Medicine Chest News - Part 3

Diffuse Interstitial Pulmonary Disease from the Perspective of the ClinicianDiffuse interstitial pulmonary disease encompasses a large number of entities having in common the diffuse infiltration of alveolar walls by inflammatory or malignant cells, connective tissue, or fluid that impairs the transfer of oxygen to the blood. In recent years, there has been heightened interest in this area of pulmonary disease, with a number of reviews having been published. To a large degree, this has resulted from the introduction of bronchoalveolar lavage, allowing studies of the humoral and cellular events involved in pathogenesis. Most reviews of diffuse interstitial pulmonary disease have emphasized pathogenic mechanisms and pathologic findings as their thrust. Read the rest of this entry »

The central clinical features of this case include dysauto-nomia, parkinsonism, and abnormalities in respiratory control. Unlike previous reports, in this patient, the medulla was morphologically intact. Instead, there was a widespread neuropathy, as well as the classic pathologic findings of Shy-Drager. The moderate abnormalities in respiratory mechanics do not, by themselves, explain the presence of hypercapnic respiratory failure. Although there was evidence of phrenic and intercostal nerve pathologic conditions, the preservation of vital capacity with changes in posture, the lack of paradoxic thoracoabdominal movements, and the presence of substantial maximal inspiratory and expiratory pressures are indications of neuromuscular apparatus sufficient to provide an adequate minute ventilation gas exchange. Read the rest of this entry »

Pathophysiologic Findings in a Patient with Shy-Drager and Alveolar Hypoventilation Syndromes: Pulmonary centrilobular emphysemaAverage inspiratory time, average cycle length, and the coefficient of variation (SD/M) for respiratory timing increased from wakefulness to sleep. In contrast, the coefficient of variation for heart rate was similar during wakefulness and sleep. There were no significant changes in respiratory pattern with medroxyprogesterone acetate (120 mg, qd for three weeks) or with acetazolamide, administered once (250 mg intravenously). The patient received positive pressure ventilatory support only during sleep. Two months after first evaluation, the patient was found pulseless, without blood pressure or respirations one-half hour before his customary bedtime. Read the rest of this entry »

The patient exhibited no respiratory distress. However, while watching television, he seemed to “forget to breathe.” Pulmonary function testing performed through the tracheostomy showed a vital capacity of 1.75 L (50 percent of predicted), forced expiratory volume in one second of 1.1 L (45 percent), and a total lung capacity determined by helium dilution of 5.12 L (92 pecent). Arterial blood gas values during wakefulness showed a pH of 7.34, P02 of 72, and PCO2 of 62 on 30 percent FIo2. His chest roentgenogram showed an elevated right hemidiaphragm. Vital capacity in the supine posture was 1.65 L, unchanged from values in the upright posture (1.70 L). Percutaneous stimulation of the phrenic nerve produced a latency of 9.2 ms on the right and 11.0 ms on the left (normal: 9 to 10 ms.) Maximal inspiratory pressures at functional residual capacity were 85 cmH20 (82 percent), expiratory pressures at total lung capacity were 90 cmHsO (48 percent). Tests of hypercapnic responsiveness with rebreathing and hypoxic responsiveness by withdrawal from administration of 100 percent 02 were abnormally low or absent. Heart rate was unchanged during testing for ventilatory responsiveness. Breathholding time was greater than 60 seconds, and the test was halted when the oxygen saturation fell below 75 percent. Read the rest of this entry »

Pathophysiologic Findings in a Patient with Shy-Drager and Alveolar Hypoventilation SyndromesRespiratory disturbances during wakefulness and sleep are common in patients with the Shy-Drager syndrome. The available pathologic studies describe lesions in the brainstem and conclude that these morphologic changes were responsible for the premorbid disturbances in respiratory control.- In this case, despite hypercapnic respiratory failure and apnea/hypoventilation during sleep, at autopsy there were no pontomedullary abnormalities.
Case Report
This hospitalized 73-year-old black man was evaluated nine months after he was admitted in respiratory failure. Two years prior to evaluation, he developed excessive daytime sleepiness, episodic shortness of breath, and confusion. Syncope and urinary frequency developed the next year. Nine months prior to evaluation, he was admitted for respiratory failure. A tracheostomy was performed because of obstructive apnea during sleep and hypercapnic respiratory failure. A transurethral resection of the prostate revealed an unsuspected adenocarcinoma of the prostate. The patient was unable to leave the hospital because of orthostatic hypotension. Read the rest of this entry »

Chemical Pneumonitis Due to Exposure to Bromine Compounds: ConclusionThis case illustrates the importance of close medical follow-up after major exposures to known respiratory irritants. Bromine and brominated compounds, similar to oxides of nitrogen and phosgene, can cause delayed toxic pulmonary edema 24 to 48 hours after exposure. No precautions were taken in this case to prevent this life-threatening possibility. Chemical pneumonitis developed and progressed over the ensuing two weeks. Prednisone has been used to treat symptomatic chemical pneumonitis; whether the earlier institution of such treatment would have prevented the development of the later complications remains an unanswered question in the absence of controlled clinical trials. Read the rest of this entry »

Bromine has a multitude of industrial applications, the largest present use being production of the anti-knock agent and fumigant, ethylene dibromide. Others include manufacture of fire retardants, flameproofing materials, and intermediate compounds in the production of film, dyes, and inks. Bromine and hydrogen bromide are potent irritants of the oral mucosa, nose, eyes, and respiratory tract. The irritative effects of bromine are so pronounced that human volunteers could not tolerate a concentration of 0.9 ppm of bromine for longer than five minutes. Some, but not all, animal experiments have shown bromine to be more toxic than chlorine. Mice exposed to bromine had periods of early (first four days) and delayed (one to two weeks) mortality, while exposure to chlorine resulted only in early mortality. Delayed mortality after bromine exposure was associated with peribronchiolar abscesses and thought to be due to the comparatively deeper tissue penetration and damage caused by bromine. Bromine may penetrate deeper into tissues than chlorine due to its greater solubility. In animals surviving the acute poisoning, histopathologic findings revealed persistent bronchiolar and bronchial spasm and delayed healing. Read the rest of this entry »

Chemical Pneumonitis Due to Exposure to Bromine Compounds: Occupational Medicine ClinicBy late June, the patient s blood gases and PFT values returned to normal. Although dyspnea on exertion persisted and chest x-ray findings had not yet completely resolved, she was allowed to resume work. Recommendations were made to take precautions against further exposure to chemicals; the treating physician also indicated that the company should take all possible measures to avoid further accidental exposure to chemical compounds. Over the summer, the subject did not work with brominated compounds, but was exposed to other known respiratory irritants including various alkalis, aldehydes, and acids. She recalled coughing while handling some of these compounds. A one-week history of increasing shortness of breath culminated in readmission to the hospital on September 17 with additional complaints of weakness, myalgia, and fever. Read the rest of this entry »

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