Gastroenteritis Flashcards
What is gastroenteritis?
How is it different from gastritis and enteritis?
Gastritis:
- inflammation of the stomach that presents with N&V
Enteritis:
- inflammation of the intestines that presents with diarrhoea
Gastroenteritis:
- inflammation of the stomach + intestines that presents with N&V + diarrhoea
What is the most common cause of gastroenteritis?
What must be done if you suspect someone has this?
- it is most commonly viral
- most patients have an affected family member / contact as it is highly contagious
- the patient must be isolated to prevent spread to others
What are the potential causes of viral gastroenteritis?
- rotavirus
- norovirus
- adenovirus
adenovirus is less common and presents with a more subacute diarrhoea
What type of E. coli is associated with gastroenteritis and how is it spread?
- E. coli is a normal intestinal bacteria
- only certain strains produce gastroenteritis (E. coli 0157)
- it is spread through contact with infected faeces, unwashed salads or water
How does E. coli 0157 produce symptoms?
What are they?
- E. coli 0157 produces the Shiga toxin
- the toxin causes abdominal cramps, bloody diarrhoea + vomiting
- the Shiga toxin destroys blood cells and leads to haemolytic uraemic syndrome (HUS)
What should be avoided if E. coli gastroenteritis is suspected?
!! antibiotics !!
- the use of antibiotics increases the risk of HUS
- antimotility medication (e.g. loperamide) can also increase the risk
this is the main reason why antibiotics / loperamide are not typically used to treat gastroenteritis
What is meant by haemolytic uraemic syndrome (HUS)?
- there is thrombosis in the small blood vessels throughout the body
- it is characterised by a triad of:
- thrombocytopenia (low platelets)
- AKI (kidneys fail to excrete waste incl. urea)
- haemolytic anaemia (due to RBC destruction)
90% of cases occur in children due to Shiga toxin-producing E.coli
Shigella can also produce the Shiga toxin
What is the presentation of HUS?
- the symptoms typically start 5 days after bloody diarrhoea due to gastroenteritis
- reduced urine output (due to AKI)
- hypertension
- haematuria (dark brown urine)
- abdo pain
- lethargy / irritability / confusion
- bruising
multiple blood clots in small vessels = thrombotic microangiopathy
What is involved in the management of HUS?
- it is a medical emergency as it has a high mortality (10%)
- management is supportive:
- antihypertensives
- blood transfusion if required to treat haemolytic anaemia
- haemodialysis if severe AKI
70-80% of patients with HUS will make a complete recovery
How is gastroenteritis caused by Campylobacter jejuni typically spread?
- also known as “travellers diarrhoea”
- raw or improperly cooked poultry
- untreated water
- unpasteurised milk
it is the most common bacterial cause of gastroenteritis worldwide
What type of bacteria is Campylobacter jejuni?
gram-negative bacteria that is curved or spiral shaped
Campylobacter - “curved bacteria”
What are the symptoms of Campylobacter jejuni gastroenteritis and how do they develop?
- there is a 2-5 day incubation period
- symptoms resolve after 3-6 days
- diarrhoea (often with blood)
- vomiting
- fever
- abdominal cramping
What is the treatment for Campylobacter jejuni gastroenteritis?
- antibiotics are considered ONLY after isolating the organism
AND
- when patients have severe symptoms or other RFs (HIV / HF)
- azithromycin or ciprofloxacin are used
How is Shigella spread?
What is the risk associated with this?
- spread through faeces contaminating drinking water, swimming pools or food
- can produce the Shiga toxin and cause HUS
What are the symptoms of Shigella gastroenteritis?
What treatment is given?
- incubation period is 1-2 days
- symptoms resolve within 1 week without treatment
- azithromycin or ciprofloxacin may be considered in severe cases
symptoms include abdominal cramps, bloody diarrhoea and fever
How is salmonella spread?
- spread through eating raw eggs / poultry
OR
- food contaminated with infected faeces of small animals
What are the symptoms of salmonella gastroenteritis?
Is treatment required?
- incubation period is 12 hours - 3 days
- symptoms resolve within 1 week
- the main symptom is watery diarrhoea that can be associated with mucus or blood
- there is also abdo pain + vomiting
antibiotics are only given in severe cases and are guided by stool culture + sensitivity
What type of bacteria is Bacillus Cereus?
How is it spread?
