Facts read from pncb.org and 1 more · last checked Nov 7, 2026
The largest area, 52 scored items, tests whether you can read a child: plot the numbers, take an age-fitted history, pick the test that answers the question, and put the right diagnosis at the top of the list.
Practice questions
60 questions written to the CPNP-PC outline; each choice is explained once you pick.
Summarized from the area's knowledge and skill statements:
Growth and developmental surveillance: plotting, percentiles, crossing lines.
History and physical: chief complaint, review of systems, visit-specific history, the age-adjusted exam.
Tests: point-of-care, laboratory and imaging, and how to read them in a child.
Screening tools: developmental, behavioral, mental health, social needs and disease-specific instruments.
Diagnosis: a ranked differential, then the working diagnosis.
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18 assessment and diagnosis questions
0 / 18 answered18 questions
Tap an option: why each one is right or wrong appears under it.
Assessment and Diagnosis · 35%
A 6-month-old's head circumference has risen from the 50th to above the 97th percentile over 2 months. The anterior fontanelle is full, and the infant has downward deviation of the eyes. Which is the MOST appropriate next step?
A head circumference crossing upward through percentiles, with a full fontanelle and sunsetting eyes, signals hydrocephalus with raised pressure; while the fontanelle is open, cranial ultrasound is the fastest way to see the ventricles.
Plain films show bone and sutures, not ventricles, so they cannot diagnose hydrocephalus.
Watchful waiting suits a large but stable head; a rapidly crossing one with signs of raised pressure cannot wait a month.
Measuring the parents is how benign familial macrocephaly is confirmed, but that head grows steadily along a high percentile with no signs of pressure.
A 2-month-old has a long, narrow head with a prominent forehead and occiput. A firm ridge is palpable along the midline from the anterior fontanelle to the back of the head. Which is the MOST appropriate next step?
A helmet molds a deformational head shape but does not treat synostosis on its own, and starting one here delays surgery.
Repositioning treats positional plagiocephaly, where the sutures are open and no ridge is felt; it cannot reopen a fused suture.
Rechecking later is reasonable for mild positional flattening, but waiting with a fused suture narrows the window for the less invasive repair.
A long narrow head with a palpable sagittal ridge is sagittal craniosynostosis; early referral matters because endoscopic repair works best in the first months.
A 2-year-old has 3–5 loose stools daily with visible undigested vegetables, never at night. The child drinks about 24 oz of apple juice daily, is active, and growth continues along the 50th percentile. The MOST LIKELY diagnosis is:
Painless loose stools with undigested food, never at night, in a thriving toddler who drinks a lot of juice fit functional (toddler's) diarrhea, which improves with less juice and more dietary fat.
Milk protein allergy typically starts in early infancy, often with blood in the stool, rather than at 2 years with undigested food.
Celiac disease usually brings poor weight gain, distension, or irritability; growth along the 50th percentile argues against it.
Giardiasis causes bloating, cramps, foul stools, and often weight loss after an exposure, not years of painless stools in a growing child.
A 4-year-old has had 3 weeks of pallor, fatigue, and leg pain that wakes the child at night. Exam shows petechiae and hepatosplenomegaly. CBC: WBC 2,100/µL, hemoglobin 7.2 g/dL, platelets 35,000/µL. The MOST LIKELY diagnosis is:
Pancytopenia with night-waking bone pain, petechiae, and hepatosplenomegaly in a preschooler is the classic picture of ALL and needs a same-day smear and oncology referral.
Mononucleosis can enlarge the spleen and dip counts mildly, but it brings fever, pharyngitis, and lymphadenopathy rather than this degree of marrow failure.
ITP lowers platelets alone in an otherwise well child; anemia, leukopenia, and an enlarged liver and spleen exclude it.
Aplastic anemia also lowers all three cell lines, but the marrow is empty, so there is no organomegaly or bone pain.
A 3-week-old who had been feeding well suddenly develops repeated green vomiting and fussiness. The abdomen is mildly distended. Which is the MOST appropriate next step?
A formula change addresses milk-protein allergy and wastes hours while the bowel can become ischemic.
Acid suppression treats reflux, which does not produce sudden bilious vomiting; treating it that way misses a surgical emergency.
Pyloric stenosis causes projectile vomiting without bile, so ordering a pyloric ultrasound for green emesis looks for the wrong lesion.
Bilious vomiting in a young infant is malrotation with volvulus until proven otherwise; an emergency upper GI series with surgical consultation is the next step.
