Failure of either contractility or deglutitive inhibition will result in failure of bolus progression and will be felt by the patient as Dysphagia. Excessive peristaltic contraction of the esophagus (nutcracker esophagus) and diffuse esophageal spasm are usually associated with pain, although Dysphagia may be a feature. More commonly Dysphagia occurs because of uncoordinated or hypotensive esophageal contraction. The most well defined example of such abnormalities would be achalasia of the cardia.
Achalasia, literally ‘failure to relax’, is characterized by uncoordinated, non-progressive contraction within the esophageal body. In addition the LOS fails to relax on swallowing, and is usually hypertensive at rest.
Achalasia presents with Dysphagia as the primary symptom. As the disease progresses the esophagus dilates proximal to the obstructing LOS, and can harbor large volumes of food, which may be regurgitated or even aspirated if it doesn’t pass distally. Patients often lose weight as the symptoms progress. Dysphagia in Achalasia is variable and can occur to solids and liquids. Patients may be able to assist esophageal emptying by employing manoeuvres such as straightening up or lifting their arms.
The cause of idiopathic Achalasia is unknown, but Chagas disease, which is a trypanosomal infection most prevalent in South America, closely mimics the esophageal changes of Achalasia. Achalasia may also be mimicked by tumor infiltration around the gastric cardia. It is important therefore to obtain an endoscopic evaluation in all cases and to maintain a high index of suspicion in older patients presenting with apparent Achalasia.
Oesophageal manometry is the cornerstone for the diagnosis of Achalasia. The pathognomonic features are failure of LOS relaxation and disordered or absent esophageal contraction, particularly in the distal esophageal body.
The finding of resting LOS hypertension is a common additional feature. Early in the evolution of the disease, some patients may exhibit strong esophageal contractions on swallowing, although the contractions will yield an isobaric waveform with non- progression. This is known as vigorous Achalasia.
Etiology of achalasia cardia
There is derangement of the neuromuscular mechanism responsible for the normal working of the cardiac sphincter which fails to relax when food reaches it. Degeneration of the ganglionic cells of the nerve plexus of the esophageal wall or the vagus nerve (or its nuclei), or an abnormality in the post ganglionic neuromuscular transmission are some of the possible causes.
The fact that the trouble often starts or is reactivated during or after mental stress (e.g. fear or mental shock) has led to the belief that it is a psychosomatic disorder. Rarely, achalasia occurs secondary to Chagas disease, gastric carcinoma infiltrating into the esophagus, lymphoma, irradiation, or due to certain toxins, drugs or infection due to neurotropic viruses.
The condition is more common in females and majority of cases occur between 25 to 35 years of age.
Pathogenesis of achalasia cardia
The disease is thought to be due to a neuromuscular disorder, possibly degeneration of the myenteric plexus (Auerbach plexus). Psychogenic or hormonal factors are also possible.
Clinical features of Achalasia Cardia
Dysphagia is the commonest presenting symptom in patients with achalasia cardia, and occurs in more than 95% of patients. In general, the Dysphagia due to motor disorders of the esophagus occurs with solids as well as liquids. However, most patients with Achalasia complain predominantly, if not exclusively, of Dysphagia to solid food. The converse, Dysphagia for liquids only, almost never occurs.
Patients often localize the Dysphagia to the region of the LES. The natural history of Dysphagia varies. Some patients notice that the Dysphagia reaches to certain degree of severity, and then stops progressing. In others, the Dysphagia continues to worsen to the extent that it results in markedly reduced oral intake, malnutrition and inanition. Emotional stress and the ingestion of cold liquids are well known exacerbating and precipitating factors. The duration of Dysphagia averages two years at presentation.
Eighty to ninety percent of patients with Achalasia experience spontaneous regurgitation of food from the esophagus. The regurgitation of food from the esophagus, the regurgitation is because of progressive stasis of food that the patient has eaten hours, or even days, previously. Some patients learn to induce regurgitation to relieve the retrosternal discomfort related to the distended esophagus. As the disease progresses, the likelihood that aspiration will occur increase. Patients may present with serious pulmonary complication like pneumonia, lung abscesses, bronchiectasis and hemoptysis.
Chest pain is present in two thirds of patients. Typically, patients describe chest pain as being retrosternal. This is a more common feature in patients with early or so called vigorous achalasia, which is characterized by prominent contractions in the body of the esophagus, documented by radiography or manometry. These contractions are simultaneous and hence esophageal musculature gets fatigued, chest pain tends to abate or disappear.
The chronic obstruction at the level of the LES may occasionally result in the development of an esophageal diverticulum in the distal esophagus. Identification of this is important as its presence increases the risk of esophageal perforation during pneumatic dilation to treat the achalasia.
It is important to rule out secondary cause of achalasia (secondary achalasia, pseudoachalasia), such as gastroesophegeal cancer and paraneoplastic syndromes, prior to making a diagnosis of idiopathic achalasia. It is better to rule out with endoscopy with judicious use of CT scan and endosonography.
If a patient with achalasia presents with significant loss of weight over a short period, esophageal cancer should be ruled out. When cancer develops, it is usually squamous, and arises in the dilated middle part of esophagus, rendering it relatively silent until late. Heartburn, and response to antacids, is indistinguishable from that seen in patients with gastroesophegeal reflux disease (GERD). In fact, some patients with achalasia are mistakenly diagnosed with GERD for many years. Other rare symptoms of achalasia include airway compromise and stridor because of compression of the trachea by the dilated esophagus.
Differential Diagnosis of achalasia cardia
The differential diagnosis of achalasia begins with the broad differential diagnosis of Dysphagia and exclusion of mechanical causes of Dysphagia. Strictures, benign neoplasm, vascular rings, webs, foreign bodies, and severe oesophagitis (peptic, infectious, chemical, drug induced) are among the frequently encountered entities.