Pediatric Infectious Disease

Russell LamJanuary 12, 2012

Objectives Measurement of a fever Acute Otitis Media UTI Pharyngitis

Case 1 A 1 year old baby has had a typical febrile

seizure. You are planning on discharging the patient home with the usual advice.

On her way out, the mother asks you about the best way to measure the baby’s temperature so she can treat it.

What do you recommend?

What is a fever? 38°C (100.4°F) measured rectally Ways of measurement

Rectal Axillary Oral Tympanic Temporal

Rectal Thermometry Traditionally gold

standard May be slow to change

in relation to core temperature

Affected by depth of measurement, local blood flow, presence of stool

Uncomfortable Perforation is possible

but rare (1/2 000 000 measurements)

Axillary Thermometry

Easy to do but inaccurate Works best if placed directly over axillary artery but

affected by local temperature CPS recommends this as screening test in neonates

Oral Thermometry

Reflects temperature of sublingual arteries

Affected by recent ingestion of food/liquid and mouth breathing

Mouth must be sealed Accuracy lies between

axillary and rectal, better with increasing age.

Mercury?

Mercury thermometers are no longer recommended by the CPS

Read thermal radiation from TM and ear canal

Crying, AOM, or earwax does not change measurement

Accuracy is again questionable

Temporal artery thermometry More accurate than

tympanic and better tolerated than rectal

Not yet recommended when definitive measurements are required

Take home point #1

Case 2 A 4 month old boy has a fever and a runny

nose for 5 days. You fully examine the child and are about to call this a URTI when you remember to check the ears!

You see this:

Other details Never had an ear infection before Never has had antibiotics What antibiotic (and dose) would you

prescribe (if any)?

Identify the normal landmarks

Normal ear landmarks

Diagnosis of AOM 3 things

Acute onset Middle ear fluid Inflammation

Pathogens Pre-Pneumococcal vaccine =

S Pneumo 42% H Flu 31% Moraxella 16%

Post-Pneumococcal vaccine = S Pneumo 44% (1998-2000) to 31% (2001-2003) H Flu non-typeable 43% (1998-2000) to 57% in (2001-

2003) Viral only

20-30%

Duration CPS (2009)

5 days in all except for <2 years Frequent AOM AOM with perforation Failure of initial abx

Cochrane Review Kozyrskyj 2010

Short (<7 days) vs long (>7 days) course abx Treatment failure higher if short course OR 1.37 CI

1.15-1.64 at eight- to nineteen days At 30 days, treatment failure similar OR 1.17 CI 0.95-

1.43 No differences if ceftriaxone used < 7 days or

azithromycin. Better GI adverse events in short-term abx and

azithromycin.

Case 2 continued A 4 month old boy,

AOM, no prior AOM, no recent abx, febrile, NKDA

Antibiotic – yes or no?

Which one? How long?

Take home point #2 AOM is 3 things: acute, inflammation, middle

ear fluid Top 3 bugs: S Pneumo, H Flu, Moraxella First line therapy: Amoxicillin 80mg/kg/day for

5 days

Case 3 Same kid is 2 years old. No AOM since his first

one. Complains of ear pain and mom states he is tugging at his left ear.

You again diagnose AOM. Antibiotics – yes/no?

Differences between CPS/TOP/AAP CPS statement (revised 2009)

6months lower limit for treatment 1st line abx amoxicillin 75-90mg/kg/day

TOP doc statement (revised 2008) 2 years lower limit for treatment 1st line abx amoxicillin 40mg/kg/day

AAP policy statement (revised 2004) 2 years lower limit for treatment

Watchful waiting Reasoning

Viruses can be found in middle ear fluid in absence of bacteria, though usually bacteria is present

Spontaneous resolution occurs in most cases NNT for symptom resolution at 48h is 15 (CPS

2009) NNT for symptom resolution at 14 days is 9 (JAMA

2010) NNH for diarrhea is 10 (JAMA 2010)

CPS (2009) Watchful waiting approach appropriate if:

>6 mos with mild signs and symptoms Observation is possible in 48-72h

Aboriginal children Unknown if watchful waiting increase risk as they

have high incidence of chronic suppurative OM

CPS (2009) Not appropriate if:

Severe symptoms (appear toxic, otalgia, high fever 39 degrees)

Chronic disease = Immunodeficiency, chronic cardiac/pulmonary disease, Down syndrome

Anatomic abnormality of the head/neck Complications of AOM (suppurative complication

or chronic perforation)