A 2-month-old has excessive tearing and squints in bright light. Both corneas appear large and slightly cloudy. The MOST LIKELY diagnosis is:
Tearing, photophobia, and large, cloudy corneas form the triad of congenital glaucoma, which needs urgent ophthalmology referral to save vision.
A blocked tear duct causes tearing and crusting, but the cornea stays clear and normal-sized and there is no light sensitivity; mistaking glaucoma for it is the classic delay.
Allergic conjunctivitis causes itchy, watery eyes in older children with atopy and is rare at 2 months; the cornea is unaffected.
Neonatal conjunctivitis brings a red eye with discharge in the first weeks; it does not enlarge or cloud the cornea.
A 2-year-old has an intermittent painless limp. The legs are unequal in length, and the thigh skin folds are asymmetric. The child walks on the toes of the shorter leg. The MOST LIKELY diagnosis is:
A toddler's fracture follows a twist and causes acute pain and refusal to bear weight, not a painless limp with unequal legs.
A painless limp with a short leg, asymmetric thigh folds, and toe-walking on the short side in a toddler suggests a dislocated hip missed in infancy; a pelvic radiograph confirms it.
Perthes disease usually starts at 4 to 8 years with hip or knee pain and loss of internal rotation, not a toddler's leg-length difference.
Transient synovitis is an acute, painful limp after a viral illness that settles within days; it does not shorten a leg.
The parent of a 2-year-old girl says her genital area 'looks closed.' She has no dysuria or discharge. Examination shows a thin, translucent midline membrane joining the labia minora, with a small opening anteriorly. The MOST LIKELY diagnosis is:
Lichen sclerosus produces white, thin, wrinkled skin around the vulva and anus with itching, not a fused midline membrane.
A transverse septum sits inside the vagina and is not visible as fusion of the labia; it usually presents with amenorrhea and pain at puberty.
A thin, translucent midline line joining the labia minora in a prepubertal girl is labial adhesion, driven by low estrogen; most are asymptomatic and many separate on their own.
An imperforate hymen lies deeper at the vaginal opening and shows as a bulging membrane in the newborn or with retained blood at menarche.
A 3-week-old exclusively breastfed infant is still jaundiced. The infant is feeding well, has regained birth weight, and the examination is otherwise normal. Which is the MOST appropriate next step?
Breast milk jaundice is a label applied only after the direct bilirubin is normal; calling it first is how cholestasis gets missed.
Jaundice past 2 to 3 weeks needs a fractionated bilirubin to look for cholestasis; biliary atresia can occur in a thriving infant and does best with surgery before about 60 days.
A transcutaneous meter estimates only the total bilirubin, so it cannot detect a raised direct fraction.
Stopping breastfeeding is not needed to diagnose or treat breast milk jaundice and risks the milk supply.
An 8-year-old boy has prolonged bleeding after a tooth extraction and a swollen, painful knee after a minor fall. A maternal uncle has a similar history. PT and platelet count are normal, and aPTT is prolonged. The MOST LIKELY diagnosis is:
Von Willebrand disease is autosomal and mostly causes mucosal bleeding; hemarthrosis after minor trauma is typical only of its rare severe form.
Immune thrombocytopenia lowers the platelet count and causes petechiae; here the platelets are normal.
Vitamin K deficiency prolongs the PT first, because factor VII has the shortest half-life.
Joint bleeding with an isolated prolonged aPTT in a boy whose maternal uncle is affected fits X-linked factor VIII deficiency.
A febrile 18-month-old's catheterized urine dipstick is positive for leukocyte esterase and negative for nitrite. Which is the MOST appropriate interpretation?
Treating a negative nitrite as ruling out infection is the classic error in young children, in whom the nitrite test is insensitive.
Bag specimens are often contaminated and are not acceptable for culture; stepping down from a catheterized sample loses accuracy.
Waiting for a positive nitrite delays treatment of a febrile UTI, which can scar the kidney.
Toddlers void often, so bacteria rarely have time to make nitrite; a positive leukocyte esterase on a catheterized sample keeps a febrile UTI likely, and the culture decides.
A 14-year-old has had sharp left-sided chest pain for 1 week, unrelated to exertion. Vital signs are normal, and the pain is reproduced by pressing along the left sternal border at the 3rd and 4th ribs. The MOST LIKELY diagnosis is:
Hypertrophic cardiomyopathy causes pain or syncope with exertion and a murmur that rises with Valsalva, not tenderness at the rib joints.
Chest pain reproduced by pressing on the costochondral junctions, with normal vital signs and no link to exertion, is costochondritis, the most common cause of chest pain in adolescents.
Pericarditis brings positional pain that eases leaning forward, often with fever or a friction rub.
Precordial catch is a sudden, seconds-long sharp pain at rest that worsens with a breath and is not reproduced by palpation.
An 11-year-old has fatigue, intermittent scleral icterus, and splenomegaly. The mother had pigment gallstones removed at age 19. Hemoglobin is 9.8 g/dL, MCHC 37 g/dL, reticulocytes 8%, and the smear shows small, dense red cells without central pallor. The direct antiglobulin test is negative. The MOST LIKELY diagnosis is:
G6PD deficiency causes episodes of hemolysis after an oxidant trigger, with bite and blister cells, rather than steady spherocytosis.
Sickle cell disease shows sickled cells and is picked up on the newborn screen; spherocytes are not its smear finding.
Spherocytes with a high MCHC, reticulocytosis, splenomegaly, a negative DAT, and a parent with early pigment gallstones point to autosomal dominant hereditary spherocytosis.
Autoimmune hemolysis also produces spherocytes, but its DAT is positive; the negative DAT is what separates the two.
A 2-month-old who is exclusively breastfed strains, turns red, and cries for 10 to 20 minutes before passing a soft yellow stool, once every 1 to 3 days. Growth and the examination, including the anus, are normal. The MOST LIKELY diagnosis is:
A fissure causes pain with streaks of bright red blood and is visible on inspection; the anal exam here is normal.
Hirschsprung disease brings delayed meconium, abdominal distension, and poor growth rather than soft stools in a thriving infant.
Constipation means hard or painful stools; these stools are soft, and a gap of several days is normal for a breastfed baby.
At least 10 minutes of straining and crying before a soft stool in a thriving infant under 9 months is infant dyschezia, a coordination problem that resolves on its own; parents are advised to avoid rectal stimulation and laxatives.
Since early childhood, a 7-year-old has been clumsy, slow to learn to ride a bike, and poor at ball sports, with messy handwriting. Strength, tone, reflexes, and intelligence are normal. The MOST LIKELY diagnosis is:
Duchenne dystrophy causes proximal weakness with a Gowers sign and large calves, so normal strength excludes it.
Lifelong motor clumsiness that hampers sports and handwriting, with normal strength, tone, reflexes, and intelligence, is developmental coordination disorder, confirmed with a standardized motor test.
Even mild spastic cerebral palsy shows raised tone and brisk reflexes, which this child does not have.
ADHD often coexists with motor clumsiness, but inattention does not explain poor coordination in a child with no attention symptoms described.
A 6-year-old has IgA vasculitis (Henoch-Schönlein purpura) with palpable purpura, arthralgia, and abdominal pain that are now improving. Which follow-up assessment is MOST important over the next 6 months?
Follow-up echocardiography is part of Kawasaki disease care, a different vasculitis that affects the coronary arteries.
Nephritis is the main long-term risk of IgA vasculitis and can appear weeks to months after the rash, so urinalysis and blood pressure are checked regularly for at least 6 months.
The platelet count is normal in IgA vasculitis, which is why its purpura is palpable; following platelets confuses it with ITP.
Inflammatory markers do not predict which child will develop kidney involvement.
A running total sits here; it fills in after your last pick.
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Where candidates slip in Area II
The wrong growth chart. The CDC recommends the WHO charts from birth to age 2 and the CDC charts from 2 onward. A toddler plotted on the wrong one can appear to fall off a curve.
BMI cut points. In children, overweight is the 85th to below the 95th percentile and obesity is the 95th or above; severe obesity is 120% of the 95th percentile (AAP obesity guideline, 2023).
Surveillance mistaken for screening. Surveillance happens at every visit. Standardized developmental screening is set at 9, 18 and 30 months, and autism screening at 18 and 24 months (AAP, 2020).
One plan for every febrile infant. The AAP 2021 febrile infant guideline separates infants aged 8–21, 22–28 and 29–60 days; the youngest group gets the full workup, including spinal fluid.
Calling a diastolic murmur innocent. Innocent murmurs are systolic, such as the vibratory Still's murmur, apart from the continuous venous hum that fades when the child lies down; an isolated diastolic murmur needs evaluation.