Diarrhea – Part 1 – Lab findings
Definition of diarrhea
- This is characterized by 3 loose stools per day and may be accompanied by:
- Abdominal pain.
- Nausea and vomiting.
Causes of Diarrhoea:
- Diarrhea may be acute or chronic.
- This may be due to:
- Viral infections. The most common cause is retrovirus among children. Other viruses are Adenovirus, cytomegalovirus, and HIV.
- Bacterial infections are due to salmonellosis, Vibrio, Campylobacter, and Yersinia. Other causes are toxigenic bacteria like Staphylococcus and Bacillus cereus, Shigella, and E.Coli.
- parasitic infestation e.g. Giardia Lamblia, and Entamoeba histolytica.
- Most of the diarrhea is due to infections.
- Age: Mostly the young are susceptible due to poor health.
- Poor general health and nutrition will predispose to diarrhea.
- Bacteria leading to diarrhea depends:
- A dose of the bacterial infection.
- Production of enterotoxin.
- Its ability to attach to the intestinal mucosa and to invades the mucosa.
- Other factors for diarrhea are:
- Poor sanitation.
- Contaminated food and water.
- Personel hygiene, washing hands with soap after defecation, prevents the fecal-oral spread.
- Food store at room temperature allows rapid bacterial growth and production of toxins.
- Food store at 4 °C cannot kill the bacteria, it can only prevent the multiplication of bacteria.
- Avoid keeping the food at room temperature, which leads to the rapid proliferation of the organism.
- AIDS has a prominent feature of diarrhea.
Diarrhea causes and diagnosis:
|Causative agent||Source||A common source of infection||Diagnosis|
|Salmonella species||Animal and humans||Milk, eggs, meat, and poultry||The specimen is feces, culture on selective media.|
|Shigella species||Humans||Food, fomites, and feco-oral route||Stool, and rectal swab on MacConkey and selective media|
|Escherichia coli||Humans||Food, water, fomites, and feco-oral route||Feces culture on MacConkey medium|
|Bacillus species||Soil||Rice||Suspected food, vomitus, and stool culture on ordinary media|
|Staphylococcus aureus||Septic lesion on food handlers||Dairy products and cooked meat||Suspected food, vomitus, or feces are cultures on ordinary media|
|Campylobacter species||Animals||Meat, milk, and poultry||Feces culture on selective medium|
|Clostridium perfringens||Animal||Meat pies, and stews||Feces and suspected food on aminoglycoside blood agar anaerobically|
|Clostridium difficle||Humans||Feco-oral, and overgrowth of strains in colon||Direct detection of toxin, and isolation on selective media|
|Vibrio cholerae||Humans||Food and water||Feces on selective medium (TCBS agar).|
|Yersinia species||Animal||Food and water||Isolation from feces or blood or rising antibody titer|
Lab. workup of the patient with diarrhea:
- History of the patient as regards the duration of the clinical symptoms.
- Any history of travel to a foreign country.
- Food history of the other people living with the patient.
- Take a stool sample or rectal swab.
- Take the sample of suspected food.
- Get the vomitus sample.
- Stool examination for ova and parasites.
- Stool cultures for pathogenic organisms.
- Bood culture in severe cases. It is advised in very young and old patients.
- Take the sample of the suspected food if possible.
- Antigen tests for G.lamblia, and E.Coli.
- Antibodies tests can diagnose parasitic diseases.
- The retrovirus can be diagnosed by a rapid antigen test.
- Causes of noninfectious disease are diagnosed by:
- Fecal fat.
- Lactose intolerance test.
- Celiac disease diagnosed by anti-endomysial and antigliadin antibody.
- Tests other than lab are colonoscopy, endoscopy, and sigmoidoscopy.
- In case of outbreak advise:
- Fecal samples from the kitchen personnel.
- Food handling practices by the workers in the kitchen.
Electrolytes findings are as follows: