Transcript Achalasia/Chagas Disease

Achalasia/Chagas
Disease
Kunwar Sohal, PGY 3
April 20, 2010
Achalasia
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Greek term that means "does not relax"
Loss of peristalsis in the distal esophagus (whose
musculature is comprised predominantly of smooth
muscle) and a failure of LES relaxation
Histologic examination reveals decreased numbers
of neurons (ganglion cells) in the myenteric
plexuses
Degeneration preferentially involves the nitric
oxide-producing, inhibitory neurons that effect the
relaxation of esophageal smooth muscle; the
cholinergic neurons that contribute to LES tone by
causing smooth muscle contraction are relatively
spared
Etiology
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Etiology of primary achalasia is not known,
however certain recognized diseases can
cause esophageal motor abnormalities
similar or identical to those of primary
achalasia
– Chagas Disease
– Malignancy: most common cause of
pseudoachalasia in most populations, through
invasion of plexus or as paraneoplastic syndrome
– Achalasia like motor abnormalities: amyloidosis,
sarcoidosis, neurofibromatosis
Diagnosis
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A barium swallow is the primary screening test
when achalasia is suspected on clinical grounds
Diagnostic accuracy of barium swallow for achalasia
is approximately 95 percent
Manometry: required for confirmation in virtually all
cases
– Elevated resting LES pressure, above 45mm Hg
– Incomplete/absent LES relaxation: in response to a
swallow
– Aperistalsis of the smooth muscle portion of the body of
the esophagus
Treatment
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Nitrates and CCBs
Botulinum toxin injection: poisons the excitatory
(acetylcholine-releasing) neurons that increase LES
smooth muscle tone
– Initial success rates of close to 80 percent are similar to
those seen with endoscopic balloon dilation and surgery
– Symptom relief wanes with time (70 percent at 3 months,
53 percent at 6 months, and 41 percent at 12 months
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Dilation of LES: for poor surgical candidates
Surgical Myotomy
Heller Myotomy and
Toupet fundoplication
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Myotomy: cut muscles
Toupet (posterior) fundoplication, the
fundus is wrapped around the back of
the esophagus
Chagas’ Disease
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Caused by the protozoan parasite, Trypanosoma cruzi
Humans can become infected with resulting acute or chronic
disease
Found only in Central and South America, Mexico and the
southern United States
WHO has estimated that 16 to 18 million people are infected
with T. cruzi, with an estimated annual infection rate of
300,000 and an annual mortality rate of >50,000 patients
Prevalence estimates are largely based upon results of testing
in blood banks. Between 1960 and 1989, the prevalence of
infected blood in selected cities of South America ranged from
1.7 percent in Sao Paulo, Brazil, to 53 percent in Santa Cruz,
Bolivia
70 to 90 percent of infected individuals are asymptomatic
carriers of T. cruzi and never develop any symptoms
Chagas’, contd
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Vector for this infection is the reduviid
bug, also known as the "kissing bug"
Once a bug is infected, it remains so
for life and can transmit infection for
several years
Chronic Chagas’ Disease
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Pathogenesis of chronic Chagas' disease is unclear
Extensive debate over whether the complications that arise
are due directly to parasite invasion or to secondary
autoimmune mechanisms
Approximately 50 percent of infected individuals develop
cardiac and/or digestive forms of the diseasetypically
demonstrate cardiomegaly, megaesophagus, and megacolon
Dilationmore R sided, signs of systemic congestion (ascites,
hepatomegaly) predominate over pulm edema
The most characteristic cardiac anatomic lesion is the
ventricular apical aneurysm which, in one series, was noted in
52 percent of 1078 autopsied chagasic patients
Histologic examination shows chronic mild myocarditis
Acute
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Most patients are asymptomatic during the
acute stage of infection
In a minority, acute infection may be
associated with a persistent local reaction,
or either Chagoma (swelling and local
lymphadenopathy) or for bites involving the
orbit
Microscopic examination shows intense
parasitism in virtually every organic system,
with prominent inflammatory changes in the
vicinity of ruptured infected cells
Diagnosis
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Diagnosis is generally made by testing
with at least two different serologic
tests
CDC recommends ELISA and IFA
(immunofluorescence assay)
Treatment
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If confirmatory testing is positive
The treatment is indicated for patients with the
acute form of the disease or in congenital disease,
no good studies in chronic
Recommendations do suggest that adults aged 1950 yrs without advanced Chagas cardiomyopathy,
that antitrypanosomal drug treatment should
generally be offerred (Bern et al, JAMA 2007)
Nifurimox is typically their first line treatment
(easier to release by CDC under current protocols),
for 90 days