Maurice Raynaud first described a group of 25 patients with ‘localasphyxia and symmetrical gangrene of the extremities’ in 1862. He proposed that the observed changes were caused by vasospasm because most of the patients had palpable pulses at the wrist and patent large arteries were observed in those patients who underwent autopsy. Over the next 70 years it became apparent that this vasospastic condition could occur either in isolation or in association with other diseases, and so a distinction was made between Raynaud's disease (occurring in isolation) and Raynaud's phenomenon (secondary to an underlying disease). More recently this distinction has become less clear cut because some patients may develop collagen disorders several years after the onset of Raynaud's symptoms and patients with apparent primary Raynaud's disease may have low levels of autoantibodies present in their serum. For these reasons both primary and secondary Raynaud's conditions are now classified under the single banner of Raynaud's syndrome.

Raynaud's syndrome therefore describes the changes which result from intermittent vasospasm of the arterioles in the hands or feet; these classically occur following exposure to cold or as a result of emotional stimuli. The vasospasm resolves with warming, leading to the classical sequence of colour changes in the extremity from pallor to cyanosis to redness although, as with many classical descriptions of diseases, the full spectrum of colour changes is seldom seen in one individual patient. The syndrome may be primary, when no other condition can be identified after appropriate investigation, or it may be secondary to a wide variety of underlying disorders.

The majority of patients with Raynaud's syndrome are female, both because primary Raynaud's is classically described as a disease of young women and because many of the underlying disorders associated with secondary Raynaud's are more common in women. Of those who actually present with the syndrome, 70 to 90 per cent are female, although many individuals with mild to moderate cold sensitivity may not be disturbed by their symptoms enough to seek medical advice. Population surveys of Scandinavian women aged 18 to 60 years suggest an overall prevalence of Raynaud's syndrome of between 15 and 22 per cent in the general female population—a substantially higher number than is actually treated. Most of the women uncovered by such population surveys have primary Raynaud's syndrome and very few have associated collagen disorders. Secondary Raynaud's syndrome is much more common in patients who present to specialist units with an interest in the disorder. Only 30 per cent of patients presenting to specialist units have primary Raynaud's syndrome; the remainder have secondary Raynaud's syndrome, and one-half of these patients will have overt or suspected connective tissue diseases. This represents the single largest group of patients presenting to specialist units with Raynaud's syndrome. Such data confirm the clinical impression that secondary Raynaud's syndrome results in a greater severity of digital ischaemia than the primary form; patients with secondary Raynaud's syndrome are therefore more likely to present to a clinician for treatment.

Distinct colour changes in the hands or feet of Raynaud's patients in response to cold are the hallmark of the syndrome. Cold exposure produces profound pallor and numbness of the digits due to spasm of the digital arteries. The digital microvasculature dilates after a few minutes due to the accumulation of carbon dioxide and the products of hypoxic metabolism. As the vasospasm begins to relax a small amount of oxygenated blood enters these dilated vessels where it rapidly becomes desaturated and the pallor changes to cyanosis. As the digital vessels relax further, so normal blood flow is re-established and a reactive hyperaemia of the dilated microvasculature ensues as the cyanosis changes to rubor of the digits (Fig. 1) 319.

Cold, emotional stimuli, or even cigarette smoking may induce an attack, and so severe is the vasospasm that its force overcomes the ability of the arterial blood pressure to keep the vessel walls apart, so that the digital arteries are completely closed during the attack (Fig. 2) 320.

