1. Acne vulgaris that begins before age 7 years warrants further investigation for endocrine abnormalities such as androgen excess or precocious puberty.
2. After iron supplementation for iron deficiency anemia, the reticulocyte count should double in 1 to 2 weeks, and hemoglobin should increase by 1 g/dL in 2 to 4 weeks. The most
common reason for persistence of iron deficiency anemia is poor compliance with supplementation.
3. It is rare for an infant to develop congestive heart failure (CHF) from supraventricular tachycardia (SVT) in <24 hours. When SVT is present for 24 to 36 hours, about 20% develop CHF. At 48 hours, the number increases to 50%.
4. After age 7 years, nocturnal enuresis (which affects 10% of children at that age)
resolves spontaneously at a rate of approximately 15% per year, so that by age 15 years about 1% to 2% of teenagers are still affected.
5. The “atopic march” is the phenomenon in which about half of infants with atopic dermatitis eventually develop asthma, and two-thirds develop allergic rhinitis.
6. While leukemias constitute the most common group of pediatric cancer diagnoses overall, neuroblastomas are the most commonly occurring cancer in children <1 year of age.
7. Coughing and choking (witnessed or by history) occur in 80% to 90% of children with
suspected foreign body aspiration, which highlights the importance of questioning about choking in a child who is evaluated for cough.
8. Idiopathic scoliosis (with a Cobb angle of 10 degrees or more) occurs in about 3% of children, but only 0.3% to 0.5% will have progression of curves that require treatment.
9. IgA nephropathy is the most common type of primary glomerular disease worldwide. Compared with adults, pediatric patients are more likely to have minimal histologic lesions and less likely to have advanced chronic lesions.
10. The most common worldwide cause of chronic gastrointestinal (GI) blood loss is hookworm infection, which is often associated with iron deficiency anemia.
11. Neonates with midline lumbosacral lesions (e.g., sacral pits, hypertrichosis, lipomas) above the gluteal crease should have screening imaging of the spine performed to search for occult spinal dysraphism.
12. A falling serum sodium concentration during diabetic ketoacidosis (DKA) treatment is worrisome because it indicates either inappropriate fluid management or the onset of syndrome of inappropriate antidiuretic hormone (SIADH) and can herald impending
cerebral edema.
13. The most identifiable cause of microscopic hematuria is hypercalciuria, defined as elevated urinary calcium excretion without concomitant hypercalcemia.
14. The median time for the rash of Lyme disease to appear after a tick bite is 7 to 10 days, but the range can be 1 to 36 days.
15. 2011 AAP guidelines no longer recommend routine voiding cystourethrogram (VCUG) for a first urinary tract infection (UTI) unless an ultrasound reveals hydronephrosis, scarring, or other findings that would suggest either high-grade vesicoureteral reflux or obstructive uropathy.
16. Always consider ovarian torsion in the differential diagnosis of abdominal pain in girls, particularly during the ages of 9 to 14 years, when ovarian cysts as potential lead points are more common because of the maturing reproductive hormonal axis.
17. Left shoulder pain after abdominal trauma is a worrisome sign that could represent blood accumulating under the diaphragm, which results in pain referred to the left shoulder (Kehr sign) due to splenic injury.
18. Because irreversible histologic changes can develop in 4 to 8 hours after the onset of testicular torsion, timely diagnosis is critical. Testicular salvage rates are <10% if symptom duration is 24 hours.
19. Carbon monoxide poisoning is often misdiagnosed because the presenting symptoms can be flu-like.
20. Most umbilical hernias <0.5 cm spontaneously close before a patient is 2 years old. A hernia >2 cm may still close spontaneously, but it may take up to 6 years.
21. Although precocious puberty occurs much more frequently in girls (80% of cases are girls), boys are more likely to have identifiable pathology.
22. Consider the use of prostaglandin E1 to maintain the patency of the ductus arteriosus in a newborn<1 month who presents in shock with evidence of CHF and cyanosis because of the possibility of a ductal-dependent cardiac lesion, such as hypoplastic left heart syndrome.
23. A hemoglobin A1C level 6.5% on two occasions is sufficient for the diagnosis of diabetes. Levels between 5.7% and 6.4% place a person at increased risk for diabetes.
