Achalasia other diagnostic studies
Achalasia other diagnostic studies On the Web
American Roentgen Ray Society Images of Achalasia other diagnostic studies
Manometry is the key diagnostic test for achalasia. Barium esophagram and esophagogastroduodenoscopy are complimentry to manometry in diagnosing achalasia. Manometric findings such as absent peristalsis or incomplete LES relaxation without any mechanical obstruction characterize achalasia. Other supportive manometric findings in achalasia include raised basal LES pressure, increased intraoesophageal pressure and simultaneous non-propagating contractions.
Other Diagnostic Studies
A probe measures the pressure waves in different parts of the esophagus and stomach during the act of swallowing. A thin tube is inserted through the nose, and the patient is instructed to swallow several times. Pressure sensors are placed by means of conventional catheters in the esophagus at a distance ranging from 3-5 cm. On conventional manometry following findings characterize achalasia:
- Residual pressure of LES > 10 mmHg.
- Incomplete relaxation of the LES.
- Increased resting tone of LES
- Aperistalsis – contractions may be absent, diffuse and not coordinated, and/or ‘vigorous’.
- Raised intraoesophageal pressure (due to stasis of food)
High Resolution Manometry
High resolution manometry (HRM) provides more detailed information about esophageal pressures. It is the gold standard investigation for diagnosing achalasia. In HRM 36 or more pressure sensors are placed at a distance of not more than 1 cm from each other. Following table depicts characteristics of achalasia on conventional and high resolution manometry:
|Conventional manometry||High resolution manometry|
|Mean fall in post deglutitive LES pressure > 8mmHg above gastric pressure
Basal LES pressure > 45 mmHg
|Impaired EJG relaxation|
Mean 4s IRP > 10 mmHg over test swallows
|No contractions and/or
Simultaneous contractions with amplitudes <40 mmHg
|Absent peristalsis (Type 1 achalasia)|
Pan esophageal pressurization (Type II achalasia)
|Peristalsis present with esophageal contractions > 40 mmHg OR
Simulataneous contractions > 40 mmHg
|Spastic achalasia (Type III achalasia)|
IRP refers to integrated relaxation pressure which is a new parameter which determines post deglutitive LES pressure of a 4 seconds duration.
Above table adapted from " ACG Clinical Guidelines: Diagnosis and Management of Achalasia" by Vaezi et al.
Cholecystokinin (CCK) stimulation test
Cholecystokinin (CCK) stimulation test: CCK causes mild contraction of the LES and a more pronounced release of inhibitory neurotransmitters in the wall of the esophagus. In normal people, LES tone will decrease due to the predominant effect of the inhibitory neurotransmitters. In patients with achalasia, however, the stimulatory effect on the LES is unopposed, and LES pressure increases.
- Vaezi MF, Pandolfino JE, Vela MF (2013). "ACG clinical guideline: diagnosis and management of achalasia.". Am J Gastroenterol. 108 (8): 1238–49; quiz 1250. PMID 23877351. doi:10.1038/ajg.2013.196.
- Kahrilas PJ (2010). "Esophageal motor disorders in terms of high-resolution esophageal pressure topography: what has changed?". Am J Gastroenterol. 105 (5): 981–7. PMC . PMID 20179690. doi:10.1038/ajg.2010.43.
- Ghosh SK, Pandolfino JE, Rice J, Clarke JO, Kwiatek M, Kahrilas PJ (2007). "Impaired deglutitive EGJ relaxation in clinical esophageal manometry: a quantitative analysis of 400 patients and 75 controls.". Am J Physiol Gastrointest Liver Physiol. 293 (4): G878–85. PMID 17690172. doi:10.1152/ajpgi.00252.2007.
- Boeckxstaens GE, Zaninotto G, Richter JE (2014). "Achalasia.". Lancet. 383 (9911): 83–93. PMID 23871090. doi:10.1016/S0140-6736(13)60651-0.