1. An Urgent and Explosive Presentation
Diane Williamson
Emergency Medicine Consultant Addenbrooke’s Hospital
October 6th ACCS Regional Training Day

2. Definitions
Diarrhoea - The frequent passage of unformed liquid stools (3 or more/day)
Dysentery - Above plus blood or mucous in the stools
Acute Gastroenteritis - Diarrhoeal disease of rapid onset characterised by nausea, vomiting, fever, abdominal pain

3. Causes Infections – Viral, bacterial, parasitic Toxins Drugs IBD
Motility Disorders
Malabsorption
Food allergy
Non-enteric – e.g. sepsis

4. Viral Gastroenteritis
Common
Benign and self-limiting for most
Life-threatening for others

5. At Risk
Elderly
Infants
Immunosuppressed
Concomitant illness

6. Epidemiology Very high incidence
Leading cause of infant mortality worldwide
2 million hospital admissions
> deaths
By age 3 effectively all children will become infected by the common agents

7. Viral Gastroenteritis
Children – rotavirus most common (seasonal Nov to April) Adults and children rotavirus enterovirus adenovirus astrovirus (sporadic) calicivirus e.g. norovirus (outbreaks) Faecal-oral transmission of contaminated food and water Norovirus can be airborne

8. Pathophysiology
Virus enters villus enterocyte causing: Osmotic diarrhoea Structural damage to bowel mucosal villi causes maldigestion of carbohydrates and malabsorption of nutrients and water Secretory diarrhoea Toxins (e.g. rotavirus NSP4) bind enterocyte causing causes Chloride ion secretion

9. Symptoms Fever, malaise, fatigue, headache, lethargy
Abdominal pain and cramps
Nausea and vomiting
Loss of appetite
Watery and frequent non-bloody stool

10. Severity Assessment History
Deaths are caused by dehydration and acidosis
Frequency, quantity and duration of vomiting and diarrhoea
Oral intake
Urine output
Weight loss
Travel

11. Severity Assessment Examination
Vital signs
Capillary refill
Mucous membranes
Reduced urine output
Mental status
Severe abdominal tenderness or guarding suggest a surgical cause

12. Indications of bacterial infection
High fever
Bloody diarrhoea
Severe abdominal pain
(>6 stools/24 h)

13. Initial Investigations
Depend on severity – children and adults with minor symptoms need advice and reassurance, not investigation
In dehydrated or otherwise unwell patients
VBG – pH, electrolytes and glucose
Urea
Creatinine
Amylase
FBC
Consider imaging

14. Specific Investigations
Rotavirus – stool antigen and antibody tests are available
Caliciviruses (norovirus) – stool PCR
C. difficile – stool C-diff and GDH toxin
Faecal viral concentration correlates with duration and severity of illness and influences management and infection control measures
Early stool sample is important – national stats are collected and Trust fined for in-hospital transmission beyond established thresholds

15. Management Oral hydration IV hydration
Correct electrolyte disturbances
Antiemetics – generally not recommended but consider if symptoms prolonged
Consider probiotics (some evidence for moderate symptom relief with Lactobacillus casei)

16. Prevention Hand hygiene Proper food handling Clean water supply
Rotavirus vaccine
Rotarix given at 8 and 12 weeks (liquid swallowed)
Has prevented >70% of rotavirus cases
6 years data, no safety concerns

17. Bacterial Gastroenteritis
Campylobacter
Clostridium difficile
E. coli
Salmonella
Shigella
V. cholera

18. Parasitic Causes
Entamoeba hystolitica
Giardia lamblia
Cryptosporidium

19. Reportable Diseases Food poisoning Infectious bloody diarrhoea
Reportable infectious agents (lab reports):
Campylobacter
Giardia lamblia
Salmonella
Shigella
Verocytotoxigenic E coli
Vibrio cholera

20. Severe or Deteriorating Presentations

21. Treat Shock AB C – access IV, IO
1L (Paed 20ml/kg) normal saline – reassess
100ml (Paed 2ml/kg) 10% dextrose and infusion
Antibiotics – treat sepsis
Fluid replacement (remember to replace ongoing losses)

22. Electrolyte Disturbances
Hyponatraemia (associated with administration of dilute oral rehydration fluids)
Hypernatraemia
Acidosis – beware shifting potassium – as in DKA, K+ moves to extracellular space causing intracellular K+ depletion, review and replace
ECG and monitor patient if K+ a concern

23. Hypokalaemia
K mmol/L: Start oral K+ replacement, or 20mmol KCl in 1000ml saline over 2-3 hours
K+ 2.5 – 3.0 mmol/L: Start 40 mmol/L over 4-6 hours
K+ <2.5 or ECG changes – prolonged QTc, Flat T- waves, high risk of arrhythmia
K+ <1.5mmol/L – paralysis, muscle weakness, apnoea
ECG, cardiac monitor patients, consider resus

24. Hyponatraemia Na >125 mmol/L or mild symptoms
Rehydrate with 0.9% NaCl over 24 to 48 hours
Recheck electrolytes 4 hourly

25. Hyponatraemia Na <125mmol/L or severe symptoms Risks:
Intracellular oedema, raised ICP, herniation
With rapid replacement and extracellular Na rise:
Osmotic Demyelination Syndrome – duration is important

26. Severe Hyponatraemia
Single dose hypertonic saline over 1 hour and review (e.g. 4ml/kg 3% saline up to 150ml) <48 hours duration, correct 1-2mEq/L/h for 4 hours to increase 4 to 6mEq/L, review >48 hours duration, as above but do not exceed 0.5-1mEq/L/h and do not exceed 6 to 8mEq/L in 24 hours Seizure management – treat hyponatraemia and may have to repeat if seizures persist Rapid response/ICM input for ongoing managment

27. Questions?