Cystic Fibrosis

Cystic Fibrosis:  An autosomal recessive genetic disorder that causes a mutation in the cystic fibrosis transmembrance conductance regulator gene that leads to impairment in the flow of water into and out of cells which results in mucus obstructions and dysfunction in the airway, lungs, liver, digestive tract, reproductive cells, skin, and kidney tubules.

Epidemiology: The disease is most common in Caucasians in whom 1:25 are carriers and in whom 1:2500 births result in a newborn with cystic fibrosis. The life expectancy of a newborn with cystic fibrosis is roughly 40 years old.

Risk Factors: As the disease is autosomal recessive, genetic analysis of parents can provide an useful assessment of risk of cystic fibrosis in a couple’s children.

Symptoms: The classical presentation of cystic fibrosis is a child 0-2 years of age presenting with recurrent infections, failure to thrive, and greasy stools. Newborns experience malabsorption, recurrent pulmonary infections especially from S. Auerus, H Influenza , and Psuedomonas Aeruginosa.  Up to 20% of newborns may also experience meconium ileus. As the child ages, 25% may develop diabetes mellitus (non insulin dependent due to pancreatic insufficiency) in addition to later suffering from cirrhosis and portal hypertension. 95% of males are sterile and females have reduced fertility as well.

Differential Diagnosis: Asthma, Aspergillosis, Bronchiectasis, Bronchiolitis, Celiac Disease, Failure to Thrive.

Investigations: The sweat chloride test is the primary tool for diagnosis of cystic fibrosis. Chest radiograph may show hyperinflation and peribronchial thickening.

Treatment: While there is currently no cure for cystic fibrosis, treatment involves careful nutrition, antibiotic therapy to prevent infections, and chest physical therapy to dislodge mucus. 95% of patients will die from respiratory complications.

 Imaging Findings
- Pancreatic lipomatous pseudohypertrophy
- Lipomatous pseudohypertrophy presents early with heterogenous attenuation, progressing to fatty infiltration and parenchymal replacement
- May see cysts in associated with fatty fibrosis
- Fat hyperintense on T1, fibrosis hypointense on T1 and T2, cysts hyperintense on T2
- Liver findings: steatosis, multinodular cirrhosis, portal hypertension, end-stage liver disease
- Biliary: Focal biliary fibrosis, cholelithiasis, ductal strictures and sclerosing cholangitis, microgallblader
- GI: obstruction, meconium ileus equivalent, risk for peptic ulceration, intussusception, pneumatosis intestinalis, rectal mucosal prolapse
- Renal: nephrolithiasis
- Lungs: hyperinflation, bronchial wall thickening, mucoid impaction,  bronchiectasis more severe in upper lobes, allergic bronchopulmonary aspergillosis
 


 

Case #1. 21 y/o female with cystic fibrosis showing coarse reticulonodular markings and bronchiectasis with dilated airspaces (arrows).