Lymphomatoid granulomatosis. Clinicopathologic study of four cases and literature review

Lymphomatoid granulomatosis (LYG) is a poorly understood inflammatory angiitis of uncertain pathogenesis with histological similarities to Wegener's granulomatosis (WG) and atypical lymphoma. Pulmonary, constitutional, cutaneous, and central nervous system manifestations predominate, but clinical signs are extraordinarily diverse. Clinical, roentgenographic, and laboratory abnormalities are nonspecific and the diagnosis is frequently missed or delayed. We describe four cases of LYG and review the previous literature with emphasis on clinical and histological features, course, and therapy. The histological characteristics of LYG are described, and compared and contrasted with WG and atypical lymphoma. In addition to reviewing typical clinical features, we report rare findings noted in two of our cases, e.g., retroperitoneal fibrosis and lytic and blastic bone lesions which expand the spectrum of the disorder and emphasize its protean nature. Our four cases reconfirm the frequency of diagnostic delay, high mortality, and poor responsiveness to therapy. In the review of our cases and previously published data, no therapeutic regimen consistently altered the course of the disease. The efficacy of corticosteroids, immunosuppressive and cytotoxic agents remains uncertain due to variable drug and dosage schedules, lack of comparable patient populations, and retrospective nature of previous reports. However, it appears that corticosteroids may transiently alter manifestations of LYG, but do not prevent ultimate progression. Cyclophosphamide may have contributed to arrest of the disease in our Cases 3 and 4, as well as in sporadic cases from the literature, but its overall efficacy appears to be limited. Multiple-agent chemotherapy has been associated wih occasional responses, but generally has been unsuccessful. Surgery and radiation therapy may be helpful in selected patients with localized disease. The role of corticosteroids, cytotoxic agents, and radiation therapy, alone or in combination, needs to be clarified by prospective cooperative trials.

Reversal of progressive, life-threatening gold hypersensitivity pneumonitis by corticosteroids

Hypersensitivity pneumonitis secondary to gold therapy has been described in only a limited number of patients. The clinical presentation is variable and optimal therapy is not well established. Two patients presenting with life-threatening respiratory insufficiency that progressed despite discontinuation of gold therapy are described. Dramatic improvement occurred following corticosteroid administration. Review of previously reported cases shows corticosteroid therapy to be efficacious. Patients with gold hypersensitivity pneumonitis may have a fulminant course and many require corticosteroids for relief.

Cryptococcus laurentii lung abscess

Pulmonary infection with Cryptococcus laurentii occurred in a patient with dermatomyositis receiving corticosteroid therapy. Infections with cryptococci other than C. neoformans are rare, and pulmonary involvement with C. laurentii has not been reported previously. The isolate was susceptible to amphotericin B but resistant to 5-fluorocytosine, and synergism could not be demonstrated with these 2 drugs. Amphotericin B without surgical resection, concurrent with reduction in the dosage of corticosteroids, resulted in clinical and roentgenogrphic resolution of the infection.

The dependence of oxygen uptake on oxygen delivery in the adult respiratory distress syndrome

The relationship between delivery and uptake of O2 was evaluated in 20 patients with the adult respiratory distress syndrome (ARDS). Eleven patients were studied acutely, after progressive increments in positive end-expiratory pressure. The remaining 9 patients underwent serial determinations of gas exchange and O2 uptake during several days, because O2 delivery varied secondary to changes in clinical status or therapeutic interventions. In all but one patients, decreasing delivery of O2 led to similar decreases in uptake of O2. In general, changes in mixed-venous PO2 were variable and had no consistent relation to cardiac output or O2 delivery. In a contrasting group of 12 patients without ARDS, delivery and uptake of O2 were not related, and mixed-venous PO2 correlated well with cardiac output. We conclude that in patients with ARDS, there is a direct relationshipl between delivery of O2 and uptake of O2. Changes in mixed-venous PO2 may not reflect changes in O2 delivery, cardiac output, or the adequacy of tissue oxygenation. Failure to recognize this may lead to inappropriate evaluation of the clinical status of the patient or the efficacy of therapy.

Endobronchial mass caused by tuberculosis

We report a case that illustrates an unusual manifestation of tuberculosis with massive atelectasis secondary to an endobronchial polypoid lesion. The rarity of this manifestation, coupled with the nonspecific findings on biopsy, delays recognition and therapy. Tuberculosis should be considered in the differential diagnosis of endobronchial mass lesions in the right clinical setting.

Depression of cardiac output is a mechanism of shunt reduction in the therapy of acute respiratory failure

The relationship between changes in cardiac output and intrapulmonary shunt associated with mechanical ventilation was evaluated in 20 patients with the adult respiratory distress syndrome (ARDS). The distribution of ventilation-perfusion (VA/Q) ratios and the level of intrapulmonary shunt was determined by the multiple inert gas technique. Pulmonary blood flow was distributed predominantly to either effective gas-exchanging units or shunt units. Positive end-expiratory pressure (PEEP) or high tidal volume ventilation led to decreases in shunt and cardiac output without altering the overall pattern of VA/Q distributions. Changes in shunt and cardiac output were quantitatively and qualitatively silimar and a strong correlation was found between changes in shunt and cardiac output with both PEEP and high tidal volumes (r = 0.76). Cardiac output depression associated with tese modes of ventilation appears to be a mechanism of shunt reduction in ARDS. Interpretation of improvements in gas exchange in ARDS must take into account concomitant hemodynamic changes.

