Initial roentgenographic manifestations of bacteriologically proven Mycobacterium tuberculosis. Typical or atypical?

Admission chest roentgenograms were reviewed of all patients diagnosed with pulmonary and extrapulmonary tuberculosis (TB) at the Medical College of Georgia--Eugene Talmadge Memorial Hospital (MCG-ETMH) during a five-year period from 1979 to 1983. Of 75 patients included, 51 had pulmonary TB, whereas 24 had extrapulmonary infection. Cavitary disease was common (28 of 51 patients with pulmonary TB). Forty-four of 51 patients with pulmonary TB had involvement of apical and/or posterior segments of the upper lobes with cavitation or infiltrates. Pleural effusion, parenchymal nodules, lymphadenopathy, and lower lung field disease were uncommon. Thirteen of 24 patients with extrapulmonary TB had abnormal admission chest roentgenograms, suggesting the possibility of Mycobacterium tuberculosis infection. Despite recent studies suggesting that TB presents with atypical roentgenographic features more commonly than reported in the past, the roentgenographic manifestations of TB in our series were typical of those previously described as pathognomonic for the disease.     

Surgical treatment of pulmonary tuberculosis in Greenland

Surgical treatment of pulmonary tuberculosis in Greenland. Follow-up of 1, 143 patients operated on for pulmonary tuberculosis at Queen Ingrid's Hospital, Godthåb, during the years 1954–1966. In particular the main group consisting of 785 resected patients is reviewed. Overall operative mortality was 1.0 per cent. At follow-up 2–12 years after surgery 104 (9 per cent) had died, and 1, 039 were in good health. Of the survivors 78 per cent were fully and 12 per cent partially fit for work while 1 per cent were unfit. Of the 1, 039 survivors 95 per cent were back at work within one year after surgery; 90 per cent had resumed their old occupation while only 6 per cent had changed occupation because of the tuberculosis. There was a close relationship between impaired work capacity and the nature and extent of the operation. By Greenland standards housing conditions of the survivors were satisfactory for 80, unsatisfactory for 5 and poor for 14 per cent.     

Pulmonary infiltrates and fever in patients with hematologic malignancy: assessment of transbronchial biopsy.

Pulmonary infiltrates associated with fever are frequently encountered in patients with acute leukemia or lymphoma; In this prospective series, we analyze 47 such episodes in 43 patients. Overall mortality was 45 per cent in patients with infiltrates and somewhat higher when they also had neutropenia (55 per cent) or acute leukemia (67 per cent). Pulmonary infiltrates could be categorized into three roentgenographic patterns: local consolidation (55 per cent); cavitary disease (13 per cent) and diffuse interstitial disease (32 percent). The exact etiology of the infiltrates could not be predicted by roentgenographic study. Microbiologic or histopathologic diagnosis was established during life in 57 per cent of the patients, with infection most commonly encountered. Twenty-one patients underwent lung biopsy procedures. Biopsy specimens were frequently diagnostic (n = 17) and often dictated therapeutic changes (n = 12). Transbronchial lung biopsy via the fiberoptic bronchoscope was utilized in 14 patients during the latter part of this study; diagnoses were obtained in nine patients. Morbidity was minimal with this procedure, and the need for thoracotomy was diminished when it was available.     

Endobronchial tuberculosis in the acquired immunodeficiency syndrome

Although many of the pulmonary manifestations of tuberculosis in the acquired immunodeficiency syndrome (AIDS) are well known, endobronchial involvement has not been previously described. We report the clinical, roentgenographic, and bronchoscopic features of three patients with endobronchial tuberculosis and AIDS. All of the patients had nonspecific symptoms of fever and cough; however, none exhibited the classic findings of dyspnea, wheezing, or hemoptysis. Smears of sputum were nondiagnostic. The chest x-ray film revealed mediastinal adenopathy in two patients and a lower lobe consolidation in the third; all had small ipsilateral pleural effusions. Endobronchial lesions were white or pink exophytic masses obstructing the airways, mimicking bronchogenic carcinoma. Areas of "classic" primary tuberculosis were seen in two of the patients. Despite ongoing clinical and roentgenographic deterioration, all patients responded well to antituberculosis medications. Given the frequency of tuberculosis in patients with AIDS and AIDS-related complex, one should maintain a high index of suspicion for involvement of the tracheobronchial tree, so as to avoid a delay in diagnosis and resultant increased morbidity and mortality.     

