Pediatrics Made Simple For NLE NRE Step 1

1. Fetal Circulation (before birth)

• Lungs are not working properly before birth.
• The placenta does oxygenation of blood.
• The umbilical cord has:
• 2 arteries
• 1 vein
• The umbilical vein carries approximately 80% oxygenated blood from the placenta to the fetus.

2. Important Shunts (and Adult Remnants)

1. Ductus venosus → connects the umbilical vein to the IVC → becomes ligamentum venosum.
2. Foramen ovale → shunts blood RA → LA → becomes fossa ovalis.
3. Ductus arteriosus → connects pulmonary artery to aorta → becomes ligamentum arteriosum.

congenital heart diseases

Feature	Acyanotic CHD (“Pink babies”)	Cyanotic CHD (“Blue babies”)
Shunt	Left → Right	Right → Left
Oxygen level	Normal (no cyanosis)	Low (cyanosis present)
Most common	VSD (overall most common CHD)	TOF in adults, TGA in children
Examples	VSD, ASD, PDA	TOF, TGA, Tricuspid atresia, Truncus arteriosus

1. Acyanotic Heart Diseases (L → R Shunt, “Pink Babies”)

General Features

• Blood flow: Left → Right shunt → mixing of oxygenated with deoxygenated blood.
• Symptoms: May appear late.
• Complication: Backward reversal of shunt → Eisenmenger syndrome (cyanosis develops).

1. Patent Ductus Arteriosus (PDA)

Causes:

• Maternal rubella infection
• Maternal ↑ prostaglandins

Auscultation: Machine-like murmur

Pulse: Wide pulse pressure

Management:

• Indomethacin → closes duct
• Prostaglandins (PGE1) → keep it open
• If not closed by 8 months → surgery

Special note: PDA must not be closed in TOF and TGA (cyanotic CHD).

2. Atrial Septal Defect (ASD)

• Shunt: Left → Right
• Auscultation: Wide, fixed splitting of S2

3. Ventricular Septal Defect (VSD)

• Shunt: Left → Right
• CXR: Cardiomegaly, delayed closure of the pulmonary valve
• Complications: Pulmonary arterial hypertension (PAH)
• Association: Down syndrome
• Investigation of choice: Echocardiography
• Types:
  1. Restrictive VSD → often closes spontaneously
  2. Non-restrictive VSD → symptoms: fatigue, poor growth, failure to thrive, malaise
     • Auscultation: Harsh holosystolic murmur
     • Treatment: Surgical closure

2. Cyanotic Heart Disease

Tetralogy of Fallot (TOF)

Mnemonic – PROV

• P → Pulmonary stenosis / Pulmonary hypertension
• R → Right ventricular hypertrophy (RVH)
• O → Overriding of the aorta
• V → Ventricular septal defect (VSD)

The most common cyanotic CHD in children

Clinical features

• Usually presents at 8–14 years
• Dyspnea
• Bluish discoloration (cyanosis)
• Squatting → increases systemic vascular resistance → improves oxygenation

Investigations

• X-ray: Boot-shaped heart
• ECG: RVH + Cardiomegaly

Treatment

Definitive: Surgical repair

Here are other materials for NLE NRE step 1

1. CHD Associations with Conditions

• Fetal alcohol syndrome → VSD
• Infant of a diabetic mother → Transposition of great vessels (TGV)
• Turner syndrome → Coarctation of the aorta
• Congenital rubella → PDA
• Congenital lupus → Congenital heart block
• Kawasaki disease → Coronary artery aneurysm

2. Classic X-ray Appearances

• TOF → Boot-shaped heart
• TGV → Egg-on-a-string (Egg shell)

3. Congenital Heart Diseases – Murmurs & Sounds

Condition	Characteristic Murmur / Sound
VSD	Harsh holosystolic murmur
ASD	Wide, fixed splitting of S2
PDA	Continuous “machine-like” murmur

3. Coarctation of Aorta

Narrowing of the aorta → ↑ blood flow in upper extremities & ↓ flow in lower extremities

Types

Feature	Pre-ductal Coarctation	Post-ductal Coarctation
Site of narrowing	Distal to the ductus arteriosus	Hypertension in the upper limbs, radio-femoral delay
Age group	Infants / < 5 years	Children & adolescents > 5 years
Severity	Severe → early presentation	Less severe → later presentation
Association	Turner syndrome	Bicuspid aortic valve
Clinical course	Early cyanosis, heart failure, poor growth	Hypertension in the upper limbs, radio-femoral delay
Prognosis	Needs urgent intervention	May present later, diagnosed on routine BP check

Clinical Features

• Upper extremities: Hypertension, redness
• Lower extremities: Hypotension, cyanosis, poor growth, failure to thrive

Blood Pressure:

• ↑ SBP in arms
• ↓ SBP in legs

Pulse: Radio-femoral (radio-temporal) delay

Investigations

• CXR
• Echo with color Doppler (diagnosis of choice)