Adult respiratory distress syndrome in obstetrics and gynecology

The diagnosis, pathophysiology, and treatment of adult respiratory distress syndrome (ARDS) are discussed and 2 cases are presented. ARDS has varied etiology but common clinical, roentgenographic, and pathologic findings; it has been increasingly recognized as an important cause of morbidity and mortality in seriously ill patients. The obstetrician-gynecologist must be aware of this condition, for survival depends upon prompt diagnosis and meticulous therapy of the condition and its underlying cause.

Fiberoptic bronchoscopy in the immunocompromised host: the significance of a "nonspecific" transbronchial biopsy

Fifty-eight flexible fiberoptic bronchoscopies were performed in 49 immunocompromised patients in the diagnostic evaluation of pulmonary infiltrates. Transbronchial lung biopsy (TBB) provided a specific diagnosis in only 12 of 47 procedures (26%). The addition of bronchial brushings to the procedures slightly increased the diagnostic yield. The yield of bronchial brushings was enhanced in patients with diffuse infiltrates on chest roentgenogram (P less than 0.05). Nonspecific inflammatory or fibrotic changes were the most common histologic finding on TBB when pulmonary parenchyma was obtained (found in 16 of 47 procedures, or 34%). Alternative specific etiologic diagnoses were established in 7 of these 16 cases by other diagnostic modalities. Contrary to previous reports, further evaluation of nonspecific changes on TBB may lead to changes in therapy and improved prognosis in selected patients. Complications related to the bronchoscopic procedures were infrequent and resulted in no prolonged morbidity.

Ventilation-perfusion distributions in the adult respiratory distress syndrome

The distribution of ventilation-perfusion ratios, as determined by the multiple inert gas elimination technique, was measured in 16 patients with the adult respiratory distress syndrome. In each case, the distribution of ventilation-perfusion ratios was bimodal. The upper mode consisted of units with normal ventilation-perfusion ratios that received a mean of 52% of the cardiac output. The lower mode, which received the remainder of the cardiac output, consisted of either pure shunt or shunt plus a small number of units with very low ventilation-perfusion ratios (less than 0.01). The measured arterial PO2 and that predicted from the distribution of ventilation-perfusion ratios were very closely correlated (r = 0.93), indicating that the hypoxemia was completely explained by the measured ventilation-perfusion inequality. In 12 patients, the effect of positive end-expiratory pressure on the distribution of ventilation-perfusion ratios was also determined. The addition of positive end-expiratory pressure uniformly resulted in a decrease in blood flow to the lower mode and an increase in the ventilation of unperfused alveoli. Increasing positive end-expiratory pressure also led to a uniform decrease in cardiac output. We conclude that the hypoxemia of the adult respiratory distress syndrome is caused by the presence of shunt or units of very low ratio of ventilation to perfusion and that positive end-expiratory pressure increases the arterial PO2 by decreasing the perfusion of unventilated lung. The mechanism of this decrease is yet to be defined.

Influence of cardiac output on intrapulmonary shunt

The effect of changing cardiac output on intrapulmonary shunt was studied in the setting of hemorrhagic pulmonary edema induced by intravenous oleic acid in 17 alpha-chloralose-anesthetized dogs. The dogs were mechanically ventilated and cardiac output was alternately depressed and augmented using either pharmacologic means or mechanical alteration of venous return. Following oleic acid, the measured ventilation-perfusion distributions, as measured by the multiple inert gas elimination technique, demonstrated a two-compartment blood flow distribution consisting of shunt and normal units. Changes in cardiac output were not associated with change in the shape of the distributions but there was a significant linear correlation between the level of cardiac output and the shunt fraction. The shunt fraction also varied directly with the mixed venous partial oxygen pressure and inversely with the pulmonary vascular resistance. These data suggest that shunt and nonshunt vessels behave differently in response to alterations of blood flow and emphasize that any interpretation of changes in shunt in the setting of diffuse lung injury must be interpreted in light of changes in cardiac output.

Application of the Calspan scene measurement system to the investigation of aircraft accidents

Investigation of transportation accidents usually involves some measurement of physical evidence at the scene. Accurate accident scene data facilitates reconstruction of the accident events and possible determination of the cause. The Calspan Scene Measurement System combines computer technology with civil engineering to provide a useful opitcal measurement device for recording the location of physical evidence at the accident scene. The Calspan Accident Investigation Vehicle, currently under development, is designed to enable investigation teams to completely analyze the evidence and causes of automobile accidents. The concepts and equipment in this system are readily adaptable to the study of aviation accidents.