Achlorhydria (absence of gastric acid secretion) can be caused by immune destruction to the stomach wall, malnutrition and marijuana use. The pentagastrin test is used as a diagnostic aid for evaluation of gastric acid secretory function.

A Mallory-Weiss tear occurs in the mucous membrane typically in the lower oesophagus. Mallory-Weiss tears are usually caused by forceful or prolonged vomiting or coughing. They may also be caused by epileptic convulsions. The tear may be followed by vomiting bright red blood or by passing blood in the stool. The incidence is 4 in 100,000 people

BCS is a good mnemonic for Barrett's dysplasia.

Barrett's Columnar replaces Squamous in Barrett’s oesophagus. This is also known as small intestinal (columnar) metaplasia. There is increased risk of oesophageal adenocarcinoma.

Nitrates, caffeine and alcohol can help relieve symptoms by relaxing lower oesophageal tone. Not all patients with GORD should undergo an OGD (should be considered if GI bleeding or symptoms of dysphagia occur). Oesophagitis is present in half of GORD patients. Oesophageal manometry or oesophageal motility study measures the strength of the lower oesophageal sphincter. This would rule out achalasia.

Achalasia: Botulinum injections are most effective of all the options for relieving a lower oesophageal sphincter restriction which leads to achalasia. Nifedipine, nitrates or sildenafil can also be used, but are less effective. Surgically, Heller’s oesophageal myotomy is the best treatment option, it can be done via an abdominal incision or laparascopically.

Bartter's syndrome is an autosomal recessive renal disorder. Presentation is often in childhood with gastrointestinal upset and polyuria. There is associated hypokalaemic alkalosis, elevated renin and aldosterone levels. Vomiting, constipation, polyuria and polydipsia are common symptoms.