Achalasia – Causes, Symptoms, Diagnosis, Treatment

Achalasia is not a common disorder in medicine. Most clinicians will not encounter a patient with this esophageal smooth muscle motility disorder, which occurs because the lower esophageal sphincter fails to relax[rx]. The esophagus also has a marked absence of peristalsis[rx]. In less than 50% of patients, the lower esophageal sphincter is hypertensive.[rx] This condition causes a functional obstruction at the gastroesophageal junction.

Esophageal achalasia is a primary smooth muscle motility disorder specified by peristalsis of the tubular esophagus in combination with a poorly relaxing and occasionally hypertensive lower esophageal sphincter (LES). These changes occur secondary to the destruction of the neural network coordinating esophageal peristalsis and LES relaxation (plexus myentericus). There are limited data on the segmental involvement of the esophagus in adults.

Synonyms of Achalasia

• cardiospasm
• dyssynergia esophagus
• esophageal aperistalsis
• megaesophagus

Pathophysiology

The esophagus is the conduit of transport for food bolus from the mouth to the stomach, but it also prevents back reflux of the contents of the stomach. Coordinated peristaltic contractions in the pharynx and esophagus pared with the relaxation of the upper and lower esophageal sphincters (LES) achieve this transport.[rx] Parasympathetic excitatory and inhibitory pathways innervate the smooth muscles of the lower esophageal sphincter. Excitatory neurotransmitters, such as substance P and acetylcholine, and inhibitory neurotransmitters, such as vasoactive intestinal peptide (VIP) and nitric oxide (the most important inhibitory neurotransmitter of the myenteric plexus), modulate lower esophageal sphincter pressure and relaxation. Individuals with achalasia lack noncholinergic, nonadrenergic inhibitory ganglion cells, but the excitatory neurons remain unaffected.[rx] This lack of inhibitory ganglion cells results in an imbalance of inhibitory and excitatory neurotransmission.[rx][rx] The result is a non-relaxed hypertensive esophageal sphincter.

Gradual neural degeneration directly results in excessive contractions of the lower esophageal sphincter and a loss of regulation. This degeneration leads to the functional obstruction, which then results in dilatation. This dilatation results in irreversible peristalsis and worsening obstructive symptoms. The reason that these changes occur is unclear.

Some studies have investigated the association of achalasia with genetic polymorphisms of the three nitric oxide synthase isoforms and specific Human infection?. সহজ বাংলা: শ্বেত রক্তকণিকা।" data-rx-term="leukocyte" data-rx-definition="Leukocyte means white blood cell, which helps fight infection. সহজ বাংলা: শ্বেত রক্তকণিকা।">Leukocyte? Antigen (HLA) classes[rx]. One European study strongly supports the notion that achalasia may be an autoimmune? disorder in which autoantibodies appear to interact with DNA, like in type 1 insulin? is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes? and lupus. A genetic association study of achalasia showed that an eight-residue insertion at position 227-234 in the cytoplasmic tail of HLA-DQß1 confers the most potent known risk factor for achalasia while two amino acid substitutions in the extracellular region of HLA-DQa1 at position 41 and HLA-DQß1 at position 45 are independent risk factors for achalasia.[rx] These investigators replicated this finding in another study, which also showed that the insertion was more common in southern Europeans compared to northern Europeans showing a geospatial north-south gradient among Europeans.[rx]

Causes of Achalasia

Achalasia is thought to occur from the degeneration of the myenteric plexus and vagus nerve fibers of the lower esophageal sphincter.[rx][rx] There is a loss of inhibitory neurons containing vasoactive intestinal peptide (VIP) and nitric oxide synthase at the esophageal myenteric plexus, but in severe cases, it also involves cholinergic neurons.[rx][rx] The exact etiology of this degeneration is unclear though many theories have been proposed. These theories include an autoimmune? phenomenon, viral? infection?, and genetic predisposition.[rx][rx] Most cases seen in the United States are primary idiopathic? achalasia; however, secondary achalasia may be seen in Chagas disease caused by Trypanosoma cruzi, esophageal infiltration by gastric carcinoma, eosinophilic gastroenteritis, lymphoma, certain viral? infections, and neurodegenerative disorders.[rx]

Symptoms of Achalasia

Achalasia symptoms generally appear gradually and worsen over time. Signs and symptoms may include:

• Inability to swallow (dysphagia?), which may feel like food or drink is stuck in your throat
• Regurgitating food or saliva
• Heartburn
• Belching
• Chest pain? that comes and goes
• Coughing at night
• Pneumonia (from aspiration of food into the lungs)
• Weight loss?
• Vomiting?

