The supply of oxygen to the myocardium is determined by coronary blood flow and oxygen carrying capacity. Coronary blood flow is a dynamic process modulated via multiple parameters. Cardiac metabolism is also affected by several factors. Under normal physiologic conditions, the demand is easily met by the supply of oxygen. In fact, there is a significant reserve on the supply side. Under certain pathologic states such as coronary artery disease, the supply of oxygen may be exhausted and an imbalance between supply and demand occurs which is translated into ischemia. The area of myocardium most susceptible to ischemia is the subendocardium due to mechanical and metabolic forces. In therapy of coronary artery disease, attention should be directed to directional changes in factors influencing supply and demand to improve blood flow to the most susceptible area.

Sixteen cases of nontraumatic left atrial-esophageal fistulas have been reported previously. These fistulas usually result from chronic peptic esophagitis or cancer. The diagnosis is suggested by the triad of chronic dysphagia, hematemesis, and acute neurologic signs. There may be cardiac manifestations such as pericarditis, atrial fibrillation, or shock. An unusual feature of these fistulas is systemic embolization of food, air, or septic necrotic debris which may result in sudden central nervous system symptoms. All reported cases resulted in death due to hemorrhage, although there was often a variable time interval between the onset of hematemesis and the patient's death. The authors report two additional cases in which an episode of pericarditis preceded fistula development. Based on these 18 cases, the spectrum of esophagoatrial fistulas is reviewed, as well as the signs which may herald fistula development.

A wide variety of lesions occur in the mediastinum in patients of every age. Twenty five to 50 percent of these primary mediastinal masses may be malignant, making early diagnosis and therapy crucial. Since most arise from normal structures in the region, localization of lesions to compartments of the mediastinum may assist in diagnosis. This article reviews imaging techniques for lesions originating in the mediastinum.

Diagnosis and particularly the management of erythema multiforme and Stevens-Johnson syndrome are controversial in medical textbooks and thus in individual cases. In these diseases, fatalities may result from various causes, including secondary infection or visceral organ damage to lung, liver, or kidneys. We present a series of 13 cases managed by one group of physicians which demonstrates the controversy in certain cases, and we review the controversy in the medical literature. Corticosteroid therapy used in this series was considered beneficial in every case by the managing physician and lifesaving in some cases. There were no fatalities in this series. Although the summation may be considered as our opinion only, the frequently suggested "controlled trial of corticosteroid therapy" can probably never be done for ethical reasons, and series such as this will have to establish the standard of therapy.

Spontaneous pneumothorax associated with Pneumocystis carinii pneumonia (PCP) in AIDS patients has been reported with increasing frequency; however, little is known about the causative histopathology. In the past year, we treated three patients with documented PCP subsequently complicated by multiple spontaneous pneumothoraces. All patients underwent open surgical repair. In contrast to traditional pathologic findings of PCP in AIDS, histologic sections of lung from each patient consistently demonstrated an extensive interstitial inflammatory process with destruction of lung tissue primarily involving the periphery of the lung. Subpleural necrosis with bleb formation as well as bullous changes persisted even in the absence of an alveolar filling process. We conclude that the mechanism for pneumothorax in PCP is spontaneous rupture of necrotic lung tissue occurring in a subgroup of AIDS patients in which the interstitial inflammatory response to Pneumocystis has been accelerated.

After almost 50 years as first-line drugs in the management of asthma and COPD, methylxanthines have been largely superceded by inhaled adrenoceptor agonist and anticholinergic bronchodilators which are more potent and far less toxic. Accumulating evidence indicates that intravenous theophylline contributes side effects, but is rarely of benefit in acute exacerbations of asthma or COPD. In the maintenance therapy of asthma, first-line therapy is dose-optimized inhaled steroids, reducing the need for bronchodilators. Inhaled adrenoceptor agonists are second line medications, anticholinergic aerosols third line, and theophylline, if needed at all, may fulfill a minor systemic steroid-sparing function in severe asthmatics on maximum doses of the inhaled medications. In the maintenance therapy of some patients with COPD, theophylline sometimes may be useful but these responders should be identified by objectively establishing therapeutic benefit. Since many patients have side effects from the methylxanthines, while their therapeutic benefit over and above dose-optimized inhaled therapy is marginal, their continued almost routine use in the management of reversible airflow obstruction is hard to justify, although this class of drugs may be useful in selected patients in whom both subjective and objective benefit can be demonstrated. In COPD, theophylline may improve exercise capacity in some patients by still incompletely understood mechanisms probably unrelated to bronchodilation.

Praziquantel is recommended as the drug of choice for all forms of schistosomiasis. We report the first case (to our knowledge) of exudative effusive polyserositis following treatment of schistosomiasis with this drug. This involved pleura, pericardium, and peritoneum and was associated with acute respiratory failure. The latter preceded the appearance of pleural effusions. We present a brief review of the literature and attract attention to the need for close observation of patients with schistosomiasis who are treated with praziquantel.

Intensive management of patients with severe head injury offers the best hope of minimizing death and functional disability in a young, working population. Secondary neurologic insult can be decreased by cardiorespiratory support and ICP control from the outset. Rapid neurologic assessment, airway management, and support of circulation are the basis of emergency management for head injury. Patients with severe head injury require intensive care management for two major reasons: management of ICP and management of organ system dysfunction. Care should not be withheld because of initially grim (and inaccurate) prognostic assessment. Newer techniques for assessing the adequacy of cerebral circulation may allow refinement of management strategies in the future.