematous, red/cracked lips, strawberry tongue 5. Cervical lymphadenopathv Unilateral, >1.5cm Differential Diagnosis Viral exanthems – measles. adeno-/enterovirus Gp A strept infection Staph; toxin-mediated dx Drug hypersensitivity Other; Leptospirosis Rocky Mt. Spotted Fever (Ricketsial diseases)

50. Other features • BCG scar inflammed • Aseptic meningitis • Sterile pyuria (ureteritis) • Hydropic gall bladder (abdo pain / vomiting) • Anterior Uveitis • Arthritis / Arthralgia • Pericardial effusion, myocarditis +/- ccf • coronarv arterv aneurvsms (late)