Infections – Review of Principles

1. Infections – Review of Principles • Use appropriate diagnostic testing to confirm diagnosis when appropriate • Use antibiotics with an appropriate spectrum of coverage for indicated conditions • Treat infections empirically when appropriate • Think of infection in your differential for a patient with an ill defined problem • When an infection fails to respond, think resistance or a different organism • Use other therapies when appropriate (eg. aggressive fluid resuscitation in septic shock, incision and drainage for abscess, pain relief)

2. Common infections of childhood • Specific lectures in the two year program will cover: • Septic shock • Meningitis • Upper respiratory infections • Sinusitis • Actue otitis media • Acute laryngotracheobronchitis • Epiglottitis • Bacterial tracheitis • Urinary tract infection • Gastroenteritis • Pneumonia • Today: other common infections that don’t “fit” anywhere else • Starting with viral bronchiolitis.....

3. ? Viral Bronchiolitis • Approach to the wheezing infant • i.e. They don’t present saying, “I have viral bronchiolitis.” • Distinguish wheezing from stridor • Stridor is inspiratory • Distinguish lower airway wheezing from upper airway wheezing • Lower airway wheezing is polyphonic, whereas monophonic wheezing is more likely upper airway • Why do infants get more wheezing? • Small airways • Resistance to flow is inversely proportional to the radius to the 4th power • Extremely compliant chest • Inward pressure during expiration predisposes intrathoracic airways to collapse

4. Bronchiolitis • Distinguishing bronchiolitis from first episode of asthma • Viral studies • Risk factors for persistent wheezing include: • Parental history of asthma and/or allergies • Maternal smoking • Persistent rhinitis • Eczema (under age one) • Frequent episodes • Consider other causes as well • Congenital malformations (eg. vascular rings) • Foreign body aspiration • Gastroesophageal reflux • CF, dysmotile cilia, immunologic problems

5. Bronchiolitis • Very common disease • More common in : • Boys • Formula fed • Crowded conditions • Infants of young mothers • Infants of mothers who smoked during pregnancy • Commonly older family member source of infection • Presents with upper respiratory symptoms in contact, usually mild • Presents with lower respiratory symptoms in infant, more often severe

6. Bronchiolitis • History • Onset, duration, associated factors • Usually starts with sneezing and clear rhinoorhea • Accompanied by poor appetite, diminshed feeding and increased temperature • Gradually, increasing respiratory distress ensues – paroxysmal wheezy cough, dyspnea, irritability • Very young infants may have apnea, sometimes as primary presentation • Birth history ( • Maternal smoking, prematurity, NICU stay • Past medical and family history • Asthma, eczema, CF, immunodeficiency • Daycare, siblings, smokers in the house, home environment • Physical examination • Pay attention to vital signs (especially RR and O2 sat) & growth chart (chronic conditions) • Look for signs of respiratory distress • Assess hydration and general appearance (wasted, clubbing) • Wheezing (not stridor) with prolonged expiratory phase (often also fine crackles throughout) • Absence of wheezing is not necessarily a good sign or a sign of improvement!

7. Bronchiolitis • Diagnostic work-up • >50% of cases of bronchiolitis caused by RSV • Other causes: parainfluenza, adenovirus, Mycoplasma, human metapneumovirus • CXR of limited benefit * • 265 children aged 2-23 months clincally diagnosed with bronchiolitis • 246 consistent with simple bronchiolitis, 17 with complex bronchioloitis and 2 inconsistent with diagnosis • 39 (14.7%) received antibiotics because of CXR findings *Schuh et al J Peds 2007

8. Treatment of Bronchiolitis • ABCs/Supportive care • Oxygen if desatting, frequent suctioning • Nasogastric feeding, potentially IV fluids depending on distress • Nursing at 30 degree angle • Monitoring for respiratory fatigue • Risk factors for severe disease: <12 weeks, premature, other comorbidity • Medication • Evidence nebulized epinephrine gives transient relief, possibly synergistic with steroids • No good evidence for steroids alone, Ribavirin or antibiotics • Prognosis • Criteria for admission: Hypoxia, respiratory distress, poor feeding/dehydration • Case fatality <1% due to apnea, respiratory failure or dehydration • Remember palivizumab for prems, chronic lung disease or congenital heart

9. What is Ruth’s diagnosis? Ruth is a 9 month old girl who is brought to your office for an itchy rash that started three days ago. She is constantly rubbing the soles of her feet against her lower leg. The rash is papulovesicular, involves the whole body, including palms and soles. (See Photo to right)

10. Scabies Sarcoptes scabiei var. Hominis transmitted by close contact and (rarely) by fomites. Female mites burrow into the skin and deposit 10-25 eggs/day as well as numerous scybala (fecal pellets) for 4-5 weeks before dying within their burrow. Eggs hatch in 3-5 days, mature in 2-3 weeks then mate and begin laying eggs to complete the life cycle. Isolated mites die within 2-3 days.

