1. Endoscopic Retrograde Cholangiopancreatography (ERCP).
2. Indications:
   • Obstructive jaundice (choledocholithiasis, biliary stricture, choledochal cyst)
   • Chronic pancreatitis (ductal stones, strictures, pseudocyst drainage)
   • Biliary / pancreatic tumors or biliary leaks post-surgery
   • Sphincter of Oddi dysfunction.
3. Precautions / Complications:
   • Risk of acute post-ERCP pancreatitis (most common complication)
   • Risk of duodenal perforation and cholangitis / sepsis
   • Hemorrhage following endoscopic sphincterotomy
   • Ensure pre-procedure correction of coagulopathy and antibiotic prophylaxis if biliary obstruction is present.

1. Hepatobiliary Scintigraphy (${}^{99\text{m}}\text{Tc}$-HIDA / Disofenin / Mebrofenin scan).
2. Key indication: Evaluation of neonatal cholestasis to differentiate Biliary Atresia (absence of tracer excretion into bowel at 24 hours despite prompt hepatic uptake) from Neonatal Hepatitis (delayed uptake with eventual bowel excretion).

1. Tracheoesophageal Fistula with Esophageal Atresia (Type C: proximal blind pouch with distal TE fistula; showing coiled red rubber catheter in proximal pouch and gas in stomach/bowel).
2. Clinical presentation: Excessive frothy salivation/drooling, choking, coughing, and cyanosis with the first feed.
3. Echocardiography requirement:
   • To rule out associated congenital heart disease (VACTERL association, present in ~35%)
   • To determine the laterality of the aortic arch (right-sided aortic arch in ~5% requires left thoracotomy instead of standard right thoracotomy).
4. Poor prognostic factors:
   • Birth weight $<1500\text{ g}$
   • Major congenital cardiac anomaly
   • Long-gap atresia ($>3\text{ cm}$ or $>2$ vertebral bodies)
   • Severe preoperative pneumonia / ventilator dependence.

1. Acute Appendicitis.
2. Radio-opaque calcified density in right lower quadrant representing an Appendicolith (fecalith).
3. USG criteria (graded compression):
   • Non-compressible, blind-ended tubular structure in RLQ
   • Outer appendiceal diameter $>6\text{ mm}$
   • Appendiceal wall thickness $>2–3\text{ mm}$ (target / bull's-eye sign on cross-section)
   • Hyperemia on color Doppler ("ring of fire") and periappendiceal hyperechoic fat / fluid collection.
4. Point of maximal tenderness over McBurney's point (with localized rebound tenderness and guarding; Rovsing sign / Psoas sign).
5. Ultrasonography is first-line; Contrast-Enhanced Computed Tomography (CECT) of the abdomen is the gold standard imaging modality.

1. Radiological signs:
   • Image A: "Double bubble" sign (gas-filled distended stomach and first part of duodenum with absence of distal gas), diagnostic of Duodenal Atresia.
   • Image B: "Triple bubble" sign (gas in stomach, duodenum, and proximal jejunum), diagnostic of Jejunal Atresia.
2. Associated syndrome: Down syndrome (Trisomy 21, present in ~30% of duodenal atresia cases).
3. Associated congenital anomalies: Annular pancreas, malrotation of gut, esophageal atresia, congenital heart defects (AVSD), and biliary atresia.

1. Contrast (Barium) enema study: Shows a narrow, constricted aganglionic rectosigmoid segment with a funnel-shaped "transition zone" leading into a markedly dilated, hypertrophied proximal colon.
2. Hirschsprung Disease (Congenital Aganglionic Megacolon).
3. Differentiation from Functional Constipation:
   • Onset: Hirschsprung presents in neonatal period with delayed meconium ($>48\text{ hr}$); functional constipation presents after 1–2 years (during toilet training).
   • Digital Rectal Exam: In Hirschsprung, rectum is empty, tight, followed by an explosive gush of liquid stool and gas upon withdrawal; in functional constipation, rectal ampulla is loaded with hard stool.
   • Soiling/encopresis: Common in functional; absent in Hirschsprung.
   • Growth: Failure to thrive common in Hirschsprung; normal in functional.
4. Investigation of choice: Full-thickness or suction Rectal Biopsy (taken at least $2\text{ cm}$ above dentate line) demonstrating absence of ganglion cells in submucosal (Meissner) and myenteric (Auerbach) plexuses, with hypertrophied nerve bundles and increased acetylcholinesterase (AChE) staining.
5. Definitive treatment: Surgical pull-through procedure (e.g., Swenson, Duhamel, Soave, or transanal endorectal pull-through [TEPT]).

