Gastroenteritis Flashcards
Gastroenteritis
Gastroenteritis may either occur whilst at home or whilst travelling abroad (travellers’ diarrhoea)
Travellers’ diarrhoea may be defined as at least 3 loose to watery stools in 24 hours with or without one of more of abdominal cramps, fever, nausea, vomiting or blood in the stool. The most common cause is Escherichia coli
Another pattern of illness is ‘acute food poisoning’. This describes the sudden onset of nausea, vomiting and diarrhoea after the ingestion of a toxin. Acute food poisoning is typically caused by Staphylococcus aureus, Bacillus cereus or Clostridium perfringens.
Gastroenteritis: Stereotypical Hx
Infection and Typical presentation
Escherichia coli
Common amongst travellers
Watery stools
Abdominal cramps and nausea
E. coli O157:H7 is a particular strain associated with severe, haemorrhagic, watery diarrhoea. It has a high mortality rate and can be complicated by haemolytic uraemic syndrome. It is often spread by contaminated ground beef.
Giardiasis
Prolonged, non-bloody diarrhoea
Cholera
Profuse, watery diarrhoea
Severe dehydration resulting in weight loss
Not common amongst travellers
Shigella
Bloody diarrhoea
Vomiting and abdominal pain
Staphylococcus aureus
Severe vomiting
Short incubation period
Campylobacter
A flu-like prodrome is usually followed by crampy abdominal pains, fever and diarrhoea which may be bloody
Complications include Guillain-Barre syndrome
Bacillus cereus
Two types of illness are seen
vomiting within 6 hours, stereotypically due to rice
diarrhoeal illness occurring after 6 hours
Amoebiasis
Gradual onset bloody diarrhoea, abdominal pain and tenderness which may last for several weeks
Salmonella Bloody Diarrhoea Constipation predominant Systemic upset Rose spots
Gastroenteritis - Incubation Period
Incubation period 1-6 hrs: Staphylococcus aureus, Bacillus cereus* 12-48 hrs: Salmonella, Escherichia coli 48-72 hrs: Shigella, Campylobacter > 7 days: Giardiasis, Amoebiasis
*vomiting subtype, the diarrhoeal illness has an incubation period of 6-14 hours
Patient with complicated PMHs and Risk of Traveller’s Diarrhoea - Example Question
A 65-year-old man is referred to gastroenterology clinic for advice prior to planned overseas travel. The patient states that he is planning to visit relatives in Brazil in two months time and is very concerned about the possibility of contracting travellers’ diarrhoea in light of his previous and current medical history.
The patient had undergone a total colectomy with ileostomy formation twenty years previously, as curative treatment for severe ulcerative colitis. He had subsequently learnt to manage his ileostomy well and had declined reconstructive surgery. Ten years previously, the patient had contracted diarrhoea while travelling in the Caribbean, which he reported had ruined his holiday and complicated his ileostomy management for weeks.
Of more pressing concern was a recent diagnosis of small-cell lung cancer, for which the patient was undergoing chemotherapy with cisplatin and etoposide. The patient’s chemotherapy regime was due to be completed four weeks before his proposed travel.
Aside from the issues outlined above, the patient’s only other past medical history included hypertension for which he took ramipril. The patient denied any drug allergies or intolerances.
Standard precautions regarding the avoidance of travellers’ diarrhoea were discussed with the patient, who fully acknowledged the risks of travelling so soon after completing chemotherapy.
What is appropriate management to help prevent travellers’ diarrhoea in this patient?
Vibrio cholerae vaccination Standard advice regarding hygiene precautions only Co-amoxiclav prophylaxis while overseas > Ciprofloxacin prophylaxis while overseas Low-dose loperamide
Travellers’ diarrhoea is most commonly caused by Escherichia coli species and Campylobacter jejuni. Less common causative pathogens include Salmonella and Shigella species, parasitic infections such as Giardia lamblia, and viruses such as norovirus.
In the majority of individuals, diarrhoea is annoying and unpleasant but does not lead to long-term sequelae. However, some groups of individuals may be unable to tolerate the consequences of dehydration from diarrhoea, or be vulnerable to invasive complications such as bacteraemia.
The patient presented in this question will be immunosuppressed secondary to his chemotherapy and has an under-lying bowel condition due to his ileostomy. Therefore, he should be considered for antibiotic prophylaxis to prevent travellers’ diarrhoea, following discussion of the risks of antibiotic associated diarrhoea and other side effects.When antibiotic prophylaxis is used, typical choices of agent are ciprofloxacin, norfloxacin or rifaximin.