Diagnosis? of Achalasia

History and Physical

Physical examination may reveal an emaciated individual.

• A frequently used grading system for achalasia is the Eckardt symptom score. It is used in the evaluation of symptoms, stages, and efficacy of achalasia treatment. It assigns the four most common symptoms of the disease (weight loss?, chest pain?, dysphagia?, and regurgitation) a score of 0-3 based on the severity of symptoms with a maximum total score of 12. A score of 0-1 corresponds to clinical stage 0, 2-3 to stage 1, 4-6 to stage 2, and greater than 6 to stage 3. Regarding prognosis?, stages 0-1 indicate disease remission?, while stages 2-3 represent a failure of treatment.[rx]

Evaluation

When there is clinical suspicion for achalasia, diagnostic studies to confirm the disease must take place as symptoms do not reliably diagnose achalasia. It is also crucial to exclude benign? and malignant? causes of lower esophageal obstruction[rx].

• Barium esophagogram (barium swallow) – The classic finding on the barium swallow is the smooth tapering of the lower esophagus to a “bird’s beak” appearance, with dilatation of the proximal esophagus and lack of peristalsis during fluoroscopy. Some cases reveal an air-fluid level and absence of intra-gastric air while in advanced disease, a sigmoid-like appearance of the esophagus may be visible. A timed barium swallow is used to access esophageal emptying. This variant of the classic barium swallow is performed by having the patient drink 236 ml of barium in the upright position and taking radiographs at one, two, and five minutes after the last swallow. The height of the barium column after five minutes and the esophageal width are measured pre and post-treatment.[rx][rx]
• Upper endoscopy? (esophagogastroduodenoscopy – EGD) – is recommended in all patients with suspected achalasia or dysphagia? to exclude premalignant or malignant? lesions involving the esophagus.[rx] EGD has low accuracy in the diagnosis? of achalasia and may be normal in the early stages of the disease. Findings in advanced cases include rosette appearance of the esophagogastric junction or an esophagus, which has become dilated, tortuous, and atonic often with retained food and saliva. The esophagus may be normal or show evidence of esophagitis due to chronic? stasis. Fire resistance of the scope passing through the esophagogastric junction, especially in an older patient or one with a short duration of symptoms and significant weight loss?, should raise the concern for pseudoachalasia, especially malignancy. Other useful studies in cases of pseudoachalasia are CT scan?, endoscopic ultrasound? (to rule out submucosal lesions), and transabdominal ultrasound.[rx][rx]
• Esophageal manometry – is the most sensitive test for the diagnosis? of achalasia and remains the gold standard.[rx] Manometry will reveal incomplete lower esophageal sphincter relaxation in response to swallowing, sometimes a lack of peristalsis in the lower esophagus, and an increase in pressure of the lower esophageal sphincter. The use of conventional manometry has mostly given way to high-resolution manometry (HRM), which also includes pressure topography plotting.[rx][rx][rx] Using HRM, achalasia is classified by the Chicago criteria (version 3.0) into three distinct categories, which have prognostic and treatment implications.
• Manometry – a small plastic tube is passed through your mouth or nose into your oesophagus to measure the muscle pressure along it at different points.
• Barium swallow – you drink a white liquid containing the chemical barium and X-rays are taken. The barium shows up clearly on X-ray? so the doctor can see how long it takes to move into your stomach.
• Endoscopy? – a thin, flexible instrument called an endoscope is passed down your throat to allow the doctor to look directly at the lining of your oesophagus, the ring of muscle and your stomach.

Recommended Courses of Action

• Esophageal manometry to reveal incomplete lower esophageal sphincter relaxation in response to swallowing, high resting lower esophageal sphincter pressure, and the absence of esophageal peristalsis.
• Prolonged esophageal pH monitoring to rule out gastroesophageal reflux disease and determine if the treatment causes abnormal reflux
• Esophagogastroduodenoscopy (EGD) to rule out any cancer of the gastroesophageal junction or fundus
• Concomitant endoscopic ultrasonography if a tumor is suspected

Treatment of Achalasia

Treatment is to ease the symptoms of achalasia by decreasing the outflow resistance caused by a non-relaxing and hypertensive lower esophageal sphincter. Current treatment modalities for primary idiopathic? achalasia are nonsurgical or surgical. Nonsurgical options are pharmacotherapy, endoscopic botulinum toxin injection, or pneumatic dilatation. Surgical options are laparoscopic Heller myotomy (LHM) and peroral endoscopic myotomy (POEM).

