Editing Stomach motility disorders

(Dysmotility of the stomach)

== Normal anatomy ==

* Proximal stomach ->     receptive relaxation, mediated by vagus nerve, when food enters. Presence     of amino acids initiates a slow tonic contraction of proximal stomach,     which increases the intraluminal pressure, mediating gastric emptying.

== Gastric emptying studies ==

* Radionucleotide scan
** Nuclear scintigraphy study -      meal of radiolabelled food
** Scans immediately after the      meal and at 1, 2 and 4 hours
** At 4 hours, retention of      10%-15% is mild, 15-35% is moderate, and >35% is severe
** Can do it with clear liquids      only to identify patients with normal solid food emptying and delayed      liquid emptying
* Barium swallow with upper GI     series
** May reveal mechanical causes      contributing to delay
* Electrogastrogram or     antroduodenal motility study
** Assesses for nerve and      muscle abnormalities
** Doesn't address functional      significance
* Wireless motility capsules
** Can measure pH, temperature      and pressure during transit

== '''Gastroparesis''' ==

* Background
** Syndrome of delayed gastric      emptying in the absence of mechanical obstruction
* Aetiology
** Vagal damage
** Prior gastric or bariatric      surgery (Roux en Y, gastric resections, anti-reflux fundoplication,      pancreaticoduodenectomy)
** Chronic illness
*** Diabetes (type I and II)
**** Can occur both with and        without insulin
**** Impaired neural control        via vagal nerve, myenteric nervous system, interstitial cells of Cajal,        and the underlying smooth muscle
**** Hyperglycaemia itself        decreases contractility of the antrum and increases contractility in        the pylorus
**** Hyperinsulinaemia may also        play a role in suppressing migrating myoelectric complex activity
*** Hypothyroidism
*** Neurological disease -       Parkinsonism, amyloidosis, paraneoplastic disease
*** Autoimmune disorders
** Post-viral gastroparesis      (look for recent viral prodrome)
** Medications
*** Narcotics
*** Anticholinergics
*** GLP-1 inhibitors
** Mesenteric ischaemia
** Idiopathic - this is      actually the most common, especially in young/middle-aged women
* Presentation
** Epigastric fullness/pain      (but this is non-specific)
*** Pain is often nocturnal ,       induced by eating, and interferes with sleep
** Early satiety, mostly to      solids
** Delayed vomiting -      especially if it occurs a day later, with undigested food
** Anorexia, dehydration,      weight loss, malnutrition
* Diagnosis
** Symptoms of gastroparesis,      absence of gastric outlet obstruction, and delay in gastric emptying      (solids at 4 hours on scintigraphy)
* Workup
** Exclude mechanical bowel      obstruction - efferent limb syndrome, anastomotic stricture,      intussusception
*** XRAY
** Evaluate for metabolic      derangements
*** Albumin takes a month to       drop - consider ordering pre-albumin
** Consider gastroscopy
*** If gastric reservoir is       large and distended, vagal issue is unlikely - since vagus mediates       distension!
** Gastric emptying studies
* Differential diagnosis
** Gastric outlet obstruction
** Gastritis, especially      secondary to H pylori
** Peptic ulcer disease
** Functional dyspepsia
** Consider gastroparesis in      setting of treatment-resistant GORD
* '''Treatment'''
** '''Resuscitation'''
*** Restore fluids and       electrolytes
*** Consider nutritional       support - TPN/nasojejunal feeding tube
**** Indication for NJT is        unintentional weight loss >10% over 3-6 months, or repeated        hospitalisations
**** Obviously NJT is        preferable to TPN
** '''Lifestyle'''
*** Modify diet - focus on       liquids (as liquid emptying is often normal), smaller and more frequent       meals, low-residue diet, lower fat content. Minimise acidic and spicy       foods, carbonated drinks, alcohol and tobacco.
** '''Medical'''
*** Treat contributing factors,       especially labile sugars in the acute setting
*** Prokinetics
**** Metoclopramide first-line
***** Dopamine antagonist
***** Stimulates antral         contractions
***** Decreases post-prandial         fundus relaxation
**** Domperidone (note that        this takes effect in antrum - may not help in some patients)
***** Dopamine antagonist
***** Needs baseline ECG and         ongoing ECGs due to prolonging of QT
***** Trial if metoclopramide         is not tolerated or doesn't help
**** Erythromycin (IV or oral,        but tachyphylaxis develops to oral)
***** Motilin agents -         stimulate fundal contraction
***** Second-line therapy
***** Azithromycin can also be         used via the same mechanism
** '''Surgical'''
*** Indication: refractory       symptoms despite maximal medical therapy
*** Pyloromyotomy/pyloroplasty       - lower outflow resistance at the pylorus
*** Gastric POEM - under       investigation
*** People have tried total       gastrectomy for patients with vagal dysfunction-mediated delayed       emptying, but it's very controversial
*** Implantation of gastric       stimulator
**** Helps with n/v but do not        increase emptying
*** Venting gastrostomy -       palliative
*** Pyloric dilation and       stenting could be considered in certain circumstances
*** Intra-pyloric botox doesn't       work

== '''Rapid gastric emptying/dumping''' ==

* See 'gastrectomy'     complications


[[Category:UGIS]]