136b - Disorders of GI Motility Flashcards

1
Q

A patient presents with progressive dysphagia. Barium swallow is attached.

What is the most likely diagnosis?

What may have caused this?

A

Achalasia

  • May be primary (idiopathic)
  • If history of acute Chaga’s disease years-decades ago, may be secondary to Chagas disease
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2
Q

Describe the pathogenesis of systemic sclerosis small bowel

A
  • Neuropathy; may be due to M3 antibodies. Cholinergic trsnmission is impaired
  • -> Smooth muscle atrophy and fibrosis due to lack of stim
  • -> Visceral myopathy

This is an example of chronic intestinal pseudo-obstruction

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3
Q

How is chronic intestinal pseudo-obstruction managed?

A
  • Diet: Stick to easily digestable foods
  • Rotate antibiotics
  • Prokinetic agents
    • Less helpful in systemic sclerosis; smooth muscle is lost :(

Surgical intervention is not indicated

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4
Q

What GI motility disorder is caused by failed migration of neuroblasts into the terminal bowel?

How is it cured?

A

Hirschprung’s disease

Surgery: resect the portion missing enteric neurons

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5
Q

How is achalasia treated?

A

Target the LES, usually surgical

  • Dilation w/baloon
  • Myotomy
    • Basically cuts the LES open
  • Botulinum toxin
  • Muscle relaxants
    • But pill is hard to swallow if you can’t swallow
  • Stenting
  • Gasrostomy tube if pt cannot tolerate surgery
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6
Q

Describe the clinical preserntation of Hirschpring’s disease (4)

A

Days old infant

  • Failure to pass meconium
  • Empty rectal vault
  • Abdominal distension
  • Vomiting
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7
Q

What test is used to diagnose gastroparesis?

A

Gastric emptying study (scintigraphy)

  • Eat a radiolabeled meal
  • Look for retention at 4h
    • Normal = <10% of the meal is still in the stomach
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8
Q

Are prokinetic agents efficacious in the treatment of chronic intestinal pseudoobstruction associated with systemic sclerosis?

A

Not really :(

In systemic sclerosis, intestinal smooth msucle undergoes atrophy and fibrosis due to impaired cholinergic transmission (M3 autoantibodies maybe)

No smooth muscle = no contraction, even if stimulation is increased

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9
Q

Which test is most sensitive for the diagnosis of achalsia?

A

Esophageal manometry

(Just like for SSc in the Esophagus/Upper GI tract, can detect lacking nervous system response in smooth muscles)

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10
Q

What is the most common cause of gastroparesis?

A

Longstanding diabetes

-> Vagal neuropathy

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11
Q

How does systemic sclerosis affect the GI tract?

A
  • Esophageal dysmotility
  • Small bowel dysmotility (chronic pseudoobstruction)

In both cases, peristalsis is imparied due to loss of smooth muscle (usually 2/2 to loss of cholinergic transmission, may result from antibodies against M3 receptors)

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12
Q

True or false:

If you swallow a piece of gum, it will stay in your stomach for 8 years

Explain

A

False!

Migrating motor complexes are responsible for getting large/indigestable objects (like a wad of gum) out of the stomach

Exception: systemic sclerosis destroys smooth muscle, migrating motor complexes are ineffective :(

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13
Q

What causes Hirschprung’s disease?

A

Absense of enteric neurons in the rectum and distal colon

  • Due to failed migration of neuroblasts into th eterminal bowel

(Congenital disorder)

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14
Q

List 3 clinical manifestations of chronic intestinal pseudo-obstruction

A

Ex: systemic sclerosis small bowel

  • Maldigestion
  • Small bowel bacterial overgrowth (due to stasis)
    • -> Diarrhea, gas, B12 deficiency
  • Diverticulosis
    • Due to bacterial overgrowth
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15
Q

Describe the pathogenesis of achalasia

A
  • Loss of ganglion cells in the myenteric (Auerbach) plexus
  • -> No nitric-oxide producing neurons
  • -> LES cannot relax to allow liquids or solids through

Remember, the baseline tone of the LES is under myenteric (smooth muscle) control; contracted at rest

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16
Q

What usually causes Ogilvie’s Syndrome?

A

Ogilvie’s syndrome = acute colonic pseudo-obstruction

Usually caused by surgery

  • -> Imbalance of autonomic nervous control
    • Decreased parasympathetic, increased sympathetic

Correct contributing factors, IV neostigmine. Colonic decompression = last resort