Pediatric Infectious Diseases

Chris McCrossinSpecial thanks to: Dr Bela Sztukowski, Dr Sue Kuhn, & Dr Brian Ward (McGill University)

April 29th, 2010

Case 1

• 4 year old child presents with cough, runny nose, itchy watery eyes and high fever x 2 days

• ROS: headache, malaise, anorexia

• O/E

• Child looks unwell, mild tachycardia, Temp 39.1, RR 28,

• Brassy/barking cough

• Bilateral conjunctivitis, rhinorrhea

• CVS/Resp/Abdo otherwise unremarkable

Outline

• Review common and uncommon but severe pediatric infectious illnesses

• Measles

• UTI’s

• Pneumonia

• Unknown cases

• Highlight Pearls of Diagnosis & Management

• Common Pitfalls

Measles

Measles Virology

• Paramyxoviridae

• Measles History:

• Old World disease spread by improved transportation

• In virgin populations outbreaks resulted in 50% mortality

• Current mortality in developed countries is < 1 per 1000 cases

Measles History

• “Brutal Example of Darwinian Natural Selection”

Thanks to Brian Ward, McGill University

Measles History

• “Viral Genocide”

Lovell WG. Secret Judgements of God. Old World Disease in Spanish America. U Oklahoma 1992.

Transmission

Reproductive Rate

HIV 1.5-2

Influenzae 7-8

Measles 50!!

Thanks to Brian Ward, McGill University

Transmission

• What does this mean?

• MEASLES IS THE MOST CONTAGIOUS VIRUS KNOWN TO MAN!

• Infectious period is from 1-2 days before the prodrome until 4 days after the rash develops

Natural History

• Day 0: Exposure

• Day 7-10: Non-Specific symptoms

• Conjunctivitis, Coryza, Cough, Fever

After symptoms start

• Day 0.5-1: Koplik Spots (enanthem)

• Day 4-7: Maculopapular Rash (exanthem)

• Recovery 2-4 days after acute phase

• Transient Immunosuppression for 30 days post infection

Guerrant, Tropical Infectious Diseases

Koplik Spots

Courtesy Dr Brian Ward

Clinical Spectrum: Developed World

• Acute Self-Limited Disease (But Severe!)

• 30% Hospitalization rate in Adults

• Complicated Disease

• Diarrhea with dehydration

• Otitis Media - Pneumonia

• Neurologic Involvement

• Subacute sclerosing Panencephalitis (1:1,000,000)

• Post-infectious Encephalomyelitis (1:1000)

• Immunocompromised Hosts

• Progressive, Giant-cell Encephalitis, Pneumonitis

Ocular Effects of Vitamin A Deficiency

Courtesy Dr Brian Ward

Treatment

1. Normally no therapy (supportive)

2. Vitamin A

• In places with mortality > 1%

• Reduces mortality by 50-80%

• Benefit also in North America (less morbidity)

3. Ribaviron

• Immunocompromised

4. Antibiotics

1.Concomitant bacterial pneumonia, AOM

5. Immune Globulin

• Newborns, Immunocompromised

Measles Bottom Line

1.Be wary of the unvaccinated child with non-specific upper respiratory symptoms (many present prior to the rash)

2.Koplik spots help you nail the diagnosis

3.Measles is the most contagious virus known to man

4.Vitamin A helps decreased morbidity and mortality

5.Newborns & Immunocompromised patients are managed differently

Urinary Tract Infections

The Issues

• Diagnosis

• Antibiotic Choices

• IV vs Oral Therapy

• Duration of Therapy

• Follow-up Imaging after Diagnosis of UTI

• Prophylaxis

Pathogens

• 78% E coli

• 10% Gram negative rods

• 4% Enterococcus

• 2% Other

Epidemiology

• Pre-test probability of UTI in febrile infants 3-24 months:

• Uncircumcised males 6%

• Circumcised male < 1%

• Females ~7% (this risk gets lower after 12 months)

Jama 2007 298(24): 2895-2904; Baren, Pediatric Emergency Medicine

Case 2

• Parents bring in their 12 month old girl because of a low grade temperature

• No focus, ROS unremarkable

• She is fully vaccinated, was a healthy term birth, and attends daycare 3 days per week

• O/E

• Well looking child with normal vitals except for T38.3

• She examines normally although she screams every time you try to go near her

The Dilemma

Renal Scarring

• Earlier we treat the less risk of scarring

• Patients treated within 24 hours of fever onset appear to have little to no risk of renal scarring

• Risk of scarring becomes more frequent in patients with untreated fever symptoms longer than 24 hours

• Clinical Significance of this is unknown

Ped Nephrol 2003; 18(2): 115-8

Does this Child Have a UTI?

