Pediatrics Flashcards
Define gestational age (GA)
Time from conception until birth
Define postnatal age (PA)
Chronological age since birth
What is post-conceptual age (PCA)/Corrected Gestational Age (CGA)/ Postmenstrual Age (PMA)?
- Age since conception
- PCA = GA + PNA
Lucy is an 11 day old neonate that was born at 30 weeks, 2 days gestational age. What is Lucy’s corrected gestational age?
31 weeks, 6 days
How old is a premature neonate?
< 37 weeks gestational age
How old is a full term neonate?
Neonate born 37-41+6/7 weeks gestational age
How old is a neonate?
- Full term neonate up to 28 days PNA
- Premature neonate whose PCA is <= 42-46 weeks
How old is an infant?
1 month to <1 year of age
How old is child/children?
1 year to 12 years of age
How old is adolescent?
13 years to <18 years of age
How does pH of a child differ from an adult?
How does that affect absorption of acid labile compounds and weak acids?
Changes in gastric pH (higher pH earlier in life)
- Absorption of acid labile compounds is increased (e.g., penicilin)
- Absorption of weak acids is decreased (e.g., phenobarbital)
How does absorption differ for neonates? (4)
- Gastric motility increases with age (normalizes at ~4 months of age)
- Increased time for gastric emptying and decreased intestinal motility in first months of life
- Slower drug absorption and longer Tmax in neonates and young infants vs older infants and children - Increased topical absorption in neonates/infants
- Reduced skeletal muscle blood flow and inefficient muscular contractions in neonates
- Higher density skeletal-muscle capillaries in infants compared to older children
- Altered absorption in subcutaneous and intra-muscular drug absorption
How does total body water change during the following stages of life:
1. Fetus
2. Preterm neonate
3. Term neonate
4. Adults
- 94%
- 85%
- 78%
- 60%
How does distribution differ for neonates/infants? (3)
- Neonates + Infants have very large extracellular and total-
body fluid
- Higher Vd of hydrophilic drugs (e.g. gentamicin) - Decreased circulating albumin and alpha-1-acid glycoprotein
- Increased unbound (free) fraction drug - Higher amount of endogenous products (i.e. unconjugated bilirubin, free fatty acids)
- Displace drugs from binding sites
What CYP enzymes appear at the following stages of life?
1. First few hours (2)
2. 2. First week (3)
3. First 1-3 months (1)
- Appear in first few hours: CYP 2D6 and CYP 2E1
- First week of life: CYP 2C19, CYP 2C9, CYP 3A4
- First 1-3 months of life: CYP 1A2
How do phase II enzymes change with age?
Glucoronyltransferase (UGT) increases with age
- Ex// acetaminophen and morphine
How is elimination different for pediatrics? (3)
- Tubular secretion is immature in neonates/infants
- Glomerular filtration increased with age
- Rapid increase in 1st two weeks of life
- Reaches adult values at 8-12 months of age - Impacts drugs with primarily renal clearance
- Ex. Vancomycin, aminoglycosides
What is the best equation to estimate CrCl in pediatrics?
Bedside Schwartz uses k = 0.413
What are some considerations when using the Schwartz equation? (3)
- Remember: this is only an ESTIMATE! Clinical picture and trends remain crucial when evaluating
- Validated mostly in chronic kidney disease patients, up to moderate CKD (eGFR 15-75 mL/min)
- Study Limitations:
- Rapidly changing serum creatinine*
- Infants < 1 year
- Obesity
- Malnutrition
- Muscle wasting
What are some dosing considerations for pediatrics? (3)
- Doses are generally based on body weight
- CHECK: mg/kg/day or mg/kg/dose - Body Surface Area
- Chemotherapy and some biologics
- Mosteller Formula most commonly used - Total daily dose of a medication should not exceed adult
maximums
- Caution in overweight children
- Example: ceftriaxone, amoxicillin
- Few exceptions: ex// vancomycin or antibiotics used in cystic fibrosis
Should maybe know some professional resources for pediatric meds and conditions (4)
- Pediatric and Neonatal Lexi-Drugs
- BC Children’s Online Formulary (pedmed.org)
- NeoFax
- CHOP or Toronto SickKids Hospital
Many dosage forms are not suitable for children. Which ones/why? (5)
- Capsules
- Tablets
- Can they Swallow? - Syrups
- Ketogenic Diet? - Suspensions
- Solutions
- Palatability?