24. Isolated primary nocturnal enuresis rarely has identifiable organic pathology.
25. Only 20% of patients with intussusception present with the classic triad of colicky pain, vomiting, and passage of bloody stool.
26. In patients with suspected rheumatic disease, clinical features that are concerning for malignancy include nonarticular bone pain, back pain as the primary presenting symptom, bone tenderness, and severe constitutional symptoms.
27. Three or more minor malformations should raise concern about the presence of a major malformation.
28. Patients with atypical Kawasaki disease are usually younger (<1 year old) and most commonly lack cervical adenopathy and extremity changes.
29. Older children with unexplained unilateral deformities of an extremity (e.g., pes cavus) should have screening magnetic resonance imaging to evaluate for intraspinal disease.
30. In patients with sickle cell disease, use of transcranial Doppler ultrasound to measure intracranial blood flow and regular transfusions to reduce the hemoglobin S content for those with abnormal values can significantly lower the likelihood of stroke.
31. Methanol, present in antifreeze and windshield washer fluid, is considered the most lethal alcohol and can cause severe, refractory metabolic acidosis and permanent retinal damage leading to blindness.
32. Hyperbilirubinemia generally is not an indication for the cessation of breastfeeding but rather for increasing its frequency.
33. Fractures that have been shown to have a high specificity for child abuse are rib fractures (particularly posteromedial) in infants, classic metaphyseal lesions of long bones, and fractures of the scapula, spinous process, and sternum.
34. About 6% of children are streptococcal carriers and will have positive throat cultures between episodes of pharyngitis.
35. The two most consistent prognostic factors for outcome for childhood acute lymphoblastic leukemia (ALL) are age at presentation (<1 year or >10 years have a worse prognosis) and extent of elevation of initial white blood cell (WBC) count ( 50,000/mm3 have a worse prognosis).
36. Infants with unexplained failure to thrive, weakness, hypotonia, and metabolic acidosis (particularly lactic acidosis) should be evaluated for a possible mitochondrial disorder.
37. Polycystic ovarian syndrome, which affects up to 10% of reproductive age women, should be suspected in overweight or obese teenagers with amenorrhea/oligomenorrhea and signs of hyperandrogenism (hirsutism, acne).
38. Women with primary genital herpes simplex virus (HSV) infections who are shedding HSV at delivery are 10 to 30 times more likely to transmit the virus than women with recurrent infection.
39. The two essential features of autism are (1) impaired social interaction and social communication and (2) restricted and repetitive patterns of behavior.
40. The daily spiking fevers of systemic juvenile idiopathic arthritis can precede the development of arthritis by weeks to months.
41. Syncope is more likely to be of a cardiac nature if there is sudden onset without prior dizziness or awareness, occurrence during exercise, history of palpitations before fainting, syncope results in an injury from a fall, and/or a positive family history of sudden death.
42. About 10% to 20% of patients with Rocky Mountain spotted fever do not develop a rash, so a high index of suspicion is needed for any patient in an endemic area who presents with fever, myalgia, severe headaches, and vomiting.
43. An overweight 5-year-old is 4 as likely to be an overweight teenager, which highlights the importance of addressing obesity at an early age.
44. The earliest evidence of nephropathy in patients with type 1 diabetes mellitus is microalbuminuria, which is the presence of small quantities of albumin in the urine, preferably measured in a first morning sample.
45. The best measure of cognitive function in a younger child is receptive language, which should be assessed in a fashion that is free of motor requirements.
46. In a toddler with suspected idiopathic thrombocytopenic purpura (ITP), the presence of splenomegaly warrants more aggressive evaluation for an associated problem (e.g., collagen-vascular disease, hypersplenism, leukemia, glycogen storage disease).
47. The most common cause of overdose deaths in children and adolescents in the United States is acetaminophen, owing to its widespread availability and frequency of use in accidental and suicidal intoxications.
48. The most reliable physical exam finding for a developmentally dysplastic hip in an older infant is limited hip abduction, which occurs as a result of shortening of the adductor muscles.
49. The most common cause of persistent seizures is an inadequate serum antiepileptic level.
50. Midline neck masses usually involve the thyroid gland or thyroid remnants, such as a thyroglossal duct cyst.
51. Most amblyopia is unilateral; vision testing solely with both eyes open is inadequate.
52. Emergency contraception should be discussed with all sexually active adolescents; 90% of teenage pregnancies are unintended.