Management

• PGE1 infusion → keep ductus arteriosus open (in infants)
• Balloon angioplasty → definitive treatment

4. Chromosomal disorder

Syndrome	Chromosome / Karyotype	Causes	Clinical Features	Associations	Prognosis / Treatment
Down Syndrome (Trisomy 21)	47, +21	– Meiotic nondisjunction (↑ risk with maternal age) – Robertsonian translocation – Mosaicism	– Intellectual disability – Flat nasal bridge – Hypotonia (floppy baby) – Single palmar crease – Sandal gap deformity – Poor growth, short stature	– Duodenal atresia (“double bubble sign”) – Hirschsprung disease – CHD (VSD > ASD) – Early Alzheimer’s – ↑ Risk of ALL & AML	Supportive therapy; multidisciplinary care
Edward Syndrome (Trisomy 18)	47, +18	Meiotic nondisjunction	– Low-set ears – Rocker-bottom feet – Clenched fists (overlapping fingers) – Micrognathia – Prominent occiput	Horseshoe kidney	45, X0
Patau Syndrome (Trisomy 13)	47, +13	Meiotic nondisjunction	– Polydactyly – Microphthalmia – Microcephaly – Holoprosencephaly – Cleft lip/palate – Cutis aplasia	CHD, CNS malformations	Die within 1 year
Turner Syndrome	Coarctation of the aorta Horseshoe kidney	Monosomy X (sex chromosome loss)	– Short stature – Webbed neck – Wide-spaced nipples – Primary amenorrhea – Streak ovaries – Lymphedema of hands/feet	47, XXY	Estrogen therapy (induces puberty, protects bone health)
Klinefelter Syndrome	↑ Risk of breast cancer & autoimmune diseases	Extra X in males (↑ maternal age risk)	– Tall male – Hypogonadism – Oligospermia/infertility – Testicular atrophy – Gynecomastia – Female-type hair distribution	↑ Risk breast cancer & autoimmune diseases	Testosterone replacement therapy

5. Double Y Chromosome (47, XYY)

Karyotype: 47, XYY

Cause: Meiotic nondisjunction (usually paternal)

Clinical Features:

• Normal height and physical development
• Frequent anger / aggressive behavior
• Severe acne
• May have mild learning difficulties

Management: Supportive care, behavioral counseling if needed

6. Hypertrophic Pyloric Stenosis

• Definition: Hypertrophy and narrowing of the pyloric sphincter → delayed gastric emptying
• Risk Factors:
  • Exact cause unknown
  • Maternal erythromycin exposure
• Clinical Features:
  • Non-bilious projectile vomiting (classic)
  • Infant remains hungry after vomiting (“hungry vomiter”)
  • Signs of dehydration
• Examination:
  • Abdominal distension
  • Olive-shaped, mobile, non-tender mass in the epigastrium
• Investigations:
  • Metabolic alkalosis (hypochloremic, hypokalemic)
  • Barium swallow → “string sign”
• Treatment:
  • Initial: NPO (nil per os), IV fluids, correct electrolytes
  • Definitive: Surgical pylorotomy

7. Intussusception

• Proximal intestine telescopes into the distal part → bowel obstruction
• Age group: 6 months – 3 years
• Epidemiology: More common in boys
• Clinical Triad:
  • Intermittent abdominal pain
  • Bloody diarrhea (“red currant jelly stools”)
  • Vomiting
• Investigations:
  • USG abdomen: “Target sign / Doughnut sign” at the site of pain
  • ABG: Metabolic alkalosis (due to vomiting)
• Treatment:
  • Initial: Air or barium enema (diagnostic + therapeutic)
  • Surgery if enema fails or perforation is suspected

8. Meckel’s Diverticulum

• Failure of the omphalomesenteric (vitelline) duct to obliterate → true diverticulum
• Epidemiology: More common in males
• Rule of 2’s:
  • 2% of the population
  • 2 times more common in boys
  • 2 inches in length
  • 2 feet from the ileocecal valve
  • 2 types of ectopic mucosa (gastric & pancreatic)
  • Symptoms before 2 years of age
• Clinical Features:
  • Often asymptomatic
  • Painless hematochezia (classic)
  • Pallor, shortness of breath due to anemia
• Investigations:
  • Technetium-99m pertechnetate scan → detects ectopic gastric mucosa
• Treatment: Surgical resection

9. Hirschsprung Disease

• Absence of ganglion cells in the intestinal wall (neural crest cell migration defect) → no peristalsis in the affected segment.
• Epidemiology / Risk Factors:
  • Male > Female
  • Premature infants
  • Associated with Down syndrome

Clinical Features

• Delayed passage of meconium (>48 hours after birth)
• Bilious vomiting
• Abdominal distention
• Failure to thrive

Examination

• DRE: Explosive discharge of stool & gas → squirt sign

Diagnosis

• Gold standard: Rectal biopsy → absence of ganglion cells
• Supportive: Contrast enema showing transition zone

