Lung function in Adamantiades–Behçet disease

G. Tatsis, G. Vaiopoulos, T. Tassiopoulos, A. Votsiou, A. Peristerakis and J. Jordanoglou

Pulmonary Department and First Department of Internal Medicine, University of Athens, Athens, Greece

Correspondence to: G. Vaiopoulos, First Department of Internal Medicine, University of Athens Medical School, Laiko General Hospital, Agiou Thoma 17, Goudi, Athens 115 27, Greece.

SIR, Adamantiades–Behçet disease (A-BD) is a multisystemic inflammatory relapsing disease of unknown aetiology, mainly characterized by recurrent aphthous and genital ulceration, skin involvement, uveitis, arthritis, venous occlusion and neurological disorders [1, 2]. Males and young people frequently have more severe disease [3]. Recently, internationally agreed diagnostic criteria have been proposed [4]. Lung function in A-BD has been under investigation for many years with controversial results [5]. It seems that the major lung dysfunction is that of airways obstruction, with a decrease in diffusion capacity.

In order to evaluate lung function in A-BD, we studied 14 non-smoking patients (seven males, seven females) fulfilling the international criteria [4] for the diagnosis of A-BD, aged 16–52 yr. Disease duration ranged from 2 to 7 yr. All these patients, without any obvious evidence of lung involvement, had a normal chest X-ray and no respiratory symptom or sign. Forced expiration was performed and the forced expirogram obtained. From this expirogram, the forced vital capacity (FVC), the forced expiratory volume in the first second (FEV1 ) and the total corrected effective time (teffTC ) were calculated [6]. The patients then performed the helium closed-circuit test, and the functional residual capacity (FRC) and total lung capacity (TLC) were evaluated [7].

Respiratory system resistance (Rrs) was measured by the interruption technique. The physiological dead space, as the ratio VD /VT , and the value of PAO2 (alveolar oxygen) were calculated according to a new method, the helium wash-out technique [8]. From the value of PAO2 and the measured value of P{alpha}O2 , the alveolar–arterial oxygen difference (A-{alpha}DO2 ) was calculated.

In Table 1Go, the number of patients with an abnormal value is shown. Normal values were taken from a group of normal non-smoking individuals according to age, sex, height and weight.


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TABLE 1.  The number of patients with an abnormal or normal value
 
A statistical analysis (paired t-test) was used to evaluate the results. The data obtained from the analysis are shown in Table 2Go.


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TABLE 2.  P values for all parameters
 
Pulmonary vascular tree involvement has been reported and in some studies the prevalence of lung involvement approaches 5% of patients with A-BD [9]. The patients described are mainly young men and the main pulmonary manifestations are haemoptysis, pleuritic chest pain and cough. Alterations of lung function tests in A-BD, without clinical pulmonary disease, are uncommon [10]. There are only a few references to lung function in A-BD. In a few cases, airways obstruction has been noted. In a study of five cases with A-BD, reversible obstruction was noticed in one [5].

Recently, at the VIIth International Conference on Behçet's Disease, Formiga et al. [10] reported the results of pulmonary function, by measuring vital capacity (VC), FEV1 , FEV1 /VC, TLC, residual volume (RV), RV/TLC and transfer lung capacity in 11 selected patients with Behçet's disease, without respiratory symptoms. From these patients, those with previous bronchial asthma or pulmonary disease were excluded. In nine of these patients, the pulmonary function tests were strikingly normal, one patient had mild restrictive lung disease unrelated to any recognizable cause and another had mild small airway disease [10].

In our study of 14 patients, many parameters usually used for estimating lung function were measured. Up until now, the teffTC has been reported to be a sensitive parameter for the estimation of airways dysfunction, especially that of small airways, and is much more sensitive than FVC and FEV1 [6].

It is generally accepted that static volumes, TLC and FRC, are decreased in restrictive pattern disease and increased in obstructive pattern disease.

The data obtained from our patients have shown that dynamic and static lung volumes (FVC, FEV1 , TLC, FRC) did not differ significantly from normal predicted values. Also, concerning the teffTC, although it was shown that in seven patients teffTC was abnormal, the difference was not statistically significant. Our data have suggested that the more sophisticated parameters, such as VD /VT or Rrs, were highly affected. Thus, VD /VT was increased in 10 patients (71%), as is also described in other studies, with a highly significant statistical difference (P<0.0001). Also, Rrs was increased in nine patients (64%) with a highly significant statistical difference (P<0.0005). These greatly increased values of VD /VT and Rrs suggest that probably the major problem with the lungs in patients with A-BD is that of obstructive pattern. This highly significant statistical difference also seems to exist for the values of PaO2 and A-aDO2 . The abnormality in pulmonary function does not relate to the duration of disease or other manifestations of A-BD.

The results shown in our study suggest that for better evaluation of lung function in A-BD, more sophisticated tests, such as the measurement of VD /VT or Rrs or A-{alpha}DO2 , need to be performed. Lung volumes seemed to be unaffected in our patients, probably due to their asymptomatic stage of disease.

References

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  6.  Jordanoglou J, Hadzistavrou C, Tatsis G, Anevlavis E, Melissinos C. Total effective time of the forced expirogram in disease: sources of error and a correction factor. Thorax 1982;37:304–8.[Abstract]
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  8.  Jordanoglou J, Tatsis G, Bissiouli Z. Calculation of the VD/VT ratio by the helium washout technique. Clin Sci 1986;70:565–9.[ISI][Medline]
  9.  Raz I, Okon E, Chajek-Shaul T. Pulmonary manifestations in Behcet's Syndrome. Chest 1989;95:585–9.[Abstract]
  10.  Formiga F, Vidaller A, Mitjavila F, Santin M, Rodriquez-Sanchon B, Pujol R. Pulmonary function in Behcet's disease (BD). VII International Conference on Behcet's disease. Tunis, Oct 10–11, 1996. Rev Rhum 1996;63:557 (Abstract).
Accepted 1 April 1999