Key facts:
Authors: Natalie Acors and Jayne Eaden
Top Tip: gastroenteritis can be a mild self-limiting disease. But some cases (including C Diff) can be life-threatening
Key Differential
Diagnoses
- Inflammatory colitis
- Ischaemic colitis (AF, elderly, ill, pain)
- Colonic carcinoma/diverticular disease
- 'Complicated gastroenteritis'
= Haemolytic-Uraemic Syndrome (eg O157 E Coli), or causing DIC
Key Investigations
- FBC, CRP
- U+E, LFT, Bone, Glucose
- BC, Stool culture (?C diff)
- AXR
Key Treatment
- IV fluids
- ± PO METRONIDAZOLE 800 mg stat, then 400 mg tds, for 14d ± PO VANCOMYCIN 125mg 6-hourly for 14d (C diff)
Key Management
Decisions
- Admit/not
- Antibiotics (not usually necessary; use if C diff)
- Steroids ± surgery (C diff)
Background
Introduction
- Onset usually rapid (vs inflammatory colitis). Not necessarily associated with fever. Usually self-limiting, requiring supportive care only
- Some pathogens extremely infectious, virulent, and can cause life-threatening disease
- Clostridium difficile ('C Diff'), often follows antibiotics, and can cause pseudomembranous colitis and present as bloody diarrhoea (like colitis). It has been associated with almost all AB, except aminoglycosides
- For C Diff, quinolones are probably the worse culprits. It can be complicated by toxic megacolon (high mortality) and perforation (very high)
- Prognosis is good in mild cases; but mortality of C diff = 5-10%, 50% severe cases; 5% need surgery (operative mortality 30%). If suspect C diff on admission, and unwell, ask for early senior surgical review
- Ischaemic colitis (elderly, AF) can be missed, with fatal consequences
Definition
- Inflammation due to infection of lining of GI tract
Risk factors
- Children
- Elderly
- Immunosuppressed
- Recent antibiotics
- Food workers
- Schools/institutions/hospitals (outbreaks)
Note: food poisoning is a notifiable disease in the UK
Organisms/causes
Bacterial
- Salmonella (epidemics, eg from poultry; typhi/paratyphi = 'typhoid/paratyphoid fever')
- Clostridium sp:
- Difficile (recent antibiotics)
- Botulinum (processed food; paralysis)
- Perfringens (meat) - Campylobacter (poultry; can precipitate Guillain Barre/Reiter's Syndromes)
- Staphylococcus aureus (meat)
- Bacillus cereus (rice)
- Vibrio parahaemolytica (raw seafood)/vibrio cholerae ('cholera')
- E Coli (eg O157, from meat/burgers; epidemics; can precipitate HUS/ARF etc)
- Shigella (any food)
- Cryptosporidium (HIV)
Viral
- Norovirus (hospital outbreaks; vomiting+; 'winter vomiting illness')
Protozoal
- Giardia, amoeba
Chemical toxins
- Mushrooms, garden flora
Symptoms
- Diarrhoea (can be bloody)/vomiting/anorexia
- Abdominal pain
Key questions
- "When was your last normal motion?"
- "Have you had any antibiotics recently?"
- "Have you had contact with anyone with gastroenteritis recently (fellow diners)?"
- Ask about recent corporate/scoial functions, swimming, canoeing, foreign travel etc
Signs
- None, or
- Fever
- Of severe sepsis/shock
- Peritonitis (guarding etc), if perforated
Note: rectal examination is mandatory
Investigation
Mild acute gastroenteritis does not necessarily need investigation; stool culture only, if relevant
Blood
- FBC; low Hb or low platelets, think ?DIC or ?Haemolytic-Uraemic Syndrome (eg O157 E Coli?), CRP
- U+E (hyper/hyponatraemia? hypokalaemia?), LFT, Bone, Glucose
± TFT - BC
- Stool culture (incl C diff)
- ABG, if unwell; metabolic acidosis (diarrhoea); alkalosis (vomiting)
Other
- ECG (AF? ie ischaemic colitis?)
- CXR (erect; perforation?)
- AXR (toxic megacolon?)