- What is the volume?
What are some way to increase palatability for oral meds? (5)
- Chocolate/strawberry syrup – coats tongue
- Peanut butter – coats tongue
- Applesauce – masks flavor, provides medium for mixing
- Ice cream – cold minimizes flavor, numbs taste buds
- Flavoring agent
- Risk of “ruining” flavor for patient
What are some considerations when using the Aliquot method? (3)
- Final volume must be a volume the child can tolerate
- E.g. don’t dilute into 50 mLs for a 1-year old child – that’s too much volume! - Is the final volume something that is easily measurable?
- 2 mLs vs 2.5 mLs vs 2.58 mLs - Is the tablet readily dissolvable in solution?
- Is the tablet available in chewable?
- Is it enteric coated or time release?
What are some tips for oral administration for peds? (5)
- Do not administer the liquid straight back into the throat
- Slowly introduce the medication to the rear cheek
- Always use standardized measuring syringes or cups, NOT
household table/tea spoons - What if the child throws up after giving the medication?
- 30 minute rule
- If the medication is given, child throws up < 30 minutes after administration, can dose again. Do not repeat if dose thrown up a 2nd time
- If the medication is given, child throws up > 30 minutes after administration, DO NOT repeat the dose. - Taste/flavouring
What are some resources for tube administration? (2)
- Lexicomp under “Administration” section
- Handbook of Drug Administration via Enteral Feeding Tubes
What are 3 types of parenteral access lines in peds?
- Peripheral IV
- Central IV
- Peripherally inserted central catheter (PICC)
- Broviac catheter
- Umbilical catheter (neonates only) - Intraosseous catheters
What are 2 methods to calculating total daily fluid requirements?
- Formula method
- 4/2/1 method
Explain the 4/2/1 method
To calculate hourly maintenance fluid rate
4 ml/kg/hr each of the first 10kg +
2 ml/kg/hr for next 10 kg +
1 ml/kg/hr for each additional kg above 20
What is the empiric fluid selection for child?
D5W/NS for all children 1 month CGA to 18 years old
Excluding:
- Renal or Cardiac disease
- Diabetic ketoacidosis
- Severe burns
- Underlying conditions that affect electrolyte regulation
For peds, blood pressure assessment requires ___, ___, and _______
age, sex, height
For peds, HTN is generally classified as what?
Either SBP or DBP greater than 95th percentile
No need to memorize values, but should know in general if in peds are the following higher or lower compared to adults:
- Blood pressure
- Heart rates
- Resp rates
- BP typically lower
- HR and RR typically higher
What are some ways to take temp in children? (5)
- Rectal - gold standard but invasive
- Axillary
- Oral - generally preferred in children who can coordinate
- Tympanic
- Infrared
What is normal temp in children?
- Standard “normal” is 37.2°C – with variation within a day
of 0.5°C
- Morning nadir, late-afternoon/early-evening peak - Neonates and infants have higher temp vs older children
and adults
- Higher surface-area to body-weight ratio
- Higher metabolic rate
What antibiotics are relatively contraindicated in less than 8 years old?
Tetracycline and derivatives (doxycycline, minocycline)
- Tetracycline chelates with Ca to form tetracycline-Ca complexes which deposit into developing bones and teeth
Fluoroquinolones contraindicated in peds why?
