Diagnosis

Progression of Respiratory Clinical Features

Chronic Sinusitis and Cough

Chronic sinusitis is common in childhood and progresses to nasal obstruction and the development of nasal polyps. Nasal polyps occur in about 25% of patients and often require surgery.¹

The first sign of CF in the lower respiratory tract is a persistent cough, sometimes accompanied by wheezing. Coughing episodes tend to last longer than one would expect for acute respiratory illnesses, and they begin to increase with frequency.^1,3

Generally, the first bacteria cultured or present in the lungs are Staphylococcus aureus and Haemophilus influenzae.³

Purulent Sputum

As the disease progresses, the coughing becomes productive, with viscous, purulent sputum. These thickened mucus secretions lead to a vicious cycle of increased infection, inflammation, and obstruction. At this stage, the patient with CF may show signs of dyspnea and have a reduced appetite, accompanied by weight loss.³ As the clinical symptoms increase, measurement of spirometry, lung volumes, and oxygenation can begin to show deterioration in lung function.³

Sputum cultures at this time still show Staphylococcus aureus and Haemophilus influenzae; however, Pseudomonas aeruginosa , often the mucoid species, is gaining prominence.³

Chronic Lung Infection

The first sign to appear on chest x-ray is hyperinflation of the lungs due to small airway obstruction. Later, there are signs of mucus impaction, bronchial cuffing, and finally, ring shadows appear signalling bronchiectasis. For unknown reasons, the right upper lobe presents the earliest and with the most severe changes.²

In the chronic infection stage, crackles may be evident with exacerbations, as well as decreased lung sounds that suggest pulmonary hyperinflation.³

Inflammatory markers are present in airway fluids. It is not clear whether infections cause the inflammation or the inflammation promotes bacterial exacerbations, but both continue to escalate.

Infection with Burkholderia cepacia may also be identified in some patients, especially later in the course of the disease; however, the predominant pathogens identified in most patients are Pseudomonas aeruginosa.³

Respiratory Failure

The inflammatory response is an important driver of damage to the lungs. As the disease progresses, rales and rhonchi are continuously present. Patients often progress to cor pulmonale as a result of pulmonary hyperinflation.

Lung transplantation may be an option for some patients. However, the majority of patients die in adulthood with complications from pulmonary disease or respiratory failure.^1,3,18

References:
1. Boucher RC. Cystic Fibrosis. In: Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL et al., editors. Harrison's Internal Medicine. 16th ed. New York: McGraw-Hill; 2005. p. 1-9.
2. Aitken M, Fiel SB, Stern RC. Cystic Fibrosis: Respiratory Manifestations. In: Taussig LM, Landau LI, editors. Pediatric Respiratory Medicine. 1st ed. St. Louis: Mosby, Inc.; 1999. p. 1-47.
3. Welsh M. Cystic Fibrosis. In: Goldman L, Ausiello D, eds. Cecil Textbook of Medicine. 22nd ed. Philadelphia: WB Saunders; 2004. p. 1-22.
18. Yankaskas JR, Marshall BC, Sufian B, Simon RH, Rodman D. Cystic fibrosis adult care: consensus conference report. Chest 2004 January;125(1 Suppl):1S-39S.