The definitive picture of the pathogenesis of Raynaud's syndrome has yet to be described. The very number and variety of hypotheses put forward to explain the abnormal sensitivity to cold of the digital vessels attests to the presence of a continuing gap in our knowledge. Maurice Raynaud was the first to put forward his ideas on the pathogenesis of the digital vasospasm when he claimed that it was due to an ‘enormous exaggeration of the excitomotor energy of the grey parts of the spinal cord which control the vasomotor innervation’. This eloquent description of sympathetic overactivity was challenged many years later by Sir Thomas Lewis, who published a series of papers on the subject in the 1930s. Lewis attributed the vasospasm to a local fault in the sensitivity of the digital arteries to cold stimuli and was able to induce attacks experimentally in the presence of an anaesthetized sympathetic supply. Conversely he was able to prevent an attack by keeping the hand warm when the rest of the body was cooled. Thus he concluded that, whatever the state of the sympathetic nervous outflow, provocation of a Raynaud's attack depended upon the local digital temperature. So persuasive were Lewis' experiments that the majority of subsequent work has concentrated on possible mechanisms of a local hypersensitivity to cold, and most workers have accepted that the central thermoregulatory system is normal in Raynaud's syndrome.

The normal vasospastic response to cold may be exaggerated if the digital vessel lumen is already narrowed by structural abnormalities. Microscopic abnormalities, ranging from slight intimal thickening through to frank intimal hyperplasia or even complete luminal obliteration, have been described in Raynaud's patients. The intimal thickening in most cases, however, is no worse than that in age-matched controls without Raynaud's syndrome and a purely structural abnormality seems an unlikely explanation for the excessive response to cold. Much attention has therefore turned to the functional aspects of vasoconstriction, with particular emphasis on sympathetic neurotransmission.

&agr;-Adrenergic receptors sensitive to catecholamines in the digital vessel walls induce vasoconstriction in response to sympathetic stimulation. Sympathetic stimulation also induces the release of histamine, which is a vasodilator, from adjacent mast cells. Histamine H&sub2;-receptors on the sympathetic nerve terminal in turn inhibit &agr;-adrenergic neurotransmission. There is some evidence that this potential negative feedback control mechanism may be impaired in patients with Raynaud's syndrome. Under normal circumstances the digital vessels dilate rapidly when a cold stimulus sufficient to induce vasoconstriction is withdrawn. In Raynaud's patients this rapid postsympathetic vasodilation is delayed or absent and vasodilation occurs only when a warm stimulus is applied. While such an observation may be explained by excessive catecholamine release, by impaired catecholamine inactivation, by histamine depletion, or by mast cell dysfunction, none of these proposals has been clearly shown to underlie a Raynaud's attack. Catecholamine concentrations are certainly higher in the venous blood coming from the hand during a Raynaud's attack, but this phenomenon may be simply the result of a diminished blood flow.

The issue is complicated further by the observation that sympathetic stimulation normally has a similar effect on blood flow in the hand whether the hand is warm or cold. In Raynaud's patients the vasoconstrictor effect of sympathetic stimulation is significantly enhanced when the hand is cold compared to when it is warm. Cold itself may therefore sensitize or enhance local &agr;-adrenergic receptor function in Raynaud's patients. While these data confirm the conclusions of Lewis that a local phenomenon underlies the onset of a Raynaud's attack, little progress has been made to date in establishing the underlying mechanism.

Several haemorheological phenomena have also been noted in the blood of Raynaud's patients. Both blood and plasma viscosity are increased and there is reduced red cell deformability, abnormal platelet adhesiveness, and reduced activity of the fibrinolytic system. It is difficult to interpret the relevance of these phenomena to the pathogenesis of Raynaud's syndrome.

At normal temperatures there is no significant difference in blood flow through the hands of normal individuals compared with Raynaud's sufferers, despite the increased viscosity in the latter group. As the hand is cooled the blood flow decreases more rapidly in Raynaud's syndrome than in normal controls and may cease altogether at 17 to 22°C, whereas there is still some flow in normal hands at these temperatures. The relative contribution of increased blood viscosity in Raynaud's patients to this cold sensitivity remains a matter for debate and it is not known whether viscosity is crucial to the pathogenesis of the syndrome or whether it is simply a secondary event.