- NOT recommended for use by Health Canada and FDA
- Risk of Arthropathy
- Juvenile Animal data showing adverse effects on cartilage development
- Appears to be a small absolute risk increase in musculoskeletal adverse events
- Severe arthropathies (i.e. tendon rupture) necessitates avoiding unless necessary
When might fluoroquinolones potentially be used in peds? (2)
- Potential use when it is reasonable alternative to parenteral therapy
- Limited use to when no safe and effective alternative
exists…
- Example: multi-drug resistant organisms in cystic fibrosis (e.g. pseudonomas aeruginosa), Extended-spectrum β-lactamase producing (ESBL) organisms, prophylaxis for extended neutropenia in oncology patients
Septra (Sulfamethoxazole/Trimethoprim) used in peds?
Contraindicated in less than two months of age
- Sulfa antibiotic displaces bilirubin from protein binding sites → hyperbilirubinemia and kernicterus
- Kernictereus – permanent brain damage resulting from hyperbilirubenemia in blood
– Can result in cerebral palsy, hearing loss, problems with vision, growth, and intellectual disabilities
High dose amoxicillin/clavulanate in peds? (3)
- High-dose amoxicillin (90 mg/kg/day) often used to overcome streptococcus pneumoniae resistance
- Addition of clavulin broadens antimicrobial coverage
- Clavulinic acid doses greater than ~8 mg/kg/day may be associated with excessive diarrhea - Amoxicillin/Clavulanate available as 4:1 & 7:1 formulation
- You may see TWO different amoxicillin prescriptions to achieve high-dose amoxicillin without giving high-dose clavulanate
- To achieve a 14:1 ratio
Acetylsalicylic Acid use in peds? (3)
- Do NOT use as an anti-pyretic or analgesic in children
- Association of Reye Syndrome in patients <18 using ASA, particularly after viral illness (flu, chickenpox)
- Acetaminophen and Ibuprofen provide safer analgesics/anti-pyretics
ASA use in peds typically not used BUT when might it be used? (3)
- Often used for cardiac conditions in pediatrics
- Kawasaki Disease
- Post-operative Congenital Heart Repair Prophylaxis
- Rheumatic Fever - Dosing varies, often rounded to convenient dosage for administration
- LEXICOMP
What are some practice pearls to be aware of for peds? (3)
- Always ensure you have a weight (and ideally height) prior to assessing ANY medication
- Be weary of units: mcg vs ug vs mg
- E.g. overdoses have happened on multiple occasions with
clonidine - Check your references, then double-check, then check again if you’re unsure – the biggest mistake you can make is to guess: so don’t do it!
What is Kawasaki disease?
Acute Systemic Vasculitis of Childhood
- Acute, self-limited febrile illness
- Leads to coronary artery aneurysms in ~25% of untreated cases
- Exact cause unknown
- More common in Japanese and black children, predominantly affecting children <5 years old
How is Kawasaki disease diagnosed? (5)
Fever > 5 days, and 4+ of the following 5 principal features:
1) Changes to lips and oral cavity
- Strawberry tongue
- Reddened, cracked lips
- Diffuse erythema to oral and pharyngeal mucosa
2) Non-purulent bilateral bulbar conjunctivitis
3) Polymorphous rash (generalized throughout body)
4) Changes in extremities
- Edematous hands/feet, erythematous soles/palms
5) Cervical lymphadenopathy
- > 1.5 cm diameter
What are some Kawasaki related complications? (3)
- Cardiac complications
- Coronary artery aneurysms
- Heart Failure - Kawasaki Disease Shock Syndrome (KDSS)
- Non-coronary vascular involvement
- Urinary abnormalities, renal dysfunction, GI abnormalities, CNS involvement less common
How is Kawasaki Disease treated? (3)
- Intravenous Immunoglobulin (IVIG) + Aspirin are mainstay of initial treatment
- IVIG 2 g/kg given as single IV infusion (ideally within 10-days of symptom) onset
- Administration of low/moderate/high dose ASA
