Practice Guidelines
CDC Issues Recommendations for Diagnosing, Managing, and Reporting Foodborne Illnesses
In collaboration with the American Medical Association, American Nurses Association-American Nurse Foundation, the U.S. Food and Drug Administration's Center for Food Safety and Nutrition, and the U.S. Department of Agriculture's Food Safety and Inspection Service, the Centers for Disease Control and Prevention (CDC) has issued new recommendations for diagnosing, managing, and reporting foodborne illnesses. The report focuses on recognizing suspicious symptoms, disease clusters, and etiologic agents, and reporting cases of foodborne illness to public health authorities. Summary tables and charts, references, and resources for health care professionals are provided. Patient scenarios, clinical vignettes, and a continuing medical education component also are included. The full report is available in the April 16, 2004, issue of the Morbidity and Mortality Weekly Report: Recommendations and Rationale and online at http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5304a1.htm.
Clinical Considerations
The CDC estimates that 76 million persons get sick, 300,000 are hospitalized, and 5,000 die as a result of foodborne illnesses per year. Primarily very young, elderly, and immunocompromised patients are affected. Foodborne illness can be caused by microorganisms and their toxins, marine organisms and their toxins, fungi, and their related toxins, and chemical contaminants. Foods that have been linked to outbreaks include milk, shellfish, unpasteurized apple cider, raw and undercooked eggs, fish, raspberries, strawberries, and ready-to-eat meats. The accompanying table lists etiologic agents to consider for various manifestations of foodborne illness.
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Recognizing Foodborne Illness
Patients with foodborne illnesses typically present with gastrointestinal tract symptoms (e.g., vomiting, diarrhea, abdominal pain), but nonspecific symptoms and neurologic symptoms also may occur. Important clues to determining the etiology of a foodborne disease are the incubation period, duration of the illness, predominant clinical symptoms, and population involved in the outbreak.
Diagnosis
Establishing a diagnosis can be difficult, particularly in patients with persistent or chronic diarrhea, those with severe abdominal pain, and those who have an underlying disease process. Because viral syndrome has a similar presentation, it must be excluded before suspecting foodborne illness. Fever, diarrhea, and abdominal cramps can be present or absent in viral or foodborne illness, so they are not good indicators. The absence of myalgias or arthralgias would make a viral syndrome less likely. Foodborne illnesses that target the neurologic system tend to cause paresthesias, weakness, and paralysis. The presence of dysentery (bloody diarrhea) also is more indicative of a foodborne illness, particularly if it is early in the course of the illness.
If any of the following signs and symptoms occur in patients, alone or in combination, laboratory testing may provide diagnostic clues (attention should be given to very young, elderly, or immunocompromised patients):
• Bloody diarrhea
• Diarrhea leading to dehydration
• Fever
• Prolonged diarrhea (three or more unformed stools per day, persisting several days)
• Neurologic involvement, such as paresthesias, motor weakness, cranial nerve palsies
• Sudden onset of nausea, vomiting, diarrhea
• Severe abdominal pain
Clinical Microbiology Testing
Stool cultures are indicated if the patient is immunocompromised, febrile, has bloody diarrhea, has severe abdominal pain, or if the illness is clinically severe or persistent. Stool cultures also are recommended if the fecal leukocyte count is high. Stool examination for parasites generally is indicated for patients with suggestive travel histories, those who are immunocompromised, those who suffer chronic or persistent diarrhea, or when the diarrheal illness is unresponsive to appropriate antimicrobial therapy. Stool examination for parasites also is recommended for gastrointestinal tract illnesses that appear to have a long incubation period. Blood cultures should be obtained when bacteremia or systemic infection is suspected.
Treatment
Selection of appropriate treatment depends on identification of the responsible pathogen (if possible) and determining if specific therapy is available. Many episodes of acute gastroenteritis are self-limiting and require fluid replacement and supportive care. Oral rehydration is indicated for patients who are mildly to moderately dehydrated; intravenous therapy may be required for more severe dehydration. Routine use of antidiarrheal agents is not recommended because many of these agents potentially have serious adverse effects in infants and young children. Antimicrobial therapy should be based on clinical signs and symptoms; the organism detected in clinical specimens; antimicrobial susceptibility tests; and appropriateness of antibiotic treatment (some enteric bacterial infections are best not treated).
Surveillance and Reporting of Foodborne Illness
Health care professionals may suspect foodborne illness because of the organism involved or other available information, such as several ill patients who have eaten the same food. Foodborne disease reporting is important for disease prevention and control. More accurate assessments of the burden of foodborne illness in the community occur when physicians and other health professionals report these illnesses to the local and state health departments. These reports may help the health department identify an outbreak in the community, improving early identification and removal of contaminated products from the commercial market.
Typically, the appropriate procedure for health care professionals to follow in reporting foodborne illnesses is to contact the local or state health department whenever they identify a specific notifiable foodborne disease. However, it is often unclear if a patient has a foodborne illness before diagnostic testing, so health care professionals also should report potential foodborne illnesses, such as when two or more patients present with a similar illness that may have resulted from the ingestion of a common food. Local health departments will then report the illnesses to the state health departments, where it is determined if further investigation is necessary.
Practice Guideline Briefs
Update on Pneumococcal Conjugate Vaccine Shortage
The Centers for Disease Control and Prevention (CDC) has recommended that physicians increase the number of doses of pneumococcal conjugate vaccine (PCV7, Prevnar) administered to healthy children from two to three. Production problems earlier this year caused shortages of the vaccine and prompted the CDC to reduce the recommended four doses to two in order to most effectively use the limited available doses.
The CDC, the Advisory Committee on Immunization Practices, the American Academy of Family Physicians, and the American Academy of Pediatrics also recommended that providers continue to administer the full four-dose series of the vaccine to children up to 15 months of age with health conditions such as sickle cell anemia or immune system disorders, who are at increased risk of severe disease. The groups said providers should defer the fourth dose of the vaccine for healthy children until production and supply data convincingly demonstrate supplies of the vaccine are adequate for routine administration of the four-dose series.
The vaccine is normally recommended for young children in a four-dose schedule: one dose each at two, four, and six months of age, and one dose between 12 and 15 months of age. This recommendation reinstates the third dose usually administered at six months for healthy children. PCV7 is not routinely recommended for children older than two years.
The CDC also issued a recommended catch-up schedule for children who missed the third dose. The highest priority for catch-up vaccination is children at high risk for invasive pneumococcal disease. Second priority is vaccination of healthy children younger than 24 months who have not received any doses of pneumococcal conjugate vaccine. The third priority is vaccination of healthy children younger than 12 months of age who have not yet received three doses.
Because of the frequency of physician visits for children during their first 18 months, catch-up vaccination might occur at regularly scheduled visits for most children who receive vaccines from their primary care physician. Physicians who administer vaccinations but do not see children routinely for other reasons should consider a notification process to contact parents of under-vaccinated children.
The catch-up schedule and additional information about the recommendations and PCV7 is available online at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5326a7.htm.
Neuroimaging Tests for Cerebral Palsy
The Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society have released a new guideline on neuroimaging tests for cerebral palsy and related disorders. "Practice Parameter: Diagnostic Assessment of the Child with Cerebral Palsy" appears in the March 2004 issue of Neurology and is available online at http://www.aan.com/professionals/practice/guideline/index.cfm.
According to the guideline, available evidence now supports the use of magnetic resonance imaging (MRI) rather than computerized tomography when cerebral palsy is suspected, although this is not yet routine. Metabolic and genetic studies need not be done routinely unless the cause of the brain's abnormality is not evident on the MRI scan or by clinical history and examination.
Because the incidence of cerebral infarction is high in children with hemiplegic cerebral palsy, diagnostic testing for coagulation disorders should be considered. However, there is insufficient evidence at present to be precise as to what studies should be ordered. Electroencephalography is not recommended unless there are characteristics suggestive of epilepsy or a specific epileptic syndrome.
Evidence also suggests that children who are diagnosed with cerebral palsy should be routinely examined for other related disorders, such as mental retardation, vision and hearing impairments, speech and language disorders, and chewing and swallowing disorders.
An early diagnosis helps the child's parent or caregiver and the child's physician understand the cause of the disorder, as well as make informed decisions on a treatment plan. Most children with cerebral palsy are diagnosed by the time they are two years of age and their condition improves as they get older.
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Copyright © 2004 by the American
Academy of Family Physicians. |
