Review Question - QID 100912

The patient's history of severe respiratory infections and positive chloride sweat test is indicative of cystic fibrosis which is a cause of azoospermia.

Cystic fibrosis is an autosomal recessive genetic disorder that affects multiple organs. It is characterized by impaired transport of chloride and sodium across an epithelium. In the lungs, this leads to viscous secretions and clogging of the airways resulting in chronic infections and bronchiectasis. Other sequelae include: failure to pass meconium in the newborn, blocked exocrine pancreatic/hepatic flow, and infertility in both men and women due to congenital absence of the vas deferens but also azoospermia and other spermatic abnormalities. CF can be diagnosed with a chloride sweat test, where levels above 60mM/L are diagnostic.

Grosse et al. review the CDC guidelines for newborn screening for cystic fibrosis. The CDC currently recommends routine screening of all newborns for cystic fibrosis. This should be accompanied by rigorous infection control practices to minimize the risk to children with cystic fibrosis detected at an early age of acquiring infectious organisms associated with lung disease from older patients. Education of parents should play an important role in any screening programs.

Radpour et al. examine the role of CFTR mutations in male and female infertility. Congenital bilateral absence of the vas deferens (CBAVD) is a purely genital deletion of CFTR that is related to cystic fibrosis. CFTR mutations are also associated with congenital absence of the uterus and vagina. Approximately 10% of obstructive azoospermia is congenital and due to mutations in the CF gene.

Illustration A shows the various manifestations of cystic fibrosis.

Incorrect answers:
Answer 1: Hypertrophic cardiomyopathy is a separate primary disease of the myocardium.
Answer 3: Ghon complexes are commonly found in primary tuberculosis.
Answer 4: Alpha-1-antitrypsin deficiency is the result of a separate process and results in a subtype of emphysema.
Answer 5: Mitral valve prolapse does not have an association with cystic fibrosis.