1. Upper Gastrointestinal (UGI) Barium contrast series / follow-through.
2. "Corkscrew" sign (spiral appearance of twisted, obstructed duodenum and proximal jejunum on the right side of the spine with low/abnormal ligament of Treitz).
3. Midgut Malrotation with Volvulus.
4. Peak age of presentation: First month of life ($>50–80\mathrm{\%}$ present in the first month/year of life with sudden bilious emesis).
5. Associated anomalies: Congenital diaphragmatic hernia, omphalocele/gastroschisis, duodenal atresia, annular pancreas, heterotaxy / polysplenia / asplenia syndromes.

1. Radionuclide studies:
   • a. ${}^{99\text{m}}\text{Tc}$-Mebrofenin / HIDA Scan (Hepatobiliary scintigraphy)
   • b. ${}^{99\text{m}}\text{Tc}$-Pertechnetate Scan (Meckel's scan)
   • c. ${}^{99\text{m}}\text{Tc}$-Sulfur Colloid / Milk Gastroesophageal Scintigraphy (Milk scan / Gastric emptying scan)
2. Indications:
   • a. HIDA scan $\to$ Diagnosis of Biliary Atresia vs neonatal hepatitis.
   • b. Meckel's scan $\to$ Detection of ectopic gastric mucosa in Meckel Diverticulum presenting with painless lower GI bleeding.
   • c. Milk scan $\to$ Evaluation of Gastroesophageal Reflux Disease (GERD), delayed gastric emptying, and pulmonary aspiration.

1. Image A: Foreign body (coin) in the Esophagus (coronal orientation in AP view). Image B: Foreign body in the Trachea / Right Main Bronchus (sagittal orientation in AP view).
2. X-ray differentiation of flat radiopaque foreign bodies (e.g., coins):
   • Esophageal Foreign Body: Lies in the coronal plane $\to$ Appears flat / circular ("face-on") on AP/PA view and end-on / edge-on on lateral view (because the flexible esophagus is compressed anteroposteriorly by the trachea).
   • Tracheal / Airway Foreign Body: Lies in the sagittal plane $\to$ Appears edge-on / end-on on AP view and flat / circular on lateral view (due to the rigid U-shaped cartilaginous tracheal rings with flexible posterior trachealis muscle).

1. Meconium Ileus (showing soap-bubble / Neuhauser sign on plain radiograph and microcolon of disuse with inspissated meconium pellets in terminal ileum on Gastrografin enema).
2. Cystic Fibrosis (Autosomal recessive; mutations in the CFTR gene on chromosome 7q31.2, most commonly $\mathrm{\Delta }\text{F508}$).
3. Operative findings: Dilated distal ileum impacted with thick, tenacious, rubbery, dark-green tarry / inspissated mucus-rich meconium pellets causing complete intraluminal obstruction.

1. Ileocolic Intussusception (showing classical "coiled-spring" appearance and "claw sign" on contrast study; "target/doughnut" sign on USG).
2. Classic triad:
   • Paroxysmal colicky abdominal pain (with crying and drawing up of legs)
   • Palpable sausage-shaped abdominal mass (typically in right hypochondrium / epigastrium with emptiness in RIF [Dance sign])
   • Passage of "red currant jelly" stools (blood mixed with mucus).
3. Contrast / Barium enema: "Coiled spring" appearance (contrast tracking around the intussusceptum) and meniscus/cupping filling defect.
4. Treatment: Non-operative reduction under fluoroscopic/ultrasound guidance via Air (pneumatic) or Hydrostatic (saline/barium) enema; emergency laparotomy if perforation, peritonitis, or failed enema reduction.

1. Loss of normal colonic haustrations, mucosal granularity, luminal narrowing, and featureless tubular rigid colon ("lead-pipe" colon sign).
2. Ulcerative Colitis (Inflammatory Bowel Disease).
3. Complications:
   • Toxic megacolon (fulminant colonic dilatation $>6\text{ cm}$)
   • Colonic perforation and peritonitis
   • Severe lower gastrointestinal hemorrhage
   • Colorectal adenocarcinoma (risk increases after 8–10 years of extensive colitis)
   • Extraintestinal manifestations: Primary Sclerosing Cholangitis (PSC), erythema nodosum, pyoderma gangrenosum, uveitis/episcleritis, arthritis.
4. Pharmacotherapy:
   • 5-Aminosalicylates (5-ASA): Mesalamine, Sulfasalazine (first-line for induction and maintenance in mild-moderate disease)
   • Corticosteroids: Oral Prednisolone or IV Methylprednisolone (for acute flares; not for maintenance)
   • Immunomodulators: Azathioprine, 6-Mercaptopurine
   • Biologics: Anti-TNF agents (Infliximab, Adalimumab), Vedolizumab, Tofacitinib.

