Achalasia is a motor disorder of the esophagus with characteristic radiographic
features on barium swallow (a dilated esophagus with air fluid levels
and a stereotypical “birds-beak” appearance at
the gastroesophageal junction) (eFig. 393.1)
and manometric findings as shown in Figure 393-1. The
manometric findings of achalasia include incomplete relaxation of
the lower esophageal sphincter and lack of normal esophageal peristalsis.
More recently, increased muscle mass has been noted with ultrasonographic evaluation
of the esophagus. The pathophysiology of achalasia is not certain,
but it seems likely that in many cases it is due to an autoimmune-mediated
process resulting in a loss of inhibitory relaxation of the LES. Congenital
or syndromatic cases likely have a separate etiology with specific
genetic abnormalities being identified in some associated syndromes
(see below). Presenting symptoms include dysphagia, regurgitation,
recurrent pneumonia, weight loss, and chest pain. The pathophysiology
of achalasia is not certain, but it seems likely that in many cases
it is due to an autoimmune-mediated process resulting in a loss
of inhibitory relaxation of the LES. Congenital or syndromatic cases
likely have a separate etiology with specific genetic abnormalities
being identified in some associated syndromes (see below). Histologic
specimens reveal a decrease in nitric oxide synthetase neurons containing
calcitonin gene–related peptide, vasoactive intestinal
peptide, and nitric oxide in the myenteric plexus of the distal
esophagus.3 Autoantibodies against neurons, CD3/CD8
predominant lymphocytic infiltrates, and evidence of complement
cascade activation has been found in the myenteric plexus in patients
with achalasia.4,5 Neuronal loss of neurons containing
calcitonin gene–related peptide, vasoactive intestinal
peptide, and nitric oxide is most marked. The overall incidence
of achalasia is 0.4 to 0.6 per 100,000, with only about 5% of
cases occurring in children and the average age of diagnosis being
about 9 years old. Achalasia occurs in association with other disorders
and syndromes, as listed in Table 393-2.
Chagas disease can be indistinguishable from achalasia and should
be considered in patients who have traveled to endemic areas, including
the southern United States and Latin America. Early presentation
of achalasia is frequently associated with an autosomal recessive
syndrome of deafness, vitiligo, short stature, and muscle weakness,
or with the syndrome of alacrima and corticotropin insensitivity
(Allgrove syndrome, or triple-A syndrome, which has been linked
with mutations on 12q13). Achalasia is also reported as part of
Alport syndrome and in children with Down syndrome.6 Rare
cases of familial achalasia and of familial coexistence of achalasia
and other esophageal motility disorders have been reported.7 Achalasia
has also been associated with autoimmune polyendocrinopathy syndrome
and multiple endocrine neoplasia type 2B. Leiomyoma or other tumors
of the stomach may masquerade as achalasia. Achalasia has also been
associated with familial visceral neuropathies, familial dysautonomia,
Sjogren syndrome, adrenoleukodystrophy and Addison disease.
Surgical treatment with a Heller myotomy (usually with an antireflux
procedure) is becoming the treatment of choice for achalasia.8 Pneumatic
balloon dilation of the LES9 ruptures the muscle
and may provide long-term relief from symptoms; however, repetitive treatments
often are necessary. Similarly, injection of the LES with botulinum
toxin10 provides transient relief, but the requirement
for repeated treatment makes these therapies less attractive for
treatment of childhood achalasia. Pharmacotherapy (eg, nifedipine)
is variably effective and rarely provides an option for long-term
management. Following treatment for achalasia, some degree of dysphagia
for solids often persists because of persistent aperistalsis of
the esophagus. This requires that patients chew food well and often
need liquid chasers to clear the esophagus. There is also a long-term
risk of esophagitis, Barrett esophagus, and esophageal adenocarcinoma
requiring consistent, long-term follow-up through adulthood.