- it is a Gram positive rod
- it is spread through inadequately cooked food
- it grows well on food not immediately refrigerated after cooking
- typically, associated with fried rice left out at room temperature
What is the course of symptoms like when Bacillus cereus is ingested?
Why do these occur?
- it produces the toxin cereulide whilst growing on the food
- cereulide causes abdominal cramping + vomiting within 5 hours of ingestion
- when it arrives in the intestines it produces different toxins that cause a watery diarrhoea
- this occurs more than 8 hours after ingestion
- all symptoms resolve within 24 hours
typical course = vomiting after 5 hrs, diarrhoea after 8 hours and resolution within 24 hours
What other conditions are associated with Bacillus cereus?
- IVDUs can develop infective endocarditis as a result of Bacillus cereus infection
- Staphylococcus is the most common cause of infective endocarditis in IVDUs
What type of bacteria is Yersinia Enterocolitica?
How does it cause infection?
- it is a Gram-negative bacillus
- eating raw or undercooked pork causes infection
- also spread through contamination with urine / faeces of mammals such as rats or rabbits
What are the typical symptoms associated with Yersinia Enterocolitica infection?
- it typically affects children and causes:
- watery or bloody diarrhoea
- abdominal pain
- fever
- lymphadenopathy
- incubation period is 4-7 days
- the illness can last for up to 3 weeks
How is the presentation of Yersinia infection different in adults / older children?
- they may present with right-sided abdominal pain due to mesenteric lymphadenitis + fever
- this can give the impression of appendicitis
mesenteric lymphadenitis = inflammation in the intestinal lymph nodes
What is the treatment for Yersinia infection?
- antibiotics are only given in severe cases
- they are guided by stool culture + sensitivities
How can Staphylococcus aureus cause gastroenteritis?
- it is not the bacteria that causes symptoms, but the enterotoxin it produces
- it produces this when growing in foods such as eggs, dairy and meat
- the toxins cause small intestine inflammation when ingested
- this results in diarrhoea, perfuse vomiting, abdominal cramps and fever
What is the course of symptoms like in Staphylococcal toxin gastroenteritis?
- symptoms start within hours of ingestion
- they settle within 12-24 hours
What is Giardia lamblia and how is it transmitted?
- it is a microscopic parasite
- it lives in the small intestines of mammals (incl. pets, farm animals + humans)
- it releases cysts into the stools of infected mammals
- the cysts contaminate food / water or are eaten to infect a new host
- this is faecal-oral transmission
What are the symptoms of Giardiasis gastroenteritis?
- infection may not cause any symptoms
- or it may cause chronic diarrhoea
How is Giardiasis infection diagnosed and managed?
- it is diagnosed via stool microscopy
- it is treated with metronidazole
What is important for prevention of gastroenteritis?
- good hygiene helps to prevent gastroenteritis
- the patient should be immediately isolated when they develop symptoms to prevent spread
How is gastroenteritis diagnosed?
- a stool sample is collected
- this is sent for microscopy, culture and sensitivities
- this establishes the causative organism and its antibiotic sensitivities
What is the first step in the management of a patient with gastroenteritis?
!! assess patient for dehydration !!
- attempt a fluid challenge
- consider outpatient management if they can tolerate oral fluids + adequately hydrated
- rehydration solutions (e.g. dioralyte) can be used if patient is NOT vomiting
- if dehydrated, IV fluids are used for rehydration and to prevent dehydration until oral fluids can be tolerated again
Alongside fluid management, what is important in the management of gastroenteritis?
!! control of oral intake !!
- once oral intake is tolerated, slowly introduce a light diet in small quantities
What advice is given about returning to school / work?
stay off work / school for 48 hours AFTER symptoms have resolved
What guidance is in place surrounding the use of antidiarrhoeal and antiemetic medication in gastroenteritis?
- antidiarrhoeal + antiemetic medication are NOT recommended
- they may be useful in mild - moderate symptoms
- AVOID ANTIDIARRHOEALS in E. coli 0157 and shigella infection
OR
- if there is bloody diarrhoea + high fever
antidiarrhoeal = loperamide
antiemetic = metoclopramide
What guidance is in place surrounding use of antibiotics in gastroenteritis?
- antibiotics are usually NOT recommended
- should only be given in patients that are at risk of complications and once the causative organism is confirmed
What are the 4 possible post-gastroenteritis complications?
- lactose intolerance
- Guillain-Barre syndrome
- reactive arthritis
- irritable bowel syndrome
