A 43-year-old man comes to the office with a several-month history of fatigue, rash, flushing, and abdominal cramps. His rash is worse with rubbing or scratching, and he has diffuse itching after hot showers. The patient is frequently dizzy and light-headed after prolonged standing and had an episode of syncope while working in the hot sun. He used to be healthy and physically active but has had to reduce his normal activity. The patient does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. Skin examination shows a maculopapular rash. Skin biopsy shows large clusters of mast cells that are positive for KIT (CD 117). Which of the following additional findings are most likely present in this patient?

Question

A 43-year-old man comes to the office with a several-month history of fatigue, rash, flushing, and abdominal cramps.  His rash is worse with rubbing or scratching, and he has diffuse itching after hot showers.  The patient is frequently dizzy and light-headed after prolonged standing and had an episode of syncope while working in the hot sun.  He used to be healthy and physically active but has had to reduce his normal activity.  The patient does not use tobacco, alcohol, or illicit drugs.  Vital signs are normal.  Skin examination shows a maculopapular rash.  Skin biopsy shows large clusters of mast cells that are positive for KIT (CD 117).  Which of the following additional findings are most likely present in this patient?

Quizplus · Accepted Answer

11ec160b_3ae6_1050_9249_3b3271d2e35d_MD0001_00 Gastric acid secretion by parietal cells in the fundus and body of the stomach is stimulated by: Intracellular calcium and cAMP activate protein kinases and lead to increased transport of H⁺ by H⁺/K⁺ ATPase into the gastric lumen. In systemic mastocytosis, clonal mast cell proliferation occurs in the bone marrow, skin, and other organs. Mast cell proliferation often is associated with mutations in the KIT receptor tyrosine kinase. These cells are characterized by prominent expression of mast cell tryptase. Excessive histamine release from degranulation of mast cells mediates many of the symptoms of the disease, such as syncope, flushing, hypotension, pruritus, and urticaria. In addition, histamine induces gastric acid secretion, which can lead to gastric ulceration. The excess acid also inactivates pancreatic and intestinal enzymes, causing diarrhea. Other gastrointestinal symptoms include nausea, vomiting, and abdominal cramps. (Choices A, B, and F) Gastric mucosal atrophy often results from colonization with Helicobacter pylori. It can also be caused by autoimmune gastritis, which may lead to pernicious anemia due to loss of intrinsic factor from parietal cells. Symptoms of atrophic gastritis may include nausea, indigestion, and epigastric discomfort, but this patient's skin symptoms are more consistent with mastocytosis. (Choice D) Gastric hypomotility (gastroparesis) occurs with diabetes mellitus, uremia, hypothyroidism, and other metabolic disorders. Gastroparesis causes constipation, early satiety, and food stasis with vomiting. (Choice E) Pancreatic endocrine tumors may secrete gastrin (Zollinger-Ellison syndrome), insulin (hypoglycemia), glucagon (hyperglycemia, rash), somatostatin (diarrhea, cholelithiasis, hyperglycemia), or vasoactive intestinal peptide (watery diarrhea, hypokalemia, achlorhydria). These disorders would not be associated with excess mast cells in the skin. Educational objective: Systemic mastocytosis is characterized by the abnormal proliferation of mast cells and increased histamine release. Histamine causes hypersecretion of gastric acid by parietal cells in the stomach as well as a variety of other symptoms (eg, hypotension, flushing, pruritus). __________ References: Mastocytosis. (http://www.ncbi.nlm.nih.gov/pubmed/24262698)

A 43-Year-Old Man Comes to the Office with a Several-Month