Pharmacologic treatments

Treatment includes the administration of

• Nitrates
• Calcium channel blockers, and
• Phosphodiesterase-5 inhibitors to reduce the lower esophageal sphincter (LES) pressure.
• Calcium channel blockers – inhibit the entry of calcium into the cells blocking smooth muscle contraction, leading to a decrease in LES pressure.
• Nitrates increase nitric oxide – concentrations in smooth muscles, causing an increase in cyclic adenosine monophosphate levels, which leads to smooth muscle relaxation. These treatments are less effective, provide only short-term relief of symptoms, and are primarily reserved for patients who are waiting for or who refused more definitive therapy, such as pneumatic dilatation or surgery.[rx][rx]
• Endoscopic injection of botulinum toxin  – can be used in high-risk patients or those who relapse? after myotomy. Botulinum toxin, derived from Clostridium botulinum, is a potent biological neurotoxin known to block the release of acetylcholine at the level of the lower esophageal sphincter[rx]. This treatment is useful in patients who may not be candidates for surgery or dilatation or alternatively, as a bridge to more definitive therapy. Limitations to botulinum toxin injections are that the effect is short-lived (lasting about 6 to 12 months), patients often require multiple treatments that are expensive and may reduce the success of subsequent surgical myotomy.[rx][rx][rx]
• Pneumatic dilatation  – of the esophagus via endoscopy is the most cost-effective non-surgical therapy for achalasia.[rx][rx] Dilatation of the esophagus is achieved by disrupting the circular fibers of the LES with air pressure using a graded dilator approach. [rx][rx][rx]
• Peroral endoscopic myotomy (POEM) – is an effective minimally invasive alternative to laparoscopic Heller myotomy to treat achalasia at limited centers.[rx] Dissection of the circular fibers of the LES is achieved endoscopically, leading to relaxation of the LES; however, the risk of gastroesophageal reflux is high because it does not include an antireflux procedure. Esophagectomy is the last resort.
• Stretching the muscle (balloon dilation) – Under a sedative or general anaesthetic, a balloon is passed into the oesophagus using a long, thin flexible tube (endoscope). The balloon is then inflated to help stretch the ring of muscle that lets food into your stomach. This improves swallowing for most people, but you may need treatment several times before your symptoms improve.
• Pneumatic dilatation – In balloon (pneumatic) dilation or dilatation, the muscle fibers are stretched and slightly torn by forceful inflation of a balloon placed inside the lower esophageal sphincter. There is always a small risk of a perforation which requires immediate surgical repair. Pneumatic dilatation causes some scarring which may increase the difficulty of Heller myotomy if the surgery is needed later. Gastroesophageal reflux (GERD) occurs after pneumatic dilatation in some patients. Pneumatic dilatation is most effective in the long-term on patients over the age of 40; the benefits tend to be shorter-lived in younger patients. It may need to be repeated with larger balloons for maximum effectiveness.^[rx]

Home Care (What do I need to do once my child goes home?)

• Diet –  Most patients are instructed to eat a soft diet for several days after the surgery. When they are advanced to a general diet, they are to continue eat with small bites and chew thoroughly.
• Activity – If the patient had the procedure with small incisions (laparoscopic), he or she can be back to normal activity in 1-2 weeks. If the surgery is done through a big incision, then he or she can be back to normal activities in six weeks, with a weight restriction of 10 pounds up until that time.
• Wound care –  The patient can shower in three days but may want to wait 5-7 days after surgery before soaking the wound.
• Medicines – Medication for pain such as acetaminophen (Tylenol) or ibuprofen (Motrin or Advil) or something stronger like a narcotic may be needed to help with pain for a few days after surgery. Sometimes, if the patient has heartburn symptoms, medications to decrease the acidity of the stomach (antihistamine blockers such as ranitidine and proton pump inhibitors such as omeprazole) may help. Stool softeners and laxatives are needed to help regular stooling after surgery, especially if narcotics are still needed for pain.
• What to call the doctor for – After discharge from surgery, problems that may indicate infection such as fevers, wound redness and discharge should be addressed. If there is a lot vomiting, chest pain or food getting stuck in the esophagus, the surgeon should be contacted.
• Follow-up care –  The patient should be seen by a surgeon at least once to check the surgical wound. The patient’s gastroenterologist may require multiple visits for months to years to make sure that the patient remains symptom free.

References