Mediastinoscopy in Patients With Presumptive Stage I Sarcoidosis: Practice Survey
We conducted a mail survey of 65 pulmonologists who were members of the Oregon Thoracic Society practicing in Oregon and southwest Washington to ascertain their practice preferences— observation, mediastinoscopy, transbronehial lung biopsy, or other—in patients with BHLps.
Characteristics and Frequencies of ABHL
Sarcoidosis: The estimated US incidence of clinically identified sarcoidosis (ie, identified either because of symptoms or by means of an incidental chest radiograph), based on race normalization of the sampled population, is 7.3X1CT. Approximately half (3.7X10-5) are SIS. The SIS rate is (3.7X10_5)(2.5X108)-9.3X103.
Tuberculosis: Hilar adenopathy, almost invariably unilateral, is a feature of primary TB, commonly a subclinical self-limited disease of childhood. In patients with progressive primary disease, systemic symptoms will alert the experienced physician to the need for further evaluation.
In >90% of patients exhibiting mediastinal disease reported from hospital settings (Table 1), a pulmonary parenchymal process coexists, symptoms are evident, the Mantoux test is positive, and paratra-cheal adenopathy exceeds the hilar component. Among patients identified with BHL, TB is a rare cause: 0 of 100 persons in Washington State,2 1 of 110 persons in Minnesota, and 1 in 212 persons with BHL in Sweden were found to have this etiology Evidence of prior TB, present in 80 (38%) subjects in the last study, indicates its high prevalence in postwar Sweden, and its inapplicability to the US population.
As most series are drawn from hospital populations, the proportion of patients with BHL-TB who are asymptomatic is likely to be underestimated. We estimate the proportion of ABHL-TB: 0.18X.0026X0.24=1.1X10-4 (bottom row, Table 1).
1) The age-specific incidence of TB coinciding with the peak age incidence of sarcoidosis (20 to 40 years) is 8.1X10-5.
Iabhl-tb is (1.1X10 -4)(8.1X10)-9.1X10-5
Isis/Iabhl-tb is 3.7X 10/9.1 X 10 = 4.1X103
The total charge for mediastinoscopy at Kaiser Permanente is approximately $3,000. To identify one case of ABHL-TB would require 4,100 mediastinoscopies at a cost of $12.3 million; 21 patients (0.5%) would be expected to experience major morbidity, and 41 (1%) would be expected to require at least 1 day of hospitalization (at $2,210) following the procedure at a total cost of $91,000. Limiting mediastinoscopy to tuberculin-positive individuals with ABHL exhibiting disproportionate enlargement of the paratracheal nodes would reduce that number > 100-fold.
Table 1—Frequency With Which TB Presents as ABHL
|First Author||Intrathoracic Adenopathy Present/No. of Patients||No. (%) Asymptomatic||No. (%) With Isolated Mediastinal Involvement||No. (%) With Isolated Mediastinal Involvement With BHL|