- Flexible sigmoidoscopy if symptoms not resolving
Key investigation
- Stool culture (+ C diff)
Specialist investigation
- CT abdomen (alternative diagnoses eg diverticular disease or carcinoma)
Differential diagnoses
- Inflammatory colitis
- Ischaemic colitis (elderly, AF, arteriopath, very ill); operate immediately, if suspect diagnosis
- Colonic carcinoma/Diverticular disease
- 'Complicated gastroenteritis' eg Haemolytic-Uraemic Syndrome (O157 E Coli) or causing DIC
- Constipation, with overflow (frail elderly)
- Rarely: Carcinoid syndrome
Treatment
Mild acute gastroenteritis does not require admission, or any treatment; it is a self-limiting disease
Treatment
(first line)
Drugs
- Nil (supportive)
Note: antibiotics only if unwell, immunosuppressed, frail elderly or certain organisms; resistance is common - ± PO METRONIDAZOLE 800 mg stat, then 400 mg tds, for 14d (C diff)
- ± PO CIPROFLOXACIN 500 mg bd (salmonella)
- If possible, avoid antidiarrhoeals; esp in C diff (danger of toxic megacolon); if necessary PO loperamide 4mg od stat, then 2mg after each loose stool
- Give laxatives in overflow diarrhoea (common in elderly)
Procedures
- IV (+fluids, if dry)
Note: if you are not giving iv fluids, why are you admitting them?; ie oral fluids at home may be appropriate -
Manage in sideroom
Key management decisions
- Antibiotics/not
-
(If C diff) steroids ± surgery/not
Stop
-
Antibiotic, if cause
-
Laxatives (a lot of elderly take these)
C Diff Treatment
(second line)
Drugs
- Moderate (3-5 motions/day; and WBC 10-15,000)
- Oral Metronidazole 400mg 8 hourly for 14 days. If no response after 48 hours, change to oral Vancomycin 125mg 6-hourly for 14 days
- Severe, Level A (≥ 5 motions/day; and one of the following: dehydration, WBC >15,000, Temp > 38.5)
- Oral Vancomycin 125mg 6-hourly for 14 days
- Severe, Level B (= A + hypotension, partial ileus, CT scan evidence of severe colitis)
- Oral Vancomycin 500mg 6 hourly for 14 days plus IV Metronidazole 500mg 8 hourly
- Also refer to Gastroenterologist and/or Surgeon today
- Severe, Level C (= A + complete ileus or toxic megacolon)
- As for B. But Vancomycin to be given via a nasogastric tube or rectal installatio
- Consider PO PREDNISOLONE 20-40 mg od/IV METHYLPREDNISOLONE 500 mg o
- Do ABG (lactate?
- Refer to Gastroenterologist and/or Surgeon urgentl
- Consider colectomy – best performed before serum lactate rises >5
- Relapses
- Use Vancomycin 125mg qds po, followed if necessary by pulsed doses of oral Vancomycin: following usual dose of 125mg 6 hourly for 10-14 days, it is given at 125mg 12 hourly for a week, 125mg once daily for a week and then 125mg every 2-3 days for 2 to 8 weeks in an attempt to restore normal colonic flora. Use the same antibiotic used to treat the initial episode
Procedures
- If ischaemic colitis, operate immediately
-
If unwell, urinary catheter, CVP, arterial line
Prescribing issues
-
Antidiarrhoeals may increase chance of toxic megacolon in C diff
Admit?
-
Usually (if case was mild, probably would not have come to hospital)
Bed plan
- Medical admission ward
- ± Gastroenterology, if not better in 48h, or suspect inflammatory colitis
- ± Gen surgery (ischaemic colitis, carcinoma, diverticular disease)
-
± ITU
Referrals
Medical
- Gastroenterology
- Microbiology
- ± Gen surgery
- ± ITU
Other
- Infection control nurse (esp if think food poisoning, c diff, or viral outbreak in hospital)
The Rest
Maxim
- "If you don't put your finger in it, you will put your foot in it"
Complications
- Bowel perforation
Follow-up
- None
Though some diseases our notifiable: - Cholera
- Dysentery (Shigella, Campylobacter, E Coli 0157, Salmonella, Balantidiasis, Entamoeba histolytica)
- Food poisoning (Toxins/infection)
Prognosis
- Prognosis is good in mild cases; but mortality of C diff = 5-10%, 50% severe cases; 5% need surgery (operative mortality 30%)
Risk stratification
(who can be managed as outpatient)
- If not unwell, and maintain oral fluids at home; patient does not need admitting, or AB
- If moderately unwell, admit, but do not necessarily give AB
2° Prevention
+ Health promotion
- Don't prescribe unecessary courses AB (especially in elderly); if you do, make courses short, then review efficacy of AB early
- Food hygiene
- Treatment of other family members in Giardia
Don't forget
- Rectal examination is mandatory
- Ischaemic colitis (especially in elderly in AF)
- Send stool off for C diff
- Chase stool culture for C diff, 24h later
- Report food poisoning (notifiable disease)
- Haemolytic-Uraemic Syndrome
Red flags
- Toxic megacolon
- Severe sepsis/shock