Achalasia


DEFINITION

A progressive disease of the oesophagus characterized by inability to swallow (especially solids), regurgitation and occasionally pain, likely due to degeneration of nerves controlling motility.
Key points: dysphagia, regurgitation, distal oesophageal narrowing, incomplete LES relaxation, absence of peristalsis on manometry.

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INCIDENCE

Uncommon (1:100,000)
M>F

Age
20-65yrs, occasionally >65 yrs.
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AETIOLOGY

Common
Primary degenerative change
- to nerves (ganglionic and post-ganglionic).

Rarer

Chagas disease (Treponosomia cruzi).
'Pseudoachalasia' due to tumour.
Infiltration by amyloid, sarcoid, etc.

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BIOLOGICAL BEHAVIOUR

Pathophysiology
Esophageal plexus nerves degenerate and function fails.
- particularly the inhibitory ganglion cells (containing VIP and NO synthase in SM).
--> LES fails to relax.
--> aperistalsis follows
--> stasis.
[Sparing of postganglionic cholinergic neurons --> unopposed cholinergic stimulation]
Unknown why these cells primarily affected; ?auto-immune infiltrate component

Classical
- small amplitude simultaneous contractions.

Vigorous

- large painful repetitive spasms.
GORD is not usually prominent.

Pathogenesis
Neuronal degeneration, perhaps post-viral

Natural History
Course chronic over years with weight loss.

Complications
Aspiration pneumonia.
Risk fx for cancer - SCC
- poss. due to continuous irritation by retained and fermenting food.
- myotomy therapy also causes reflux, elevating risk.

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MANIFESTATIONS

Symptoms

Local

Dysphagia (100%)
- usually 2 year history of difficulty swallowing before presentation.
- solids and liquids, but especially solids
Regurgitation (>60%)
- slime, largely undigested, often past meals.
Patient drinks lots with meal
- and maneouvres body to force swallow (e.g. valsalva).
Chest discomfort, pain (40%)
- relieved by vomiting.
Worsened by hurried eating.

Systemic

Weight loss if solids avoided.
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INVESTIGATIONS

Investigation
First barium swallow, then endoscopy.
Manometry is the key test.

CXR

Dilated oesophagus, occasionally fluid-air level, no gastric air bubble.

Barium swallow

First investigation of choice
- beak like narrowing of LES.
- dilated 'sigmoid' esophagus.
- non-relaxation of the LES

Endoscopy
Rules out pseudoachalasia, eg due to tumours.

Manometry
= key to diagnosis
*1. Absence of peristalsis in oesophageal body*
- classically low amplitude aperistaltic contractions
*2. Incomplete LES (50%) relaxation on swallow.*

Differentiating Hypertensive LES
>95% centile for LES pressure but not achalasia
- relaxation of LES is normal (cf abnormal in achalasia)
- Intrathoracic pressure usually positive (cf negative in achalasia)
- peristaltic swallow responses present (never in achalasia)

Other tests

Fluoroscopy

Peristalsis lost in bottom 2/3.

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MANAGEMENT

Directed toward symptom relief.
Aim is to achieve gravity drainage through LES, as peristalsis gone.

Four options
-
medical Rx
- endoscopic botox
- pneumatic dilatation
- surgical myotomy

Conservative
while awaiting definitive Rx
Soft foods.

Medical
generally only in non-surgical / other Rx candidates
Ca channel blockers
- 10% response; minimal over placebo
Botulin toxin injection
- 60% response at 6mo, 30% at 2.5 yrs
- RCTs show much less effective long term than myotomy (87.5% at 2 yrs).
Nitroglycerin 0.3-0.6mg sublingually before meals alleviates pain.
- ososorbide dinitrate 2.5-5mg orally effective.
Also sildenafil (viagra).

Surgical / Endoscopic
Balloon dilation
Initial success is ~80%
- steadily declines
- 60% by 3 yrs
- 50% at 10 yrs, even after repeat dilatations.
- perf rate is ~2-5%
- reflux rate 25-35%
RCTs vs surgery show much better long term outcomes for surgery (98% at 5 yrs vs 70% in one study)

Hellers myotomy
Usually when balloon dilation fails.
- effective in 90%
- even in patients with a low LES pressure, or dilated esophagus.
See Hellers Myotomy

What if the symptoms recur post-myotomy?
Repeat dilatations and myotomy can be attempted.
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