Active pulmonary tuberculosis in patients with lung cancer

To clarify the features of the coexistence of active pulmonary tuberculosis in patients with lung cancer, we analyzed clinical data on 25 cases with coexisting lung cancer and active pulmonary tuberculosis encountered at Tokyo National Chest Hospital during the period from 1991 to 1998. There were 23 men and 2 women, with a mean age of 70 years. The incidence of lung cancer among patients with active pulmonary tuberculosis at our hospital was 0.7 per cent, while the incidence of active pulmonary tuberculosis in untreated lung cancer patients at our hospital was 1.9 per cent. We classified the 25 cases into 2 groups as follows: (1) tuberculosis sequential to lung cancer (11 cases) and (2) tuberculosis concurrently detected with lung cancer (14 cases). All patients in the former group were transferred from other hospitals after diagnosing the coexistence of pulmonary tuberculosis during the management of lung cancer. Histological types of lung cancer were squamous cell carcinoma in 12, adenocarcinoma in 9, and small cell carcinoma in 4, and as to the disease stage, stages III to IV were predominant. Analysis on relationship of chest X-ray findings between lung cancer and pulmonary tuberculosis revealed that in general, the location of lung cancer and tuberculosis seemed to be independent. Tuberculosis in the sequential group was more extensive and severer than in the concurrent group. In the concurrent group, treatment for tuberculosis was successful except for one case, and coexisting tuberculosis did not seem to affect the course of lung cancer among this group. However, in the sequential group, 5 patients died within 3 months, 2 of them died of tuberculosis. We consider that in the management of lung cancer, physicians should consider the possibility of coexistent active pulmonary tuberculosis and should not make delay in the diagnosis of active pulmonary tuberculosis.     

Tuberculosis in patients with human immunodeficiency virus infection. How often does it mimic Pneumocystis carinii pneumonia?

Adjunctive corticosteroid therapy is recommended for selected human immunodeficiency virus (HIV)-infected patients with presumed Pneumocystis carinii pneumonia. Because corticosteroids may exacerbate undiagnosed tuberculosis, we evaluated the frequency with which tuberculosis in HIV-infected patients mimics P carinii pneumonia. Over a 12-month period, we identified 105 HIV-infected patients with pleuropulmonary tuberculosis and 84 patients with P carinii pneumonia who were sufficiently hypoxemic to warrant corticosteroid therapy. Of the 105 patients with tuberculosis, acid-fast smears of clinical samples were positive in 49 cases, and chest roentgenographic findings suggested tuberculosis in an additional 44 cases. The 12 patients with negative acid-fast smears and nonspecific chest roentgenographic findings presented a potential diagnostic dilemma between tuberculosis and P carinii pneumonia. Pneumocystis carinii pneumonia should not have been a presumptive diagnosis of eight of these 12 patients because of absence of pulmonary symptoms and chest roentgenographic abnormalities (four cases), a CD4 count greater than 500/cu mm (three cases), or marked lymphadenopathy suggestive of tuberculosis (one case). Thus, only 4 percent (4/105) of HIV-infected patients with pleuropulmonary tuberculosis had clinical and chest roentgenographic features mimicking P carinii pneumonia. Two of these four patients were sufficiently hypoxemic to warrant corticosteroid therapy. Thus, if corticosteroids had been routinely used during the study period, 84 patients with P carinii pneumonia would have been treated, including two patients with undiagnosed tuberculosis. We conclude that the use of corticosteroids for presumed P carinii pneumonia carries a small but acceptable risk of inadvertent exacerbation of tuberculosis, provided clinical and chest roentgenographic features do not suggest tuberculosis.     

Chest roentgenogram in pulmonary tuberculosis. New data on an old test

The utility of routine admission chest roentgenograms (CXRs) was evaluated in detecting pulmonary tuberculosis and the relationship between roentgenographic patterns and the likelihood of finding acid-fast bacilli (AFB) on sputum smear. Of 58 patients whose chief complaints were unrelated to pulmonary tuberculosis, the CXR suggested tuberculosis in 52 cases (90 percent). In 45 cases, the emergency room physician failed to elicit the patient's respiratory symptoms and did not consider tuberculosis as a diagnostic possibility. In 18 individuals, the diagnosis was missed in the emergency room because of failure to obtain a CXR. Among patients whose roentgenograms showed cavitation or extensive alveolar infiltrate, sputum smears showed AFB in 98 percent of cases. If alveolar infiltrate was absent, or if the roentgenographic pattern was not that of adult reactivation disease, sputum smears revealed AFB in only one half of the cases. We conclude that routine admission CXRs are useful in hospitals serving populations where tuberculosis is still common, and the probability of detecting AFB on sputum smear is greatly influenced by the roentgenographic findings.     