• Most Useful Clinical Features

• Previous UTI (LR 2.3-2.9)

• Temp > 40 (LR 3.2-3.3)

• Suprapubic tenderness (LR 4.4)

Jama 2007 298(24): 2895-2904

Does this Child Have a UTI?

• Laboratory Features

• If any one positive:

• Sn 100%, SP 70%

• 20% of young children with a documented UTI will have negative urinalysis

Sensitivity Specificity

LE 80% 80%

Nitrites 50% 98%

WBC’s 75% 80%

Bacteria 80% 80%

Baren, Pediatric Emergency Medicine 2008

BMC Pediatrics 2005; 5(4)

Bag Specimens

• Urine Dip on Bag Specimen

• Sn 85%, Sp 62%

• Urine Dip on Cath Specimen

• Sn 71%, Sp 97%

J Pediatr 2005; 147(4):451-6

Diagnostic Approach Jama 2007 298(24): 2895-2904

Diagnostic Approach Jama 2007 298(24): 2895-2904

Diagnostic ApproachJama 2007 298(24): 2895-2904

Case 3

• 9 month old female presents to the ED with fever, vomiting, and had two loose stools today

• Looks non-toxic but irritable and has a temp of 39.8

• RR normal, HR slightly elevated

• Physical exam is unremarkable

• Dip from cath urine is + for both Nitrates and LE

Antibiotics

• Oral vs IV

• Oral Cefixime considered equivalent to IV Cefotaxime

• Based on 1999 study that included 1-24 month olds

• Oral Amox/Clav also acceptable

• Special considerations:

• Vomiting

• Age

• Severity

• Allergies

• Underlying renal anomaly

Pediatrics 1999; 104: 79-86; Cochrane Review 2009

Antibiotics

• IV Choices

• Ceftriaxone

• Long 1/2 life

• ID can see in 12 hours and still give a repeat dose at the time of their f/u visit

• Gentamicin

• 5 mg/kg once daily is adequate

• Effective, relatively low toxicity profile with this dosing BUT practical considerations make it less favorable

Antibiotics

• Local Resistance Patterns

• E coli

• 41% sensitivity to amoxicillin

• 96% sensitivity to cefotaxime and nitrofurantoin

• 72% sensitivity to TMP-SMX

• 92% sensitive to gentamicin

• 57% sensitive to keflex

• Oral Choices

• Cefixime

• Nitrofurantoin

• ? Ciprofloxacin if you are really stuck

Calgary Lab Services Antibiogram

Imaging

• Ultrasound

• not useful unless you are specifically looking for a secondary complication like an abscess

• VCUG

• the only follow-up investigation needed for pediatric UTIs

• VCUG is done on every 1st time child presenting with a febrile UTI under the age of 5 years

• If referred to ID they will arrange the VCUG, if sent home you can arrange and have them F/U with GP or refer to pediatrician for F/U

Pediatrics 1999; 103(4): 843-52

UTI Bottom Line

1.Urine culture is the gold standard for diagnosis

2.The younger the child, the more likely you are to get false negative urine dips and urine micro’s

3. PO antibiotics are equally effective in treating pediatric UTIs but be practical!!

4.Ensure child has appropriate F/U and testing arranged

5.Remember that really young patients with probable non-urinary cause for fever also have significant rate of SBI’s

Pneumonia

The Issues

• Who needs a CXR?

• Does the CXR pattern predict etiology?

• Antibiotic choices and resistance

Etiology

• Close to 50% of cases are of unknown etiology

• 3 months - 5 years

• Streptococcus pneumoniae

• Non-typeable H. influenzae

• Moraxella catarrhalis

• S. pyogenes

• 6-16 years

• Mycoplasma

• Chlamydia pneumoniae

Pneumococcal Disease in Canada

• Since Prevnar

• IPD decreased 56%

• 6 non-vaccine serotypes have increased but only 19A has increased to statistically significant numbers

• PCN resistance has remained unchanged (17%)

• Cefotaxime & Ceftriaxone resistance remains unchanged overall; however the incidence of 19A resistance has increased significantly (32% of 19A isolates in children)

Vaccine 2010; 28:2130-2136

Who Needs a CXR?

Who Needs a CXR?

• Best individual finding for ruling out pneumonia is the absence of tachypnea

• Chest indrawing and other signs of increased WOB are better for ruling in pneumonia

• Auscultation doesn’t help much

• If all clinical signs (RR, auscultation, WOB) are negative then CXR is unlikely to add much

Jama 1998; 279(4): 308-313

Who Needs a CXR? Pediatrics 2004; 113:e186-189

Case 4

• 12 M old M presents with 3 day hx of fever, cough, respiratory distress

• Admitted to hospital x 1 week

• Swabs + for RSV

• Discharged home and returns 1 day post discharge with T 39.0

• O/E:

• RR 38, HR 140, T37.3

• Intercostal retractions

• Alert, well hydrated, minimal distress, non-toxic appearance, fine bilateral expiratory crackles

CXR’s taken within 15 hours of each other

Does the pattern on CXR predict the bug?