Anti-motility agents such as loperamide can be helpful in limiting diarrhoea in individuals unable to tolerate dehydration, but does not have a role in preventing infection. Symptoms of invasive colitis, such as severe abdominal pain or bloody diarrhoea, are contra-indications to the use of anti-motility agents due to the risk of intestinal perforation. Vaccination against cholera is effective, however is not a common cause of travellers’ diarrhoea.
SALMONELLA
Salmonella
The Salmonella group contains many members, most of which cause diarrhoeal diseases. They are aerobic, Gram negative rods which are not normally present as commensals in the gut.
Typhoid and paratyphoid are caused by Salmonella typhi and Salmonella paratyphi (types A, B & C) respectively. They are often termed enteric fevers, producing systemic symptoms such as headache, fever, arthralgia
Features
•initially systemic upset as above
•relative bradycardia
•abdominal pain, distension
•constipation: although Salmonella is a recognised cause of diarrhoea, constipation is more common in typhoid
•rose spots: present on the trunk in 40% of patients, and are more common in paratyphoid
Possible complications include
•osteomyelitis (especially in sickle cell disease where Salmonella is one of the most common pathogens)
•GI bleed/perforation
•meningitis
•cholecystitis
•chronic carriage (1%, more likely if adult females)
Salmonella - Example Question
An elderly gentleman presents with a three day history of bloody diarrhoea and feverishness. He has no significant travel history. His past medical history is listed as hypertension, osteoarthritis and gout. On examination his temperature is 38.0ºC, heart rate 95/min, blood pressure 120/80 mmHg and his abdomen is soft and non-tender. A stool sample has grown Salmonella. What is the best treatment?
Metronidazole Doxycycline Clarithromycin > Ciprofloxacin Amoxicillin
The BNF recommends treating invasive diarrhoea (causing bloody diarrhoea and fever) with ciprofloxacin. Most viral or bacterial gastroenteritis do not require treatment. The BNF recommends antibiotics for bacterial gastroenteritis in severe infections or in immunocompromised patients. Clarithromycin is used for traveller’s diarrhoea and non-invasive diarrhoeal illnesses when treatment is necessary.
Most serious Complication of Salmonella Typhoid - Example Question
A returning traveller presents to the emergency department with a 10 day history of fever, cough and abdominal pain. He has spent the last 2 weeks in Jakarta, Indonesia. His vital signs are: temperature: 40.1ºC, heart rate 85 beats/minute, blood pressure 120/80 mmHg
On examination his spleen is enlarged and there is a rose spot rash over the chest. Blood culture grows salmonella typhi and the on-call doctor diagnoses enteric fever (typhoid).
If left untreated, what is the most important and serious complication that can occur within the following 2 weeks?
Chronic carriage within gallbladder > Bowel perforation and haemorrhage Splenic infarction and rupture Acute liver failure Bacterial meningitis
The most serious and frequent complications of Typhoid are bowel perforation and haemorrhage. This is caused by bacterial destruction of the Peyer’s patches in the small intestine and classically occurs late in the second week of illness or early in the third week. Other complications include myocarditis and endocarditis.
Chronic bacterial carriage in the gall bladder does occur, but this is not the most serious complication. It renders the patient chronically infective and capable of transmitting the disease. Acute liver failure does not occur, but mild jaundice may result from cholecystitis or hepatitis. Bacterial meningitis is a very rare complication not often reported.
Listeria
Listeria
Listeria monocytogenes is a Gram positive bacillus which has the unusual ability to multiply at low temperatures. It is typically spread via contaminated food, typically unpasteurised dairy products. Infection is particularly dangerous to the unborn child where it can lead to miscarriage.
Features - can present in a variety of ways
diarrhoea, flu-like illness
pneumonia , meningoencephalitis
ataxia and seizures
Suspected Listeria infection should be investigated by taking blood cultures. CSF may reveal a pleocytosis, with ‘tumbling motility’ on wet mounts
Management
Listeria is sensitive to amoxicillin/ampicillin (cephalosporins usually inadequate)
Listeria meningitis should be treated with IV amoxicillin/ampicillin and gentamicin
In pregnant women
pregnant women are almost 20 times more likely to develop listeriosis compared with the rest of the population due to changes in the immune system
fetal/neonatal infection can occur both transplacentally and vertically during child birth
complications include miscarriage, premature labour, stillbirth and chorioamnionitis
diagnosis can only be made from blood cultures
treatment is with amoxicillin
Bloody Diarrhoea
Shigella 48-72h incubation -Bloody diarrhoea, vomiting, abdo pain
Amoebiasis >7d incubation - Gradual onset bloody diarrhoea and abdo pain, may last several weeks
Campylobacter 48-72h incubation -Flu-like Prodrome, followed by crampy abdo pain, fever and diarrhoea which may be bloody
E. coli O157:H7 is a particular strain associated with severe, haemorrhagic, watery diarrhoea. Can be complicated by haemolytic uraemic syndrome. Spread by contaminated ground beef.