1. Celiac Disease (Gluten-Sensitive Enteropathy).
2. Gold standard: Upper GI Endoscopy with multiple (at least 4–6) duodenal/jejunal mucosal biopsies showing Marsh classification III changes (total/subtotal villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes $>25/100$ enterocytes). Supported by serology: Anti-tissue transglutaminase (anti-tTG IgA) and anti-endomysial antibody (EMA IgA).
3. Initiation of a strict, lifelong Gluten-Free Diet (GFD).
4. Food permissions:
   • a. Cornflakes $\to$ Yes (Permitted if gluten-free certified)
   • b. Maggi noodles $\to$ No (Prohibited, contains wheat gluten)
   • c. Sago (sabudana) $\to$ Yes (Permitted)
   • d. Oats cereal $\to$ No (Prohibited unless certified pure uncontaminated gluten-free oats)
   • e. Bajra roti $\to$ Yes (Permitted, pearl millet is naturally gluten-free)
   • f. Dalia $\to$ No (Prohibited, broken wheat contains gluten)

(Permitted: a, c, e; Prohibited: b, d, f)

1. Bilateral Cleft Lip and Complete Cleft Palate.
2. Embryological basis:
   • Cleft Lip: Failure of fusion between the medial nasal prominence and maxillary prominence on one or both sides (during 4th to 7th weeks of gestation).
   • Cleft Palate: Failure of the secondary palatal shelves (lateral palatine processes) to fuse with each other and with the primary palate/nasal septum (during 7th to 12th weeks of gestation).
3. Timing of surgical repair:
   • Cleft Lip Repair (Cheiloplasty): Around 3 months of age (Rule of 10s: Weight $\ge 10\text{ lbs}$, $\text{Hb}\ge 10\text{ g/dL}$, $\text{WBC}\le 10,000$, age $\ge 10\text{ weeks}$).
   • Cleft Palate Repair (Palatoplasty): Around 9–12 months of age (before development of normal speech and phonation).

1. Sengstaken-Blakemore (SB) Tube (or Minnesota tube).
2. Indication: Temporary emergency balloon tamponade for acute, life-threatening gastroesophageal variceal hemorrhage refractory to initial pharmacological therapy (octreotide/terlipressin) and endoscopic intervention (EVL/sclerotherapy).
3. Mechanism: Triple-lumen tube with two inflatable balloons:
   • Gastric balloon: Inflated with $100–250\text{ mL}$ of air and retracted against the gastroesophageal junction to compress submucosal feeding vessels and fundal varices.
   • Esophageal balloon: Inflated to a pressure of $30–45\text{ mmHg}$ to provide direct mechanical compression against bleeding esophageal varices.

1. PM POSHAN (Mid-Day Meal) Nutritional Norms:
   • Primary (Classes I–V): At least 450 calories and 12 g protein per child per day (100 g food grains, 20 g pulses, 50 g vegetables, 5 g oil).
   • Upper Primary (Classes VI–VIII): At least 700 calories and 20 g protein per child per day (150 g food grains, 30 g pulses, 75 g vegetables, 7.5 g oil).
   • Micronutrient supplementation: Weekly Iron and Folic Acid (WIFS), biannual deworming (Albendazole).
2. Minimum feeding days: At least 200 days/year for primary schools and 220 days/year for upper primary schools.

Severe Vitamin E deficiency (due to chronic severe fat malabsorption and cholestasis leading to spinocerebellar ataxia, posterior column loss, peripheral neuropathy, and absent DTRs).

1. Infantile Hypertrophic Pyloric Stenosis (IHPS) (showing elongated pyloric canal and "doughnut / target" sign on transverse view, "cervix sign" on longitudinal view).
   • USG diagnostic criteria:
     • Pyloric muscle wall thickness $\ge 3.0–4.0\text{ mm}$ (single muscular wall)
     • Pyloric canal length $\ge 14–17\text{ mm}$
     • Transverse pyloric diameter $\ge 10–14\text{ mm}$
2. Medical therapy: Oral or IV Atropine sulfate ($0.01–0.04\text{ mg/kg/day}$ titrated) with incremental feeds (reserved for cases where surgery is contraindicated).
3. Borchardt's Triad of Acute Gastric Volvulus:
   • Severe, sudden epigastric pain and distension
   • Intractable retching with minimal or no emesis
   • Inability to pass a nasogastric / orogastric tube into the stomach.

