Dysphagia, vomiting, anti-emetics Flashcards
What are the stages of swallowing?
oral stage
pharyngeal stage
oesophageal stage
What are 2 types of dysphagia?
oropharyngeal - unable to transfer food bolus from mouth to upper oesophagus
oesophageal - sensation of food sticking in throat or chest after swallowing
Causes of oropharyngeal dysphagia
neuromuscular disorders:
- stroke
- head injury
- brainstem tumours
- MND
- muscular dystrophies
- MS
- Parkinson’s disease
- MG
mechanic obstruction:
- oropharyngeal tumours
- pharyngeal pouch
- cricopharyngeal bar
Causes of oesophageal dysphagia
dysmotility:
- achalasia
- hypercontractile oesophagua
- hypertonic lower oesophageal sphincter
- diffuse oesophageal spasm
- scleroderma
mechanical obstruction:
- benign stricture
- malignant stricture
- oesophageal tumour
- oesophageal web
- eosinophilic oesophagitis
- external compression
Investigations for dysphagia
SALT assessment
video fluoroscopy
oesophageal manometry
gastroscopy
What is eosinophilic oesophagitis?
chronic immune-mediated condition
eosinophilic infiltrate of oesophageal epithelium
treatment = swallowed steroids
associated with atopy
2 important areas in medulla that initiate nausea + vomiting
emetic centre
chemoreceptor trigger zone
What are the 5 receptors that may trigger the chemoreceptor trigger zone?
serotonin (5HT3)
histamine (H1)
muscarinic
dopamine (D2)
substance P (neurokinin/neuropeptide)
Ondansetron MOA
5HT3 antagonist
Ondansetron indication
cytotoxic drug induced vomiting
Metoclopramide/prochlorperazine MOA
dopamine antagonist
Metoclopramide indication
opiate induced vomiting
(can worsen CNS symptoms, eg. worsens symptoms in Parkinson’s)
Cyclizine MOA
histamine antagonist
Cyclizine indication
motion sickness
Hyoscine MOA
muscarinic antagonist