The cardiovascular manifestations of the hypereosinophilic syndrome. Prospective study of 26 patients, with review of the literature.

The major cause of morbidity and mortality in patients with the hypereosinophilic syndrome is cardiac dysfunction. A review of 65 cases from the literature (historic series) revealed the following cardiovascular manifestations to be most common: dyspnea (60 per cent), signs of congestive heart failure (75 per cent), murmur of mitral regurgitation (49 per cent), cardiomegaly (37 per cent), T wave inversions on electrocardiogram (37 per cent) and pathologic findings of endocardial fibrosis, myocardial inflammation and mural thrombus formation (57 per cent). We have prospectively followed 26 patients with the hypereosinophilic syndrome for up to nine years (average follow-up prospectively was 3.3 years, retrospectively 5.7 years). Common cardiac findings in our 26 patients were dyspnea (42 per cent), chest pain (27 per cent), signs of congestive heart failure (38 per cent), murmur of mitral regurgitation (42 per cent), cardiomegaly (35 per cent) and T wave inversions (35 per cent). Thus, these patients demonstrated cardiovascular manifestations similar to those in the historic series, although the literature review showed a higher incidence of overt congestive heart failure.Of 22 patients having echocardiograms, 55 per cent demonstrated some clinical, roentgenographic or electrocardiographic evidence of cardiac involvement, but 82 per cent had echocardiographic abnormalities. This suggests that the echocardiogram is a sensitive and perhaps early indicator of cardiac involvement in this disease. Common echocardiographic findings included increased left ventricular wall thickness (68 per cent), left ventricular mass (73 per cent) and left atrial size (37 per cent). Prospective echocardiographic follow-up of 18 patients (for up to four and a half years) revealed that seven of eight untreated or inadequately treated patients had increases in left ventricular wall thickness, whereas all 10 adequately treated patients had decreases (eight of 10) or no change (two of 10) in left ventricular wall thickness. This suggests that adequate antihypereosinophilic therapy (with prednisone and/or hydroxyurea) may stabilize and, in some cases, reverse the cardiac manifestations of the hypereosinophilic syndrome.In previous studies, congestive heart failure due to eosinophilic cardiomyopathy has been reported to be very resistant to therapy. In our patients with congestive heart failure, treatment has been almost invariably effective when digitalis and diuretics were combined with adequate antihypereosinophilic therapy.     

Incidence and treatment of the patent ductus arteriosus in the ill premature neonate

Two to 15 per cent of the patients admitted to a Neonatal Intensive-Care Unit developed signs of cardiac disease due to a PDA. In a four-year period, of 90 patients with a diagnosis of the PDA, confirmation was made in 44 (surgery, 27; autopsy, 12; and aortography, 5). Eighty per cent were 33 weeks gestation or less.Two-thirds of the patients went into congestive heart failure. Over $\text{1}\text{2}$ of these had severe respiratory distress and 44 per cent required a respirator. The diagnosis of a PDA and cardiac failure was made clinically by the presence of characteristic murmur frequently accompanied by a diastolic murmur, bounding pulses, hepatomegaly, apnea and bradycardia, roentgenographic evidence of perihilar edema and/or increased pulmonary vascularity, and an abnormal electrocardiogram.Twenty-seven patients underwent surgical ligation of the PDA. There were no deaths in the operating room. The survival rate in those over 1,000 grams was 80 per cent. Of those patients that died due to the PDA, nearly 60 per cent had bronchopulmonary dysplasia as an associated finding.     

Pulmonary manifestations of disseminated cryptococcosis in patients with AIDS

Forty-eight patients with disseminated cryptococcosis and AIDS were retrospectively studied to define the pulmonary manifestations. Cryptococcus neoformans (CN) was first isolated from a pulmonary site in 12 patients. Disseminated disease was subsequently documented in all these patients. Symptoms and roentgenographic manifestations (normal, nodular/circumscribed infiltrates, pleural effusions, lobar consolidation) were diverse. Interstitial infiltrates predicted the presence of another opportunistic lung infection besides cryptococcosis in five patients (three untreated and two treated patients). Infectious causes other than cryptococcosis were established by culture and clinical course in five of the ten patients who developed chest roentgenographic abnormalities during amphotericin B therapy. Endobronchial abnormalities were identified in four patients at bronchoscopy. Bronchoalveolar lavage (9/9) and pleural fluid (3/3) cultures were sensitive tests for detection of pulmonary involvement with CN.     

