Gastroenteritis for the Nurse Practitioner Licensing Exam
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Gastroenteritis for Nurse Practitioner Licensing Exam
Definition
- Gastroenteritis: Inflammation of the stomach and intestines caused by infectious agents (viruses, bacteria, parasites) or non-infectious factors (toxins, food allergies, medications).
- Leads to diarrhea, vomiting, abdominal pain, and dehydration.
Etiology
- Viral Gastroenteritis:
- Norovirus: Common cause in adults, associated with outbreaks in closed environments (e.g., cruise ships, nursing homes).
- Rotavirus: Affects children, leading to severe diarrhea. Vaccine-preventable.
- Adenovirus and Astrovirus: Mainly affect children and immunocompromised individuals.
- Bacterial Gastroenteritis:
- Escherichia coli (E. coli): ETEC causes traveler’s diarrhea; STEC can lead to hemolytic uremic syndrome (HUS).
- Shigella: Causes dysentery (bloody diarrhea), highly contagious.
- Salmonella: Associated with contaminated poultry and eggs; causes gastroenteritis or enteric fever.
- Campylobacter jejuni: Linked to undercooked poultry; post-infectious complication includes Guillain-Barré syndrome.
- Clostridioides difficile: Causes pseudomembranous colitis, associated with antibiotic use.
- Parasitic Gastroenteritis:
- Giardia lamblia: Acquired via contaminated water, causes prolonged diarrhea and malabsorption.
- Entamoeba histolytica: Causes amebic dysentery and liver abscesses, seen in areas with poor sanitation.
Clinical Features
- Symptoms:
- Diarrhea: Watery (viral or toxin-mediated) or bloody (invasive bacterial causes).
- Vomiting: More common in viral gastroenteritis (e.g., Norovirus).
- Abdominal pain: Common in both viral and bacterial infections.
- Fever: Typically seen in bacterial gastroenteritis.
- Dehydration: A major complication, especially in infants and the elderly.
Diagnosis
- Clinical Evaluation: Based on history of exposure (e.g., travel, recent antibiotic use).
- Laboratory Tests: Stool culture or PCR for severe cases; C. difficile toxin assay for recent antibiotic use; stool ova and parasites for suspected parasitic infections.
Treatment
- Rehydration:
- Oral Rehydration Therapy (ORT): First-line treatment for dehydration.
- Intravenous Fluids: Used in cases of severe dehydration.
- Antibiotics: Reserved for specific bacterial infections (e.g., Shigella, C. difficile).
- Probiotics: May reduce the duration of symptoms in viral gastroenteritis.
Complications
- Dehydration: Major concern, especially in vulnerable populations.
- Hemolytic Uremic Syndrome (HUS): Associated with STEC infection.
- Guillain-Barré Syndrome: Linked to Campylobacter infection.
- Toxic Megacolon: Seen in severe C. difficile infections.
Prevention
- Vaccination: Rotavirus vaccine for infants.
- Hygiene: Proper handwashing, food handling, and safe water consumption.
Key Points
- Gastroenteritis is commonly caused by viral, bacterial, or parasitic infections.
- Symptoms include diarrhea (watery or bloody), vomiting, abdominal pain, and dehydration.
- Diagnosis is often clinical, with stool tests for severe or prolonged cases.
- Treatment focuses on rehydration, with antibiotics used for specific bacterial causes.
- Complications include dehydration, hemolytic uremic syndrome, and toxic megacolon (C. difficile).