History and exam

Key diagnostic factors

common

diarrhea

Usually a history of acute diarrhea (<2 weeks).

nausea and vomiting

Staphylococcus aureus, Bacillus cereus, norovirus, or rotavirus is suspected when vomiting is the major presenting symptom. Ingestion of poisonous mushrooms or heavy metals may also present with nausea and vomiting.[2]

Other diagnostic factors

common

abdominal pain

Abdominal pain is commonly severe in inflammatory processes. Painful abdominal muscle cramps suggest underlying electrolyte loss, as in severe cholera.

Yersinia enterocolitis may mimic the symptoms of appendicitis or Crohn ileitis (right lower quadrant pain and guarding), as can trematodiasis.

bloating

Bloating for a relatively long period should raise the suspicion of giardiasis.

fever

Suggests invasive pathogen or agent causing systemic disease. Fever may result from infection outside the gastrointestinal tract or superimposed infections.

dehydration

Dehydration may be minimal early in the diarrheal illness, with no signs of dehydration present. Moderate dehydration is indicated by thirst, restless or irritable behavior, decreased skin elasticity, and sunken eyes. In severe dehydration, symptoms become more severe with shock, diminished consciousness, lack of urine output, cool, moist extremities, a rapid and feeble pulse, low or undetectable blood pressure, and pale skin. Patients with severe dehydration may also experience orthostasis.

blood or mucus in stool

Indicates invasion of the intestinal or colonic mucosa. Proctitis syndrome, seen with shigellosis, is characterized by tenesmus, rectal discomfort, and frequent painful bowel movement containing blood, pus, and mucus.

uncommon

profuse rice-water stool

Suggests cholera or a similar process. This leads to large-volume watery stools in the absence of blood, pus, or severe abdominal pain. Profound dehydration may result.

reactive arthritis

Can be seen with Salmonella, Shigella, Campylobacter, and Yersinia infections.

skin manifestations

Rose spot macules on the upper abdomen may be seen in Salmonella typhi infection.

Erythema nodosum is suggestive of Yersinia infection.

Patients with Vibrio vulnificus or V alginolyticus may present with cellulitis.

ear, nose, and throat manifestations

Exudative pharyngitis is suggestive of Yersinia infection.

Patients with Vibrio vulnificus or V alginolyticus may present with otitis media.

hepatosplenomegaly

May be seen in Salmonella typhi infection.

neurologic manifestations

May encompass paresthesia, metallic taste, visual disturbances, hallucinations, confusion, respiratory depression or distress, bronchospasm, and cranial nerve palsies. Neurologic symptoms may be caused by botulism, noninfectious agents (including pesticides and mushrooms), and Campylobacter jejuni (Guillain-Barre syndrome). Diplopia, reduced muscle tone, and slurred speech are associated with botulism.

hepatobiliary disease

Patients with trematodiasis can present with features of biliary colic, cholestasis, cholelithiasis, hepatic abscess, or hepatitis.[5]

pulmonary symptoms

Patients with trematodiasis can present with chronic cough, chest pain, dyspnea, or hemoptysis.[5]

other intestinal features

Patients can present with mucosal ulceration or malnutrition.[5]

manifestations of ectopic infection

Ectopic infection from trematodiasis can include central nervous system, heart, reproductive organ, spleen, skin, or blood vessel manifestations.[5]

Risk factors

strong

older people and pregnant women

Pregnant women and those at the extremes of age are at higher risk of, and more vulnerable to, foodborne illness. They may experience a severe illness that may require hospitalization. Increased risk results from both direct factors (e.g., aging immune system resulting in decreased intestinal motility and immune function and increased susceptibility to systemic illness) and indirect factors (e.g., improper food preparation and handling practices that may increase the likelihood of illness).[17][18][19]

chronic disease

Some chronic diseases (e.g., diabetes and cancer) and chronic use of immunosuppressive medications (e.g., corticosteroids, antitumor necrosis factor therapy, and chemotherapies) are associated with increased vulnerability to opportunistic infections.[17][20][21]​ People with alcohol-use disorder and people with chronic liver disease (hemochromatosis or cirrhosis) are at increased risk of infections due to Vibrio vulnificus from raw shellfish.[22]

recent history of travel

May indicate specific pathogens.

immunocompromised state

Immunocompromised states (from specific conditions or related to medications) are associated with higher risk of more frequent and more severe foodborne illness.[23] 

history of contact with other people with food poisoning

Friends or family may have presented with similar symptoms.

If 2 or more people have symptoms of diarrhea, then this is considered an outbreak.

Certain pathogens are notifiable. UK Health Security Agency: ​notifiable diseases and causative organisms: how to report Opens in new window CDC: how to report a foodborne illness - healthcare professionals Opens in new window

consumption of undercooked meat

Associated with Salmonella, Campylobacter, Shiga toxin-producing Escherichia coli, Clostridium perfringens, and hepatitis E.[24]

consumption of raw seafood

Associated with norovirus, Vibrio species, hepatitis A, and trematoda (flukes).

consumption of homemade canned foods

Associated with Clostridium botulinum.

consumption of unpasteurized soft cheeses

Associated with Listeria, Salmonella, Campylobacter, Shiga toxin-producing E coli, and Yersinia.

consumption of deli meats

Associated with listeriosis.

consumption of unpasteurized milk or juice

Associated with Salmonella, Campylobacter, Shiga toxin-producing E coli, Yersinia, and Brucella.

consumption of raw eggs

Associated with Salmonella.

improper food handling and storage

Associated with higher risk of developing and transmitting foodborne illness. Examples include: improper refrigeration and storage (home-canning); not rinsing cutting boards and sinks before and after washing fresh produce; not keeping raw animal products separated from fresh produce in the refrigerator, or when transporting from shop to home; not using a meat thermometer to determine whether meat is cooked; not refrigerating foods promptly; putting large quantities of hot food in the refrigerator without portioning into smaller amounts; thawing frozen food on the counter; using refrigerators that are too warm (≥43°F [6°C]) for safe storage of food.[1][17][20][25][26] 

gastric acid suppression

Antacids and proton pump inhibitors increase the risk of bacterial invasion as the usual antimicrobial barrier function of gastric acid is reduced, particularly in high risk individuals such as those who are ages >65 years, immunocompromised, or pregnant.[27][28][29]

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