Medicine
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Review Case Reports
D-lactic acidosis. A review of clinical presentation, biochemical features, and pathophysiologic mechanisms.
This report describes a case of d-lactic acidosis observed by the authors and then reviews all case reports of d-lactic acidosis in the literature in order to define its clinical and biochemical features and pathogenetic mechanisms. The report also reviews the literature on metabolism of d-lactic acid in humans. The clinical presentation of d-lactic acidosis is characterized by episodes of encephalopathy and metabolic acidosis. ⋯ Development of the syndrome requires the following conditions 1) carbohydrate malabsorption with increased delivery of nutrients to the colon, 2) colonic bacterial flora of a type that produces d-lactic acid, 3) ingestion of large amounts of carbohydrate, 4) diminished colonic motility, allowing time for nutrients in the colon to undergo bacterial fermentation, and 5) impaired d-lactate metabolism. In contrast to the initial assumption that d-lactic acid is not metabolized by humans, analysis of published data shows a substantial rate of metabolism of d-lactate by normal humans. Estimates based on these data suggest that impaired metabolism of d-lactate is almost a prerequisite for the development of the syndrome.
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Mitochondrial respiration, the most efficient metabolic pathway devoted to energy production, is at the crosspoint of 2 quite different genetic systems, the nuclear genome and the mitochondrial genome (mitochondrial DNA, mtDNA). The latter encodes a few essential components of the mitochondrial respiratory chain and has unique molecular and genetic properties that account for some of the peculiar features of mitochondrial disorders. However, the perpetuation, propagation, and expression of mtDNA, the majority of the subunits of the respiratory complexes, as well as a number of genes involved in their assembly and turnover, are contained in the nuclear genome. ⋯ Given the complexity of mitochondrial genetics and biochemistry, the clinical manifestations of mitochondrial disorders are extremely heterogenous. They range from lesions of single tissues or structures, such as the optic nerve in Leber hereditary optic neuropathy or the cochlea in maternally inherited nonsyndromic deafness, to more widespread lesions including myopathies, encephalomyopathies, cardiopathies, or complex multisystem syndromes. The recent advances in genetic studies provide both diagnostic tools and new pathogenetic insights in this rapidly expanding area of human pathology.
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We studied 19 peripartum patients with acute respiratory failure associated with pregnancy. Although it is an uncommon event, noncardiogenic pulmonary edema is the most common cause of respiratory failure in the peripartum period. This acute lung injury syndrome was observed to be associated with a variety of complications of pregnancy including premature labor, the use of tocolytics, infection, hypertension, leukoagglutinin reactions, aspiration, abruptio placentae, and amniotic fluid embolism. ⋯ It is not clear what the predominant mediator is, but we have focused on platelet activating factor. It is also not established whether the mediator(s) is of amniotic fluid origin or a result of maternal anaphylactoid-type of response to a fetal or amnioplacental antigen. In conclusion, monitoring maternal oxygenation either directly or indirectly by oximetry should be considered routinely in the peripartum period, especially in complicated pregnancies, to detect at an early stage "asymptomatic" or preclinical cases of noncardiogenic pulmonary edema, in hopes of then modifying management to prevent their progression.
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Multicenter Study
Fever of unknown origin (FUO). II. Diagnostic procedures in a prospective multicenter study of 167 patients. The Netherlands FUO Study Group.
From January 1992 until January 1994, we used a standardized diagnostic protocol for the 167 immunocompetent patients with fever of unknown origin (FUO) admitted on the internal medicine wards in all 8 university hospitals in the Netherlands. This protocol consisted of a standardized coded history and standardized physical examination for all 167 patients. A number of additional obligatory investigations had to be performed in the first week of admission for all patients, and all potentially diagnostic clues (PDCs) thus retrieved had to be registered. ⋯ Supportive treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) can be helpful at this stage. Only rarely do patients deteriorate while using NSAIDs without presenting new PDCs. In these rare patients, further diagnostic workup should be performed or a therapeutic trial with, for example, antibiotics, steroids, or antituberculous agents started.
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Diffuse alveolar hemorrhage (DAH) complicating systemic lupus erythematosus (SLE) remains a devastating pulmonary complication of this systemic disease. We conducted this study to review the clinicopathologic presentation and the effects of prior treatment, presence of infection, and current treatment on the survival and outcome of patients with DAH and SLE. We reviewed the records of 15 SLE patients who experienced 19 episodes of DAH over a 10-year period in a single tertiary care hospital. ⋯ Evidence for lupus nephritis is present in the great majority of cases. Most cases demonstrate the histologic pattern of pulmonary capillaritis. The mortality is adversely affected by the need for mechanical ventilation, either the presence of infection at the time of admission or the development of infection in the hospital, and the use of cyclophosphamide for treatment of the acute event.