Clinical Pediatrics Syllabus

What is the standard caloric density of prepared term infant formula and breast milk?

Both provide approximately 20 kcal/oz, or about $0.67\,\text{kcal/mL}$ (67 kcal per 100 mL).

At what age is complementary feeding (introduction of solids) recommended to begin, and why not earlier?

Complementary foods should begin at about 6 months. Earlier introduction (before 4 months) risks aspiration, displaces milk, and the gut/renal systems are immature; delaying much beyond 6 months risks nutrient (especially iron) deficiency and feeding difficulties.

Which nutrients most commonly become limiting around 6 months, making complementary feeding necessary?

Iron and zinc become limiting as fetal iron stores deplete by ~6 months; energy and protein needs also outstrip milk alone.

Distinguish marasmus from kwashiorkor.

Marasmus is severe wasting from total calorie (energy) deficiency: marked muscle/fat loss, weight <60% expected, no edema. Kwashiorkor is protein deficiency with adequate/near-adequate calories: edema, fatty liver/hepatomegaly, skin/hair changes, apathy, weight 60-80% with edema masking loss.

What is the WHO definition of severe acute malnutrition (SAM) in children 6-59 months?

Weight-for-height Z-score $< -3$ SD, OR mid-upper arm circumference (MUAC) $< 115\,\text{mm}$, OR presence of bilateral pitting edema.

What are the classic features of vitamin A deficiency and vitamin D deficiency in children?

Vitamin A: night blindness, xerophthalmia, Bitot spots, increased infection risk. Vitamin D: rickets — bowed legs, rachitic rosary, widened wrists, craniotabes, delayed fontanelle closure.

What clinical triad and lab findings characterize scurvy (vitamin C deficiency)?

Perifollicular hemorrhage, bleeding/swollen gums, poor wound healing, and subperiosteal hemorrhages causing painful pseudoparalysis of limbs; from deficient collagen synthesis due to lack of vitamin C.

What is the classic clinical picture and treatment of measles, and what are its major complications?

Prodrome of cough, coryza, conjunctivitis (3 C's) plus Koplik spots, then a cephalocaudal maculopapular rash. Treatment is supportive plus vitamin A. Complications: otitis media, pneumonia, encephalitis, and subacute sclerosing panencephalitis (SSPE).

What virus causes bronchiolitis, and what is the typical age and clinical presentation?

Respiratory syncytial virus (RSV) is the most common cause. Occurs in infants <2 years (peak 3-6 months) with coryza progressing to wheeze, tachypnea, crackles, and respiratory distress; management is supportive.

Describe roseola infantum (exanthem subitum): cause and hallmark clinical course.

Caused by HHV-6 (sometimes HHV-7). High fever for 3-5 days that resolves, followed by a maculopapular rash appearing as the fever breaks; may cause febrile seizures.

What is the causative organism and characteristic rash of chickenpox, and what is a serious congenital consequence?

Varicella-zoster virus causes crops of vesicles at different stages ('dew drops on a rose petal') that are pruritic and centripetal. Maternal infection can cause congenital varicella syndrome (limb hypoplasia, cicatricial skin lesions, eye/CNS defects).

What are the most common bacterial causes of acute otitis media in children?

Streptococcus pneumoniae, non-typeable Haemophilus influenzae, and Moraxella catarrhalis. First-line treatment is high-dose amoxicillin.

What organisms most commonly cause bacterial meningitis in neonates versus older infants/children?

Neonates (<1 month): Group B Streptococcus, E. coli, Listeria monocytogenes. Older infants/children: Streptococcus pneumoniae and Neisseria meningitidis (Hib now rare with vaccination).

What is the clinical presentation and typical cause of epiglottitis, and why is it now rare?

Acute onset high fever, drooling, dysphagia, muffled voice, tripod positioning, and stridor without cough, classically caused by Haemophilus influenzae type b. It is now rare due to Hib vaccination.

What are the classic features of pertussis (whooping cough) and its causative organism?

Bordetella pertussis causes catarrhal, paroxysmal (severe coughing fits with inspiratory 'whoop' and post-tussive vomiting), and convalescent stages. Infants may present with apnea. Lymphocytosis is characteristic; treat with macrolides.

What parasite causes the most common intestinal helminth infection in children worldwide, and how does it present?

Enterobius vermicularis (pinworm) is most common; it causes perianal pruritus (worse at night). Diagnosed by the tape test; treated with mebendazole or albendazole, with repeat dose in 2 weeks and treatment of the household.

How does Giardia lamblia infection present in children, and how is it treated?

Giardia causes chronic, foul-smelling, fatty diarrhea (malabsorption), bloating, flatulence, and failure to thrive. Transmitted fecal-orally/via contaminated water; treated with metronidazole or tinidazole.

What are the classic features of Ascaris lumbricoides infection in children?

Roundworm ingested via contaminated food/soil; larval lung migration causes cough and eosinophilic pneumonitis (Löffler syndrome), and heavy adult worm burden can cause intestinal obstruction, malnutrition, or biliary obstruction. Treated with albendazole/mebendazole.

According to a typical routine schedule, which vaccines are given at birth?

Hepatitis B (first dose) is given at birth; in endemic countries BCG and oral polio (OPV-0) are also given at birth.

Distinguish live-attenuated from inactivated vaccines with examples, and state the key contraindication for live vaccines.

Live-attenuated (e.g., MMR, varicella, BCG, oral polio, rotavirus) replicate and give strong lasting immunity; inactivated/subunit (e.g., IPV, hepatitis B, DTaP, Hib, pneumococcal) require boosters. Live vaccines are generally contraindicated in significant immunodeficiency and pregnancy.

