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August 2014: Post summaries and take home points

Myelodysplastic syndrome (MDS)

  • Umbrella term for disorders in which body does not produce enough myeloid cells and the cells produced do not function correctly.
  • Myeloid cells are a type of white cells including eosinophils, basophils, neutrophils and mast cells.
  • MDS patients have low blood counts.
  • Sometimes asymptomatic.
  • Spleen is often swollen.
  • Bone marrow biopsy is diagnostic.
  • There are a number of causes of MDS.
  • Stem cell transplant may be considered in severe cases.
  • Transplant has 50% survival after 3 years.
  • Majority of MDS patients progress to acute myeloid leukemia (AML).
  • 23% of SM-AHNMD have SM and MDS.

Cutaneous mastocytosis and systemic symptoms

  • Urticaria pigmentosa (UP) and telangiectasia macularis eruptiva perstans (TMEP) are forms of cutaneous mastocytosis (CM).
  • CM is caused by dense infiltrates of mast cells in the skin.
  • Skin is the organ most likely to be infiltrated by mast cells.
  • Patients with UP or TMEP who do not have SM can still have symptoms affecting organs other than the skin.
  • CM patients can have shortness of breath, low blood pressure, nausea, vomiting, diarrhea and other mast cell symptoms.
  • Mast cell mediators release in the skin can move through the tissue and trigger other mast cells.
  • The more skin covered by rash, the more likely systemic reactions are.
  • Having systemic symptoms does not mean you have SM.
  • If you develop CM as an adult, you are likely to develop SM.
  • Chronic elevation of tryptase, expression of CD25 by skin mast cells or presence of D816V CKIT mutation can indicate SM will develop.
  • Systemic symptoms in CM are treated the same way as in SM or MCAS.
  • MCAS does not refer to a state of reactivity or severe symptoms.

The question I get asked the most

  • SM is not cancer.
  • It is not cancer because the cells do not proliferative enough to endanger life.
  • Most SM patients have indolent disease, for which life expectancy is normal.
  • ASM has more features in common with cancer.
  • MCL is cancer.

Anticholinergic effects of mast cell medications

  • Anticholinergics block the molecule acetylcholine from sending signals in the central and peripheral nervous sytems.
  • Blocking acetylcholine can cause many side effects, including:
  • Decreased GI motility
  • Dry mouth and throat
  • Dilation of pupils
  • Rapid heart rate
  • Visual disturbances
  • Urinary retention
  • Cognitive issues
  • Myoclonic jerks
  • A lot of antihistamines are anticholinergics.
  • Cyproheptadine, promethazine, desloratadine, loratadine, diphenhydramine, clemastine, doxepin, doxylamine, ipratropium, hydroxyzine and meclizine are anticholinergics.
  • Alprazolam, diazepam, ranitidine, prednisone and hydrocortisone may be anticholinergics.
  • Cetirizine and fexofenadine are not anticholinergics.

Pregnancy in mastocytosis

  • Many allergic conditions are exacerbated by menses.
  • Sex hormones influence mast cell activation and degranulation.
  • Mastocytosis patients often discontinue antihistamine and antimediator medications during pregnancy.
  • During pregnancy, 45% of mastocytosis patients had itching, 40% had flushing, 24% had GI symtpoms, 9% had anaphylaxis.
  • 22% had worsened symptoms throughout pregnancy.
  • 18% developed new symptoms.
  • 33% had improved symptoms during pregnancy.
  • 15% had complete resolution of symptoms.
  • All resolutions occurred during the first trimester and most lasted throughout the pregnancy.
  • Anaphylaxis during pregnancy was resolved without epinephrine.
  • 45% had no change in symptoms during pregnancy.
  • Anesthesia and medications for labor were safe in mastocytosis patients.
  • Premedication at initiation of labor is recommended.
  • Rate of prematurity and birth complications were similar to general population.

Histamine effects on neurotransmitters (serotonin, dopamine and norepinephrine)

  • Medications that block the H1 receptor increase dopamine release.
  • Histamine stimulates prolactin release via the H2 receptor, which inhibits dopamine production.
  • Histamine can increase metabolism of norepinephrine, serotonin and dopamine.
  • About 40% of serotonin released by mast cells.
  • Serotonin causes many GI symptoms.
  • Mast cells release dopamine.
  • Frequent mast cell activation decreases dopamine production.
  • Dopamine can be converted to norepinephrine.
  • Dopamine is responsible for cognitive alertness.
  • Norepinephrine is responsible for concentration and vigilance.
  • Increased histamine increases norepinephrine production and secretion.