• Focal consolidation can occur with both S. pneumoniae and with atypicals like mycoplasma

• “Round Pneumonia” is more commonly caused by S. pneumoniae

• Other things to consider

• Atelectasis with reactive airways disease

• Tuberculosis

• Foreign Bodies

Strep pneumo

Strep pneumo

Rhinovirus

Parainfluenzae + HHV6

CXR: Does it tell us anything?

• Alveolar infiltrates are suggestive of bacterial etiology; however...

• Up to 1/3rd of alveolar infiltrates will be secondary to viral illnesses

• Bacterial infections can cause interstitial infiltrates on CXR (up to 50% in one study)*

• Performing a CXR in mild and moderately ill appearing children increases antibiotic prescription and hospitalization rates without changing morbidity, mortality, or duration of symptoms**

• No evidence exists to suggest that CXR improves outcome in ambulatory children with acute lower respiratory illness***

• However, there are no reported studies that examine the clinical signs and symptoms of pneumonia in conjunction with a negative CXR****

*Thorax 2002; 57:438-441

**Cochrane Database Syst Rev 2000 (2)

***Baren Pediatric Emergency Medicine 2008

Treatment: < 5 Years Old

• Amoxicillin is the Drug of Choice

• PCN Allergy

• Clindamycin

• Macrolide

• If fail to respond in 24-48 h consider mycoplasma or chlamydia and add or substitute a macrolide

• Macrolides cover:

• All of the most common CAP pathogens BUT up to 50% resistance to S. pneumoniae in some regions

Treatment:> 5 Years Old

• Macrolides are the drug of choice

• Can use Doxycycline if > 8 yrs old

• Also consider fluoroquinolone in the older ambulatory child*

Special Treatment Considerations

• Patients with

• G-tube fundo

• CP

• Developmental Delay

• Consider adding Clindamycin to cefuroxime (aka “C squared”)

Resistance Patterns

• S. Pneumoniae

• Calgary (2006-2008)*:

• 89% Sn to PCN

• 100% Sn Ceftriaxone

• 90% Sn Erythromycin

• 100% Sn Levofloxacin

• United States

• 30-35% Macrolide Resistance

*Data Courtesy of CLS

Emerg Inf Dis 15 (2009) 1260-1264

Pneumococcal Resistance Int J Antimicro Agents 2009; 34:375-379

Pneumococcal Resistance Int J Antimicro Agents 2009; 34:375-379

Pneumococcal Resistance Vaccine 2009; 27:3553-3560

Pneumonia Therapy

Outpatient Most Common Pathogen First Line Therapy Second Line Therapy

1-3 monthC. trachomatis, RSV, S.

pneumonia, parainfluenzaeErythromycin or

Azithromycin

4mo - 5 yr Streptococcus pneumoniaeAmoxicillin (80-90

mg/kg/day)

5 yr & olderMycoplasma pneumoniae, Chlamydia pneumonia, S.

pnemoniae*

Macrolide (or doxy if > 8 yrs old)

Ceftriaxone + Azithromycin

Hospitalized

< 5 yr AmpicillinIf heading to ICU:

cefotaxime + azithromycin + vancomycin

> 5 yrCeftriaxone + Azithro +/- Vanco (if evidence of lung

necrosis)

Second or Third gen cephalosporin

Sanford Guide

Pen Allergic Patients

• “...but doctor the last time someone gave my Jimmy penicillin he spent a month in the ICU...”

• Other options:

• For the < 8 age group

• Macrolide (Erythro, Clarithro, Azithro)

• Clindamycin

• Children > 8

• Doxycycline

• Fluoroquinolone*

Duration of Therapy

• 7-10 Days

• 5 Days if using Azithromycin

• No evidence for these suggestions

Admission

• Age < 6 months

• Toxic appearance

• Severe respiratory distress

• Dehydration

• No response to appropriate antibiotics

• Immunocompromised status

• Bi-lobar pneumonia

• Comorbidities

Complications

• Necrosis

• Empyema

• Parapneumonic Effusion

• Lung Abscess

A brief word on TB in children

• CXR is most often normal

• Miliary TB > Focal pulmonary infiltrate

• Greatest RF for TB in children < 2 years of age is household contact

• TB meningitis is much more common in peds than in adults

• Consider the diagnosis in Native North American populations and in foreign born immigrants

Pneumonia Bottom Line

• We probably put more weight into the CXR than what we need to

• Consider ability/willingness for patient to follow-up in your treatment plan

• Remember that treatment is largely empirical and that empirical treatment is based on age

Reference

Reference