May 2015: Post summaries and take home points

Deconditioning is when the body becomes acclimated to less physical stress and becomes less able to function properly under normal conditions.
Bed rest can cause deconditioning.
The cardiovascular system changes within 24 hours of bed rest.
In less than a week, 10% of blood volume is lost.
When deconditioned, your body does not make appropriate changes when changing position.
This is called orthostatic intolerance (OI).
Chronic illness can cause deconditioning.

Orthostatic intolerance(OI) is symptoms that interfere with or prevent standing up.
OI affects heart rate, blood pressure and distribution of blood to the brain.
In OI, the body incorrectly initiates a fight or flight response.
Orthostatic hypotension is a reduction of systolic blood pressure of more than 20 mm Hg or diastolic blood pressure of more than 10 mm Hg within three minutes of standing.
POTS patients have daily OI symptoms with excessive tachycardia when standing (increase of 30 bpm when standing or over 120 bpm in adults).
Postural syncope (fainting) can be caused by orthostatic intolerance or vasovagal syncope (VVS).
Fainting is caused by lack of blood flow to the brain.
Mast cell disease is known to cause orthostatic intolerance.

POTS (postural orthostatic tachycardia syndrome) is one type of orthostatic intolerance (OI).
POTS is characterized by an increase of heart rate of 30 bpm or more when standing in the absence of orthostatic hypotension.
Neuropathic POTS is caused by the veins in the legs not constricting enough to maintain blood pressure when standing.
Hyperadrenergic POTS is caused by the nervous system telling the heart to beat faster and harder.
HyperPOTS patients have fluctuating or elevated blood pressure, tachycardia, hypertension and excessive sweating.
One study found that 38% of mast cell patients had hyperPOTS.
One study found that 28.9% of POTS patients had less blood volume than normal.
POTS patients have persistent tachycardia, push less blood out of the heart per beat than normal, have a smaller than normal part of the heart, and do not use oxygen effectively during exercise.
POTS is often associated with conditions that provoke exercise intolerance, like fibromyalgia, chronic fatigue syndrome and deconditioning.

Syncope (fainting) is loss of consciousness due to temporary loss of blood supply to the brain.
About 40% of people will faint in their lifetime.
Vasovagal syncope(VVS) is a form of orthostatic intolerance (OI).
VVS is often preceded by lightheadedness, sweating, weakness, nausea and visual disturbances.
VVS patients can go long periods without OI symptoms.
Ingestion of 16 oz of water in five minutes effectively treats OI episodes of all types.
OI symptoms can be triggered by large meals, sudden change in position, extended time laying down, heat and alcohol.
Physical maneuvers and compression garments can decrease OI symptoms in some patients.
Increasing salt and water intake is recommended for adults with orthostatic hypotension or POTS.

Deconditioning and physical inactivity increase risk for cardiovascular disease.
A person can lose 10-20% of muscle strength in one week of bed rest.
Muscle loss is greatest in lower back and legs.
After three days of bed rest, connective tissue and muscles begin to contract.
Osteoporosis is more likely in deconditioned patients.
After twelve weeks of bed rest, almost 50% of bone density can be lost.
Frequent bed rest increases risk of blood clots.
Bed rest can reduce strength of muscles supporting the respiratory system, leading to cough and pneumonia.
15-30% of bedrest patients develop kidney stones.
Frequent bed rest can cause neurologic, cognitive and psychiatric disturbances.
Thyroid, adrenal and pituitary hormones become dysregulated with bed rest.

Exercise induces mast cell degranulation and release of newly made mediators.
Histamine, tryptase and leukotrienes increase following exercise in patients who have exercise induced bronchoconstriction.
Treating with montelukast and loratadine suppressed release of histamine and leukotrienes.
Leptin is elevated in obese patients.
Leptin makes airways more reactive and more inflamed.
Leptin increases the allergic response including leukotriene production.
Asthmatics who are obese are less likely to respond to inhaled corticosteroids but respond to anti-leukotriene medications.
Leukotriene E4 was elevated in both obese and lean asthmatics after exercise.
9a,11b-PGF2 (metabolite of PGD2) was elevated in obese and lean asthmatics after exercise.

Regular exercise can be protective against asthma.
Histamine is released in lungs due to exercise.
Histamine becomes depleted during exercise.
Plasma epinephrine does not rise in asthmatics following exercise.
Inhalation of cromolyn before exercise can prevent or mitigate induced asthma in many patients.
Treating with H1 and H2 antihistamines decreased endurance during exercise.
Histamine is important in inducing exercise tolerance.

There are several pathways that can cause urticaria and angioedema:
IgE activation of mast cells
C3a and C5a activation of mast cells
Production of bradykinin
IgG activation of mast cells
NSAIDs
Non-immunologic methods such as radiocontrast dyes, pressure on the skin, heat, etc.

There are several conditions that present similarly to chronic urticaria and angioedema.
Development of urticaria during pregnancy is not unusual.
Cutaneous mast cell patients often have urticaria like lesions.
MCAS can also cause angioedema and urticaria.
Angioedema in the absence of urticaria is rare.
Hereditary angioedema (HAE) is caused by deficiency or dysfunction of C1 esterase inhibitor in most patients.
HAE patients do not have coincident urticaria.
Acquired angioedema is caused by antibodies to the C1 esterase inhibitor, which can be from cancer.
Angioedema can affect any part of the body.

Exact incidence of immediate anaphylaxis from surgery or anesthesia is unknown in mast cell patients
Mast cell patients should premedicate for surgery.
Anxiety, temperature changes, irritation of skin, physical trauma and pain can all cause mast cell activation.