1. Primary Immunodeficiency / Selective IgA Deficiency / Cystic Fibrosis (Giardiasis / recurrent mucosal infections).
2. Antibiotic-Associated Diarrhea (Clavulanate-induced hypermotility $\pm$ secondary Candida diaper dermatitis).
3. Shigella dysentery (Shigellosis) (produces Shiga toxin inducing neurotoxicity/febrile seizures and invasive bloody diarrhea).
4. Lactose Intolerance (Primary / Secondary lactase deficiency) (undigested lactose causes osmotic diarrhea and hydrogen gas fermentation).

1. Caroli Disease (isolated ductal ectasia) / Caroli Syndrome (ductal ectasia associated with Congenital Hepatic Fibrosis).
2. Recurrent bacterial Ascending Cholangitis (due to bile stasis, intrahepatic lithiasis, and bacterial superinfection).
3. Components of Caroli Syndrome:
   • Non-obstructive congenital segmental saccular dilatation of intrahepatic bile ducts
   • Congenital Hepatic Fibrosis (portal hypertension, splenomegaly, varices)
   • Autosomal Recessive Polycystic Kidney Disease (ARPKD / medullary sponge kidney / renal tubular ectasia).
4. PKHD1 gene on chromosome 6p12 (encoding Fibrocystin / Polyductin).

Feature	Osmotic Diarrhea	Secretory Diarrhea
Stool Volume	Usually $<200\text{ mL/day}$ ($<10\text{ mL/kg/day}$)	Large volume, $>200\text{ mL/day}$ ($>20\text{ mL/kg/day}$)
Response to Fasting	Stops / Diarrhea resolves	Continues unabated
Stool Sodium	Low ($<70\text{ mEq/L}$)	High ($>70–90\text{ mEq/L}$)
Stool Reducing Substances	Positive (in carbohydrate malabsorption)	Negative
Stool Osmotic Gap	Elevated ($>100\text{ mOsm/kg}$)	Low ($<50\text{ mOsm/kg}$)
Stool pH	Acidic ($\text{pH}<5.5$)	Neutral / Alkaline ($\text{pH}>6.0$)

1. Vasoactive Intestinal Peptide (VIP): VIPoma (Verner-Morrison / WDHA syndrome) $\to$ Somatostatin analogs (Octreotide), tumor resection.
2. Gastrin: Gastrinoma (Zollinger-Ellison syndrome) $\to$ High-dose PPIs (Omeprazole), surgical excision.
3. Serotonin / Tachykinins: Carcinoid tumor (Carcinoid syndrome) $\to$ Octreotide, Cyproheptadine, surgical resection.
4. Calcitonin: Medullary Thyroid Carcinoma (MTC) $\to$ Total thyroidectomy with central neck dissection, Vandetanib/Cabozantinib.
5. Histamine: Systemic Mastocytosis / Mastocytoma $\to$ $H_1+H_2$ antihistamines, Cromolyn sodium.

1. PFIC Types:
   • PFIC Type 1 (Byler disease): Inactivating mutation in ATP8B1 gene (encoding FIC1 flippase); normal/low serum GGT.
   • PFIC Type 2 (Byler syndrome): Mutation in ABCB11 gene (encoding BSEP - Bile Salt Export Pump); normal/low serum GGT, high risk of early HCC.
   • PFIC Type 3: Mutation in ABCB4 gene (encoding MDR3 - Multidrug Resistance Protein 3 / phosphatidylcholine translocator); High serum GGT.
2. Fat-Soluble Vitamin Supplementation in Cholestasis:
   • Vitamin A: 5,000–15,000 IU/day orally (water-miscible / Aquasol A)
   • Vitamin D: 3,000–8,000 IU/day of $D_3$ or $3–5\text{ µg/kg/day}$ of Alfacalcidol / Calcitriol
   • Vitamin E: 50–200 IU/kg/day of d-$\alpha$-tocopheryl polyethylene glycol-1000 succinate (TPGS)
   • Vitamin K: 2.5–5 mg orally 2–7 times weekly or $1–2\text{ mg}$ IV/SC monthly.

