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In medicine, Raynaud’s phenomenon or Raynaud phenomenon is excessively reduced blood flow in response to cold or emotional stress, causing discoloration of the fingers, toes, and occasionally other areas. This condition may also cause nails to become brittle with longitudinal ridges. Named after French physician Maurice Raynaud (1834–1881), the phenomenon is believed to be the result of vasospasms that decrease blood supply to the respective regions.
Raynaud’s phenomenon by itself is just a sign (hypoperfusion) accompanied by a symptom (discomfort). When linked to pathogenesis, it can be part of Raynaud’s disease (also known as primary Raynaud’s phenomenon), where the cause is unknown, or part of Raynaud’s syndrome (secondary Raynaud’s phenomenon), which is a syndrome caused by a known primary disease, most commonly connective tissue disorders such as systemic lupus erythematosus. Measurement of hand-temperature gradients is one tool used to distinguish between the primary and secondary forms.
It is a hyperactivation of the sympathetic nervous system causing extreme vasoconstriction of the peripheral blood vessels, leading to tissuehypoxia. Chronic, recurrent cases of Raynaud phenomenon can result in atrophy of the skin, subcutaneous tissues, and muscle. In rare cases it can cause ulceration and ischemic gangrene.
An image taken by a thermographic camera. The top hand belongs to a person who suffers from Raynaud’s, the bottom hand does not. Red indicates a heat signature whilst green indicates little/no heat.
The condition can cause pain within the affected extremities, discoloration (paleness), and sensations of cold and/or numbness. This can often be distressing to those who are not diagnosed, and sometimes it can be obstructive. If someone with Raynaud’s is placed in too cold a climate, it could potentially become dangerous.
- When exposed to cold temperatures, the blood supply to the fingers or toes, and in some cases the nose or earlobes, is markedly reduced; the skin turns pale or white (called pallor), and becomes cold and numb.
- When the oxygen supply is depleted, the skin color turns blue (called cyanosis).
- These events are episodic, and when the episode subsides or the area is warmed, the blood flow returns and the skin color first turns red (rubor), and then back to normal, often accompanied by swelling, tingling, and a painful “pins and needles” sensation.
All three color changes are observed in classic Raynaud’s. However, not all patients see all of the aforementioned color changes in all episodes, especially in milder cases of the condition. Symptoms are thought to be due to reactive hyperemias of the areas deprived of blood flow.
In pregnancy, this sign normally disappears owing to increased surface blood flow. Raynaud’s also has occurred in breastfeeding mothers, causing nipples to turn white and become extremely painful. Nifedipine, a calcium channel blocker and vasodilator, was recommended to increase blood flow to the extremities and noticeably relieved pain to the breast in an extremely small study group.
Raynaud’s disease, or “Primary Raynaud’s”, is diagnosed if the symptoms are idiopathic, that is, if they occur by themselves and not in association with other diseases. Some refer to Primary Raynaud’s disease as “being allergic to coldness.” It often develops in young women in their teens and early adulthood. Primary Raynaud’s is thought to be at least partly hereditary, although specific genes have not yet been identified.
Smoking increases frequency and intensity of attacks, and there is a hormonal component. Caffeine also worsens the attacks. Sufferers are more likely to have migraine and angina.
Raynaud’s syndrome, or “Secondary Raynaud’s,” occurs secondary to a wide variety of other conditions. Secondary Raynaud’s has a number of associations:
It is important to realize that Raynaud’s can herald these diseases by periods of more than twenty years in some cases, making it effectively their first presenting symptom. This may be the case in the CREST syndrome, of which Raynaud’s is a part.
Patients with Secondary Raynaud’s can also have symptoms related to their underlying diseases. Raynaud’s phenomenon is the initial symptom that presents for 70% of patients withscleroderma, a skin and joint disease.
When Raynaud’s phenomenon is limited to one hand or one foot, it is referred to as Unilateral Raynaud’s. This is an uncommon form, and it is always secondary to local or regional vascular disease. It commonly progresses within several years to affect other limbs as the vascular disease progresses.
It is important to distinguish Raynaud’s disease (primary Raynaud’s) from syndrome (secondary Raynaud’s). Looking for signs of arthritis or vasculitis as well as a number of laboratory tests may separate them.
A careful medical history will often reveal whether the condition is primary or secondary. Once this has been established, an examination is largely to identify or exclude possible secondary causes.
- Digital artery pressure: pressures are measured in the arteries of the fingers before and after the hands have been cooled. A decrease of at least 15 mmHg is diagnostic (positive).
- Doppler ultrasound: to assess blood flow.
Raynaud’s syndrome (secondary Raynaud’s) is managed primarily by treating the underlying cause and, as with Raynaud’s disease (primary Raynaud’s), avoiding triggers, such as cold, keeping a warm core body temperature and avoiding smoking (including passive smoking) andsympathomimetic drugs.
Drugs can be helpful for moderate or severe RP.
- Vasodilators - calcium channel blockers such as the dihydropyridines nifedipine, amlodipine or diltiazem, preferably slow release preparations – are often first line treatment. They have the common side effects of headache, flushing, and ankle edema; but these are not typically of sufficient severity to require cessation of treatment. The limited evidence available shows that calcium channel blockers are only slightly effective in reducing how often the attacks happen.
- Patients with severe RP prone to ulceration or large artery thrombotic events may be prescribed aspirin.
- Sympatholytic agents, such as the alpha-adrenergic blocker prazosin may provide temporary relief.
- Losartan can, and topical nitrates may, reduce the severity and frequency of attacks, and the phosphodiesterase inhibitors sildenafil and tadalafilmay reduce their severity.
- Angiotensin receptor blockers or ACE inhibitors may aid blood flow to the fingers, and there is some evidence that angiotensin receptor blockers (often losartan) reduce frequency and severity of attacks, and possibly better than nifedipine.
- The prostaglandin iloprost is used to manage critical ischemia and pulmonary hypertension in RP, and the endothelin receptor antagonistbosentan is used to manage severe pulmonary hypotension and prevent finger ulcers in SSc.
- Statins have a protective effect on blood vessels, and SSRIs such as fluoxetine may help RP symptoms but the data is weak.
- In severe cases, a sympathectomy procedure can be performed. Here, the nerves that signal the blood vessels of the fingertips to constrict are surgically cut. Microvascular surgery of the affected areas is another possible therapy. Infusions of prostaglandins, e.g. prostacyclin, may be tried, with amputation in exceptionally severe cases.
- A more recent treatment for severe Raynaud’s is the use of Botox. The 2009 article studied 19 patients ranging in age from 15 to 72 years with severe Raynaud’s phenomenon of which 16 patients (84%) reported pain reduction at rest. 13 patients reported immediate pain relief, 3 more had gradual pain reduction over 1–2 months. All 13 patients with chronic finger ulcers healed within 60 days. Only 21% of the patients required repeated injections. A 2007 article describes similar improvement in a series of 11 patients. All patients had significant relief of pain.