53. An infant with vomiting, lethargy, hypoglycemia and no ketones on urinalysis should be evaluated for a fatty-acid oxidation defect.
54. Without a booster after age 5 years, pertussis protection against infection is about 80% during the first 3 years after immunization, dropping to 50% after 4 to 7 years, and to near 0% after 11 years.
55. Asthma rarely causes clubbing in children. Consider other diseases, particularly cystic fibrosis.
56. Only5% of obese adolescents have an identifiable pathologic cause, such as an endocrine problem (e.g., hypothyroidism) or an uncommon syndrome (e.g., Prader-Willi) for their obesity.
57. Bilingual children develop speech milestones normally; two-language households should not be presumed as a cause of speech delay.
58. Sulfonamides and antiepileptic medications (especially phenobarbital, carbamazepine and lamotrigine) are the medications most commonly associated with Stevens-Johnson syndrome and toxic epidermal necrolysis.
59. The most common specific etiology diagnosed in pediatric patients with a systemic febrile illness after international travel is malaria. More than half of the world's population lives in areas where malaria is endemic.
60. The most common condition presenting as a food impaction in an adolescent is eosinophilic esophagitis.
61. The optimal time for surgical repair of an undescended testicle is 12 months of age or shortly thereafter as spontaneous descent after 9 months is unlikely and ultrastructural changes in the seminiferous tubules can occur in the second year of life unless orchidopexy is performed.
62. The classic picture of appendicitis is anorexia followed by pain, then by nausea and vomiting, with subsequent localization of findings to the right lower quadrant. However, there is a large degree of variability, particularly in younger patients.
63. An infant with nonsyndromic sensorineural hearing loss should be tested for mutations in the connexin 26 gene. Mutations in that gene contribute to at least 50% of autosomal recessive hearing loss and about 10% to 20% of all prelingual hearing loss.
64. The Gorlin sign is the ability to touch the tip of the nose with the tongue, which can be seen in conditions associated with hypermobility syndromes, such as Ehlers-Danlos syndrome.
65. A pelvic examination is not required before prescribing oral contraceptives for teenagers without risk factors. Appropriate screening for sexually transmitted infections and possible cervical dysplasia can be scheduled, but delaying oral contraception unnecessarily increases the risk for pregnancy.
66. A skin scale that bleeds easily on removal (Auspitz sign) is characteristic of psoriasis and is related to the rupture of capillaries high in the papillary dermis.
67. The most frequent cause of chronically elevated aminotransferases among children and adolescents in the United States is nonalcoholic fatty liver disease (NAFLD), which is commonly seen in obese patients with the metabolic syndrome.
68. Seizures with fever in patients >6 years should not be considered febrile seizures.
69. A pop or snap sensation in the setting of acute knee injury is usually associated with an anterior cruciate ligament injury, a meniscal injury, and/or patellar subluxation.
70. Hypercapnia (elevated PCO2) in a patient with an acute asthma attack is a serious sign that the child may be tiring or becoming severely obstructed.
71. Signs and symptoms of acute poststreptococcal glomerulonephritis (e.g., gross hematuria, hypertension, oliguria) begin about 7 to 14 days after pharyngitis and as long as 6 weeks after a pyoderma.
72. Premature babies should be immunized in accordance with postnatal chronologic age.
73. During the first year of life, hypotonia is more common than hypertonia in patients who are ultimately diagnosed with cerebral palsy.
74. A male child with a liver abscess should be considered to have chronic granulomatous disease until proven otherwise.
75. Items in the preparticipation sports physical exam that identify a patient at risk for sudden death include Marfanoid features, pathologic murmurs, weak or delayed femoral pulses, and evidence of an arrhythmia (rapid or irregular heartbeat).
76. Up to 10% of normal, healthy children may have low-level (1:10) positive antinuclear antibody testing that will remain positive. Without clinical or laboratory features of disease, it is of no significance.
77. The most common cause of chronic pelvic pain in adolescents without a history of pelvic inflammatory disease is endometriosis.
