Dear Editor,

Professor Smyth describes the occurrence of non-specific arthritis in some patients with cystic fibrosis (CF) in her recent article on diagnosis and management of cystic fibrosis.[1] As a consequence of the increased life expectancy in CF, rheumatic diseases are more likely to be observed, particularly in older patients.[2]

Two specific arthropathies are described in CF; an episodic arthritis (EA), or cystic fibrosis arthropathy (CFA), more common in children than adults, and hypertrophic pulmonary osteoarthropathy (HPOA), seen usually in adults but does occur in children.[2]

CFA [3, 4] is characterised by recurrent, painful attacks of mono- or polyarthritis. Patients are frequently found to have erythema nodosum-like rash, and more rarely purpuric skin lesions. The synovitis usually lasts between 1 day to several weeks. While it can resolve, active disease persists in many cases with progression to a chronic arthritis. These patients are negative for both rheumatoid factor (RF) and antinuclear antibodies (ANA).[2, 3, 4] However, Schidlow et al. [5] describe one female patient with CF and arthritis found to have a raised RF, whose titres increased with worsening lung function.

HPOA is characterised by abnormal proliferation of the skin and distal osseous tissue of the extremities resulting in digital clubbing. This is associated with long bone pain, radiological evidence of periosteal new bone formation and impaired pulmonary function. Onset is often insidious, causing pain in the wrists, knees and ankles. The disease pattern is frequently symmetrical, with associated joint swelling and periarticular tenderness.[2] The pain associated with HPOA is often initially responsive to anti-inflammatory medication, but drug therapy becomes less effective with disease progression.

Arthritis associated with CF has previously been little recognised. It has specific forms now acknowledged to be a major cause of disability in about 10% of young adults with the disease.[2]

Alexandra Colebatch, Richard Hull

Paediatric Rheumatology, Queen Alexandra Hospital, Portsmouth

References

[1] Smyth, R. Diagnosis and Management of Cystic Fibrosis. Arch Dis Child Educ Pract Ed. 2005; 90: ep1-ep6.

[2] Dixey, J., Redington, A., Butler, R., et al. The Arthropathy of Cystic Fibrosis. Annals of the Rheumatic Diseases. 1988; 47, 218-223.

[3] Merkel, P. Rheumatic Disease and Cystic Fibrosis. Arthritis and Rheumatism. 1999; 8: 1563-1571.

[4] Newman, A., Ansell, B. Episodic Arthritis in Children with Cystic Fibrosis. The Journal of Pediatrics. 1979; 94: 594-596.

[5] Schidlow, D., Goldsmith, D., Palmer, J., Huang, N. Arthritis in Cystic Fibrosis. Archives of Disease in Childhood. 1984; 59: 377-379.

Dear Editor,

Williams [1] highlights the key points in the management of inhaled foreign bodies (FB). One of the important points is to request inspiratory and expiratory chest radiographs if FB aspiration is suspected. Because young children are unable to co-operate, paired inspiratory and expiratory films are not always possible. The lateral decubitus film is a useful and convenient method to determine the presence of air trapping [2] as we show in the following case. When the child is placed on his side, the splinting of the dependent hemithorax results in restriction of movement of the thoracic cage on that side and under aeration of the lung while the hemithorax on the opposite side is unrestricted and the lung is well aerated.

A 22 months old, previously healthy, child presented with a 10 days history of cough, and fever. He had not improved after a week’s antibiotic course. A history of foreign body aspiration was not forthcoming. He had low-grade pyrexia, saturation of 91% on air, tachypnoea, mild recessions, reduced air entry on the left hemithorax and no added sounds. A chest x ray (fig 1) showed loss of the right heart border with generalised air space shadowing through out the lung, no midline shift and relatively hyperlucent left lung. On senior review and further direct questioning, possibility of choking on a peanut was elicited. As he was unable to cooperate for an expiratory film, a left lateral decubitus film (fig 2) was performed. This showed over expansion of the left (air trapping in the involved lung making it more hyperlucent despite being in the dependent position) but normally aerated right hemithorax. On a rigid bronchoscopy a peanut was removed piecemeal from the left main bronchus.

Figure 1.

Figure 2.

References:

1.Williams H. Inhaled foreign bodies. Arch Dis Child. Ed. Pract. 2005; 90: ep31-ep33.

2.The lateral decubitus film: an aid in determining Air-trapping in children. Capitanio MA, Kirkpatrick JA. Radiology; 1972:103; 460-462).