Nausea and Vomiting Flashcards
The vomiting centre consists of mainly histamine and ACh receptors. Which 4 main systems can activate the vomiting centre?
Vestibular system
CNS
CTZ
CN9+10
Name 4 causes of N&V due to vestibular system.
What receptors do these affect the vomiting centre via?
BPPV
Labyrinthitis
Motion sickness
Menieres disease
Affect VC via ACh and Histamine receptors
Name 4 causes of N&V due to CTZ.
What receptors do these affect the vomiting centre via?
Think “chemicals in blood” for CTZ causes
Medications
Alcohol/toxins
Hormones
Electrolytes
Affect VC via dopamine
Name 5 CNS causes of N&V.
Pain Anxiety Raised ICP Meningitis Encephalitis
Name 4 Cranial nerve 9/10 causes of N&V.
What receptors do these affect the VC via?
Think “abdominal and heart problems”
GI obstruction
GI infection
Inflammation of diaphragm
Liver/pancreas/GB/peritoneum infection
Affect VC via serotonin and ACh
What information regarding the details of the vomit are important?
- Contents - undigested = oesophageal disorders. Partially digested = gastric outlet obstruction / gastroparesis. Bile = small bowel obstruction. Faeculent = distal intestinal or colonic obstruction. Blood/coffee ground = haematemesis.
- Timing - early morning = pregnancy or raised ICP.
- 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
Relief of pain after vomiting is consistent with?
Obstruction
A fever may indicate which causes of N&V
Any infectious or inflammatory cause:
Gastroenteritis, appendicitis, cholecystitis, cholangitis, pancreatitis, hepatitis, UTI, meningoencephalitis
Neurological symptoms (NB NOT VERTIGO) may indicate what?
Meningitis, encephalitis, migraine, raised ICP
What could a long delay with bowel movements suggest?
Long delay = bowel obstruction (Eg ileus)
Diarrhoea and vomiting suggests what?
Infectious gastroenteritis
Name 2 industrial chemicals that can cause vomiting
Arsenic and organophosphate fertilisers
What are classical symptoms of meningitis?
Stiff neck, photophobia, headache
Tenderness on palpation of the abdomen reveals what?
Inflammation somewhere in peritoneal cavity
What does guarding and rigidity on palpation suggest
Peritonitis
How do bowel sounds sound in ileus?
How do bowel sounds sound in mechanical obstruction?
Bowel sounds absent in ileus
High-pitched/tinkling in mechanical obstruction
Which blood tests should be ordered for N&V patients?
- FBC and CRP
- U&Es
- VBG - pH and lactate (how sick is patient)
- Liver enzymes - cholestatic picture (raised ALP and GGT) vs hepatitis (raised ALT and AST)
- Amylase - exclude pancreatitis
Name 3 indications for spine abdominal radiograph
- Looking for bowel obstruction
- Foreign body
- Toxic megacolon
Metoclopramide is an antiemetic. What must you be cautious about when using it
It is pro kinetic and can make things worse if obstruction is present. Better to use cyclizine or ondansetron.
A combination of diarrhoea and vomiting over a few days indicates what diagnosis?
Gastroenteritis
When is morning sickness most common?
First trimester
A doubling of creatinine levels within pregnancy indicates?
AKI
Vomiting, abdominal pain, polydipsia, polyuria and headache (+ decreased consciousness/Kussmaul breathing) are signs of?
Often the lab reports may also show ketosis and acidaemia
DKA
Acidosis with low bicarbonate indicates which type of acidosis? Respiratory or metabolic
Metabolic
How is DKA managed acutely?
IV fluids to rehydrate
IV infusion of insulin
Which 2 features indicate raised ICP as a cause of N&V?
- Headaches worse lying down
2. Early morning N&V
What could point to appendicitis as a cause of N&V
Peritonism, febrile and pain in RIF
When would you give cyclizine
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
When would you give metoclopramide
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
When would you give ondansetron.
5-HT (serotonin) agonist - acts on receptors in gut and CTZ. Useful for chemotherapy induced and postop vomiting
When would you give haloperidol
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