1. Conditions mimicking Reye syndrome:
   • Medium-Chain Acyl-CoA Dehydrogenase (MCAD) deficiency and other Fatty Acid Oxidation Disorders (FAODs)
   • Urea Cycle Disorders (e.g., OTC deficiency)
   • Organic acidemias (Methylmalonic, Propionic, Isovaleric acidemia)
   • Carnitine palmitoyltransferase (CPT I/II) deficiency
   • Mitochondrial disorders / Glutaric aciduria type II
   • Toxic ingestion: Aspirin toxicity, Valproate hepatotoxicity, Jamaican vomiting sickness (hypoglycin A).
2. Lovejoy Clinical Staging of Reye Syndrome:
   • Stage I: Vomiting, lethargy, sleepiness, lab evidence of liver dysfunction (hyperammonemia, elevated transaminases).
   • Stage II: Delirium, combativeness, disorientation, hyperventilation, hyperactive reflexes.
   • Stage III: Light coma, obtundation, decorticate rigidity, intact pupillary light reflexes.
   • Stage IV: Deepening coma, decerebrate rigidity, loss of oculocephalic reflexes, fixed dilated pupils, liver dysfunction improving.
   • Stage V: Flaccidity, loss of DTRs, respiratory arrest, isoelectric EEG, death.

Pattern of Hepatic Injury	Representative Causative Drug
Centrilobular Necrosis	Acetaminophen (Paracetamol overdose), Halothane
Microvesicular Steatosis	Valproic acid, Tetracycline, Aspirin
Hepatic Fibrosis / Cirrhosis	Methotrexate, Vitamin A toxicity
Cholestatic Hepatitis	Amoxicillin-Clavulanate, Chlorpromazine, Erythromycin estolate
Biliary Sludge / Pseudolithiasis	Ceftriaxone
Sinusoidal Obstruction Syndrome (VOD)	Busulfan, Cyclophosphamide, Actinomycin-D
Hepatic Vein Thrombosis (Budd-Chiari)	Oral contraceptive pills (Estrogens/Androgens)

1. Image A: Giardia lamblia (trophozoite / cyst; characteristic teardrop-shaped binucleated flagellate). Image B: Enterobius vermicularis (Pinworm egg; planoconvex, D-shaped translucent ovum).
2. Treatment:
   • For Giardia: Metronidazole ($15–30\text{ mg/kg/day}$ for 5–7 days), Tinidazole, or Nitazoxanide.
   • For Enterobius: Albendazole ($400\text{ mg}$ single dose, repeated after 2 weeks) or Mebendazole / Pyrantel pamoate (treat all household contacts).

1. Bell Stage II NEC (showing distinct intramural gas bubbles / Pneumatosis intestinalis and branching portal venous gas).
2. Radiological criteria (Bell's Staging):
   • Stage II (Definite NEC): Pneumatosis intestinalis $\pm$ Portal venous gas.
   • Stage III (Advanced / Perforated NEC): Pneumoperitoneum (free intraperitoneal air under diaphragm / "football sign" / Rigler's double wall sign indicating bowel perforation requiring emergency surgical laparotomy/drainage).
3. Other conditions with pneumatosis intestinalis: Hirschsprung-associated enterocolitis, severe rotavirus enteritis, ischemic bowel injury, immunosuppressed graft-versus-host disease (GVHD).

1. Cholestatic Metabolic Bone Disease / Severe Hepatic Rickets (secondary to malabsorption of fat-soluble Vitamin D and calcium due to absence of intraluminal bile salts).
2. Prevention: High-dose water-miscible Vitamin $D_3$ (5,000–8,000 IU/day) or Calcitriol ($0.05–0.2\text{ µg/kg/day}$), medium-chain triglyceride (MCT) enriched formulas, and elemental calcium supplementation ($50–100\text{ mg/kg/day}$).
3. Medical management of pruritus:
   • Ursodeoxycholic acid (UDCA): $15–20\text{ mg/kg/day}$
   • Rifampicin: $5–10\text{ mg/kg/day}$ (enzyme inducer)
   • Cholestyramine: $0.25–0.5\text{ g/kg/day}$ (bile acid sequestrant)
   • Antihistamines (Hydroxyzine) / Opioid antagonists (Naltrexone).
4. Alagille Syndrome (Arteriohepatic Dysplasia, autosomal dominant JAG1 or NOTCH2 mutation).

