1B upper GI tract Flashcards
Label these diagrams of oesophageal anatomy
What are the 4 anatomical contributions to the lower oesophageal sphincter (LOS)’s effectiveness?
- 3-4cm of the distal oesophagus is within the abdomen so if there’s an increase in intraabdominal pressure there’s also increase in LOS pressure
- Diaphragm surrounds LOS (left and right crux)- contract like a pair of scissors around LOS when diaphragm contracts and contribute to its effectiveness
- An intact phrenoesophageal ligament
- Angle of His
Describe the intact phrenoesophageal ligament
- It’s an extension of inferior diaphragmatic fascia
- It has 2 limbs:
- One goes superiorly and attaches to lower part of oesophagus
- Other goes inferiorly and attaches to cardia of stomach
What is the angle of His?
Normally there’s an acute angle between the abdominal oesophagus and fundus of stomach at oesophageal junction that prevents reflux disease
What are the 4 stages of swallowing?
- Stage 0: Oral phase
- Stage 1: Pharyngeal phase
- Stage 2: Upper oesophageal phase
- Stage 3: Lower oesophageal phase
What happens in the oral phase?
- Chewing and saliva prepare bolus
- Both oesophageal sphincters constricted
What happens in the pharyngeal phase?
- Pharyngeal musculature guides food bolus towards oesophagus
- Upper oesophageal sphincter opens reflexly
- LOS opened by vasovagal reflex (receptive relaxation reflex)
What happens in upper oesophageal phase?
- Upper sphincter closes
- Superior circular muscle rings contract and inferior rings dilate
- Sequential contractions of longitudinal muscle
What happens in the lower oesophageal phase?
Lower sphincter closes as food passes through
How is the motility of the oesophagus determined?
- By pressure measurements (manometry)
- Peristaltic waves are around 40 mmHg
What is the LOS resting pressure and how does that change during receptive relaxation?
- Resting pressure is 20 mmHg
- Decreases by <5 mmHg during receptive relaxation
What mediates the LOS resting pressure?
Inhibitory noncholinergic nonadrenergic (NCNA) neurones of myenteric plexus
What is a functional disorder of the oesophagus?
Absence of an oesophageal stricture (abnormal narrowing of oesophagus)
What are the causes of an oesophagus stricture absence?
- Abnormal oesophageal contraction
- Failure of protective mechanisms for reflux
What are some examples of abnormal oesophageal contraction?
- Hypermotility
- Hypomotility
- Disordered coordination
What is an example of a failure of protective mechanism for reflux?
Gastro-Oesophageal Reflux Disease (GORD)
What is dysphagia?
Difficulty in swallowing
What is important when describing dysphagia?
To describe the localisation- cricopharyngeal sphincter or distal
What types of dysphagia are there?
- For solids and fluids
- Intermittent or progressive
- Precise or vague in appreciation
What is odynophagia?
Pain on swallowing
What is regurgitation?
- Return of oesophageal contents from above an obstruction
- May be functional or mechanical
What is reflux?
Passive return of gastroduodenal contents to the mouth
Define achalasia
- Hypermotility of oesophagus due to loss of ganglion cells in Aurebach’s myenteric plexus in LOS wall
- Leads to decreased activity of inhibitory NCNA neurones
What does achalasia lead to?
- Increased resting pressure of LOS
- Receptive relaxation sets in late and is too weak so during reflex phase the LOS pressure is much higher than stomach
- Swallowed food collects in oesophagus causing increased pressure throughout with dilation of oesophagus
- Propagation of peristaltic waves cease
What is primary achalasia?
- Majority of achalasia is primary
- Aetiology is unknown
What is secondary achalasia?
Diseases causing oesophageal motor abnormalities similar to primary achalasia
What are examples of secondary achalasia?
- Chagas’ Disease - chronic infection of a parasite
- Protozoa infection
- Amyloid/Sarcoma/Eosinophilic Oesophagitis
What is the course of achalasia?
- Insidious onset- symptoms for years prior to seeking help
- Without treatment there’s progressive oesophageal dilation of oesophagus
What does achalasia increase the risk of?
- Increases risk of oesophageal cancer by 28 fold
- Annual incidence is only 0.34%
What are the two main treatments of achalasia?
- Pneumatic dilatation (PD)
- Surgery
What happens in pneumatic dilatation (PD)?
PD weakens LOS by circumferential stretching and in some cases, tearing of muscle fibres- done by inserting balloon and expanding it in LOS
What is the efficacy of PD?
71-90% of patients respond initially but many patients subsequently relapse
What happens in surgery for achalasia?
- Heller’s myotomy- a continuous myotomy (cutting of musculature and exposing mucosa) performed for 6cm on the oesophagus and 3cm onto stomach
- Dor fundoplication then done- anterior fundus folded over oesophagus and sutured to right side of myotomy
What are the risks of surgery for achalasia?
- Oesophageal and gastric perforation- 10-16%
- Division of vagus nerve- rare
- Splenic injury- 1-5%
Define scleroderma
Autoimmune disease where hypomotility happens in early stages due to neuronal defects leading to atrophy of smooth muscle of oesophagus
What does scleroderma cause?
- Peristalsis in distal portion ultimately ceases fully
- Decreases resting pressure of LOS
- GORD develops
What is scleroderma often associated with?
CREST syndrome
- Calcinosis- deposits of calcium in soft tissue
- Raynaud’s phenomenon- constriction of peripheral blood vessels, can lead to problems with hands
- Esophageal problems
- Sclerodactyly- thickening of digits of hands and toes
- Telangiectasia- dilated or broken blood vessels near surface of skin
What is the treatment for scleroderma?
- Exclude organic obstruction and make sure they don’t have malignancy
- Improve of peristalsis with prokinetics (cisapride). This doesn’t work too well because once peristaltic failure occurs it’s usually irreversible
What is corkscrew oesophagus?
- Disordered coordination of contraction of oesophagus
- Leads to dysphagia and chest pain
- Pressures of 400-500 mmHg
What can we see when investigating corkscrew oesophagus?
- Marked hypertrophy of circular muscle
- Corkscrew shaped oesophagus on Barium