**Question:** Meconium ileus is a manifestation of -

A. Cystic Fibrosis
B. Hirschsprung's disease
C. Umbilical hernia
D. Congenital abnormality of the intestine

**Core Concept:**
Meconium ileus is a clinical condition characterized by the accumulation of thick, blackish-green, meconium-filled small bowel loops in neonates born with cystic fibrosis (CF). Meconium, the first stool produced by the fetus in utero, is typically passed within the first 24 hours of life. When it accumulates in the bowel due to impaired peristalsis and poor transit, it causes obstruction and leads to complications like malabsorption and malnutrition.

**Why the Correct Answer is Right:**
Meconium ileus is a manifestation of Cystic Fibrosis (CF) because it results from the impaired peristalsis and poor transit of meconium in the bowel due to the underlying genetic disorder. CF is a common autosomal recessive genetic disorder characterized by the production of thick, sticky mucus in various organs, such as the lungs, pancreas, and gastrointestinal tract. The thick mucus forms plugs that obstruct the airways in CF lungs and impairs the exocrine glands' function in the pancreas. In the gastrointestinal tract, the thick mucus leads to impaired meconium transit and poor bowel motility, resulting in meconium ileus.

**Why Each Wrong Option is Incorrect:**

A. Hirschsprung's disease (HD) is a congenital disorder characterized by the absence of ganglion cells in the myenteric plexus, resulting in hypotonic bowel and absent or weak propulsive contractions. This is different from meconium ileus, which is caused by the thick mucus production in CF.

B. Hirschsprung's disease (HD) is another congenital disorder that causes intestinal obstruction due to the absence of ganglion cells in the myenteric plexus. This differs from meconium ileus, which is caused by the thick mucus production in Cystic Fibrosis (CF).

C. Umbilical hernia is a congenital condition where the abdominal organs protrude through a weak point in the abdominal wall, usually around the umbilicus. This is unrelated to meconium ileus, which is caused by thick mucus production in Cystic Fibrosis (CF).

D. Congenital abnormalities of the gastrointestinal tract can lead to meconium ileus. However, the correct answer is Cystic Fibrosis (CF) because thick mucus production is the primary pathophysiology of meconium ileus, not the specific congenital abnormality. CF is an autosomal recessive disorder with abnormal mucus production, leading to impaired meconium transit and poor bowel motility. In contrast, the other options (A, B, C, and D) represent unrelated conditions that can cause gastrointestinal tract abnormalities but do not account for the thick mucus production causing meconium ileus.