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
31) Cellular shift • Ketotic metabolic acidosis → H+ moves into cells in exchange for K+ moving out
32) HIV infection • Given the patients age, he most likely has an acquired immunodeficiency (eg, HIV)
33) Administration of 0.9% saline, intravenously • Management should begin with a bolus of normal saline
34) Pneumococcal meningitis • Low glucose with granulocytic predominance on CSF analysis is consistent with bacterial meningitis
35) Intramuscular lorazepam
• PCP intoxication → treat their aggression and calm them down with a benzo
36) Cystic fibrosis
• Highly viscous mucus → Impaired mucociliary escalator (→ history or respiratory problems) and bronchiectasis
37) Congenital heart disease with right-to-left shunt
• Tetralogy of Fallot tet spell
• Baby cries and becomes agitated → RVOT (right ventricular outflow obstruction) worsens → reversal of shunt across VSD → cyanosis
• RVOT → ↓ blood flow through lungs → ↓ pulmonary vascularity
• Systolic murmur is coming from the RVOT, not from the VSD
38) Herpes zoster • Immunosuppression (chemo) + painful vesicular rash in dermatomal distribution
• HSV is usually in peri-oral and genital areas (not confined to a dermatome)
39) Reassure him that this is normal
• Pubertal gynecomastia is seen in 50-70% of pubertal boys
• Typically resolves without treatment in a few months
40) Epidural hematoma • Head injury over parietal bone → pterion skull fracture → middle meningeal artery rupture → lens-shaped hyper-density that doesn’t cross suture lines
41) Malabsorption of fats and carbohydrates
• Giardiasis disrupts microvilli on enterocytes in the small intestine → malabsorption and loose oily foul-smelling stools
• If untreated → severe weight loss and vitamin deficiency
42) Congenital melanocytic nevus • Benign melanocyte proliferation with ↑ density of hair follicles
43) Increased vascular permeability
• Sepsis status post mechanical ventilation → ↑ vascular permeability → ARDS
• Waterhouse-Friderichsen syndrome: Neisseria → vascular collapse and permeability
→ petechiae
44) Fluids
• Give fluids to replace what was lost to the 3rd space
45) Medulloblastoma
• Affects the cerebellum medially (vermis) → truncal ataxia (eg, unsteady gait)
• Pilocytic astrocytoma affects the cerebellum peripherally (hemisphere) → limb ataxia (eg, dysmetria)
• Medullo = Medial, Pilocytic = Peripheral
46) Nonsteroidal anti-inflammatory drug therapy • Primary dysmenorrhea (normal physical exam) first-line treatment is NSAIDs and/or OCP
47) Decreased biliary excretion
• Liver is able to conjugate bilirubin, but cant excrete it → direct hyperbilirubinemia (all other answer choices would lead to indirect hyperbilirubinemia)
• Wouldn’t develop kernicterus because conjugated bilirubin doesn’t cross BBB
48) Ulcerative colitis • Abdominal cramps relieved by passing stool + bloody bowel movements
• Arthritis is the most common non-GI related issue in UC
49) Thyroid dysfunction
• Clinical manifestation of congenital hypothyroidism: lethargy, enlarged fontanelle, protruding tongue, hypotonia, umbilical hernia, constipation, jaundice
50) Needle decompression • Hyper-resonance + tracheal deviation = tension pneumothorax • Needle decompression would relieve air pressure surrounding the left lung and allow it to expand
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