Cystic Fibrosis – At A Glance

Cystic fibrosis is an autosomal recessive inherited disease that causes an increase in viscosity of secretions particularly in the lungs and digestive system.

It is the most common inherited lethal condition in Caucasians.

This disease affects exocrine function of glands, mainly pancreas, leading to pancreatic insufficiency. But can affect other organ systems as well.

There is no cure for the disease. The treatment is aimed to improve the quality of life, but the life span of these patients are reduced.

Life expectancy is around 40 years

Incidence : 1 in 2500 births

In UK 1 : 25 are CF carriers

Aetiology And Pathophysiology Of Cystic Fibrosis

It is an autosomal recessive disorder

Defect in cystic fibrosis transmembrane conductance regulator gene (CFTR) located in the long arm of chromosome 7

CRTR gene codes a cAMP – regulated chloride channels
Defect in chloride transport and associated water transport across the cells
Increased viscosity of secretions in the respiratory tract, pancreas, GI tract, sweat glands, etc
Thick mucous secretions are difficult to be cleared out
Mainly seen in the respiratory tract – Difficult mucous clearance 
Leading to its presentation

Clinical Presentation Of Cystic Fibrosis

  • Neonatal period
    • Meconium ileus (10%)
      • Abdominal distention
      • Failure to pass meconium
    • Failure to thrive
    • Intussusception
  • Recurrent respiratory tract infection 
    • Cough – Initially dry, later becomes productive and purulent
    • Shortness of breath / Trachypnoea
    • Chest pain 
    • Wheezing
    • Clubbing
    • Crackles
  • GI manifestations
    • Malabsorption
    • Pancreatic insuffiency leading to 
      • Steatorrhoea 
      • Vitamin A, D, E, K deficiency 
    • Cholesterol gall stones 
    • Hepatosplenomegaly
    • Rectal prolapse – Due to bulky stools
  • Infertility in males and delayed puberty (Amenorrhoea) / subfertility in females 
  • Short stature
  • Nasal polyps
  • Rare manifestations
    • Diabetes mellitus
    • Liver diseases
    • Osteoporosis

Investigations Of Cystic Fibrosis

  • Screening tests 
    • In the UK – Heel prick test done at birth
  • Sweat chloride test (Best)
    • 2 positive test results on 2 separate days 
    • More than 60 mmol/L of chloride – Cystic fibrosis
    • 30-60 mEq/L – Carriers
  • Genetic test
    • Done from saliva
  • Chest X-Ray PA view
    • To see the pulmonary involvement
    • Initially hyperventilation / air trapping is seen
    • Features of bronchiectasis in the upper lobe
  • Ultrasonography
    • To see meconium ileus 
    • Hyperechoic mass at terminal ileum

Treatment Of Cystic Fibrosis

There is no cure for the disease
Treatment is directed to control the symptoms and to prevent the development of complications

  • Multidisciplinary approach
  • Respiratory management 
    • Bronchodilators are helpful 
    • Regular chest physiotherapy and postural drainage
      • Should be performed twice a day
      • Parental education is important to achieve this goal 
    • Deep breathing exercises
    • Mucolytic agents -Dornase alfa nebulization 
    • Antibiotics – If necessary
      • Inhaled tobramycin is helpful for pseudomonas infections
  • Nutritional supplementation 
    • High calorie diet, which includes a high fat content 
    •  Vitamin supplementation 
    • Pancreatic enzyme supplementation – Enterocoated microspheres 

Cystic fibrosis children can develop frequent respiratory tract infections 
Commonly caused by….
  • Pseudomonas aeruginosa
  • Staphylococcus aureus
  • Burkholderia cepacia
  • Apergillus

Cepacia Syndrome

It is a complex of features seen commonly in cystic fibrosis patients.

Cepacia Syndrome is characterized by….

  • Rapid progressive fever
  • Necrotizing pneumonia 
  • Progressive respiratory failure
  • Weight loss

Treated with antibiotics (Aminoglycoside + Ceftazidime)

Has a poor outcome

Complications Of Cystic Fibrosis

  • Osteoporosis
  • Diabetes mellitus
  • Fertility problems
    • Infertility in males 
    • Delayed puberty (Amenorrhoea) / subfertility in females
  • Nasal polyps
  • Liver diseases

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