11. Scabies • Clinical Manifestations • 1-2mm papules, sometimes excoriated, crusting or scaly • Threadlike burrows are virtually pathognomic • Bullae and pustules common and may have wheals, papules, vesicles, dermatitis • Nodular scabies variant with red-brown nodules in covered areas (axilla, groin, genitalia) • Preferred sites are interdigital spaces, wrist flexors, anterior axillary folds, ankles, umbilicus, belt line, groins as well as genitals (adult men) and areolae (adult women) • Head, neck, palms and soles spared – except in infants • Differential Diagnosis • Varicella, viral exanthem, drug reactions, folliculitis • Diagnosis confirmed with microscopy (drop of mineral oil, No. 15 blade, glass slide) • Scabies variants • Norwegian scabies – Usually in immunocompromised, more severe variant, difficult to treat • Canine scabies – papules, vesicles and wheal on chest, abdo and arms. Self-limited in humans. Treat the dog • Treatment • Permethirn 5% cream entire body from neck down for 8-12 hours. Repeat in one week. • Pay attention to highly infested areas and treat the scalp in infants • Entire family should be treated, even those who are asymptomatic • Clothing, linens and towels should be laundered. Stuffed animals in garbage bag for 3-4 days. • Alternate therapies include lindane 1% or oral ivermectin

12. What is Liam’s diagnosis? Your son Liam comes home from school one day and says he has an itchy scalp. You look and find the following? (see picture to right) What is your diagnosis and treatment plan?

13. Pediculosis Pediculus humanus capitis are wingless, 2-4 mm long, six-legged insects that live on the scalp. Untreated, they live for 3-4 weeks, feeding every 3-6 hr by sucking blood and simultaneously injecting saliva. After mating, the adult female louse produces 5-6 eggs/day for 30 days . The eggs hatch in 9-10 days. Nymphs mature in 9-15 days. They can live for up to 3 days away from their host. Common modes of transmission include shared combs, brushes or towels.

14. Scabies • Clinical Manifestations • Intensely pruritic after sensitization (3-4 weeks), but some never itch. • Usually fewer than 10 adult lice, which are more likely visible if hair is combed with fine toothed comb. Nits (0.5mm translucent eggs laid near the base of the hair that cannot be knocked off the hair with the fingers) are usually detectable in occipital region, but may indicate past infestation. • Secondary pyoderma can develop from scalp trauma resulting in matting together of hair and cervical and occipital lymphadenopathy • Hair loss may occur from pyoderma, but not directly from the pediculosis • Treatment • R&C shampoo, Kwellada-P, Nix Creme rinse useful, but some resistance documented • Hexit, PMS-lindane associated with neurotoxicity and bone marrow suppression (some resistance also) • Work into hair until wet, let sit for 10 minutes (4 for 1% lindane), rinse thoroughly, repeat in 7-10 days. • All household contacts should be treated, nits should be removed with a fine toothed comb, clothing and bed linens should be laundered and combs and brushes discarded or treated with pediculicide. • Children in the class should be given information about diagnosis, but “no nit” policies are not supported. • Other forms of pediculosis • Pediculosis corporis is rare in children except under conditions of poor hygiene • Small, intensely pruritic red maculeépapule with hemorrhagic punctum on shoulders, trunks, buttocks • Live in the seams of clothing and only go to skin to feed. Vectors of disease (typhus, trench fever, relapsing fever) • Treatment is improved hygiene and hot water laundering of infested clothing and bedding • Pediculosis pubis • Phthirus pubis is 1-2mm in length and wide, so looks like crab. Usually seen in adolescents. May occasionally be seen on eyelashes in children • Steel-gray spots less than 1 cm (maculae cerulae) on groin, abdo and trunk . Lice hard to spot, but nits visible or palpable. • Treatment is pyrethrin or lindane with repeat in 7-10 days . Treat eyelashes with petrolatum 3-5x daily for 8-10 days. • Consider sexual abuse in younger children

15. Cellulitis • Typically caused by Staphylococcus aureus or Streptococcus pyogenes, usually through a break in the skin. Children under five also get H. influenzae type B and S. pneumoniae • Edema, warmth, erythema and tenderness of affected area, typically spreading over time • Uncommonly associated with regional adenopathy, fever, chills and malaise • Complications include: abscess, bacteremia, osteomyelitis, septic arthritis, thrombophlebitis , endocarditis and necrotising fasciitis • Cultures from site rarely grow organism (25%; maybe 30% from site of origin) • Neonates with cellulitis require FSWU and braod spectrum antibiotics • Otherwise, treatment is with : • Parenteral antibiotics if fever, lymphadenopathy or constitutional signs • Cloxacillin or cefazolin • Oral antibiotics if afebrile, no lymphadenopathy and WBC <15,000 • Cephalexin or cloxacillin (if able to take tablets) • Clindamycin if MRSA suspected