1. Left-sided Congenital Diaphragmatic Hernia (Bochdalek Hernia) with mediastinal shift to the right.
2. Embryological defect: Failure of fusion/closure of the posterolateral pleuroperitoneal membrane with the septum transversum and dorsal mesentery between the 8th and 10th weeks of gestation.
3. Pathophysiological causes of respiratory distress:
   • Ipsilateral and contralateral Pulmonary Hypoplasia (decreased bronchial branching and alveolar surface area)
   • Severe Persistent Pulmonary Hypertension of the Newborn (PPHN) with right-to-left shunting
   • Space-occupying compression of the lung parenchyma and mediastinum by herniated abdominal viscera.

1. Gastroschisis (full-thickness abdominal wall defect to the right of the intact umbilical cord, with evisceration of bowel loops devoid of a covering membrane).
2. Differential diagnosis: Omphalocele (Exomphalos).
3. Differentiating features:

Feature	Gastroschisis	Omphalocele
Location	Paraumbilical (usually right)	Central (through umbilical ring)
Covering Sac	Absent (exposed edematous bowel)	Present (peritoneum + amnion)
Umbilical Cord Insertion	Normal to the left of defect	Onto the apex of the sac
Associated Anomalies	Rare ($\sim 10\mathrm{\%}$, intestinal atresia)	Very Common (50–70%): Cardiac, Beckwith-Wiedemann, Trisomies

4. Immediate management:
   • Wrap exposed bowel in sterile, warm saline-soaked gauze and place infant in a sterile bowel bag ("silo") up to the axillae to prevent heat and fluid loss.
   • Insert NG/OG tube for gastric decompression.
   • IV hydration (1.5–2 times maintenance due to fluid evaporative loss) and broad-spectrum IV antibiotics.
   • Primary or staged surgical closure.

1. Slit-lamp examination of the cornea for Kayser-Fleischer (KF) rings (copper deposition in Descemet's membrane).
2. Wilson Disease (Hepatolenticular Degeneration) (autosomal recessive, ATP7B gene on chr 13q14).
3. Diagnostic tests:
   • Serum Ceruloplasmin: Low ($<20\text{ mg/dL}$ or $<200\text{ mg/L}$)
   • 24-hour Urinary Copper excretion: Elevated ($>100\text{ µg/day}$ or $>0.6\text{ µmol/day}$)
   • Hepatic copper concentration on liver biopsy: $>250\text{ µg/g}$ dry weight (gold standard).
4. Management:
   • Copper chelators: D-Penicillamine ($20\text{ mg/kg/day}$ with Pyridoxine/Vit $B_6$ $25–50\text{ mg/day}$) or Trientine
   • Maintenance / Presymptomatic: Oral Zinc sulfate / acetate ($50–150\text{ mg}$ elemental zinc/day to induce intestinal metallothionein)
   • Dietary restriction: Avoid copper-rich foods (shellfish, nuts, chocolate, mushrooms, liver)
   • Orthotopic Liver Transplantation for acute fulminant hepatic failure or decompensated cirrhosis.

• 1. Secretory Diarrhea $\to$ b. Vibrio cholerae infection (enterotoxin-mediated CFTR stimulation)
• 2. Osmotic Diarrhea $\to$ e. Lactase deficiency (carbohydrate malabsorption)
• 3. Increased Motility $\to$ d. Thyrotoxicosis
• 4. Decreased Motility / Stasis $\to$ c. Blind loop syndrome / SIBO
• 5. Decreased Absorptive Surface Area $\to$ a. Celiac disease (villous atrophy) / Short bowel syndrome

(Match: 1-b, 2-e, 3-d, 4-c, 5-a)

1. Metabolic causes of constipation: Hypothyroidism, Hypercalcemia, Hypokalemia, Diabetes insipidus, Renal tubular acidosis (RTA), Multiple Endocrine Neoplasia (MEN 2B).
2. Complications of severe vomiting:
   • Hypokalemic, hypochloremic metabolic alkalosis
   • Dehydration and prerenal azotemia
   • Mallory-Weiss mucosal tear / Boerhaave esophageal rupture
   • Aspiration pneumonia / chemical pneumonitis
   • Reflux esophagitis / tooth enamel erosion.
3. Calculation:
   $\text{Stool Osmotic Gap}=\text{Stool Osmolality}-2\times (\text{Stool }{\text{Na}}^{+}+\text{Stool }{\text{K}}^{+})$
   $\text{Stool Osmotic Gap}=290-2\times (40+50)=290-180=110\text{ mOsm/kg}$
4. Clinical significance:
   • $\text{Gap}>100\text{ mOsm/kg}\to$ Osmotic Diarrhea (unabsorbed solutes present in stool).
   • $\text{Gap}<50\text{ mOsm/kg}\to$ Secretory Diarrhea (pure electrolyte secretion).

