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Department
of Podiatry - Vascular Assessment
Vasospastic
disorders
Vasomotor
disorders is an umbrella term comprising a number of pathologies that
involve localised vessel spasm or change, affecting blood supply and return
to an area (Kidawa, 1992). Reviewing the microvascular anatomy, the arterioles
and venules possess higher concentrations of spirally orientated smooth
muscle cells than the larger vessels, allowing constriction and dilation
of the vessels. Just prior to the arteriole-capillary junction, the last
smooth muscle cell is called the pre-capillary sphincter, and is capable
of completely obstructing supply to its capillary bed (Kidawa, 1992; Marieb,
1998).
Vasomotor
control is be regulated by either a-receptor neural stimulation, myogenic
regulation of blood pressure, and metabolic reaction to local metabolic
conditions (Kidawa, 1992). The stimulus for change originates in the medulla,
and passes through the sympathetic branch of the autonomic nervous system
to the smooth muscle cells, contricting these cells and hence decreasing
luminal size and blood flow (Kidawa, 1992; Marieb, 1998).
Vasospasticity may be caused by various stimuli:
•
The endocrine glands: hypothalamus for heat regulation, also parietal,
thyroid and adrenal glands.
• Mental stimuli: anxiety, social pressure, worry, grief, fear
etc.
• Physical stimuli: visceral or somatic pain
• Haemorrhage and autoimmune disease.
The
most common condition podiatrists will encounter is Raynauds syndrome.
Raynauds syndrome can be defined as episodic vasoconstriction of the small
digital arteries with exposure to cold (Cotran, 1999). The disorder may
be classified into two types:
1)
Raynauds disease, or primary Raynauds, has no underlying pathology
and no progression of the disorder for 2 years.
2) Raynauds phenomenon is secondary to underlying disease, such
as atherosclerosis, systemic lupus erythematosus, scleroderma and Buergers
disease.
Raynauds syndrome presents as burning, tingling, numbness and often
pain of the extermities, especially the toes, fingers, nose and ears.
There are 4 phases to Raynauds (Anderson, 1999):
1)
Pallor (pale): upon exposure to cold, vasoconstriction occurs
to decrease skin temp (preserve heat) and metabolism
2) Cyanosis (blue): vasoconstriction of venules occurs, holding
deoxygenated blood in the area
3) Rubor (red): a reactive hyperaemia occurs as arterioles
eventually relax, allowing a rush of blood to the area
4) Return to normal
A patient
with Raynaud's disease, showing the pallor phase in a hand.
Another
patient with Raynaud's disease, this time showing the cyanosis phase
in the hallux.
Raynauds syndrome may be relatively asymptomatic, and only induced by
exposure to cold. However, in severe longstanding cases, the skin and
subcutaneous tissue may atrophy and breakdown, with ulcer formation and
gangrene possible but rare (Cotran, 1999)
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