Nausea and Vomiting

Question 1

The vomiting centre consists of mainly histamine and ACh receptors. Which 4 main systems can activate the vomiting centre?

Answer 1

Vestibular system
CNS
CTZ
CN9+10

Question 2

Name 4 causes of N&V due to vestibular system.

What receptors do these affect the vomiting centre via?

Answer 2

BPPV
Labyrinthitis
Motion sickness
Menieres disease

Affect VC via ACh and Histamine receptors

Question 3

Name 4 causes of N&V due to CTZ.

What receptors do these affect the vomiting centre via?

Answer 3

Think “chemicals in blood” for CTZ causes

Medications
Alcohol/toxins
Hormones
Electrolytes

Affect VC via dopamine

Question 4

Name 5 CNS causes of N&V.

Answer 4

Pain
Anxiety
Raised ICP
Meningitis
Encephalitis

Question 5

Name 4 Cranial nerve 9/10 causes of N&V.

What receptors do these affect the VC via?

Answer 5

Think “abdominal and heart problems”

GI obstruction
GI infection
Inflammation of diaphragm
Liver/pancreas/GB/peritoneum infection

Affect VC via serotonin and ACh

Question 6

What information regarding the details of the vomit are important?

Answer 6

1. Contents - undigested = oesophageal disorders. Partially digested = gastric outlet obstruction / gastroparesis. Bile = small bowel obstruction. Faeculent = distal intestinal or colonic obstruction. Blood/coffee ground = haematemesis.
2. Timing - early morning = pregnancy or raised ICP.
3. Association with eating - vomiting within an hour of eating = high GI tract obstruction (ask about PUD). Vomiting after a long postprandial delay = low GI tract obstruction (e.g. small bowel). Early satiety/postprandial bleeding/abdominal discomfort = gastroparesis / outlet obstruction

Question 7

Relief of pain after vomiting is consistent with?

Answer 7

Obstruction

Question 8

A fever may indicate which causes of N&V

Answer 8

Any infectious or inflammatory cause:

Gastroenteritis, appendicitis, cholecystitis, cholangitis, pancreatitis, hepatitis, UTI, meningoencephalitis

Question 9

Neurological symptoms (NB NOT VERTIGO) may indicate what?

Answer 9

Meningitis, encephalitis, migraine, raised ICP

Question 10

What could a long delay with bowel movements suggest?

Answer 10

Long delay = bowel obstruction (Eg ileus)

Question 11

Diarrhoea and vomiting suggests what?

Answer 11

Infectious gastroenteritis

Question 12

Name 2 industrial chemicals that can cause vomiting

Answer 12

Arsenic and organophosphate fertilisers

Question 13

What are classical symptoms of meningitis?

Answer 13

Stiff neck, photophobia, headache

Question 14

Tenderness on palpation of the abdomen reveals what?

Answer 14

Inflammation somewhere in peritoneal cavity

Question 15

What does guarding and rigidity on palpation suggest

Answer 15

Peritonitis

Question 16

How do bowel sounds sound in ileus?

How do bowel sounds sound in mechanical obstruction?

Answer 16

Bowel sounds absent in ileus

High-pitched/tinkling in mechanical obstruction

Question 17

Which blood tests should be ordered for N&V patients?

Answer 17

1. FBC and CRP
2. U&Es
3. VBG - pH and lactate (how sick is patient)
4. Liver enzymes - cholestatic picture (raised ALP and GGT) vs hepatitis (raised ALT and AST)
5. Amylase - exclude pancreatitis

Question 18

Name 3 indications for spine abdominal radiograph

Answer 18

1. Looking for bowel obstruction
2. Foreign body
3. Toxic megacolon

Question 19

Metoclopramide is an antiemetic. What must you be cautious about when using it

Answer 19

It is pro kinetic and can make things worse if obstruction is present. Better to use cyclizine or ondansetron.

Question 20

A combination of diarrhoea and vomiting over a few days indicates what diagnosis?

Answer 20

Gastroenteritis

Question 21

When is morning sickness most common?

Answer 21

First trimester

Question 22

A doubling of creatinine levels within pregnancy indicates?

Answer 22

AKI

Question 23

Vomiting, abdominal pain, polydipsia, polyuria and headache (+ decreased consciousness/Kussmaul breathing) are signs of?

Often the lab reports may also show ketosis and acidaemia

Answer 23

DKA

Question 24

Acidosis with low bicarbonate indicates which type of acidosis? Respiratory or metabolic

Answer 24

Metabolic

Question 25

How is DKA managed acutely?

Answer 25

IV fluids to rehydrate

IV infusion of insulin

Question 26

Which 2 features indicate raised ICP as a cause of N&V?

Answer 26

1. Headaches worse lying down

2. Early morning N&V

Question 27

What could point to appendicitis as a cause of N&V

Answer 27

Peritonism, febrile and pain in RIF

Question 28

When would you give cyclizine

Answer 28

Antihistamine and antimuscarinic - useful if vestibular causes.

Useful in postop nausea, bowel obstruction (as it is anti kinetic), motion sickness/labyrinthine aetiologies and raised ICP

Question 29

When would you give metoclopramide

Answer 29

5-HT (serotonin) agonist, dopamine antagonist.

Useful for CTZ causes, and its pro kinetic so use if delayed stomach emptying. DO NOT GIVE IN BOWEL OBSTRUCTION. Be cautious in parkinsons patients as it is antidopaminergic

Question 30

When would you give ondansetron.

Answer 30

5-HT (serotonin) agonist - acts on receptors in gut and CTZ. Useful for chemotherapy induced and postop vomiting

Question 31

When would you give haloperidol

Answer 31

Dopamine antagonist. Removes inhibition to normal gastric motility in low doses. Can be used to treat drug induced. raised ICP and metabolic causes of N&V