1. Pierre Robin Sequence (PRS).
2. Classic triad:
   • Severe Micrognathia / Retrognathia (hypoplastic mandible)
   • Glossoptosis (posterior displacement of tongue causing airway obstruction)
   • U-shaped (or V-shaped) Cleft Palate.
3. It is a Sequence (a primary embryological defect—mandibular hypoplasia—initiates a cascade of secondary developmental abnormalities: preventing the tongue from descending, thereby obstructing midline fusion of the palatal shelves).
4. Other clinical sequences:
   • Potter Sequence (renal agenesis $\to$ oligohydramnios $\to$ pulmonary hypoplasia + facial compression + clubfoot)
   • Prune Belly Sequence (urethral obstruction $\to$ massive megacystis $\to$ abdominal muscle deficiency + cryptorchidism).
5. Stickler Syndrome: An autosomal dominant connective tissue disorder (collagen COL2A1, COL11A1 mutations) characterized by Pierre Robin sequence associated with severe myopia, retinal detachment, sensorineural hearing loss, and premature spondyloepiphyseal degenerative arthropathy.

1. True (Prolamin fractions of wheat, barley, and rye trigger the autoimmune mucosal response).
2. False (Strongly associated with HLA-DQ2 [$\sim 95\mathrm{\%}$] and HLA-DQ8 [$\sim 5\mathrm{\%}$]).
3. True (Non-classical celiac disease frequently presents without diarrhea as isolated short stature or refractory IDA).
4. True (Celiac disease with epilepsy and bilateral occipital calcifications - CEC syndrome).
5. True (Enteropathy-Associated T-Cell Lymphoma [EATL] is a severe malignancy associated with chronic untreated celiac disease).
6. False (Total villous atrophy / flat mucosa is also seen in severe cow's milk protein allergy, autoimmune enteropathy, tropical sprue, and post-gastroenteritis enteropathy).
7. True (Strict gluten-free diet aims for $<20\text{ ppm}$ / $<10–20\text{ mg/day}$ gluten intake).

(Answers: 1-True, 2-False, 3-True, 4-True, 5-True, 6-False, 7-True)

1. Abetalipoproteinemia (Bassen-Kornzweig syndrome) (autosomal recessive mutation in the MTTP microsomal triglyceride transfer protein gene; failure to synthesize ApoB-48 and ApoB-100).
2. Diagnostic findings:
   • Retinal examination: Atypical Retinitis Pigmentosa (pigmentary retinopathy / loss of night and color vision).
   • Peripheral blood film: Acanthocytes ("spur cells", thorny star-shaped erythrocytes present in $>50\mathrm{\%}$).
3. Nervous system involvement: Degeneration of spinocerebellar tracts, posterior columns (proprioception/vibration loss), peripheral neuropathy, and cerebellar ataxia.
4. Treatment:
   • Restriction of dietary long-chain saturated fats with medium-chain triglyceride (MCT) oil supplementation
   • Massive doses of fat-soluble vitamins: Vitamin E ($100–300\text{ mg/kg/day}$ orally to halt neurological and retinal damage) and Vitamin A ($10,000–25,000\text{ IU/day}$).

• 1 $\to$ b. Bacillus cereus (preformed emetic heat-stable toxin cereulide in reheated fried rice)
• 2 $\to$ c. Campylobacter jejuni (unpasteurized milk, undercooked poultry; pseudoappendicitis/bloody diarrhea)
• 3 $\to$ a. Salmonella enterica (eggs, poultry; inflammatory gastroenteritis)
• 4 $\to$ d. Staphylococcus aureus (preformed enterotoxins A–E in dairy/mayonnaise salads)

• 1 $\to$ b. Protein-Losing Enteropathy (resists degradation by intestinal proteases)
• 2 $\to$ a. Pancreatic exocrine insufficiency ($<200\text{ µg/g}$ indicates insufficiency; gold standard non-invasive test)
• 3 $\to$ c. Neutrophilic intestinal inflammation (differentiating IBD from IBS)
• 4 $\to$ d. Carbohydrate malabsorption (lactose, sucrose)
• 5 $\to$ e. Pancreatic exocrine function
• 6 $\to$ f. Intestinal mucosal permeability

1. Wangensteen-Rice Invertogram (or Cross-Table Lateral Prone Radiograph), demonstrating Imperforate Anus / Anorectal Malformation (ARM).
2. Surgical management:
   • Low ARM: Single-stage Primary Anoplasty / Cutback Anoplasty in the neonatal period (without diverting colostomy).
   • High / Intermediate ARM: Initial emergency Divided Sigmoid Colostomy with mucus fistula, followed at 3–6 months by definitive Posterior Sagittal Anorectoplasty (PSARP / Peña procedure).
3. True/False:
   i. True (Low lesions have good sphincter development and good prognosis for continence).
   ii. True (High lesions have poor pelvic musculature and frequent genitourinary fistulae).
   iii. True (Prone cross-table lateral film after 18–24 hours allows rectal gas to reach the distal-most pouch without infant inversion distress).

