Gastroenterology & Hepatology
Question 23 of 73
A 27 year old woman presents to the Emergency Department complaining of a 3 day history of progressive muscle weakness and paraesthesia which started in both feet and appears to be spreading up her legs. She is now finding it difficult to walk. On further questioning, you determine that about 2 weeks ago she had a few days illness with bloody diarrhoea following a take away from a chicken shop. Which of the following is the most likely causative pathogen?
Answer:
These clinical features are suggestive of Guillain-Barre syndrome; an acute, ascending progressive peripheral neuropathy, characterised by weakness, paraesthesia and hyporeflexia. About 75% of cases have a history of preceding infection, usually of the respiratory and gastrointestinal tract. Campylobacter jejuni is the most commonly implicated gastrointestinal pathogen, which fits with the history of bloody diarrhoea following contaminated poultry.Gastroenteritis
Gastroenterology & Hepatology
Last Updated: 4th October 2022
Gastroenteritis is a transient disorder due to enteric infection with viruses, bacteria, or parasites. It is characterised by the sudden onset of diarrhoea, with or without vomiting.
Definitions
Episodes of diarrhoea can be classified into several categories:
- Acute diarrhoea is defined as three or more episodes of partially-formed or watery stool in a day, lasting for less than 14 days
- Persistent diarrhoea is an acutely starting episode of diarrhoea that lasts for more than 14 days
- Dysentery is an acute infectious gastroenteritis characterised by loose stools with blood and mucus often accompanied by pyrexia and abdominal cramps. Organisms that can cause bloody diarrhoea include Campylobacter, Entamoeba histolytica, Escherichia coli, Salmonella serotypes, and Shigella.
- Traveller's diarrhoea is diarrhoeal disease starting during, or shortly after, foreign travel. The organisms that most commonly cause traveller's diarrhoea are Escherichia coli, Salmonella (non-typhoidal), Viruses, Cryptosporidium, and Giardia.
- Antibiotic-associated diarrhoea usually refers to diarrhoea that occurs in a person who is taking (or recently took) antibiotics, and it is increasingly common. A frequent causative organism is Clostridium difficile.
Causes
- Viruses
- Rotavirus – most common cause of infantile gastroenteritis
- Norovirus – most common cause of viral infectious gastroenteritis in adults
- Adenovirus - commonly cause infections of the respiratory system but can also cause gastroenteritis, particularly in children
- Hepatitis A
- Raw or undercooked shellfish from contaminated waters, raw produce, contaminated drinking water, uncooked foods, and cooked foods that are not reheated after contact with an infected food handler
- Bacteria
- Campylobacter spp
- Unpasteurized (raw) milk, chicken, shellfish, turkey, contaminated water
- Escherichia coli
- Contaminated food, especially undercooked ground beef, unpasteurized (raw) milk and juice, soft cheeses made from raw milk, and raw fruits and vegetables (such as lettuce, other leafy greens, and sprouts), contaminated water
- Salmonella spp.
- A variety of foods have been linked to Salmonella, including vegetables, chicken, pork, fruits, nuts, eggs, beef and sprouts
- Shigella spp.
- Contact with an infected person or consumption of contaminated food or water. Shigella foodborne outbreaks are most often associated with contamination by a sick food handler
- Yersinia enterocolitica (rare)
- Listeria
- Campylobacter spp
- Parasites
- Cryptosporidium
- Entamoeba histolytica
- Giardia
- Bacterial toxins
- Staphylococcus aureus
- Foods that are not cooked after handling, such as sliced meats, puddings, pastries, and sandwiches, are especially risky if contaminated with Staph
- Bacillus cereus
- A variety of foods, particularly rice and leftovers, as well as sauces, soups, and other prepared foods that have sat out too long at room temperature
- Clostridium perfringens
- Beef, poultry, gravies, food left for long periods in steam tables or at room temperature, and time and/or temperature abused foods
- Staphylococcus aureus
Clinical features
The diagnosis of gastroenteritis is usually made on the basis of clinical symptoms and signs. Diagnostic investigations are rarely needed, but examination and culture of a stool sample may be necessary to determine the cause.
- Diarrhoea (loose or watery stools, usually at least three times in 24 hours) is the main symptom of gastroenteritis.
- Other symptoms may include:
- Nausea.
- Sudden onset of vomiting.
- Blood or mucus in stool.
- Systemic features (for example fever or malaise).
Complications
- Dehydration and electrolyte disturbance
- Dehydration and electrolyte imbalance from severe diarrhoeal disease can progress to acidosis and circulatory failure, with hypoperfusion of vital organs, renal failure, and eventual death
- Bacteraemia and sepsis
- Haemolytic uraemic syndrome (HUS) – characterised by AKI, haemolytic anaemia and thrombocytopenia (Enterohaemorrhagic E coli and, less commonly, Shigella)
- Reactive complications (Salmonella, Campylobacter, Yersinia enterocolitica, and Shigella infections)
- Arthritis
- Carditis
- Urticaria
- Erythema nodosum
- Conjunctivitis
- Reactive arthritis (Urethritis, arthritis and uveitis)
- Systemic invasion by Salmonella with endovascular infections and localised infections in bones, joints, meninges, or the gallbladder
- Colonic perforation (Clostridium difficile, Salmonella, and Shigella infections)
- Toxic megacolon (Clostridium difficile, Shigella, cytomegalovirus (CMV), or Yersinia infection)
- Intestinal obstruction (Shigella infections, helminth infections, and opportunistic infections in patients with AIDS)
- Guillain-Barre syndrome (Campylobacter enteritis)
- Malnutrition
- Intractable diarrhoea
- Irritable bowel syndrome
- Acquired/secondary lactose intolerance
- Reduced absorption of drugs (for example antiepileptic drugs, antidiabetic drugs, contraception, malaria prophylaxis, and anticoagulation)
Assessment
- Assess for:
- Features of dehydration and shock.
