Скачать или смотреть The Sticky Mucus Disease That Affects Everything! – Pediatrics Test #1

Explanation:
A) Cystic Fibrosis (CF): An autosomal recessive disorder caused by mutations in the CFTR gene on chromosome 7, leading to defective chloride channels. This results in thickened mucus affecting the lungs, pancreas, and intestines. Common features include recurrent pulmonary infections (e.g., Pseudomonas aeruginosa), pancreatic insufficiency (steatorrhea, fat-soluble vitamin deficiencies), meconium ileus in neonates, and infertility in males due to congenital bilateral absence of the vas deferens (CBAVD). Diagnosis is confirmed via elevated sweat chloride test and genetic testing. Management includes airway clearance, pancreatic enzyme replacement, and CFTR modulators (e.g., ivacaftor for specific mutations).
B) Primary Ciliary Dyskinesia (PCD) (Kartagener Syndrome): An autosomal recessive disorder characterized by dysfunctional dynein arms in cilia, leading to impaired mucociliary clearance. Presents with chronic sinusitis, recurrent respiratory infections, bronchiectasis, and situs inversus in about 50% of cases. Unlike CF, PCD does not cause pancreatic insufficiency or abnormal sweat chloride levels. Diagnosis is made via nasal nitric oxide testing, electron microscopy of cilia, or genetic testing.
C) Congenital Adrenal Hyperplasia (CAH): A group of autosomal recessive disorders affecting cortisol biosynthesis, most commonly due to 21-hydroxylase deficiency. Leads to excess androgen production, resulting in virilization of female infants, salt-wasting crises, and precocious puberty in males. Unlike CF, CAH does not cause recurrent pulmonary infections or meconium ileus.
D) Neonatal Respiratory Distress Syndrome (NRDS): A condition seen in preterm infants due to surfactant deficiency, leading to alveolar collapse and respiratory failure. Presents with tachypnea, grunting, nasal flaring, and ground-glass opacities on chest X-ray. Unlike CF, NRDS is not associated with pancreatic insufficiency or meconium ileus.

References:

Nelson Textbook of Pediatrics, 21st Edition
Cystic Fibrosis Foundation Clinical Practice Guidelines, 2023
"Pathophysiology of Cystic Fibrosis and Emerging Therapies," New England Journal of Medicine, 2022
Tags: pediatrics, cystic fibrosis, autosomal recessive disorders, CFTR gene mutation, sweat chloride test, meconium ileus, pancreatic insufficiency, recurrent lung infections, Pseudomonas aeruginosa, bronchiectasis, fat-soluble vitamin deficiency, infertility in males, CFTR modulators, primary ciliary dyskinesia, Kartagener syndrome, congenital adrenal hyperplasia, neonatal respiratory distress syndrome, differential diagnosis, pediatric pulmonology, gastroenterology, medical education, USMLE, NEET PG, PLAB, medical board exams

Question:
A 3-month-old infant presents with failure to thrive, recurrent respiratory infections, and bulky, foul-smelling stools. A sweat chloride test is significantly elevated. What is the most likely diagnosis?

Options:
A) Cystic Fibrosis
B) Primary Ciliary Dyskinesia
C) Congenital Adrenal Hyperplasia
D) Neonatal Respiratory Distress Syndrome

Answer:
A) Cystic Fibrosis

Title:
The Sticky Mucus Disease That Affects Everything! – Pediatrics Test #1

Field:
Pediatrics