Gastroenteritis & infectious colitis Flashcards
What is gastroenteritis and IC?
Gastroenteritis = inflammation of the GI tract involving the stomach and small intestines
Often known as infectious diarrhoea – viral or bacterial
What is the aetiology of gastroenteritis and IC?
Bacterial - Less common
Including: Campylobacter jejuni, Escherichia coli, Cholera (not common UK), Clostridium difficile, Staphylococcus aureus = Food poisoning , Salmonella = Food poisoning
Typhoid – salmonella typhi, Shigella and Bacillus cereus
Viral = most common
Mainly UGI symptoms – N&V
Rotavirus and Norovirus (most common)
Also astrovirus and enteric adenovirus
Parasitic
RF: recent travel, animal contact, drinking contaminated water
Protozoa – most commonly Giardia lamblia
10% of gastroenteritis in children
More commonly in developing world
Occurs in those who have travelled, children who attend day-care, homosexual men and following disasters
Often the cause of persistent “Traveller’s diarrhoea”
Cryptosporidium
Non-infectious
Medications: NSAIDs
Diseases: Lactose intolerance, gluten intolerance, Crohn’s disease
Toxins
What are the risk factors of gastroenteritis and IC?
Contaminated food products Travel Poor hygiene Extremes of age: Under 5 or over 60 Contact history Immunocompromise: Underlying illness, poor nutrition, or immunosuppressive therapy Contact with infected animals
What is the epidemiology of gastroenteritis and IC?
3-5 billion cases every year – nearly every American once a year
Children and developing world most commonly affected
Children under the age of 2 in the developing world frequently get 6 or more infections every year
Highest mortality
5 million cases due to Cholera
2nd most common infection after the common cold
Viral - Can occur sporadically or as epidemic outbreak
Rotavirus - Leading cause of diarrhoea worldwide
Spread easily under overcrowding and poor hygiene
Seasonal in northern climates
Most adults and older children possess serum antibodies
Norovirus - Most common cause on non-bacterial outbreaks – up to 80% of all outbreaks
90% of adults are seropositive – but immunity is not long lasting
Bacterial
E. coli - Affects all ages, races and sexes
Extremes of age and immunocompromised more susceptible to complications and prolonged infection
Enterotoxigenic E. Coli is the leading cause of traveller’s diarrhoea (30%)
Adults develop immunity
What are the symptoms?
Diarrhoea
Nausea and vomiting
Abdominal pain/discomfort
Lack of energy
What are the signs?
Dehydration
Moderate Dry mucous membranes Reduced skin turgor Tachycardia Postural hypotension Oliguria
Severe Shock Tachycardia Peripheral vasoconstriction Hypotension (SBP <90)
Fever
Diarrhoea
o Cholera – rice water stools
o Shigella – bloody diarrhoea
o Cryptosporidosis – watery diarrhoea
o Typhoid - + maculopapular rash on trunk (rose spots), fever, headache, malaise
o Giardia – Chronic (weeks) - pale stools, offensive smell, abdo pain, bloating, nausea
What investigations would you do?
First line Stool cultures (+ admit + oral fluids) If systemic illness (fever, dehydration) Blood or pus in stool Immunocompromise Recent hospitalization/Abs/travel Food poisoning outbreak Rectal intercourse Raw seafood
FBC - Raised WBC, Anaemia
Renal function
Raised urea and creatinine
Hypokalaemia
Other investigations
Stool PCR
Blood cultures
Inflammatory markers
AXR
Loss of haustrations
Bowel wall thickening
Thumb print sign
Endoscopy
Abdominal CT
How is it managed?
Hospital admission Vomiting and unable to retain oral fluids Shock or severe dehydration Fluid intake Oral rehydration salt solution Anti-emetic Contact precautions Antidiarrheal/antimotility drugs (e.g. loperamide)
Abs
Clostridium difficile – oral metronidazole + hospital isolation
Cholera – IV fluids +/- oral azithromycin
Giardia – oral metronidazole
What are possible complications?
Electrolyte abnormalities – metabolic acidosis
Most commonly hyper/hypo-natraemia and hypokalaemia
Acute RF
Severe volume depletion leads to hypotension causing ATN
Food intolerance
Lactose/carbohydrate/protein intolerance due to loss of intestinal brush-border enzymes
IBS
E. coli specific
Haemolytic uraemic syndrome = haemolytic anaemia, thrombocytopenia and ARF
Bacteraemia
Reduced effects of medications
What is the prognosis?
Excellent prognosis for most patients
Usually no long-term consequences after recovery
Most patients respond to supportive therapy, recovering in 2-5 days
Carbohydrate/protein intolerance may develop after a bout of viral gastroenteritis
Majority of deaths are due to volume depletion
Highest fatalities of E. Coli infections are due to EHEC, as a result of HUS - 50% require temporary dialysis