78. Headaches that awaken children from sleep, are associated with vomiting without nausea, are made worse by straining or coughing, and have intensity changes with changes in body position are concerning for pathology that is causing increased intracranial pressure.
79. Pulse oximetry screening for complex congenital heart disease in asymptomatic infants in the nursery is abnormal if oxygen levels are <90% in either limb or if oxygen saturation is 90% and <95% in both limbs or >3% difference between limbs on initial and repeat testing.
80. Significant proteinuria, in addition to hematuria, is much more likely to be caused by an underlying renal pathology compared with hematuria alone.
81. In the evaluation of children with constipation, the most important physical exam component is the rectal exam because large amounts of stool in the rectal vault almost always indicate functional constipation.
82. In children with simple obesity (e.g., familial), linear growth is typically enhanced; in children with endocrinopathies (e.g., Cushing syndrome, hypothyroidism), linear growth is usually impaired.
83. Telogen effluvium, the most common cause of diffuse hair loss in children, develops 2 to 5 months after a stressful event (e.g., surgery, birth, large weight loss) and resolves gradually without therapy.
84. The most important variable that influences mortality in necrotizing fasciitis is the time to surgical debridement.
85. Crawling is one of the least valuable markers of development because there is enormous variability in the timing of crawling and a significant percentage of normal infants never crawl before walking.
86. Newborns diagnosed with chlamydial conjunctivitis should not be treated with topical therapy alone because this will not eradicate the organism from the upper respiratory tract and may fail to prevent the development of chlamydial pneumonia. Oral macrolide therapy is required.
87. Psychogenic cough should be considered in a child with persistent dry, honking, explosive daytime cough that disappears with sleep or during the weekend.
88. Up to 20% of adolescents with menorrhagia may have a bleeding disorder, most commonly von Willebrand disease.
89. Intelligibility increases by about 25% per year from 25% at age 1 year to 100% at age 4 years. Significantly delayed intelligibility should prompt hearing and language evaluation.
90. Infants infected in the perinatal period with hepatitis B have a >90% chance of developing chronic hepatitis B infection, and of these, 25%go on to develop hepatocellular carcinoma.
91. Following an episode of acute otitis media, about 70% of patients will continue to have a middle ear effusion at 2 weeks, 40% at 1 month, 20% at 2 months and 10% at 3 months.
92. Acute kidney injury (AKI) has replaced the term acute renal failure (ARF) to reflect the more appropriate concept that smaller reductions in kidney function (short of complete organ failure) have significant clinical repercussions in terms of morbidity and mortality.
93. Since the introduction of pneumococcal conjugate vaccines, bacteremia rates for Streptococcus pneumoniae have fallen dramatically to <1% in febrile, nontoxic appearing children from ages 3 to 36 months.
94. Most pediatric deaths in the United States associated with influenza tend to result from either (1) an exacerbation of an underlying medical condition or an invasive procedure, or (2) coinfection from another pathogen, most commonly Staphylococcus aureus.
95. The most common genetic lethal disease, defined as a disease that interferes with a person’s ability to reproduce as a result of early death or impaired sexual function, is cystic fibrosis.
96. Measles, after an incubation period of 4 to 12 days, typically presents with cough, coryza, and conjunctivitis followed by the characteristic morbilliform rash with macular and papular features.
97. Cytomegalovirus is the most common congenital infection, up to 1.3% in some studies, but 80% to 90% of infected neonates are asymptomatic at birth or in early infancy.
98. A ciliary flush, which is circumcorneal hyperemia in which conjunctival redness is concentrated in the area adjacent to the cornea (limbus), is worrisome as a possible sign of significant ocular pathology (e.g., keratitis, anterior uveitis, acute angle-closure glaucoma). Urgent referral to an ophthalmologist is required.
99. Recommendations to decrease the risk of sudden infant death syndrome (SIDS) include placing infants in a nonprone position for sleep; use of a firm sleep surface; breastfeeding; room-sharing without bed-sharing; routine immunizations; consideration of a pacifier; and avoidance of soft bedding, overheating and exposure to tobacco smoke, alcohol and illicit drugs.
100. Occasional strabismus is common in young infants because the macula and fovea are poorly developed at birth, but intervention should be considered for symptoms that persist beyond 2 to 3 months of age.
