Functional Dyspepsia – Causes, Symptoms, Treatment

Functional dyspepsia is one of the most common functional gastrointestinal disorders and affects more than 20% of the population.  There are three different subtypes:

• epigastric pain syndrome (EPS),
• postprandial distress syndrome (PDS), and
• overlapping PDS and EPS.

Pathophysiology

Although the exact mechanism is not well understood, the pathophysiology of functional dyspepsia is complex. Several different mechanisms are thought to contribute to each subtype.[rx] Traditionally, functional dyspepsia has been attributed to disturbances in gastric physiologic factors divided into macroscopic and microscopic mechanisms. Macroscopic mechanisms include gastroesophageal reflux (GERD), delayed gastric emptying, and visceral hypersensitivity alterations in the nervous system. Microscopic mechanisms include impaired barrier function, altered sensitivity to duodenal acid or lipids, and gastroduodenal inflammation.[rx] Additional mechanisms include environmental insults like food inducing gastroduodenal physiologic changes, infections causing inflammation, and allergen exposure can lead to eosinophil recruitment in genetically predisposed patients. Psychological factors like anxiety and depression can cause a negative stimulus to the brain-gut axis, suggesting that there is central processing of visceral stimuli from sensations in the gastrointestinal tract.[rx][rx][rx][rx]

Causes of Functional Dyspepsia

The etiology of functional dyspepsia is likely multifactorial; however, the exact cause is not clearly understood.  Several risk factors have been seen to be associated with the condition.[rx]

• Enteric infections: H. pylori, Escherichia coli O157, Campylobacter jejuni, and Salmonella.
• Recent antibiotic use
• Use of non-steroidal anti-inflammatory drugs
• Being overweight
• Smoking
• Psychosocial dysfunction

Medications

• Aspirin and many other painkillers such as nonsteroidal anti-inflammatory drugs (NSAIDs)
• Steroids (such as prednisone, methylprednisolone, and Decadron)
• Estrogen and oral contraceptives
• Antibiotics (such as erythromycin and tetracycline)
• Thyroid medication
• Blood pressure medication
• Cholesterol medications (statins)
• Pain medications (codeine and other narcotics)

Diseases

• Ulcers
• GORD, where acids from the stomach reflux back up the oesophagus
• Stomach cancer (rare)
• Gastroparesis (a condition where the stomach doesn’t empty properly; this often occurs in diabetics)
• Stomach infections
• Irritable bowel syndrome
• Chronic pancreatitis
• Thyroid disease
• Pregnancy

 Symptoms Of Functional Dyspepsia

• Abdominal pain
• Heartburn or acid indigestion (acid reflux)
• Bloating (full feeling)
• Excessive gas (belching, burping or flatulence)
• Nausea with or without vomiting
• Acidic taste in the mouth
• Gurgling, rumbling, or growling stomach discomfort
• Constipation or diarrhea
• Decreased appetite
• Burning sensation in the chest or upper abdomen, often called heartburn
• Abdominal pain
• Bloating (full feeling)
• Burping and passing wind
• Nausea and vomiting
• Acidic taste

Diagnosis of Functional Dyspepsia

Functional dyspepsia is diagnosed based on the Rome IV criteria.  It is defined by the presence of one or more of the following symptoms: epigastric pain or burning, early satiety, and postprandial fullness in the absence of structural disease using imaging or endoscopy.[rx][rx][rx] First, patients should be tested and treated for Helicobacter pylori (H. pylori) if they are less than 60 years of age.[rx][rx] Then, further treatment consists of symptom management with proton pump inhibitors (PPI), H2 receptor antagonists (H2RA), prokinetic agents, and even antidepressants.[rx][rx] Alarms symptoms such as weight loss, dysphagia, or vomiting, or if greater than age 60, warrant an endoscopic evaluation.[rx]

History and Physical

• Typical symptoms can be divided into the subtypes PDS and EPS, and there exists an overlap between the two syndromes. These symptoms can be acute or chronic. PDS patients report loss of appetite, early satiation, nausea, retching, vomiting, and bloating.
• In EPS, patients have stomach cramping and other upper abdominal pain. Some symptoms are non-gastrointestinal. Patients often report associated diaphoresis, headache, sleep disorders, and irritable bladder.
• Functional dyspepsia symptoms usually do not progress and lack red flag signs of unintentional weight loss, dysphagia, night sweats, and persistent vomiting.[rx] Patients usually have an unremarkable physical exam, and this can assist in excluding other diagnoses.[rx]