Risks of watchful waiting Mastoiditis/Meningitis/Intracranial abscess

Exceedingly rare! 2500rx to prevent 1 case of mastoiditis

Cochrane Reviews Sanders 2009

Analyzed 10 RCTs abx versus placebo Pain reduced at 2-7 days (RR 0.72 CI 0.70-0.74)

NNT 16 to reduce ear pain 1 case of mastoiditis in antibiotic treated child (out

of 2000 pts) Vomiting, diarrhea, rash higher if on abx

NNH 24

Who needs ENT referral? TOP (2008)

>3 episodes in 6 months >4 episodes in 12 months Cleft palate or craniofacial malformation OME for 3 months with hearing loss > 20dB

Take home point #3 AOM is rarely associated with suppurative

complications Treatment is primarily based on symptom

relief Symptoms generally self resolve without

therapy Watchful waiting approach is appropriate for

many over age 6 months

Case 3 A 2 year old girl presents with fever,

decreased intake. She is previously healthy. You examine her and she looks unwell and her

HR is 150 sleeping. You bolus her, write some orders for antibiotics, and get some blood work. You also want to check a urine.

What kind of sample should you get?

What is an appropriate specimen?• Most children with UTI present to primary care

givers• Therefore, the collection of a urine specimen

must be– Simple, Reliable, Cost effective, Acceptable

• Current methods– Suprapubic aspiration– Urethral catheterization– Perineal bag specimen– Clean catch

Suprapubic Aspiration• Procedure: Needle and syringe used to collect

urine from bladder through aseptic area of skin

• Pros: Most microbiologically accurate• Cons:– invasive– requires technical skill– yield varies

• U/S guidance can increase yield from 60% to 97%

Urethral catheterization Procedure: Insertion of a sterile number 5

feeding tube into cleansed urethra Pros: Very accurate

83% specific versus 89% in SPA Very low risk of introducing infection

Cons: Invasive Risk of urethral trauma Success rate quite varied, from 23-90%

Perineal Bag Procedure: Taping a sterile plastic collection

bag over the genitalia and waiting for patient to void

Pros: Simple, non-invasive Cons: High rate of contamination (up to 50%)

Higher overall cost from misdiagnosis If antibiotics are appropriate, a bag specimen is

insufficient to document presence of UTI Bags are good for urinalysis and microscopy, only

good for culture if negative Transport cultures to lab ASAP after collection

Clean Catch Procedure: Like it sounds, where you catch

urine in a sterile container Pros: Microbiologically accurate Cons: Difficult to obtain

Evidence:• Bag versus catheter– Culture of a urine bag was 100% sensitive, 70%

specific– Culture of a catheter sample was 95% sensitive

and 99% specific• AAP Recommendation (2011)– If 2 mos-2years, if you diagnose UTI with a bag,

you need confirmatory testing

What is an appropriate specimen? (NICE 2007) If toilet trained (>3 years) =

Clean catch! If not toilet trained (<3 years) =

Catheter if sick (as you will likely start abx) and cannot do confirmatory testing afterwards

Bag if left on <30 minutes only for microscopy and urinalysis culture useful only if negative if positive, must perform confirmatory testing

Take home point #4 If you need to start antibiotics, do not obtain a

bag specimen. You must use SPA or catheterization.

Clean catch is an option if the child is old enough and cooperative.

A negative bag culture rules out UTI.

Case 3 continued You get an in and out and the urinalysis

suggests UTI. She looks quite sick so you want to admit her and will start her on antibiotics.

What parenteral antibiotic should you choose?

What are the common UTI organisms? KEEPS

Klebsiella Enterobacter/Enterococcus E. Coli Pseudomonas Proteus Staph saprophyticus

Which IV antibiotic to use? Bugs and drugs 2006 – Amp/Gent or Cefotax

or Ceftriaxone

NICE 2007 - No real difference between of the any parenteral antibiotics Clavulin IV vs Cefotaxime Cefepime vs Ceftazidime Cefotaxime vs Ceftriaxone

AAP 2011 – Careful with aminoglycosides if evidence of renal toxicity

Case 4 2 yo girl who looks well but has 4 days of

fever of 39 degrees and no focus. She is walking around the ED and looks great despite her fever.

Would you SPA or catheterize her? Would you bag her?

If not so sick… AAP 2011

If 2 mos-2yrs, suggest urinalysis by most convenient method if parents/clinician resistant to SPA or catheterization.

If urinalysis supports UTI, then need culture specimen (SPA or cath).