16. Skin abscess • Primarily due to MSSA, but MRSA becoming more common • Clinical distinction between MSSA and MRSA not possible • Discharge or pus from the abscess should be sent for culture • Recurrences are very common • All forms of S. aureus can cause osteomyelitis, septic arthritis, necrotizing fasciitis, sepsis and pneumonia, so concern abscesses could progress if not treated with oral antibiotics. • The only paediatric randomized trial showed no complications and equivalent post­drainage cure rates at 10 days with TMP/SMX versus placebo • More recurrences at 10-day but not 30-day follow-up in the placebo group • Therefore, most children can be managed initially with drainage alone • Patients must be reassessed if systemic symptoms, worsening local symptoms, no improvement after 48 h. Significant fever or other systemic signs should be treated with parenteral antibiotics • Empiric post-drainage oral antibiotics should be used from presentation if : • younger than three months of age • other significant systemic illness • significant associated cellulitis with or without low-grade fever • TMP/SMX as oral treatment covers almost 100% of MRSA (but not group A strept) • Can also use doxycycline (older than 8) or clindamycin

17. Treyvon’s itchy scalp Treyvon’s parents bring him in because he has hair loss and an itchy scalp for the past few weeks. What is his diagnosis? What is the best treatment option?

18. Tinea capitis • Typically caused by Trichophyton tonsurans or Mycosporum canis, but also other spp. • Infection typically a papulosquamous eruption often causing hair loss (“black-dot ringworm”) • Severe inflammatory response (“kerion”) sometimes develops • Severe host inflammatory reaction with secondary bacterial infection • Elevated, boggy, granulomatous mass studded with pustules • Permanent scarring and hair loss may result • Differential diagnosis includes: • Seborrheic dermatitis, psoriasis, alopecia areata, trichotillomania, dystrophic hair disorders • Rarely – secondary syphilis, discoid SLE, lichen planopilarir • Definitive diagnosis KOH preparation and culture • (Microsporum spp may fluoresce with Wood’s lamp) • Treatment is with oral griseofulvin (20mg/kg/d) for 8-12 weeks. • Side effects include nausea, vomiting, headache, blood dyscrasias, phototoxicity, hepatotoxicity • Continue for one month after culture becomes negative • Topical therapy alone is ineffective, but may reduce shedding of spores • Itraconazole if adverse reaction, intolerance or resistance to griseofulvin • Shaving of scalp is not necessary.

19. Emma’s rash It first started on her feet.... And then went to her face.

20. Tinea pedis • Most typical in preteen and adolescent males (who frequent public pools) • Pathogens: T. rubrum, T. mentagrophytes, Epidermophyton floccosum • Subdigital crevices are fissured and macerated with peeling • Characterised by tenderness, itch and persistent foul odour • Often associated with id reaction • Probably a reaction to circulating fungal antigens • Typically characterised by grouped papules, vesicles and occasionally pustules • Inflammatory vesicular type can occur with T. Mentagrophytes • Predisposing factors: occlusive footwear and warm, humid weather • Differential diagnosis: • Simple maceration, infections (bacterial, candidal), dermatitis (contact, atopic, juvenile plantar) • KOH preparation and culture make the diagnosis • Treatment • Avoidance of occlusive footwear, careful drying after bathing, absorbent anti-fungal powder • Topical imidazole preparation (ketoconazole, clotrimazole, miconazole) is curative

21. Tinea corporis Usually caused by T. rubrum or T. mentagrophytes , contracted from direct contact with infected person. Occasionally caused by M. canis, often contracted from infected pet. Dry, mildly erythematous, raised scaly plaque that spreads centrifugally and usually clears centrally (aka “ringworm”). Differential includes granuloma annulare, nummular eczema, pityriasis rosea, psoriasis, seborrheic dermatitis, erythema chronicum migrans, tinea versicolor. Diagnosis by KOH prep & culture. Treatment is topical anitfungals for 2-4 weeks or oral griseofulvin for four weeks for extensive or severe disease.

22. Tinea cruris and unguium • Tinea cruris • Most often adolescent males • Small, raised scaly erythematous patch on inner thigh which spreads peripherally (often with vesicles at the margin) and eventually forms bilateral, irregular patches with sharp margins and hyperpigmented center • More common in obese or excessive sweaters • Diagnosed by KOH preparation and culture • Treatment is loose cotton underwear and topical imidazoles • Tinea unguium • Ranges from a white superficial onychosis to invasive, subungual infection with thick, yellow, brittle nails that loosen from the nail bed and can even turn black and crack or break off • Shavings (preferably from deeper areas of nail) for KOH prep and culture necessary • Treatment • Oral itraconazole (double normal dose for one week per month x 3-4 months) • Oral terbinafine (daily for 12 weeks) is more effective • Oral griseofulvin and topical preparations inneffective