Dynamics and features of infiltrative pulmonary tuberculosis in patients over 50 years of age

Medical histories of 244 new cases of infiltrative tuberculosis of the lung were studied. The age of the patients was over 50 years. It was revealed that in the majority of the patients (118 persons, 48.4 per cent) the disease was detected on their taking medical advice and 72.9 per cent (86 subjects of them) had destructive lesions in the lungs. Planned fluorographic examinations revealed such a form of pulmonary tuberculosis less frequently (96 persons, 39.3 per cent) and detection of destructive lesions in them amounted to 63.5 per cent (61 out of 96 persons). In 57.4 per cent of the patients (140 out of 244) concomitant pathological processes in the viscera were detected. 66.4 per cent of them had destructions in the lung tissue.     

Delayed diagnosis of tuberculosis in patients with human immunodeficiency virus infection

PURPOSE: To determine the frequency with which the diagnosis of tuberculosis is delayed in patients with concomitant human immunodeficiency virus (HIV) infection, and to identify reasons for such delays. PATIENTS AND METHODS: We reviewed medical records of 52 consecutive HIV-infected patients with culture-proven tuberculosis seen at a 1,900-bed general hospital serving a predominantly indigent population in Los Angeles, where the prevalences of HIV infection and tuberculosis are high. The late-treatment (LT) group consisted of 25 patients in whom tuberculosis was untreated prior to death (n = 6) or treated more than 22 days after presentation (n = 19). The early-treatment (ET) group comprised 27 patients in whom antituberculous therapy was begun less than 16 days after presentation. RESULTS: Symptoms, physical and laboratory findings, chest roentgenographic abnormalities suggestive of tuberculosis (hilar adenopathy, pleural effusion, miliary pattern, cavitation, predominant upper lobe infiltrate), and frequencies of concomitant nontuberculous disease were similar in LT and ET groups. Delayed diagnosis of tuberculosis was attributable to errors in management in 21 (84%) of 25 LT group patients. The most common error was failure to obtain at least three sputum samples for acid-fast smear and mycobacterial culture in patients with clinical and chest roentgenographic findings compatible with tuberculosis (15 cases). Acid-fast sputum smears were positive in 25 (61%) of 41 cases of pulmonary tuberculosis. Acid-fast smears of stool were positive in eight (42%) of 19 cases. Blood cultures yielded Mycobacterium tuberculosis in 18 (38%) of 48 cases. CONCLUSIONS: Delayed therapy of tuberculosis in HIV-infected patients at our medical center was common and was not due to atypical manifestations of tuberculosis. In most cases, delays could have been avoided if adequate numbers of sputum samples for acid-fast smear and mycobacterial culture had been obtained, and if empiric antituberculous therapy had been given to symptomatic patients in whom chest roentgenographic findings were suggestive of mycobacterial disease.     

The reactivation of pulmonary tuberculosis in persons in registry groups III and VII and those removed from dispensary observation

Clinicoroentgenological findings on 3262 patients registered in groups III and VII of the dispensary observation were studied for a period of 12 years and 425 cases of tuberculosis relapses were analyzed. On the basis of the data it was suggested to divide tuberculosis relapses into real reactivation (65.6 per cent) and pseudoreactivation (26.4 per cent). Pseudoreactivation of tuberculosis in 46.4 and 42.0 per cent of the patients was diagnosed because of mistakes of roentgenologists and phthisiologists, respectively. Diagnosis of tuberculosis pseudoreactivation in 11.6 per cent of the patients was associated with diagnostic difficulties. 8 per cent of the pseudoreactivations interpreted as relapses referred to overdiagnosis of tuberculosis activity. Therefore, real reactivation of pulmonary tuberculosis was only in 2/3 of the patients.     