A wide variety of other conditions may occur in association with Raynaud's syndrome (Table 1) 191 and, in the case of the connective tissue disorders, the Raynaud's attacks may precede other features of the disease by several years. No single common thread has been identified among these disorders which may help to explain the pathogenesis of Raynaud's syndrome and not all of the patients with these disorders go on to develop Raynaud's syndrome. Patients who present with apparent primary Raynaud's syndrome may also exhibit abnormalities on immunological screening of their serum, although the significance of such findings is often uncertain.

Secondary Raynaud's syndrome most commonly occurs in association with the connective tissue diseases. Between 40 and 80 per cent of patients with scleroderma will develop Raynaud's syndrome and the syndrome is often a presenting feature of scleroderma, although it may take several years after the onset of Raynaud's attacks before a definitive diagnosis is made. The incidence of Raynaud's syndrome is reported variously as 35 per cent in systemic lupus erythematosus, 22 per cent in dermatomyositis, and 11 per cent in rheumatoid arthritis. Many of these patients exhibit evidence of structural disease in the digital arteries on arteriography, with irregularity or obstruction of the lumen due to intimal proliferation. Such arteriographic changes are common in the connective tissue diseases and do not correlate with the presence or absence of Raynaud's attacks. Indeed many normal people over the age of 50 years have similar arteriographic findings and it is therefore difficult to implicate organic arterial obstruction on its own as a cause of the syndrome in patients with connective tissue disease.

Raynaud's syndrome is seen in patients with arteriosclerotic disease in the limbs, particularly when the arteriosclerotic obstruction is sufficiently severe to reduce the digital blood pressure. When the digital blood pressure is low the normal vasospastic response to cold can more easily close off the vessel lumen against the reduced intravascular blood pressure. Thus although the sympathetic and local responses to cold are entirely normal and appropriate, the effects of cold-induced vasospasm are exaggerated and a Raynaud's attack ensues.

Thromboangiitis obliterans (Buerger's disease) is particularly associated with Raynaud's syndrome because, in addition to obstruction of the medium sized arteries of the forearm and calf, the digital vessels are commonly involved (Fig. 3) 321. Such segmental involvement in the inflammatory thrombotic process results in a similar exaggeration of the normal vasospastic response to cold described above for arteriosclerosis because of the consequent reduction in digital blood pressure. Raynaud's attacks are the presenting feature of thromboangiitis obliterans in 12 to 25 per cent of patients and the disease itself may account for up to 12 per cent of the cases presenting to specialist units with Raynaud's syndrome. Thromboangiitis obliterans is particularly associated with smoking and remissions are often induced by abstinence from tobacco. Under these circumstances abnormalities of the digital pulses in the disease have sometimes been noted to disappear when the patient stops smoking, only to recur if the patient starts smoking again.

Raynaud's syndrome is the classical occupational hazard of people who use vibrating tools such as chainsaws or pneumatic drills in their job. The attacks do not occur while the tool is being used, but later on when the hand is cooled. There may be a latent interval of several years between the regular use of a vibrating tool and the onset of the syndrome. The prolonged exposure to vibration may damage the endothelium lining the digital arteries and the subsequent subintimal fibrosis leads to widespread palmar and digital artery obstruction (Fig. 4) 322. The suggestion that the vibration may have a direct effect on sympathetic nerve endings has not gained widespread support.

Cold injury may also induce Raynaud's syndrome and has also been noted as an occupational hazard, particularly in the frozen food processing industry. Chronic continued exposure to cold is less important than rapid alternate cooling and warming of the hands such as occurs when workers handling frozen foods plunge their hands into warm water every few minutes to keep them warm. Alterations in working practices to avoid this alternate cooling and warming have substantially decreased the incidence of this particular occupational hazard.

Thoracic outlet syndrome may present with Raynaud's syndrome. It is unusual for both the neurological and vascular symptoms of thoracic outlet obstruction to coexist in the same patient and it is usually the vascular variety with subclavian artery stenosis, post-stenotic dilatation, and microembolization of the digital vessels which results in Raynaud's syndrome. Raynaud's syndrome may occur in patients with a coincident asymptomatic cervical rib and so it is important to demonstrate a definite vascular abnormality by angiography before attributing the Raynaud's syndrome to thoracic outlet obstruction.

