GI Medicine 4 - Approach to Acute GI Disease Flashcards
What are the four stages of vomiting?
Prodromal - signs of nausea
Retching - duodenal peristalsis
Expulsion - pyloric contraction, fundic and lower oesophageal sphincter relaxation, abdominal contraction, diaphragmatic descent. Protection of airway.
Relaxtion - return of breathing.
List three consequences of vomiting
Dehydration
Acid-base disturbance
Aspiration pneumonia
What happens during typical vomiting with a patent pylorus?
Primarily lose HCO3- and K+ leading to metabolic acidosis and hypoK+
What happens during vomiting where there is a pyloric obstruction?
Primarily lose HCL- and K+, leading to metabolic alkalosis and hypoK+
Which receptor does maropitant antagonise?
NK1 Antagonism
Which receptors does metoclopramide effect (at lower and higher doses)?
Lower dose - D2 receptor antagonist
Higher doses - 5-HT3 receptor antagonist
What is metaclopramide used for?
Anti-emetic, pro-kinetic, stimulates gastric and duodenal motility.
What are the four types of diarrhoea?
Osmotic
Secretory
Permeability
Motility
How can buscopan help diarrhoea?
Antimuscarinic - reduces smooth muscle contractions - used for colicy pain/IBS type.
How may opiods help diarrhoea symptoms?
Delay GI transit - leading to constipation.
How would you first work out whether acute vomiting/diarrhoea is primary GI or extra-GI disease?
Unless the history/exam directs us towards primary GI disease, we should exclude extra-GI causes BEFORE in depth evaluation into primary causes.
What are the three main types of cause of acute vomiting/diarrhoea?
Inflammatory, trauma, toxic
What are the three main types of cause of chronic vomiting and diarrhoea?
Inflammatory
Neoplastic
Metabolic
If a patient had diarrhoea that was large volume, normal frequncy and there was no urgency, where would expect the origin of this diarrhoea to be?
Small intestinal
Describe large intestinal diarrhoea.
Small volume
Increased frequency
With urgency
With straining - tenesmus
With difficulty - dyschezia