A year's experience with tuberculosis in a private urban teaching hospital in the postsanatorium era

Because brief general hospital admission and extended ambulatory management have replaced sanatorium care for tuberculosis, we reviewed 41 cases admitted to a private urban hospital during 1971–1972 to assess the spectrum of disease and the problems created by the closing of sanatoriums. Almost half the cases were misdiagnosed, exposing an average of 35 hospital personnel to unisolated patients with positive smears. Clinical manifestations often were subtle. Of those with pulmonary involvement, 14 per cent denied having symptoms and less than half had positive sputum smears. Transfer to ambulatory care for half the patients was complicated by having different physicians manage their hospital and outpatient care, with poor communication between the two. Outpatient physicians were sent discharge summaries for fewer than two thirds of their patients, and then only after an average $\text{2}\text{1}\text{2}$ month delay. Similarly, slowness in case reporting impaired contact investigation. Only three contacts were identified per patient, and only 71 per cent of these were investigated. Improved diagnostic ability, better communication with public health workers, and attention to details of transfer to ambulatory care are necessary for effectively integrating the present components of tuberculosis management.     

Adrenocortical function in patients investigated for active tuberculosis.

Previous reports have identified adrenal insufficiency in groups of patients with active pulmonary tuberculosis. To investigate this possibility, serum cortisol levels were measured in consecutive patients admitted to the hospital for investigation of active tuberculosis. Blood was drawn for cortisol determination promptly at the time of hospital admission, in the morning and afternoon before commencing chemotherapy for the suspected tuberculosis, and before the diagnosis was confirmed. Thirty-seven patients were assessed; 19 of these patients were subsequently proven to have active pulmonary tuberculosis, six had pulmonary disease caused by mycobacteria other than tuberculosis, and 12 had radiologic appearance indicating tuberculosis, accompanied by a significant tuberculin skin reaction but with negative sputum cultures and no change in roentgenographic appearance during the course of treatment. In evaluating the adrenocortical function, the morning and afternoon serum cortisol level was measured and the diurnal change in serum cortisol level (the difference between afternoon and morning levels) was calculated. There was no association of either morning cortisol levels or diurnal change in cortisol levels with age, gender, or race. There was no difference among the three groups in either cortisol determination. Although difference in morning cortisol levels between those with extensive as compared with limited disease was not statistically significant (p = 0.349 from analysis of variance), there was a significantly decreased diurnal change in cortisol levels in those with extensive disease as compared with those with limited disease (+2.7 +/- 188.3 vs -259.1 +/- 177.1). We conclude that patients in our hospital with active pulmonary tuberculosis do not exhibit decreased adrenocortical function as compared with groups of patients without active pulmonary tuberculosis.     

Tuberculosis care in general hospitals: Arizona's experience.

In June 1973 the state of Arizona transferred all in-hospital care of patients with tuberculosis from the State Sanatorium to general hospitals. Eleven general hospitals, 2 extended care facilities, and 30 physicians are under contract; the state pays billed charges after payment from any third-party insurers. Admission to the Tuberculosis Hospitalization Program is controlled by the state and requires real evidence of need for hospital care; there are no residency or indigency requirements. During the first 2 years of the program, 279 patients were admitted for hospital care. The average length of stay was 23.6 days; a marked decrease from the 93-day average in the sanatorium in 1971-1972. Of the 274 patients discharged during the first 2 years, 232 had a final diagnosis of tuberculosis; 105 of these were discharged with sputum smears positive for acid-fast bacilli. Although the cost per patient day was higher than in the sanatorium, the average cost of hospitalization per patient was lower because of the decrease in length of stay. Thirty-five per cent of the patients had some insurance coverage and/or Medicare. An employee skin testing program was required in all hospitals participating in the program. Although there was a 3.5 per cent conversion rate among all hospital employees, there were only 5 converters among employees exposed to patients with tuberculosis under the program. None of the employees was found to have tuberculosis. Of 70 patients with active tuberculosis who have been followed 12 to 24 months, 65 are bacteriologically negative. The general hospital program has been well accepted by patients, physicians, hospitals, and the public.     

Avascular necrosis in systemic lupus erythematosus. Silent symmetric osteonecroses.

The symptomatic joint disease secondary to avascular necrosis of bone (ANB) in 31 of 375 (8 per cent) patients with systemic lupus erythematosus (SLE) was characterized by polyarticular (90 per cent) and symmetric (83 per cent) involvement. Progressive deterioration requiring orthopedic intervention occurred in 11 (35 per cent) patients. No distinguishing clinical or treatment differences were found comparing patients with symptomatic ANB and selected cortico-steroid-treated, asymptomatic, control subjects with SLE. Complete roentgenographic surveys revealed symmetric, polyarticular abnormalities of subchondral and cortical bone consistent with ANB in eight of 31 (26 per cent) of the control subjects. A positive correlation was found between roentgenographic ANB and disease treatment with high doses of corticosteroids. The study suggests that ANB may be present in excess of 30 per cent of the patients with SLE and is most often subclinical, asymptomatic and nonprogressive.     

