39 / 242
39
ACHALASIA AND PERORAL ENDOSCOPIC MYOTOMY POEM
4
INTRODUCTION
Achalasia is a rare and disabling disease that is characterised by reduced motility of the
oesophagus, coupled with the inability of the lower oesophagus sphincter (LOS) to relax
sufficiently. The word achalasia is derived from the Greeks word (a)chalasis, which can be
translated as “no relaxation”.
1
Patients usually experience retrosternal pain and progressive
dysphagia, when taking solid or liquid food.
2
The basic causes of achalasia are not known
yet.
1
In this article, we will discuss the clinical picture of achalasia and the possible treatment
options. Moreover, we will focus on a relatively new endoscopic treatment for achalasia: the
peroral endoscopic myotomy (POEM). At the moment, this technique is being used only in
two hospitals in the Netherlands and is performed under general anaesthesia outside the
operation room at the endoscopy suite.
EPIDEMIOLOGY
Achalasia is an uncommon disease. Worldwide, the incidence is approximately 1 of 100,000;
this means in the Netherlands, there are approximately 1500 patients. This disease has a
significant impact on the quality of life, efficiency of labour, and functional status of the
patient. An additional problem is that patients often have to undergo several invasive
interventions.
1
PATHOPHYSIOLOGY
The pathophysiology of achalasia is largely unknown. An association with the Down
syndrome and Parkinson’s disease, familial accumulation, and the results of twin studies
suggest a partial genetic basis for this disease. In addition, viral infections and immunologic
factors could also become important; it seems that autoimmune diseases aremore common
in patients with achalasia. T-lymphocytes have an important role in this context. Achalasia
is on histopathological examination characterised by the destruction of ganglion cells in
the plexus myentericus of the distal oesophagus and the LOS. The plexus myentericus is
important in the coordination of oesophageal peristalsis. In patients with achalasia, this
plexus is infiltrated by T-lymphocytes. This results in a reduced activity of inhibitory neurons
and an imbalance between activation and relaxation of the smooth muscle fibres of the
oesophagus and LOS. The result of this imbalance is an impaired relaxation and excessive
contractility of the muscle layer leading to constriction of the oesophageal lumen with
shortening during swallowing and an abnormal peristalsis with an increased tonus in the
LOS. The outcome of this combination is stasis of food, liquid, and saliva above the LOS.
1