Salmonella: 12-48hr incubation period, produces systemic symptoms such as headache, fever, arthralgia. Diarrhoea may be bloody, Constipation usually predominant (TYPHOID)
Traveller’s Diarrhoea
At least 3 loose to watery stools in 24h assoc with or without one or more of
- Abdo cramps
- Fever
- Nausea
- Vomiting
- Blood in stool
Patient has to have travelled!
Most common cause = E-coli
Campylobacter
Campylobacter = commonest bacterial cause of infectious intestinal disease in the UK
Majority of cases are caused by the GRAM NEGATIVE BACILLUS CAMPYLOBACTER JEJUNI
Spread by the faecal-oral route and has incubation period of 1-6d
Features:
- prodrome: headache, malaise
- diarrhoea: often bloody
- abdominal pain
Mx:
- usually self limiting
- BNF advises treatment only if severe OR pt is immunocompromised
- Severe if high fever, bloody diarrhoea, over 8 stools a day
- 1st line Abx = Clarithromycin
Cx:
- Guillain Barre syndrome may follow Campylobacter Jejuni
- Reiter’s syndrome
- Septicaemia
- Endocarditis
- Arthritis
Giardiasis
Giardiasis
Giardiasis is caused by the flagellate protozoan Giardia lamblia. It is spread by the faeco-oral route
Features
often asymptomatic
lethargy, bloating, abdominal pain
non-bloody diarrhoea
chronic diarrhoea, malabsorption and lactose intolerance can occur
stool microscopy for trophozoite and cysts are classically negative, therefore duodenal fluid aspirates or ‘string tests’ (fluid absorbed onto swallowed string) are sometimes needed
Treatment is with metronidazole
Traveller’s Diarrhoea
Travellers’ diarrhoea is most commonly caused by Escherichia coli species and Campylobacter jejuni. Less common causative pathogens include Salmonella and Shigella species, parasitic infections such as Giardia lamblia, and viruses such as norovirus.
In the majority of individuals, diarrhoea is annoying and unpleasant but does not lead to long-term sequelae. However, some groups of individuals may be unable to tolerate the consequences of dehydration from diarrhoea, or be vulnerable to invasive complications such as bacteraemia and should be considered for antibiotic prophylaxis to prevent travellers’ diarrhoea, following discussion of the risks of antibiotic associated diarrhoea and other side effects. When antibiotic prophylaxis is used, typical choices of agent are ciprofloxacin, norfloxacin or rifaximin.
Most serious and frequent Cx of Typhoid
The most serious and frequent complications of Typhoid are bowel perforation and haemorrhage. This is caused by bacterial destruction of the Peyer’s patches in the small intestine and classically occurs late in the second week of illness or early in the third week. Other complications include myocarditis and endocarditis.
Salmonella Example Question
A 31-year-old gentleman presents with fever, headache, abdominal pain and a rash on the chest 3 weeks after visiting South America.
On examination the temperature is 38.2ºC. There is a rash on the chest consisting of rose-coloured blanching papules. The respiratory rate is 20 breaths/min and the heart rate is 58 beats per minute. The chest is clear to auscultation. The abdomen is diffusely tender and there is mild splenomegaly.
Initial blood results are as follows:
Hb 128 g/l Platelets 184 * 109/l WBC 3.9 * 109/l Na+ 131 mmol/l K+ 3.3 mmol/l Urea 7.2 mmol/l Creatinine 141 µmol/l Bilirubin 46 µmol/l ALP 147 u/l ALT 96 u/l Albumin 38 g/l CRP 52 mg/l
What is the most appropriate initial antimicrobial therapy?
Ampicillin Chloramphenicol Trimethoprim-sulfamethoxazole > Cefotaxime Streptomycin
This is a fairly classical presentation of typhoid fever, also known as enteric fever. This is a potentially fatal multisystemic illness caused primarily by Salmonella enterica.
The rash here refers to rose spots which occur in up to 30% of people infected with this organism. Characteristically, rose spots are seen in untreated typhoid fever. They usually occur between the second and fourth week of the illness. They characteristically present as groups of 5-15 pink blanching papules distributed between the level of the nipples and umbilicus.
The treatment of choice is cefotaxime or ceftriaxone.
Ciprofloxacin may be used as an alternative in sensitive organisms.