The value of roentgenographic and fiberbronchoscopic findings in predicting outcome of adults with lower lung field tuberculosis

Proper antituberculosis chemotherapy may not prevent occurrence or progression of endobronchial involvement in patients with pulmonary tuberculosis. We previously reported a higher incidence of endobronchial involvement in adults with lower lung field tuberculosis (LLFTB). We evaluated the value of roentgenographic and fiberbronchoscopic findings in predicting the outcome of adults with LLFTB after 9 months of antituberculosis chemotherapy. The most common change on chest roentgenograms among 101 patients with LLFTB was consolidation, followed by cavitary lesion, lung collapse, and solitary mass. Intrathoracic lymphadenopathy (hilar and/or mediastinal lymphadenopathy) was found in 12 cases. Sputum smear for acid-fast bacilli was positive in 64 patients, and sputum culture for tuberculous bacilli was positive in 37 of 50 patients. Endobronchial involvement was found in 45 of 63 patients who underwent fiberbronchoscopic examination. Of these 45, 18 had ulcerative granuloma, 12 had fibrostenosis, eight had submucosal infiltration, and seven had mucosal redness and swelling. A higher incidence of endobronchial involvement was found in the patients with LLFTB when they presented with roentgenographic findings of pulmonary consolidation, lung collapse, or associated intrathoracic lymphadenopathy. The outcome seemed unfavorable in the patients with LLFTB who presented with roentgenographic findings of lung collapse or pulmonary consolidation, or in those who presented with fiberbronchoscopic findings of fibrostenosis or ulcerative granuloma. Our results show that roentgenographic and fiberbronchoscopic findings are of value in predicting outcome of patients with LLFTB. With proper antituberculosis chemotherapy and close follow-up, fiberbronchoscopy may be clinically indicated in patients with LLFTB to assess the presence and severity of endobronchial involvement. Early surgical intervention can be considered in those with severe endobronchial involvement before serious sequelae occur.     

The development of clinical tuberculosis following infection with tubercle bacilli. 1. A theoretical model for the development of clinical tuberculosis following infection, linking from data on the risk of tuberculous infection and the incidence of clinical tuberculosis in the Netherlands

Information on the risk of tuberculous infection in the Netherlands has been linked with information on the incidence of tuberculosis, in an attempt to estimate the risks of developing the disease following infection or reinfection. It was postulated that: (a) those with a recent primary infection had a characteristic risk of developing progressive primary tuberculosis; (b) those with a distant (i.e. not recent) primary infection and a recent reinfection had a characteristic risk of developing exogenous tuberculosis; and (c) those with a distant primary infection but no recent reinfection had a characteristic risk of developing endogenous tuberculosis. The information on the risk of tuberculous infection was used to estimate the size of the population in each of these infection classes for different age-groups and calendar years in the Netherlands. Using multiple regression to link these population figures with the information on tuberculosis incidence in the same age group and calendar year, it was possible to estimate the above risks of developing tuberculosis. For Netherlands males aged 15-69 years during the period 1951-70 the three risks of developing pulmonary tuberculosis were estimated to be: (a) 5.06 per cent annually (for 5 years) following primary infection; (b) 1.91 per cent annually (for 5 years) following reinfection; (c) 0.0253 per cent annually, after the first 5 years following primary infection, in the absence of reinfection. The corresponding (and significantly different) estimated annual risks of development of pulmonary tuberculosis for females were 5.85, 1.10 and 0.0020 per cent respectively. From these risks, it may be estimated that the degree of protection conferred by a distant primary infection, against pulmonary tuberculosis arising from a recent reinfection, was 63 per cent for males and 81 per cent for females. The estimated relative proportions of cases of progressive primary, exogenous and endogenous tuberculosis varied considerably with age and calendar year. Progressive primary tuberculosis was dominant at the younger ages, exogenous and endogenous tuberculosis at older ages. At these older ages, the great majority of cases in the Netherlands in the early 1950s appeared to be exogenous in origin, but by 1970, with the decrease in the risk of infection, the exogenous contribution had dwindled substantially, especially among males.