Gastroenteritis

Good Handwashing and appropriate food handling is key to preventing the spread of further disease.

About

• Inflammation of the stomach and intestinal epithelium and submucosa
• Typically acute and infective coming on soon after exposure to agent
• Most cases never come near the hospital
• Close monitoring e.g. admission for IV fluids for diabetics, pregnancy, paediatrics, immunocompromised, elderly, coexisting diseases

Causes

Mechanism

Mechanism	Example
Non inflammatory	Vibrio cholerae, Enterotoxigenic E.coli produce toxins which cause the cells lining the gut to secrete water and electrolytes
Inflammatory	Enteroinvasive E.coli and Shigella and salmonella typhi release cytokines and generally damage the epithelium

Organisms	Code: D=Diarrhoea, V = Vomiting AP=Abdominal pain F=fever S=Sepsis
Staph aureus	D&V&AP within 6 hrs of ingestion of infected meat
Bacillus cereus	D/V Within 6 hours of ingestion of infected rice
Scombrotoxin	D/V and Flushing and hot mouth within 1 hour of eating fish. Scombroid fish poisoning is due to ingestion of food high in Histamine. Antihistamines are given and fluid resuscitation. Proper storage after the fish is caught would prevent this
Ciguatera fish poisoning	D/V/AP tingling all over. Within minutes of ingestion. Ciguatera fish poisoning is due to fish that contain a dinoflagellate that releases ciguatoxin. Management is supportive with fluid replacement. Patients feel hot when cold and vice versa. Diarrhoea and cramps persist. Unusual sensations may persist for many months
Salmonella	D/V/AP/F/S Between 12 and 48 hours after infected meat, eggs, chicken
Norovirus	D/V(projectile)/AP within 12-48 hrs. Faeco-oral and from vomitus. Infectious even after symptoms resolve up to 48 hrs
Rotavirus	D/V/F within 1-7 days
Clostridium botulinum	V/Paralysis/Botulism from canned and processed foods. Diplopia, facial weakness and weakness in his arms and hyporeflexia
Clostridioides difficile	V/D/AP. Seen In those on broad-spectrum antibiotics. Faeco-oral spread. Spores. Toxin producing. Pseudomembranous colitis. Toxic megacolon
Clostridium perfringens	D/AP from meat within 24 hours
Vibrio cholerae	See section. From contaminated water.
Campylobacter	D(bloody)/V/F/Acute AP within 5 days of milk, chicken, water. May develop Guillain-Barré syndrome.
E.Coli O157	D(bloody), D/V/F/P within 12-72 h,Haemolytic uraemic syndrome
Yersinia enterocolitica	D, AP, F from infected milk
Cryptosporidium parvum	D/Cramps. Associated with HIV and life-threatening if low CD4. From infected unboiled water. Incubation period 4-12 days
Giardia lamblia	D/Malabsorption from cats,dogs within 1 wk-1 month
Entamoeba histolytica	D/Malabsorption within 1 wk-1 month
Shigella	D(bloody)/Fever,AP within2-3 day of infection from food
Vibrio parahaemolyticus	D/AP/V within 48 hours of infected seafood

Clinical

• Acute onset of nausea, vomiting, anorexia, fever in some cases
• Waves of Intestinal colic and diarrhoea which may be watery faeces initially or mucus or even blood-stained
• Abdominal discomfort, ↑ Bowel sounds
• Dehydration and hypotension in severe cases

Investigations

• Done only in a select few with severe symptoms
• FBC ↑ WCC ↑ CRP
• U&E ↑ Urea, ↑ Creatinine if dehydrated or ↑↑ may suggest renal failure associated with E Coli O157
• Stool samples for microscopy and culture and toxin analysis
• Blood cultures if pyrexial
• AXR - may show gas-filled bowel loops, no faeces

Prevention when abroad

• Avoid unbottled or unboiled water
• Avoid ice cubes and salads and peel your own fruit
• Recently prepared hot food only

Management

• Fluid management using IV fluids if needed
• Oral rehydration sachets
• Loperamide and Codeine phosphate can be used
• Ciprofloxacin if salmonella, shigella or campylobacter suspected with systemic infection or if elderly or immunocompromised
• Notifiable disease in the United Kingdom

Important complications

• Guillain-Barré syndrome with campylobacter
• Haemolytic uraemic syndrome with E.coli O157
• Precipitate Diabetic ketoacidosis in Type 1 DM not following sick day rules
• Hypovolaemic shock
• Muscle weakness - Botulinum toxin