At what ages is the MMR vaccine typically given, and what is its main contraindication?

MMR is given at 12-15 months and again at 4-6 years. Contraindicated in severe immunodeficiency, pregnancy, and anaphylaxis to a vaccine component (e.g., neomycin/gelatin).

Define croup (laryngotracheobronchitis): typical cause, age, and hallmark signs.

Usually caused by parainfluenza virus in children 6 months-3 years. Presents with a barky/seal-like cough, inspiratory stridor, and hoarseness, often worse at night. Managed with corticosteroids (dexamethasone) and nebulized epinephrine if severe.

What are the diagnostic criteria and cornerstone chronic management of childhood asthma?

Diagnosis is based on recurrent wheeze/cough/dyspnea with reversible airflow obstruction ($\geq 12\%$ FEV1 improvement post-bronchodilator). Cornerstone chronic therapy is inhaled corticosteroids, with short-acting beta-agonists as reliever.

What is the pathophysiology and hallmark presentation of pyloric stenosis?

Hypertrophy of the pyloric muscle causing gastric outlet obstruction, typically in first-born males at 3-6 weeks. Presents with projectile non-bilious vomiting, a palpable 'olive' mass, visible peristalsis, and hypochloremic hypokalemic metabolic alkalosis.

What is intussusception, its classic age and presentation, and the classic imaging finding?

Telescoping of bowel (usually ileocolic) in infants 6 months-2 years. Presents with intermittent colicky pain (drawing up legs), a sausage-shaped mass, and 'red currant jelly' stools. Ultrasound shows a 'target/donut' sign; treated with air/contrast enema reduction.

How do the vomiting characteristics differentiate pyloric stenosis, duodenal atresia, and malrotation with volvulus?

Pyloric stenosis: non-bilious projectile vomiting (~3-6 weeks). Duodenal atresia: bilious vomiting from birth with 'double bubble' sign (associated with Down syndrome). Malrotation/volvulus: sudden bilious vomiting, a surgical emergency due to ischemia.

What is a febrile seizure — define simple versus complex, and typical age range?

A seizure with fever (no CNS infection) in children 6 months-5 years. Simple: generalized, <15 minutes, once in 24 hours. Complex: focal, prolonged (>15 min), or recurrent within 24 hours. Simple febrile seizures have an excellent prognosis.

What are the clinical features and inheritance pattern of Duchenne muscular dystrophy?

X-linked recessive dystrophin gene mutation affecting boys; presents ~2-5 years with proximal weakness, Gower's sign, calf pseudohypertrophy, and markedly elevated creatine kinase. Progressive with loss of ambulation by adolescence.

How is iron deficiency anemia characterized on blood indices, and what is its most common cause in toddlers?

Microcytic ($\downarrow$ MCV), hypochromic anemia with low ferritin and high RDW/TIBC. In toddlers the most common cause is excessive cow's milk intake and inadequate dietary iron; treat with oral iron.

Compare the inheritance and hemoglobin patterns of sickle cell disease and beta-thalassemia major.

Both are autosomal recessive. Sickle cell: point mutation ($\beta^{s}$, Glu$\to$Val) causing HbS, vaso-occlusive crises; beta-thalassemia major: absent/reduced beta-globin chains causing severe transfusion-dependent anemia with $\uparrow$ HbF and HbA2, and extramedullary hematopoiesis.

What are the karyotype and cardinal features of Down syndrome (Trisomy 21)?

Karyotype 47,XX/XY,+21 (usually meiotic nondisjunction). Features: hypotonia, upslanting palpebral fissures, epicanthal folds, single palmar crease, flat facial profile, Brushfield spots, and increased risk of AV septal defects, duodenal atresia, hypothyroidism, and leukemia.

Contrast the karyotypes and key clinical features of Turner syndrome and Klinefelter syndrome.

Turner (45,X): phenotypic female, short stature, webbed neck, gonadal dysgenesis/amenorrhea, coarctation of aorta, normal intelligence. Klinefelter (47,XXY): phenotypic tall male, small testes, gynecomastia, infertility, mild learning difficulties.

What is the inheritance pattern and biochemical defect in phenylketonuria (PKU), and how is it managed?

Autosomal recessive deficiency of phenylalanine hydroxylase causing phenylalanine accumulation. Untreated causes intellectual disability, seizures, eczema, and a musty odor. Detected by newborn screening and managed with a phenylalanine-restricted diet.

Explain multifactorial inheritance and give two pediatric examples.

Multifactorial (polygenic) inheritance results from the combined effect of multiple genes plus environmental factors; it does not follow simple Mendelian ratios and recurrence risk rises with number of affected relatives and severity. Examples: neural tube defects, cleft lip/palate, congenital heart disease, and pyloric stenosis.

What is the inheritance pattern of neurofibromatosis type 1, and name two diagnostic features?

Autosomal dominant (NF1 gene, chromosome 17). Diagnostic features include $\geq 6$ café-au-lait macules, axillary/inguinal freckling, neurofibromas, Lisch iris nodules, and optic gliomas.

How does autosomal dominant inheritance differ from autosomal recessive inheritance in terms of recurrence risk and pedigree pattern?

Autosomal dominant: one mutant allele suffices; affected individuals in every generation (vertical transmission); each child of an affected parent has a $\frac{1}{2}$ risk. Autosomal recessive: two mutant alleles needed; often skips generations (horizontal); two carrier parents give each child a $\frac{1}{4}$ risk, with $\frac{2}{3}$ of unaffected offspring being carriers.