Nausea and Vomitting Flashcards
What are the four main input systems that can activate the vomiting centre?
Vestibular system
CNS
Chemoreceptor trigger zone
Cranial nerves IX and X
How can the inputs to the vomiting centre be used to categorise the causes of nausea and vomiting?
Vestibular system => Vertigo
CTZ = Chemicals in the blood
CNS = Brain problems
Abdo and heart problems = Cranial nerves IX, X
What characteristics of the contents of vomit may help with your differetials?
Undigested - Oesophageal disorders
Partially digested - Gastric outlet obstruction, gastroparesis
Bile - Small bowel obstruction (distal to the ampulla of Vater)
Faeculent - Distal intestinal or colonic obstruction
Faecal - Gastrocolonic fistula
Blood/coffee-ground - haematemesis
Large volume - Less likely to be functional
What might early morning vomiting suggest?
Pregnancy and raised intracranial pressure
Why is it important to ascertain the associated of a patients vomiting with eating?
Vomiting within an hour of eating suggests an obstruction high in the GI tract - peptic ulcer disease can cause scarring
Vomiting after a longer post-prandial delay is consistent with an obstruction lower in the GI tract
Early satiety, post-prandial bloating and abdominal discomfort together suggests gastroparesis or outlet obstruction
What other symptoms are important to ask about in patients with nausea and vomiting?
Fever
Headache/visual disturbances
Vertigo
Why should you ask patients with vomiting and nausea about their bowel movements?
Delayed/absolute constipation suggests bowel obstruction
Diarrhoea and vomiting suggest infectious gastroenteritis
What are important questions to ask someone with nausea and vomiting to work out if they’ve had exposure to infectious?
Close contact with others suffering from VD
Living in close quarters
Recent foreign travel
Unusual meals recently
Antibiotic use
Acute (
Gastroenteritis
Food poisoning
Appendicitis
Mesenteric adenitis
Cholecystitis
Pancreatitis
Acute (
Small bowel obstruction
DKA
Drug side effects/overdose
Toxins
LBO
Mesenteric ischaemia
MI
Pain
Acute (
Meningitis
Raised ICP
Migraine
Acute (
Labyrinthitis
Meniere’s
BPPV
Motion sickness
Acoustic neuroma
Acute (
Gastric outlet obstruction
Chronic (>1 month) nausea and vomiting with weight loss?
Upper GI obstruction: mechanical or functional
Coeliac disease
Chronic (>1 month) nausea and vomiting with no weight loss?
Oesophagitis
Pharyngeal pouch
How might surgeons approach SBO?
A trial of conservative management
- Fluid and NG aspiration
- Review regularly to ensure he does not deteriorate
Surgery, if:
- There are signs of strangulation or peritonism
- After ~48 hours the obstruction has not resolved
- There is no history of abdominal surgery, making adhesion less likely and more sinister causes more likely
What are the 8 types of incision that may be found on the abdomen?
1) Kocher’s (or subcostal) incision: cholecystectomy
2) Rooftop incision: Whipple’s surgery, gastric surgery
3) Transverse abdominal incision for nephrectomy
4) Midline incision: laparotomy, e.g. exploratory, bowel obstruction, gynaecological
5) Paramedian incision: as for midline incision
6) Gridiron or McBurney’s incision: appendicectomy
7) Lanz incision: appendicectomy
8) Pfannesteil incision: Caesarean section, gynaecological operation
What is the MOA of cyclizine?
When may its use be indicated?
Antihistamine and antimuscarinic effects that block ACh receptors in vestibular and vomiting centres
Post-operative nausea, bowel obstruction nausea (as it is akinetic), motion sickness and other labyrinthine aetiologies, and also in conditions causing raised ICP
What is the MOA of metoclopramide?
When may its use be indicated?
Agonist properties at 5-HT4 receptors and antagonist properties at D2 receptor such as those found in chemoreceptor trigger zone and myenteric plexus of the GI tract
Prokinetic and therefore indicated in causes of delayed stomach emptying eg as a side-effect of opiates, gastroparesis
What is the MOA of ondansetron?
When may it be indicated?
5-HT3 serotonin antagonist that acts on receptors in the gut and the chemoreceptor trigger zone
It is useful for chemotherapy induced and post operative vomiting
What is the MOA of haloperidol?
When may it be indicated?
An antagonist of D2 receptors such as those found in the chemoreceptor trigger zone and myenteric plexus or the GI tract
It is useful in treating drug-induced and metabolic causes of nausea and vomiting, and also vomiting due to raised ICP
