A 26-year-old woman comes to the office due to recurrent nausea and vomiting for the past several months. The patient experiences nausea and epigastric discomfort after meals and often feels full after eating only a small portion of food. On several occasions, she has had emesis containing particles of food that she ate several hours earlier. The patient has a 15-year history of type 1 diabetes mellitus complicated by diabetic nephropathy. Her medications include a basal-bolus insulin regimen and lisinopril. She does not use tobacco, alcohol, or illicit drugs. Vital signs are within normal limits. The abdomen is soft and nontender with no organomegaly. Bowel sounds are normal. Testing of stool for occult blood is negative. An upper gastrointestinal endoscopy is unremarkable. Which of the following mechanisms is most likely responsible for this patient's current symptoms?

Question

A 26-year-old woman comes to the office due to recurrent nausea and vomiting for the past several months.  The patient experiences nausea and epigastric discomfort after meals and often feels full after eating only a small portion of food.  On several occasions, she has had emesis containing particles of food that she ate several hours earlier.  The patient has a 15-year history of type 1 diabetes mellitus complicated by diabetic nephropathy.  Her medications include a basal-bolus insulin regimen and lisinopril.  She does not use tobacco, alcohol, or illicit drugs.  Vital signs are within normal limits.  The abdomen is soft and nontender with no organomegaly.  Bowel sounds are normal.  Testing of stool for occult blood is negative.  An upper gastrointestinal endoscopy is unremarkable.  Which of the following mechanisms is most likely responsible for this patient's current symptoms?

Quizplus · Accepted Answer

11ec160b_3add_d2e3_9249_d9c446a496c3_MD0001_00 This patient with diabetes has postprandial nausea, vomiting, early satiety, and regurgitation of undigested food particles, which is suggestive of diabetic gastroparesis. Gastroparesis is a type of autonomic neuropathy involving the gastrointestinal tract and is characterized by delayed gastric emptying not due to an obstruction. Normal postprandial gastric activity is a multistep process that occurs in response to food ingestion. After food passes down the esophagus, vagally stimulated enteric neurons release nitric oxide to induce relaxation of the fundus of the stomach and accommodate the incoming food bolus. Specialized gastric pacemaker cells (interstitial cells of Cajal) initiate pacesetter potentials (slow waves), which generate circumferential contractions of the gastric smooth muscle (peristalsis). Peristalsis facilitates food mixing and propulsion toward the pylorus. Chronic hyperglycemia in patients with diabetes can result in destruction of the enteric neurons. Loss of nitric oxide-containing neurons results in impaired fundal relaxation, and loss of the interstitial cells of Cajal results in uncoordinated smooth muscle contractions and ineffective peristalsis, both of which delay gastric emptying. (Choice A) Chronic hyperglycemia can cause vagus nerve denervation with axonal damage, which can contribute to diabetic gastroparesis. However, the vagal motor nucleus is located in the brainstem and is typically unaffected by diabetes. (Choice B) Disruption of the lower esophageal sphincter can cause symptoms of acid reflux. Although severe gastroesophageal reflux can cause regurgitation, a history of heartburn or epigastric pain would be expected. In addition, upper endoscopy typically shows evidence of esophagitis (eg, mucosal erythema, exudates). (Choice D) Cholecystokinin is secreted in response to fat- or protein-rich meals and slows gastric emptying to improve digestion of these nutrients. Cholecystokinin secretion may actually be reduced in diabetes and is not thought to be a major cause of diabetic gastroparesis. (Choice E) Hypertrophy of pyloric smooth muscles is seen in congenital pyloric stenosis, which causes projective vomiting and is typically diagnosed in infancy. The smooth muscle cells typically remain normal in diabetic gastroparesis. Educational objective: Diabetic gastroparesis results from the destruction of enteric neurons due to chronic hyperglycemia, leading to impaired relaxation and disordered and ineffective peristalsis. This causes delayed gastric emptying, which presents as postprandial fullness, regurgitation of undigested food, nausea, and vomiting. __________ References: Diabetic gastroparesis. (http://www.ncbi.nlm.nih.gov/pubmed/25667022)

A 26-Year-Old Woman Comes to the Office Due to Recurrent