Case 4 continued The pt voids into a bag and it is promptly

removed within 30 minutes and immediately dipped, then sent to the lab for microscopy

Urinalysis: - nitrites/ + WBC / - RBC Now what?

How do I interpret a urinalysis?• Nitrites– Created when bacteria reduce urinary nitrates to

nitrites• Not all bacteria do this (streptococcus, enterococcus,

staphylococcus)• Require a few hours to form• False negative with Urine bilinogen, low urine pH,

vitamin C, low nitrogen containing food• Leukocyte esterase– Detects esterase, an enzyme in WBC

• False negative with high urine SG, urine glucose, proteinuria, meds (vitamin C, gentamicin, tetracycline, nitrofurantoin)

Case 4 continued Microscopy comes back on the urine WBC 10/HPF, bacteria seen What do you prescribe? Do you refer for an ultrasound? VCUG?

What is good oral therapy? Options

TMP/SMX Cefixime

Once a day and as effective as parenteral therapy Nitrofurantoin

Do not use if renal involvement is likely. Is excreted in urine but does not reach appropriate concentration in blood stream to protect kidneys

Amoxicillin Increasing E coli resistance

Duration of therapy and prophylaxis? AAP 2011

If 2 mos-2years, strong recommendation to complete 7-14 day oral course regardless of whether or not parenteral antibiotics were given

After course, should start prophylaxis until imaging performed TMP/SMX Nitrofurantoin Nalidixic acid

What imaging should you perform? AAP 2011 – Fair evidence only

If 2 mos-2 years, if good response to antibiotics in 48 hours, then U/S at earliest convenience

If poor response to antibiotics in 48 hours, then prompt U/S

No VCUG needed for first UTI VCUG for recurrent febrile UTI or if abdominal

ultrasound is abnormal

Rationale Older children with 1st UTI likely do not have

significant reflux/kidney abnormality If no improvement in a young child, need to

look urgently for anatomic abnormality (obstruction) or abscess

Take home point #5 Cefixime is a good option for > 6 months, well

looking child Duration of oral therapy is 7-14 days

regardless if IV abx were used Ultrasound but timing depends on pts

response to treatment No VCUG for first time UTI Antibiotic prophylaxis is needed until imaging

is complete

Case 5 A 5 year old male is complaining of sore

throat, and has a tactile temperature. He has no other signs of URTI. He has cervical lymphadenopathy.

You look into his throat and see this:

How likely is he to have strep throat? Should you swab his throat? Should you start empiric antibiotics?

Diagnosis of GAS TonsillopharyngitisModified Centor Score (McIsaac score)

CMAJ 1998;158:75; CMAJ 2000;163:811

Criteria Score

Temp > 38C 1

No cough 1

Tender AC LN 1

Tonsils swollen/exudate

1

Age 3 – 14 1

Age 15 – 44 0

Age >44 -1

Total 0 - 5

Total Score Likelihood GAS

%

0 1 – 3

1 5 – 10

2 11 – 17

3 28 – 35

4 or 5 51 – 53

Complications of Streptococcal Tonsillopharyngitis

Suppurative Peritonsillar abscess Retropharyngeal abscess Cervical adenitis Streptococcal Toxic Shock Syndrome

Non-suppurative Post-streptococcal glomerulonephritis Acute rheumatic fever Post-streptococcal arthritis PANDAS (pediatric autoimmune

neuropsychiatric disorders associated with streptococcus)

Complications of Streptococcal Tonsillopharyngitis

Good evidence that appropriate antibiotic therapy reduces risk of suppurative complications

Improves symptoms by 1 day and infectivity after 24h

Acute rheumatic fever – reduced risk if appropriate antibiotic therapy given within 9d of symptoms and continued for 10d

Post-streptococcal glomerulonephritis – no evidence that antibiotic therapy reduces risk of development once pharyngitis has occurred

Management (TOP 2008) Swab first, treat only if positive Treat with 10 days always with PenVK unless

contraindicated No repeat swab needed unless recurrence of

symptoms

Carriers? Generally don’t get rheumatic fever Document carriage with a swab when pt is

asymptomatic Eradication only if:

Family member with PSGN or rheumatic fever Outbreak of rheumatic fever Outbreak of pharyngitis in closed community Repeat transmission within families >3/year of symptomatic pharyngitis

Take home point #6 Use the strep throat score to predict who

should be swabbed, not who has strep throat You can always wait for the culture to come

back, but you can safely give the parent a wait-and-see prescription

Treatment of strep throat are mainly for the prevention of rheumatic fever, versus symptom control

Questions?