Gastroenteritis

Question 1

What is gastroenteritis?

How is it different from gastritis and enteritis?

Answer 1

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

Question 2

What is the most common cause of gastroenteritis?

What must be done if you suspect someone has this?

Answer 2

• 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

Question 3

What are the potential causes of viral gastroenteritis?

Answer 3

• rotavirus
• norovirus
• adenovirus

adenovirus is less common and presents with a more subacute diarrhoea

Question 4

What type of E. coli is associated with gastroenteritis and how is it spread?

Answer 4

• 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

Question 5

How does E. coli 0157 produce symptoms?

What are they?

Answer 5

• 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)

Question 6

What should be avoided if E. coli gastroenteritis is suspected?

Answer 6

!! 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

Question 7

What is meant by haemolytic uraemic syndrome (HUS)?

Answer 7

• there is thrombosis in the small blood vessels throughout the body
• it is characterised by a triad of:

1. thrombocytopenia (low platelets)
2. AKI (kidneys fail to excrete waste incl. urea)
3. 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

Question 8

What is the presentation of HUS?

Answer 8

• 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

Question 9

What is involved in the management of HUS?

Answer 9

• 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

Question 10

How is gastroenteritis caused by Campylobacter jejuni typically spread?

Answer 10

• also known as “travellers diarrhoea”
• raw or improperly cooked poultry
• untreated water
• unpasteurised milk

it is the most common bacterial cause of gastroenteritis worldwide

Question 11

What type of bacteria is Campylobacter jejuni?

Answer 11

gram-negative bacteria that is curved or spiral shaped

Campylobacter - “curved bacteria”

Question 12

What are the symptoms of Campylobacter jejuni gastroenteritis and how do they develop?

Answer 12

• there is a 2-5 day incubation period
• symptoms resolve after 3-6 days

1. diarrhoea (often with blood)
2. vomiting
3. fever
4. abdominal cramping

Question 13

What is the treatment for Campylobacter jejuni gastroenteritis?

Answer 13

• antibiotics are considered ONLY after isolating the organism

AND

• when patients have severe symptoms or other RFs (HIV / HF)
• azithromycin or ciprofloxacin are used

Question 14

How is Shigella spread?

What is the risk associated with this?

Answer 14

• spread through faeces contaminating drinking water, swimming pools or food
• can produce the Shiga toxin and cause HUS

Question 15

What are the symptoms of Shigella gastroenteritis?

What treatment is given?

Answer 15

• 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

Question 16

How is salmonella spread?

Answer 16

• spread through eating raw eggs / poultry

OR

• food contaminated with infected faeces of small animals

Question 17

What are the symptoms of salmonella gastroenteritis?

Is treatment required?

Answer 17

• 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

Question 18

What type of bacteria is Bacillus Cereus?

How is it spread?

Answer 18

• 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

Question 19

What is the course of symptoms like when Bacillus cereus is ingested?

Why do these occur?

Answer 19

• 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

Question 20

What other conditions are associated with Bacillus cereus?

Answer 20

• IVDUs can develop infective endocarditis as a result of Bacillus cereus infection
• Staphylococcus is the most common cause of infective endocarditis in IVDUs

Question 21

What type of bacteria is Yersinia Enterocolitica?

How does it cause infection?

Answer 21

• 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

Question 21

What are the typical symptoms associated with Yersinia Enterocolitica infection?

Answer 21

• it typically affects children and causes:

1. watery or bloody diarrhoea
2. abdominal pain
3. fever
4. lymphadenopathy

• incubation period is 4-7 days
• the illness can last for up to 3 weeks

Question 22

How is the presentation of Yersinia infection different in adults / older children?

Answer 22

• 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

Question 23

What is the treatment for Yersinia infection?

Answer 23

• antibiotics are only given in severe cases
• they are guided by stool culture + sensitivities

Question 24

How can Staphylococcus aureus cause gastroenteritis?

Answer 24

* 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**

Question 25

What is the course of symptoms like in Staphylococcal toxin gastroenteritis?

Answer 25

* symptoms start within **hours** of ingestion * they settle within **12-24 hours**

Question 26

What is Giardia lamblia and how is it transmitted?

Answer 26

* 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**

Question 27

What are the symptoms of Giardiasis gastroenteritis?

Answer 27

* infection may not cause any symptoms * or it may cause **chronic diarrhoea**

Question 28

How is Giardiasis infection diagnosed and managed?

Answer 28

* it is diagnosed via **stool microscopy** * it is treated with **metronidazole**

Question 29

What is important for prevention of gastroenteritis?

Answer 29

* **good hygiene** helps to prevent gastroenteritis * the patient should be **immediately isolated** when they develop symptoms to prevent spread

Question 30

How is gastroenteritis diagnosed?

Answer 30

* a **stool sample** is collected * this is sent for **microscopy, culture and sensitivities** * this establishes the **causative organism** and its **antibiotic sensitivities**

Question 31

What is the first step in the management of a patient with gastroenteritis?

Answer 31

**!! 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

Question 32

Alongside fluid management, what is important in the management of gastroenteritis?

Answer 32

**!! control of oral intake !!** * once oral intake is tolerated, slowly introduce a **light diet** in **small quantities**

Question 33

What advice is given about returning to school / work?

Answer 33

stay off work / school for **48 hours AFTER** symptoms have resolved

Question 34

What guidance is in place surrounding the use of antidiarrhoeal and antiemetic medication in gastroenteritis?

Answer 34

* 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** ## Footnote antidiarrhoeal = loperamide antiemetic = metoclopramide

Question 35

What guidance is in place surrounding use of antibiotics in gastroenteritis?

Answer 35

* antibiotics are usually **NOT recommended** * should only be given in patients that are at **risk of complications** and once the **causative organism is confirmed**

Question 36

What are the 4 possible post-gastroenteritis complications?

Answer 36

* lactose intolerance * Guillain-Barre syndrome * reactive arthritis * irritable bowel syndrome