- See table below.
- Features that might suggest an alternative diagnosis.
- Check temperature, blood pressure, and heart and respiratory rates.
- Assess for abdominal tenderness.
- Personal risk factors, such as age, pregnancy, comorbidities, and the use of certain medications.
- Certain medications (for example diuretics and angiotensin-converting enzyme inhibitors) can exacerbate dehydration and renal failure.
- Be aware that the efficacy of certain medications (for example warfarin, anticonvulsants, and the oral contraceptive pill) may be affected by severe diarrhoea.
- Severity of illness.
- Frequency and consistency of stools.
- The presence of blood in stools.
- Frequency of vomiting.
- Ability to eat and drink.
- Possible cause of gastroenteritis.
- Recent contact with someone with acute diarrhoea and/or vomiting.
- Exposure to a known source of enteric infection (possibly contaminated water or food).
- Recent travel abroad.
- Recent antibiotics or hospital admission within the last 8 weeks — suspect infection with Clostridium difficile.
- Use of drugs such as proton-pump inhibitors and metformin.
- Features of dehydration and shock.
| Mild dehydration | Moderate dehydration | Severe dehydration |
|---|---|---|
|
|
|
| Usually no signs |
|
|
Management
- Consider the need for hospital admission.
- Arrange emergency admission to hospital if the person:
- Is vomiting and unable to retain oral fluids.
- Has features of shock or severe dehydration.
- Other factors influencing admission (clinical judgement should be used) include:
- Recent foreign travel.
- Older age (people 60 years of age or older are more at risk of complications).
- Home circumstances and level of support.
- Fever.
- Bloody diarrhoea.
- Abdominal pain and tenderness.
- Faecal incontinence.
- Diarrhoea lasting more than 10 days.
- Increased risk of poor outcome, for example comorbidities.
- Arrange emergency admission to hospital if the person:
- Give rehydration advice in patients not requiring fluid resuscitation
- In most otherwise healthy adults, encouraging fluid intake (especially if supplemented with fruit juice and soups) will be sufficient.
- Consider supplementing fluid intake with oral rehydration salt solution in adults at increased risk of a poor outcome. This includes people who are 60 years of age or older, frail, or with comorbidities with which dehydration, hypovolaemia, or haemoconcentration would be a problem (for example cardiovascular disease or thrombotic tendencies).
- Perform a stool sample analysis, if indicated, and consider the need for antibiotics.
- Stool cultures are usually not necessary for most adults who present with acute, watery diarrhoea.
- Send a stool specimen if:
- The person is systemically unwell.
- There is blood or pus in the stool.
- The person is immunocompromised.
- There is a history of recent hospitalisation and/or antibiotic treatment.
- Diarrhoea occurs after foreign travel to anywhere other than Western Europe, North America, Australia, or New Zealand.
- Diarrhoea is persistent and giardiasis is suspected.
- There is uncertainty about the diagnosis of gastroenteritis.
- Consider the need for antidiarrhoeal or antiemetic drugs.
- Antidiarrhoeal (or antimotility) drugs are not usually necessary for the management of gastroenteritis. However, they may be useful for symptomatic control in adults with mild-to-moderate diarrhoea, for example if quicker resolution of diarrhoea would enable the person to continue essential activities. If required, loperamide is the antimotility drug of choice.
- Do not prescribe antimotility drugs if the person has:
- Blood and/or mucus in the stools, or high fever (indicating dysentery).
- Confirmed, probable, or suspected vero cytotoxin-producing Escherichia coli 0157 (VTEC) infection.
- Shigellosis.
- Antibiotics are not recommended for adults with acute diarrhoea of unknown pathology. Antibiotics may be appropriate when gastroenteritis is due to a known microbiological cause.
- Give advice on preventing the spread of infection.
- They should not go to work or other institutional settings until at least 48 hours after diarrhoea and vomiting has stopped. Public health authorities will advise if a pathogen is isolated from the person's stool sample (for example Salmonella, Escherichia coli O157): longer periods of exclusion are required in some circumstances.
- Notify the Local Authority Proper Officer (in England and Wales, the local Consultant in Communicable Disease Control) if a case of any of the following is suspected:
- Cholera.
- Bloody diarrhoea presumed to be due to gastroenteritis.
- Food poisoning (organisms that can be implicated in food poisoning include Campylobacter, Escherichia coli O157:H7, Salmonella, Shigella, Giardia, Yersinia enterolytica, Entamoeba histolytica, and norovirus).
- Haemolytic uraemic syndrome (HUS).
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
