6/7. Esophageal Disorders Flashcards
Triad of issues seen in Achalasia
Impaired relaxation of LES, Increased LES tone and loss of peristalsis in body of esophagus
Pathophysiology of Achalasia:
Abnormal function of the lower esophageal sphincter in achalasia is due to
impaired and then loss of inhibitory (NO) activity
Histopathologic examination of myotomy specimens with Achalasia has shown
– Degeneration of _______ in myenteric plexus
– Inflammatory______ infiltration
ganglion cells
lymphocytic
Clincal presentation of Achalasia:
peak age
Predominant symptoms
7th decade
dysphagia in up to >90% pts; first solids then liquids
Chest pain, heartburn, regurgitation and weight loss occur in up to 60% patients
Why does achalasia sometimes have subtle symptom devo?
slow progression and accommodative behavior is common:
– Slow and stereotypical eating movements
– Avoiding social events with meals
How do we Dx achalasia?
Two or three modalities are generally needed
(manometry, radiography and endoscopy)
• Barium esophagram or manometry have a number
of different appearances
DDx or Secondary Achalasia
- Malignancy: Direct infiltration is usually caused by adenocarcinoma
- Other Infiltrative disorders: Amyloidosis, sarcoidosis
- Chagas disease: Trypanosoma cruzi, diffuse enteric myenteric destruction
- Para-neoplastic syndromes: Small cell carcinoma of the lung
- Autonomic nerve damage: Diabetes, polio, or surgical damage
Tx for Achalasia
focus mainly on disruption of LE
- Pharmacotherapy– Nitric oxide donors or Anticholinergic Agents
- Endoscopic therapy – Botolinum toxin injection (inhibits release of
acetylcholine) or Pneumatic dilation - Operative Therapy
characterized by dis-coordinated contraction of the muscularis layer and interferes with efficient delivery of food and fluids to the stomach.
The______ epithelium of the esophagus
is resistant to abrasion from foods but is sensitive to acid.
stratified squamous
The sub-mucosal glands of the proximal and distal esophagus contribute to mucosal protection by secreting
mucin and bicarbonate
Protection from acid in stomach
hydrogen ions (H+) must cross the mucus–unstirred water layer– bicarbonate barrier before contact can be made with the surface of the epithelium. Diffusion of pepsin, but not H+, is blocked by mucus; however, H+ can **be neutralized by bicarbonate ions (HCO3-)** residing in the unstirred water layer
Why does teh esophagus suck at mucus protection?
the preepithelial defense in the esophagus is poorly developed, having a limited mucus–HCO3- barrier to buffer back diffusing H+
Epithelial defence includes apical cell membrane and intercellular junctional complex.
Functional components include intracellular buffering by ________ and ______ and H+ extrusion processes (Na+/H+ exchange and Na+-dependent Cl-/HCO3- exchange)
negatively charged proteins and bicarbonate ion (HCO3-)
The most important barrier against reflux is:
is the constant LES tone
• LES prevents reflux of acidic gastric contents, which are under constant positive abdominal pressure
The lower esophageal sphincter and the crural
diaphragm constitute the intrinsic and extrinsic
sphincters, respectively. The two sphincters are
anatomically superimposed and are anchored to
each other by the_______ ligament.
phrenoesophageal
Reflux of gastric juices is central to the
development of mucosal injury in_____
• Duodenal bile reflux may exacerbate the damage
GERD
Inflammation from reflux induces production of ______ which incresaes ______ in the muscle
IL-6 which increases H2O2
The H2O2 from IL-6 appears to be the main cause of increase
in
platelet-activating factor (PAF) and PGE2
PAF and PGE2 (which are a reusult of H2O2) reduce
ACh release and LES tone–> leading to reflux
Gastroesophageal junction (GEJ) barrier is defective and allows injurious contact between esophageal epithelium and gastric contents
Incompetent LES
Most common type of imcompotent LES cause?
Spontaneous, transient LES relaxation which then leads to reflux and drop of pH in the eosphagus