NBME Pediatrics Form 4 - Answers & Explanations

Updated: Jul 27, 2020

1) Observe hand-washing techniques

• Poor hand-washing is the major cause of Rotavirus transmission (fecal-oral route)

2) Acute osteomyelitis

• Point tenderness, ↑ ESR, ↑ uptake by bone scan = osteomyelitis

• Metaphysis (highly vascular) is the most common site of osteomyelitis in children (usually develops secondary to hematogenous spread)

3) Increased insulin secretion

• Maternal hyperglycemia in the 2nd and 3rd trimesters → ↑ insulin

• After delivery, fetal insulin production takes time to decrease but maternal glucose exposure ends as soon as the umbilical cord is clamped → neonatal hypoglycemia

4) Placement of the newborn under warming lights

• Neonatal hypothermia

• Acrocyanosis occurs when blood vessels shrink in response to cold temperatures (common in newborns)

5) Sodium

• D5W is isotonic, however the body rapidly consumes the glucose → fluid becomes hypotonic → hyponatremia → seizure

6) Spirochete Borrelia burgdorgeri (spirochete) → Lyme disease • Erythema migrans = red circular lesion with a clear center

7) Administration of adenosine

• Paroxysmal supraventricular tachycardia (PSVT)

• If stable, vagal maneuvers should be attempted to terminate the tachycardia (eg, ice bag); If vagal maneuvers do no convert the SVT to normal sinus rhythm, IV adenosine should be administered

• If unstable → synchronized direct current cardioversion

8) Heat exhaustion

• High heat and humidity impair the the body’s capacity for dissipating heat (via evaporation)

• Heat exhaustion clinical criteria: Athlete has difficulty continuing exercise, ↑ Body temperature, and no significant dysfunction of the CNS (eg, seizure, delirium) is present

• Hyponatremia dehydration would have altered mental status

9) Reassurance that this growth pattern is within normal limits

• This baby is tracking along the 5th percentile - changing the diet is not indicated if the child is just constitutionally small

• Growth failure is either persistent weight below the 5th percentile, or falling of the growth chart (crossing 2 major percentile lines)

10) Administration of methylene blue • Methylene blue is the first line treatment for Methemoglobinemia - reduces Fe3+ to Fe2+

11) Vaginal foreign body

• Toilet paper is the most common vaginal foreign body

• Presents with foul-smelling vaginal discharge, intermittent vaginal bleeding or spotting

12) Acute renal failure • Post-strep glomerulonephritis can occur even if the infection was treated (with penicillin)

13) Twisting of there spermatic cord

• Testicular torsion → absence of cremasteric reflex + acute onset pain 14) Cor pulmonale

• Clinical features of cor pulmonale: peripheral edema, ↑ JVP, loud S2, right sided heave, pulsatile liver/hepatomegaly from congestion

• Decline of FVC during the past year indicates primary chronic lung disease

15) Galactosemia

• Classic galactosemia (absence of galactose-1-phosphate uridyltransferase) presents as soon as lactose is introduced into the diet (present in breast milk) → feeding intolerance, failure to thrive, jaundice, hepatomegaly, and infantile cataracts

• ⊖ dipstick glucose assay and a ⊕ reducing test = substance other than glucose is present in urine (ie, galactose, lactose, and fructose)

• Fructose intolerance doesn’t present until the baby consumes fructose containing food (eg, juice, fruit)

16) Juvenile arthritis • Inflammatory/rheumatologic joint pain is classically worse in the morning

• ↑ WBC/platelet count, ↓ RBC, ↑ inflammatory markers

17) Thyroid dysgenesis

• Inactivity, slow feeding, constipation, ↓ T4 = Hypothyroidism

• The most common cause of congenital hypothyroidism worldwide is thyroid dysgenesis

18) Antibody deficiency

• Bruton agammaglobulinemia → ↓ Ig of all classes → recurrent bacterial infections

• Scant lymph nodes and tonsils (primary follicles and germinal centers absent)

19) Decreased synthesis of global chains • Hypochromic microcytic anemia • Thalassemia has normal RDW and Target cells • RDW would be increased in iron deficiency due to anisocytosis

20) Acute lymphoblastic leukemia • ↓ Hb (pallor), ↓ platelets (petechiae), ↑ WBC, diffuse adenopathy

21) Anemia of chronic disease • JIA → ↑↑↑ acute phase reactants → anemia of chronic disease

22) Blood under the periosteum of the parietal bone

• Cephalohematoma is a subperiosteal hemorrhage that causes no overlying skin discoloration and is limited to one bone only (doesn’t cross suture lines)

• Subgaleal hemorrhage is under the galea aponeurotica

• Caput succedaneum is a soft tissue swelling that can cross suture lines

23) Increased renin production • Umbilical artery catheterization → showers of emboli/thrombi → lodge in renal artery → renal artery thrombosis → ↑ renin release → HTN

24) Triamcinolone • Triamcinolone is a synthetic corticosteroid • Eczema (atopic dermatitis) tends to happen in people with allergies or asthma

• Eczema should be treated with long-acting steroids or emollients

25) Staphylococcus aureus

• Large dense consolidation and fixed effusion are consistent with an abscess (Staph aureus loves to dorm abscesses)

Staph aureus resistent to amoxicillin

26) Exchange transfusion

• Most likely due to Rh hemolytic disease of newborn

• Total Bilirubin >25 (or trending that way) and resistant to phototherapy → exchange transfusion

• Bilirubin is toxic to cochlear nuclei; hyperbilirubinemia → hearing loss in newborns

27) IgA nephropathy

• Episodic hematuria that occurs concurrently with respiratory or GI infections

• PSGN typically occurs 2-3 weeks after an infection and would have decreased complement levels

28) Reassurance that this is a benign murmur

• Features of a benign murmur: early or mid-systolic, grade ≤ 2/6, low-low-pitched musical pure, insignificant medical history

29) Partial obstruction of the right main stem bronchus

• Majority of aspirated foreign bodies end up in right mainstream bronchus → focal monophonic wheezing

• Foreign body creates a kind of one-way valve → hyperinflation

30) Decrease his intake of milk and fruit juice

• > 95th percentile for weight and BMI = obese

• Milk and fruit juices have a lot of sugar