Nausea and Vomiting

Question 1

Where is the vomiting centre located?

Answer 1

Medulla oblongata

Question 2

What are the two main types of receptors found within the vomiting centre?

Answer 2

Histamine receptors

Acetylcholine receptors

Question 3

What are the four main inputs to the vomiting centre?

Answer 3

Vestibular system
CNS
Chemoreceptor Trigger Zone (CTZ)
Cranial Nerves IX & X

Question 4

List some causes of nausea and vomiting for each of the four mechanisms below:
Vestibular system 
CNS
Chemoreceptor Trigger Zone (CTZ)
Cranial Nerves IX & X

Answer 4

- Vestibular System - vertigo
BPPV
Meniere’s disease 
Labyrinthitis 
Motion sickness
- CNS – brain problems 
Pain 
Anxiety
Raised ICP 
Meningitis/Encephalitis
- CTZ – chemicals in the blood  
Alcohol
Drugs 
Toxins
Electrolytes 
Hormones 
- CN IX & X – abdomen and heart problems 
GI obstruction
GI infection
Inflammation of the diaphragm
Infection/Inflammation of organs (e.g. hepatitis, pancreatitis)

Question 5

List some key features of the history of presenting complain that you should ask about.

Answer 5

Contents
Timing
Association with eating
Pain

Question 6

Describe different types of vomit and how they relate to their aetiology.

Answer 6

Undigested – the food hasn’t reached the stomach, probably an oesophageal problem
Partially digested – gastric outlet obstruction, gastroparesis
Bile – SBO distal to ampulla of Vater
Faeculent – distal intestinal or colonic obstruction
Blood/coffee-ground – haematemesis causes

Question 7

Which causes of nausea and vomiting are associated with early-morning vomiting?

Answer 7

Raised ICP

Pregnancy

Question 8

Explain how the association between the nausea/vomiting and eating helps narrow down the differential diagnosis.

Answer 8

Within 1 hr of eating = high GI obstruction (proximal to gastric outlet)
Longer, post-prandial delay = lower GI obstruction
Early satiety, post-prandial bloating and abdominal discomfort = gastroparesis or outlet obstruction

Question 9

List some important associated symptoms to ask about.

Answer 9

Fever
Headache, visual disturbance, focal neurological deficits
Vertigo

Question 10

Explain how asking about the patient’s bowel movements can help narrow the differential diagnosis.

Answer 10

Absolute constipation – bowel obstruction

Diarrhoea – suggests gastroenteritis

Question 11

List some risk factors for infectious diarrhoea.

Answer 11

Close contacts with similar symptoms
Living in close quarters
Unusual meals
Recent travel

Question 12

List some drugs/toxins that are associated with causing nausea and vomiting.

Answer 12

Medications (e.g. opiates, chemotherapy)
Industrial chemicals (e.g. arsenic, organophosphates)
Alcohol and drugs

Question 13

Why is it important to enquire about previous abdominal surgery?

Answer 13

Previous abdominal surgery increases the risk of forming adhesions, which can lead to bowel obstruction

Question 14

How can the causes of chronic nausea and vomiting be subdivided?

Answer 14

- Weight loss 
Upper GI obstruction (e.g. cancer) 
Functional dysphagia (e.g. achalasia)
Coeliac disease 
- No weight loss 
Oesophagitis 
Pharyngeal pouch

Question 15

List some causes of nausea and vomiting that are associated with:
Abdominal Pain
Headache
Vertigo
Onset shortly after eating food
None of the above

Answer 15

- Abdominal Pain
With fever: infection (e.g. gastroenteritis), inflammation (e.g. appendicitis, cholecystitis) 
Without fever: DKA, SBO, drug side-effects, toxins
- Headache
Meningitis 
Raised ICP 
Migraine 
- Vertigo
Labyrinthitis 
Meniere’s disease 
BPPV
Motion sickness
- Onset shortly after eating food
Gastric outlet obstruction
- None of the above
Drug side-effect 
Psychogenic 
Hyperthyroid
Renal failure + uraemia

Question 16

List some particularly worrying signs that are associated with nausea and vomiting.