1. Palmar erythema & Spider nevi: Impaired hepatic clearance and metabolism of Estrogens, resulting in hyperestrogenemia and peripheral arteriolar vasodilation.
2. Leukonychia: Chronic Severe Hypoalbuminemia ($\text{serum albumin}<2.5\text{ g/dL}$) altering the vascular bed of the nail matrix.
3. Dupuytren's contracture: Palmar fascial fibrosis and myofibroblast proliferation mediated by free radicals, alcohol toxicity, and fibroblast growth factors.
4. Fetor hepaticus: Exhalation of volatile Dimethyl sulfide / Mercaptans resulting from severe portosystemic shunting and impaired hepatic clearance of methionine metabolites.
5. Parotid swelling: Chronic sialadenosis due to autonomic neuropathy, malnutrition, and protein deficiency.

1. Wilson Disease (Hepatolenticular Degeneration).
2. Endocrine manifestations: Hypoparathyroidism, delayed puberty, primary amenorrhea / infertility, gynecomastia, and renal tubular acidosis (RTA with nephrocalcinosis).
3. Gold standard test: Hepatic copper quantification by liver biopsy ($>250\text{ µg/g}$ dry tissue weight) or biallelic pathogenic mutations in the ATP7B gene.
4. Pharmacotherapy:
   • D-Penicillamine
   • Trientine hydrochloride
   • Zinc acetate / sulfate
   • Ammonium tetrathiomolybdate (for neurological disease).
5. Mechanism of anemia: Coombs-negative acute intravascular hemolytic anemia caused by acute massive release of free non-ceruloplasmin-bound copper from necrotic hepatocytes, inducing lipid peroxidation of red cell membranes and glutathione depletion.

• a: Early acute infection / window period prior to core antibody seroconversion.
• b: Acute Hepatitis B infection (High infectivity; positive HBsAg and Anti-HBc IgM).
• c: Vaccine-induced Immunity (Isolated anti-HBs positivity with negative core antibodies).
• d: Chronic Hepatitis B infection (Persistence of HBsAg $>6$ months with IgG anti-HBc).
• e: Past resolved natural infection with immunity (Positive anti-HBs and positive IgG anti-HBc).

1. Older Child (3 years of age, $\ge 12$ months):
   • Administer Hepatitis A Inactivated Vaccine (single dose of 0.5 mL IM prior to travel; provides $>95\mathrm{\%}$ protection within 2–4 weeks).
   • Complete the 2-dose series by administering the second booster dose 6–12 months later.
2. Younger Infant (9 months of age, $<12$ months):
   • Inactivated HAV vaccine is not routinely licensed for infants $<12$ months.
   • Administer Hepatitis A Standard Immune Globulin (IG): $0.06\text{ mL/kg}$ IM (since anticipated travel duration is 3–5 months).
   • When the infant reaches 12 months of age, standard Hepatitis A vaccination can be initiated.

1. Cystic Fibrosis presenting with Rectal Prolapse and chronic suppurative lung disease / exocrine pancreatic insufficiency.
2. Genetic basis: Autosomal recessive mutation in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene located on chromosome 7q31.2 (commonest mutation: $\mathrm{\Delta }\text{F508}$).
3. Pathophysiology of rectal prolapse:
   • Exocrine pancreatic insufficiency causes severe malabsorption, steatorrhea, and bulky voluminous stools.
   • Chronic increased intra-abdominal pressure from persistent paroxysmal coughing.
   • Malnutrition leading to loss of perirectal ischiorectal fat pads and hypotonic pelvic floor musculature.
4. Neonatal Screening: Dried blood spot measurement of Immunoreactive Trypsinogen (IRT) on Guthrie card, followed by second-tier DNA mutation panel (IRT/DNA protocol) and confirmatory Quantitative Pilocarpine Iontophoresis Sweat Chloride Test ($\text{Sweat Chloride}\ge 60\text{ mmol/L}$ is diagnostic).