A foul smelling frothy stool in cystic fibrosis result from the presence of large amount of

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2023

Medical & Surgical Nursing

Hard

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2023

Explanation

In cystic fibrosis, abnormally thick mucus blocks the pancreatic ducts, preventing digestive enzymes from reaching the small intestine.
A key enzyme that is blocked is lipase, which is essential for the digestion of dietary fats.
When fats are not digested, they are passed into the stool, a condition called steatorrhea.
Steatorrhea is characterized by stools that are frothy, greasy, bulky, and have a particularly foul smell, matching the description in the question.

Option A: Phenylalanine is an amino acid. The most common CF mutation involves the deletion of phenylalanine in the CFTR protein, but this amino acid does not accumulate in the stool or cause its foul, frothy nature.
Option C: While some carbohydrate malabsorption occurs in CF due to amylase deficiency, it typically causes symptoms like watery diarrhea, abdominal cramping, and flatulence, not the greasy, frothy stools of steatorrhea.
Option D: Protein malabsorption (creatorrhea) also happens in CF due to protease deficiency and contributes significantly to malnutrition and failure to thrive, but it is not the primary cause of the frothy and greasy characteristics of the stool.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Gastrointestinal Manifestations of Cystic Fibrosis as background academic context rather than a clinical decision trigger.
Nurses play a crucial role in educating patients with CF and their families about Pancreatic Enzyme Replacement Therapy (PERT), emphasizing that enzymes must be taken with every meal and snack to be effective.
Assessing stool characteristics (frequency, consistency, odor, and presence of oil/grease) is a key nursing responsibility to monitor the effectiveness of PERT and overall nutritional status.
Nutritional counseling is vital. Patients need a high-calorie, high-fat, high-protein diet to overcome malabsorption and meet the increased energy demands of chronic illness.

How to Approach the Question

First, identify the core concepts in the question: the disease ('cystic fibrosis') and the specific symptom ('foul smelling frothy stool').
Recall the primary pathophysiology of cystic fibrosis, focusing on its effect on exocrine glands, particularly the pancreas.
Connect the pancreatic dysfunction to its role in digestion. The pancreas secretes enzymes to break down fats, proteins, and carbohydrates.
Consider how a deficiency of each type of enzyme would manifest in the stool. A lack of lipase (for fat digestion) classically causes steatorrhea.
Evaluate the options based on this understanding. 'Undigested fat' is the direct cause of steatorrhea, which perfectly matches the description of foul, frothy, and greasy stools. The other substances cause different symptoms.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 455-457

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 40-42