13. 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? List 4 mechanisms

Answer 3

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

Question 4

List some causes of nausea and vomiting caused by the vestibular system (vertigo)

Answer 4

BPPV
Meniere’s disease
Labyrinthitis
Motion sickness

Question 5

List some of the causes of nausea and vomiting caused by the CNS (brain problems)

Answer 5

Pain
Anxiety
Raised ICP
Meningitis/Encephalitis

Question 6

List some of the causes of nausea and vomiting caused by the CTZ (chemicals in the blood)

Answer 6

Alcohol
Drugs 
Toxins
Electrolytes 
Hormones

Question 7

List some of the causes of nausea and vomiting caused by CN IX & X (abdomen and heart problems)

Answer 7

GI obstruction
GI infection
Inflammation of the diaphragm
Infection/Inflammation of organs (e.g. hepatitis, pancreatitis)

Question 8

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

Answer 8

Contents
Timing
Association with eating
Pain

Question 9

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

Answer 9

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 10

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

Answer 10

Raised ICP

Pregnancy

Question 11

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

Answer 11

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 12

List some important associated symptoms to ask about.

Answer 12

Fever
Headache, visual disturbance, focal neurological deficits
Vertigo

Question 13

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

Answer 13

Absolute constipation – bowel obstruction

Diarrhoea – suggests gastroenteritis

Question 14

List some risk factors for infectious diarrhoea.

Answer 14

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

Question 15

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

Answer 15

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

Question 16

Why is it important to enquire about previous abdominal surgery?

Answer 16

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

Question 17

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

Answer 17

Weight loss

• Upper GI obstruction (e.g. cancer)
• Functional dysphagia (e.g. achalasia)
• Coeliac disease

No weight loss

• Oesophagitis
• Pharyngeal pouch

Question 18

List some causes of nausea and vomiting that are associated with abdominal pain

Answer 18

With fever: infection (e.g. gastroenteritis), inflammation (e.g. appendicitis, cholecystitis)
Without fever: DKA, SBO, drug side-effects, toxins

Question 19

List some causes of nausea and vomiting that are associated with headache

Answer 19

Meningitis
Raised ICP
Migraine

Question 20

List some causes of nausea and vomiting that are associated with vertigo

Answer 20

Labyrinthitis
Meniere’s disease
BPPV
Motion sickness

Question 21

List some causes of nausea and vomiting that are associated with onset shortly after eating food

Answer 21

Gastric outlet obstruction

Question 22

List some other causes of nausea and vomiting

Answer 22

Drug side-effect
Psychogenic
Hyperthyroid
Renal failure + uraemia

Question 23

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

Answer 23

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 24

List some signs of meningitis.

Answer 24

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 25

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

Answer 25

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

Question 26

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

Answer 26

Absent bowel sounds -> ileus | Tinkling bowel sounds -> obstruction

Question 27

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

Answer 27

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 28

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

Answer 28

AXR | Erect CXR

Question 29

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

Answer 29

Small bowel – valvulae conniventes, 3 cm diameter | Large bowel – haustra, 6 cm diameter

Question 30

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

Answer 30

Pregnancy test

Question 31

Outline the management of a patient with acute abdomen.

Answer 31

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

Question 32

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

Answer 32

Metoclopramide – it has a prokinetic effect on the GI tract

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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 35

Describe the typical presentation of gastroenteritis.

Answer 35

Nausea, vomiting, diarrhoea, fever and abdominal pain | Last a matter of days and resolves by itself

Question 36

What does ketonuria in a patient without diabetes suggest?

Answer 36

Starvation

Question 37

How can food poisoning be differentiated from gastroenteritis?

Answer 37

Food poisoning is caused by bacterial toxins | Symptoms don’t tend to persist longer than 24 hrs

Question 38

Describe the typical presentation of DKA.

Answer 38

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

Question 39

Outline the management of DKA.

Answer 39

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 40

When does morning sickness typically affect pregnant women?

Answer 40

First trimester

Question 41

Outline the management of morning sickness.

Answer 41

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

Question 42

What term is used to describe severe morning sickness?

Answer 42

Hyperemesis gravidarum

Question 43

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

Answer 43

Prochlorperazine Chlorpromazine Ondansteron Metoclopramide

Question 44

Describe the distinguishing clinical features of raised ICP.

Answer 44

Early morning nausea and vomiting | Headaches worse when lying down

Question 45

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

Answer 45

CN VI – it has the longest intracranial course