Lesson of the Week: Acute laryngeal obstruction in rheumatoid arthritis

Case report

This 55 year old woman had developed seropositive, erosive rheumatoid arthritis in 1966 at the age of 26. Her disease deteriorated and required treatment with non-steroidal anti-inflammatory drugs and then, by 1980, with prednisolone. Methotrexate was started in 1990 and discontinued in 1992. She had undergone splenectomy in 1968, presumably for Felty's syndrome, and bilateral pantalar fusions in 1990 for severe hindfoot symptoms.

She was first seen by DHB in 1993 for assessment of deteriorating joint symptoms. Rheumatoid nodules, bilateral parotid swellings, and scleromalacia were noted, together with a destructive deforming arthritis particularly affecting the hands, feet, and shoulders. Investigation showed haemoglobin 118 g/l, leucocytes 14.4 × 10⁹/l, platelets 689 × 10¹²/l, erythrocyte sedimentation rate 84 mm in the first hour, C reactive protein 49 mg/l, antinuclear antibody titre 640 (homogenous/speckled pattern), rheumatoid factor positive. Treatment with azathioprine and prednisone was started.

The history of chest disease began at age 49. There were no childhood problems, no family history of chest disease, and no industrial or animal exposure. She complained of chronic dyspnoea with acute exacerbations precipitated by coughing or the sensation of aspirating saliva. There were no nocturnal symptoms but she had smoked over 40 cigarettes daily between the ages of 20 and 35. Examination showed generalised late inspiratory crackles throughout both lung fields. There was no clubbing or wheeze. Respiratory function testing (fig 1) showed a mixed obstructive and restrictive picture with raised residual volume but not total lung capacity. There was poor gas mixing with a low alveolar ventilation/total lung capacity ratio, but gas transfer was normal. Taken with the clinical findings these results were thought to be consistent with a diagnosis of bronchiolitis obliterans.

Fig 1

Results of full pulmonary function tests performed in February 1994 at the time of intermittent wheeze (top) and results of spirometry performed through tracheostomy (bottom). Va=accessible alveolar volume; TLC=total lung capacity; DLCO= diffusion capacity of lung for carbon monoxide, or TLCO (carbon monoxide transfer factor); KCO=transfer coefficient

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In March 1994 she was admitted with acute stridor and was grossly cyanosed. Emergency bronchoscopy showed fixed adduction of the vocal cords, which were parted with the bronchoscope, giving immediate relief of symptoms. She was started on 40 mg prednisone daily, but four days later her stridor recurred, tracheostomy was performed, and she has chosen to maintain this ever since. Subsequent pulmonary function tests, performed through the tracheostomy, showed persistence of the previous abnormalities. In particular, the flow volume loop was very similar to that in the original test (fig 1). Laryngoscopy performed later showed persistent adduction of the vocal cords, with limited movement.

Discussion

Dyspnoea in a patient with rheumatoid arthritis may have many causes related to the disease, its complications, or its treatment or may be entirely incidental. In this patient investigation suggested one cause, bronchiolitis obliterans, but this did not explain her acute dyspnoeic episodes, which had been ascribed to “asthma” and had been treated as such.

Arthritis of the cricoarytenoid joint is a rare cause of dyspnoea; involvement in rheumatoid arthritis is probably frequently overlooked if the published figures for incidence are true.2 3

Bilateral paralysis of the vocal cords produces characteristic changes in the flow volume loop.7 Upper airway obstruction is suggested by a forced expiratory flow at 50% lung volume/forced inspiratory flow at 50% lung volume greater than 4 or forced expiratory volume in 1 second/peak expiratory flow rate greater than 10 ml/l/min. Both these were normal on the original tests. Peak inspiratory flow was low but there is no established normal range and the value was not significantly better when measured through the tracheostomy. Intermittent laryngeal obstruction caused by cricoarytenoid arthritis is not emphasised in standard texts and will not be detected by respiratory function tests.

Cricoarytenoid arthritis may be chronic and present for many years without becoming apparent. Its presentation may be acute, and, if not recognised and treated, fatal. Common symptoms such as hoarseness may be absent and simple tests for laryngeal obstruction can give normal results. In rheumatoid arthritis parenchymal lung disease may coexist with cricoarytenoid arthritis. We suggest that the investigation of dyspnoea, even when intermittent, in a patient with rheumatoid arthritis should routinely include laryngoscopy.

We thank Dr D Laing for his help in the management of this case.