Evaluation

The American College of Gastroenterology (ACG) recommends the routine use of upper endoscopy in patients older than 60 years to rule out malignancy, especially in the setting of red flag signs. If patients do not respond to treatment, it is reasonable to pursue more specialized testing specific to the symptoms.[rx]

In addition to a physical exam and questions about your symptoms, a doctor may perform the following tests. To exclude organic causes, evaluation can start with laboratory tests, including blood count, complete metabolic panel, thyroid function, and inflammatory markers. [rx]

• Blood tests
  • complete blood count (CBC)
  • the liver panel, amylase, and lipase (for pancreatitis)
  • kidney function test
  • guaiac test (a test for blood in the stool)
• Helicobacter pylori (H. pylori) testing, either by stool test or breath test
• Abdominal ultrasound
• Esophagogastroduodenoscopy (EGD, or endoscopy)
  • capsule endoscopy
• Colonoscopy
• Upper GI and small bowel X-ray series
• CT Scan or MRI of the abdomen
• Gastric emptying study
• Instrumental examinations include esophagogastroduodenoscopy with biopsy and abdominal ultrasonography.

Treatment of Functional Dyspepsia

Treatment can be challenging, where the main aim is symptom control.[rx][rx] Initial management begins with an explanation of the diagnosis and discussing the patient’s expectations for treatment. If it is suspected, H. pylori eradication is recommended as the first treatment for all patients with functional dyspepsia, as this improves symptoms and decreases the risk of peptic ulcers and gastric cancer.[rx][rx] After this, treatment is a two-step process.

• The first-line treatment is with a proton pump inhibitor or H2 receptor antagonist for at least four weeks.
• Antacids –These counter the effects of stomach acid. Examples include Alka-Seltzer, Maalox, Rolaids, Riopan, and Mylanta. These are over-the-counter (OTC) medicines that do not need a prescription. A doctor will usually recommend an antacid medication as one of the first treatments for dyspepsia.
• H-2-receptor antagonists–These reduce stomach acid levels and last longer than antacids. However, antacids act more quickly. Some of these are OTC, while others are only available on prescription. Some people may experience nausea, vomiting, constipation, and headaches after taking these. Other side effects may include bruising or bleeding.
• Proton pump inhibitors (PPIs) – Examples include Aciphex, Nexium, Prevacid, Prilosec, Protonix, and Zegerid. PPIs are highly effective for people who also have gastroesophageal reflux disease (GERD). They reduce stomach acid and are stronger than H-2-receptor antagonists.
• Prokinetics – This medication is helpful for stomachs that empty slowly. One example of a prokinetic drug is Reglan. Side effects may include tiredness, depression, sleepiness, anxiety, and muscle spasms.
• Antibiotics –  If H. pylori is causing peptic ulcers that result in indigestion, an antibiotic will be prescribed. Side effects may include an upset stomach, diarrhea, and fungal infections.
• Antidepressants – If the doctor finds no causes for indigestion after a thorough evaluation, and the person with dyspepsia has not responded to treatments, the doctor may prescribe low-dose antidepressants.
• Antidepressants sometimes ease discomfort by reducing the sensation of pain. Side effects may include nausea, headaches, agitation, constipation, and night sweats.
• Psychological therapy – For people with functional dyspepsia, psychological therapy can help manage the cognitive aspects of indigestion. Cognitive-behavioral therapy, biofeedback, hypnotherapy, and relaxation therapy may be recommended.

Then, if symptoms persist, subsequent treatment with tricyclic antidepressants, or prokinetic agents like metoclopramide and acotiamide (not available in the U.S.) are pursued.[rx][rx][rx][rx][rx][rx] Adjunctive or alternative non-pharmacologic therapies include psychotherapy, herbal supplementation, lifestyle modification, dietary interventions, acupuncture, and electrical stimulation.[rx]

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3975977/
• https://www.ncbi.nlm.nih.gov/books/NBK441938/
• https://www.ncbi.nlm.nih.gov/books/NBK409/
• https://www.ncbi.nlm.nih.gov/books/NBK519548/
• https://www.ncbi.nlm.nih.gov/books/NBK519548/
• https://www.ncbi.nlm.nih.gov/books/NBK554563/
• https://en.wikipedia.org/wiki/Regurgitation_(digestion)
• https://www.health.harvard.edu/digestive-health/9-ways-to-relieve-acid-reflux-without-medication