Treatment

• Surgical resection of the aganglionic segment (pull-through procedure)

Key Differentiation in Delayed Meconium

• If respiratory symptoms present → think Cystic Fibrosis
• If no respiratory symptoms:
  • DRE → gush of stool → Hirschsprung disease
  • DRE → no stool → Other intestinal obstruction (e.g., ileal atresia, meconium ileus in CF)

10. Cystic Fibrosis (CF)

• Genetics:
  • Autosomal recessive
  • Mutation in the CFTR gene (Chromosome 7)

Clinical Features

• Respiratory:
  • Chronic cough, recurrent lung infections
  • Wheeze, bronchiectasis
  • Salty-tasting skin (due to high NaCl in sweat)
• Gastrointestinal:
  • Pancreatic insufficiency → malabsorption, steatorrhea, FTT (failure to thrive)
  • Delayed passage of meconium (meconium ileus) in neonates
• Other:
  • Male infertility (absence of vas deferens)

Diagnosis

• Sweat chloride test: > 60 mmol/L = diagnostic
• Genetic testing for CFTR mutation (confirmatory)

Treatment

• Nutritional:
  • High-calorie, high-protein diet
  • Supplement fat-soluble vitamins (A, D, E, K)
• Pulmonary:
  • Bronchodilators
  • Anti-inflammatory drugs
  • Antibiotics (for recurrent infections)
  • Chest physiotherapy
  • Oxygen supplementation in advanced disease

11. Kawasaki Disease

A multi-segment, medium-vessel vasculitis, primarily affecting children < 5 years. Considered an autoimmune phenomenon.

Phases

1. Acute phase (1–2 weeks):
   • High fever > 5 days
   • Rash, conjunctivitis, strawberry tongue, lymphadenopathy, extremity changes
   • ↑ Risk of myocarditis
2. Subacute phase (2–8 weeks):
   • Desquamation (peeling of skin on fingers/toes)
   • ↑ Risk of coronary artery aneurysm
3. Chronic phase:
   • Gradual resolution of symptoms
   • ESR and CRP return to normal

Clinical Features (Mnemonic: CRASH & Burn)

• Conjunctivitis (bilateral, non-purulent)
• Rash (polymorphous)
• Adenopathy (cervical, usually unilateral)
• Strawberry tongue + mucosal changes (red, cracked lips)
• Hand and foot changes (edema, erythema, peeling)
• Burn: Fever > 5 days

Treatment

• High-dose Aspirin (anti-inflammatory, antipyretic, antiplatelet)
• IVIG (prevents coronary aneurysm if given early)
• Low-dose Aspirin (continued up to 6 weeks or longer if coronary involvement persists)
• Corticosteroids (for refractory disease)

12. Juvenile Idiopathic Arthritis (JIA)

• Autoimmune disease → joint inflammation
• Morning stiffness + gradual loss of movement
• Symptoms last ≥ 6 weeks
• Age: < 16 years

Types

Type	Key Features
Pauciarticular JIA	Few joints (≤ 4) No systemic symptoms Uveitis (slit lamp exam) ANA (+), RF (–)
Polyarthritis JIA	≥ 5 joints involved Systemic symptoms present
Systemic JIA	Triad → Salmon pink rash, Hepatosplenomegaly, High grade fever ANA (–), RF (–)

13. Acute Otitis Media (AOM)

Inflammation of the middle ear cavity.

Causes:

• Bacterial: Streptococcus pneumoniae, Haemophilus influenzae
• Viral: Measles, Influenza, RSV
• Non-infectious: Allergy

Clinical Features:

• Otalgia (ear pain)
• Fever
• Excessive crying
• Difficulty sleeping

Otoscopic Findings:

• Erythematous tympanic membrane (TM)
• Bulging or retraction of TM
• Decreased TM mobility

Treatment:

• First line: Co-amoxiclav

Complications (if untreated):

• Mastoiditis
• TM perforation → conductive hearing loss
• Meningitis
• Chronic suppurative otitis media (CSOM)

14. Bronchiolitis

Inflammation of small airways, usually in children < 2 years.

Cause:

• Most common: Respiratory Syncytial Virus (RSV)

Clinical Features:

• Cough
• Dyspnea, shortness of breath
• Chest tightness
• Auscultation: “Washing machine wheeze”

Treatment:

• Primarily supportive care
• Resistant/severe cases: Palivizumab, Ribavirin

15. Meningitis

Causes (Age-wise):

• Neonates: Group B Streptococcus (Streptococcus agalactiae)
• Infants: Streptococcus pneumoniae
• Adolescents (14–18 yrs): Neisseria meningitidis
• Middle-aged adults: Streptococcus pneumoniae
• Viral: HSV (Herpes Simplex Virus)
• Fungal: Cryptococcus neoformans

Clinical Signs:

• Kernig’s sign (+)
• Brudzinski’s sign (+)

Treatment:

• Ampicillin + Cefotaxime