A model for medical knowledge representation application to the analysis of descriptive pathology reports.

A new knowledge-representation system is presented, designed for medical knowledge-based applications and in particular for the analysis of descriptive medical reports. Knowledge is represented at two levels. A definitional level uses a concept-type hierarchy, a relation-type hierarchy, and a set of schematic graphs to define the concepts used and the relations between them, as well as different types of cardinality restrictions on these relations. A set of compositional hierarchies using the classic "has-part" relation as well as a new set-inclusion relation allows concept composition to be precisely defined. An assertional level allows the creation and manipulation of empirical data, in the form of graphs using the concepts, relations, and constraints defined at the definition level. The use of cardinality constraints in graph unification is considered in the context of descriptive medical discourse analysis.

Clinical and laboratory comparison of botulism from toxin types A, B, and E in the United States, 1975-1988.

Cases of adult botulism (n = 309) were studied to identify clinical differences between toxin types and to evaluate the sensitivity of diagnostic laboratory testing. Patients with illness from type E toxin had the shortest incubation periods. Sporadic case-patients were more severely ill: 85% required intubation compared with only 42% in multiperson outbreaks. Of patients with type A botulism, 67% required intubation compared with 52% with type B and 39% with type E. Toxin testing was positive for 40%-44% of serum and stool specimens obtained within 3 days of toxin ingestion and for 15%-23% of specimens obtained thereafter, while 37% of stool specimens obtained > 3 days after toxin ingestion were positive by culture. Patients with type A botulism have more severe illness. In general, specimens obtained early are more likely to be positive by toxin assay, and stool cultures are more sensitive than toxin detection for specimens obtained later in the illness.

Foodborne disease outbreaks in nursing homes, 1975 through 1987.

OBJECTIVE: --To describe the epidemiology of foodborne disease outbreaks in nursing homes and to identify where preventive efforts might be focused. DATA SOURCES: --Reports by state and local health departments of foodborne disease outbreaks occurring from January 1, 1975, through December 31, 1987. STUDY SELECTION: --Foodborne disease outbreaks reported to the Centers for Disease Control, Atlanta, Ga, on standard investigation forms. DATA EXTRACTION: --Each foodborne disease outbreak report was examined by an epidemiologist or statistician. Outbreaks were considered to have a known pathogen if confirmed by laboratory tests, and a known vehicle when an epidemiologic investigation implicated a specific food item. DATA SYNTHESIS: --From 1975 through 1987, 26 states reported 115 outbreaks of foodborne disease in nursing homes, causing illness in 4944 persons and death in 51. These outbreaks represented 2% of all reported foodborne disease outbreaks and 19% of outbreak-associated deaths in this period. Of 52 outbreaks with a known cause, Salmonella was the most frequently reported pathogen, accounting for 52% of outbreaks and 81% of deaths. Salmonella enteritidis outbreaks accounted for 56% of the Salmonella-associated deaths since 1981. The implicated food vehicles in S enteritidis outbreaks were made with eggs or prepared with equipment contaminated with eggs. Staphylococcal foodborne disease was the next most commonly identified cause, accounting for 23% of outbreaks. CONCLUSIONS: --Since the elderly are at high risk for serious morbidity from foodborne disease, nursing homes should practice careful food handling, preparation, and storage procedures; provide education for food handlers; and have active infection control programs to rapidly detect and control outbreaks of foodborne disease.