Answer 16

Peritonitis (guarding, motionless, rigid abdomen, absent bowel sounds)
Signs of bowel obstruction
High fever (infection)
Signs of raised ICP 
Signs of MI 
Signs of meningitis 
Reduced consciousness 
Haematemesis

Question 17

List some signs of meningitis.

Answer 17

Photophobia
Neck stiffness
Headache
Kernig’s sign (when the hip is flexed, there is resistance against knee extension)
Brudzinski’s sign (flexion of the neck causes flexion of the hip)

Question 18

List some key features of inspection when performing an abdominal examination on a patient presenting with nausea and vomiting.

Answer 18

Hydration status (vomiting can lead to dehydration)
Abdominal distension 
Scars 
Hernias 
Jaundice

Question 19

List two important signs that may be picked up on auscultation of the abdomen.

Answer 19

Absent bowel sounds –> ileus

Tinkling bowel sounds –> obstruction

Question 20

List some blood tests that would be undertaken in a patient presenting with nausea and vomiting and explain why they would be performed.

Answer 20

FBC and CRP – high WCC and CRP in infection
U&Es – vomiting can cause derangement of electrolyte levels
LFTs – check for hepatobiliary cause of nausea/vomiting
VBG – check lactate and pH to get an idea of how sick the patient is
Amylase – rule out pancreatitis
Group and save

Question 21

List two forms of imaging that may be useful in patients with nausea and vomiting.

Answer 21

AXR

Erect CXR

Question 22

How are the small and large bowel differentiated on an AXR?

Answer 22

Small bowel – valvulae conniventes, 3 cm diameter

Large bowel – haustra, 6 cm diameter

Question 23

Which test is important to consider in young female patients presenting with nausea and vomiting?

Answer 23

Pregnancy test

Question 24

Outline the management of a patient with acute abdomen.

Answer 24

Nil-by-mouth
Drip and suck
Analgesia
Anti-emetics

Question 25

Which anti-emetic must you take caution with when using in a patient with acute abdomen?

Answer 25

Metoclopramide – it has a prokinetic effect on the GI tract

Question 26

Which form of imaging is useful in a patient with suspected bowel obstruction?

Answer 26

CT scan – allows localisation of the obstruction and identification of a cause

Question 27

Under what circumstances is surgery indicated in patients with bowel obstruction?

Answer 27

Signs of strangulation or peritonism
After 48 hrs if it hasn’t resolved
No history of previous abdominal surgery – this suggests that there may be a more sinister cause (not adhesions)

Question 28

Describe the typical presentation of gastroenteritis.

Answer 28

Nausea, vomiting, diarrhoea, fever and abdominal pain

Last a matter of days and resolves by itself

Question 29

What does ketonuria in a patient without diabetes suggest?

Answer 29

Starvation

Question 30

How can food poisoning be differentiated from gastroenteritis?

Answer 30

Food poisoning is caused by bacterial toxins

Symptoms don’t tend to persist longer than 24 hrs

Question 31

Describe the typical presentation of DKA.

Answer 31

Drowsy
Polyuria/Polydipsia
Abdominal pain
Nausea and vomiting 
If severe: Kussmaul breathing, reduced consciousness

Question 32

Outline the management of DKA.

Answer 32

IV fluids to rehydrate
IV insulin (sliding scale)
Monitor capillary ketones and serum K+ concentration
Switch to subcutaneous insulin once pH and capillary ketones have normalised

Question 33

When does morning sickness typically affect pregnant women?

Answer 33

First trimester

Question 34

Outline the management of morning sickness.

Answer 34

Advise dietary changes (e.g. avoiding spicy food)
Anti-emetics (e.g. promethazine)
Electrolyte replacement
Thiamine supplementation

Question 35

What term is used to describe severe morning sickness?

Answer 35

Hyperemesis gravidarum

Question 36

List some strong anti-emetics that may be used in such cases of severe morning sickness.

Answer 36

Prochlorperazine
Chlorpromazine
Ondansteron
Metoclopramide

Question 37

Describe the distinguishing clinical features of raised ICP.

Answer 37

Early morning nausea and vomiting

Headaches worse when lying down

Question 38

Which cranial nerve palsy is most commonly involved in raised ICP and why?

Answer 38

CN VI – it has the longest intracranial course