Possible causes of esophageal spasms

Although the etiology of esophageal spasms is unknown, there are several possible scenarios:

• An increased release of acetylcholine appears to be a factor, but the triggering event is not known.
• Gastric reflux or a primary nerve or motor disorder.
• Microvascular compression of the vagus nerve in the brainstem has been demonstrated in recent research as a possible triggering event.
• Hot or cold foods [2]

Esophagus Physiology 

The esophagus is comprised of two layers of muscle, the inner circular, and the outer longitudinal layers. The esophagus can be divided into three zones, each with separate anatomy and physiology. [4]

Upper zone

Made entirely of striated muscle, this zone initiates the contractions that propel the food down the esophagus. The upper esophageal sphincter is located in the upper zone. It prevents food from returning the same way up.

Middle zone

The middle zone is made of striated and smooth muscles. It is made of the inner circular muscle layer and the outer longitudinal muscle layer which work in conjunction to propel the food.

Lower zone

The lower segment is the lower esophageal sphincter. This circular muscle is a thickening of the smooth muscle that is contracted to prevent reflux. The pressure in the LES should normally be 15-25 mm Hg.

Esophageal Muscles

Upper esophageal sphincter 

When functioning properly, the esophagus can detect the presence of food at the upper esophageal sphincter. It coordinates progression of food down the esophagus to the stomach. Evaluation of the upper esophageal sphincter reveals constant spiking activity. When a person starts swallowing food, the tonic contraction of the UES is inhibited, opening the UES to allow passage of food. The longitudinal muscles must contract to propel the food, which is followed immediately by the contraction of the circular muscles. That’s how the initial wave starts, propelling the food down to the middle zone.

Esophageal middle zone 

The middle zone of the esophagus propels the food from the upper zone to the lower zone. This segment consists of two muscle layers, an inner circular and outer longitudinal layer.

There is only one but a very important difference — in the middle zone, the striated muscle transitions to smooth, or involuntary, muscle. If the muscle contraction of this part of esophagus is not orderly, food bolus cannot progress.

There are two forces that propel food:

• First, gravity pulls the food caudally.
• Second, the organized contractions of the muscles propel the food caudally. 

Lower esophageal sphincter 

The lower zone is comprised of the lower esophageal sphincter. This is a condensation of the smooth muscles. This muscle is contracted and must relax to allow food to pass. Failure of the LES to relax and allow a food bolus to pass is termed achalasia.

Diagnosis Of Esophageal Spasms

Physical examination and patient history 

A doctor can often determine the cause of esophageal spasms by doing a physical exam and asking a patient a series of questions. These include questions about what foods or liquids trigger symptoms, where it feels like food gets stuck, other symptoms or conditions she or he may have, and whether a patient is taking medications.

Laboratory studies

Laboratory evaluation usually does not help in the diagnosis if patients' history and physical examination are unremarkable for other diseases mentioned in the differential diagnosis.

Blood sugar and hemoglobin A1C levels should be checked to rule out diabetes. However, patients can have esophageal spasm and diabetes concomitantly. The findings discovered by monitoring a patient's pH can demonstrate reflux, which can present with somewhat similar symptoms. 

Barium swallow test

It is important to point out that barium swallow is the best possible imaging study to help in the diagnosis of an esophageal spasm. Barium swallow images show typical appearance of multiple simultaneous contractions. This is often referred to as a corkscrew appearance.

CT scan

The hypertrophy of the muscle wall is the cause of the increased thickness that is observed on CT scan images. The normal thickness of the esophagus is less than 3 mm and in cases of esophageal spasms it is much thicker.

Many other disease processes, including malignancy, can cause thickening of the esophagus that can be seen and that’s why it also helps to rule out some of these conditions.

Even in patients with symptoms of esophageal spasms, thickening seen on CT scan images should not be dismissed as muscular hypertrophy secondary to the esophageal spasms without further investigation. That’s why further analysis is necessary. 

Manometry

Manometry in patients with nutcracker esophagus demonstrates contractions that progress in an orderly manner, with an excessive amplitude. Amplitude greater than two standard deviations above the normal value is considered diagnostic for nutcracker esophagus.

Endoscopy 

An endoscopy is a very useful diagnostic tool to examine the condition and function of the esophagus. Tests measure acid levels in the esophagus as well as the strength and pattern of muscle contractions in the esophagus. [5]