Although carpal tunnel syndrome may be present in up to 15 per cent of patients with Raynaud's syndrome, nerve compression does not appear to contribute to the vasospasm, since division of the flexor retinaculum does not relieve the Raynaud's syndrome. A collagen disorder may underlie both conditions, so that they occur in association with each other without any specific cause and effect relationship.

Ergotamine is a potent vasoconstrictor used in the treatment of migraine. Prolonged use, especially in excessive dosages, may result in peripheral vasoconstriction manifesting as Raynaud's syndrome.

The presence of cold agglutinins or cryoglobulins in the blood produces hyperviscosity of the blood upon exposure to cold; blood flow in the digital arteries therefore virtually ceases in the digital vessels at low temperatures. Cold agglutinins adsorb on to red blood cells at temperatures between 24°C and 34°C and produce a reversible haemagglutination. The digital vessels are then plugged by masses of agglutinated red cells. Subsequent haemolysis of the agglutinated cells may produce haemoglobinuria and haemolytic anaemia.

Cryoglobulins in the blood obstruct the digital vessels by undergoing cold precipitation within them. The cryoglobulins may occur idiopathically but can also be secondary to a malignant reticulosis.

Changes in blood viscosity appear to be the primary mechanism for the obstruction to blood flow in these syndromes rather than any excessive response to sympathetic activity: the episodic digital ischaemia usually disappears if the cold agglutinins disappear.

The diagnosis of Raynaud's syndrome depends mainly upon the history of colour changes induced by cold exposure or occasionally by emotion. The involved extremity turns pale and numb when cold and makes a slow recovery when warmed, taking 15 to 45 min to pass through the stages of cyanosis and redness back to a normalcolour. Pain in the digits is not a usual feature but may occur, particularly in the secondary varieties where there is digital vessel occlusion and a significant amount of ischaemic tissue damage, leading to ulceration and gangrene. This ischaemic damage may become so severe that the patient may require digital amputation despite the presence of a normal radial pulse (Fig. 5) 323.

Such ischaemic tissue damage is extremely rare in the primary form of Raynaud's syndrome where the attacks are solely related to vasospasm and there is no obstructive element. Primary Raynaud's syndrome tends to occur in young women under 30 and is usually symmetrical, involving either the hands or the feet or both together. No associated disease is present and symptoms continue for 2 or more years without the development of any evident aetiology. Pain is unusual except when bacterial or fungal paronychia complicates the attacks.

Raynaud's attacks may be the presenting feature of a number of associated diseases, evidence for which should also be sought for in the history and examination. Patients with connective tissue disorders such as rheumatoid disease or systemic lupus erythematosus may complain of arthralgia and have stiff, painful and swollen joints. Patients with scleroderma may complain of dysphagia or diarrhoea and on examination may have a pinched face with a small tight mouth and inelastic skin. Telangiectasia may be present on the lips and hands and there may be missing digits where severe digital ischaemia has necessitated amputation.

Peripheral pulses should be felt for evidence of arteriosclerotic disease, and a history of heavy smoking may suggest the presence of thromboangiitis obliterans in a young male with Raynaud's symptoms. The presence of a subclavian bruit with Raynaud's syndrome in the ipsilateral hand suggests thoracic outlet obstruction, and there may also be differences in blood pressure between the two arms.

A careful history of drug use should be elicited, particularly if the patient takes migraine preparations containing ergotamine. The patient's occupational history is also important as they may have changed their job and only confess to cold exposure or the use of vibrating tools in a previous occupation on direct questioning.

The hands or feet themselves may look completely normal on examination, particularly in the warmth of the consulting room. The history of colour changes is usually sufficient to make the diagnosis, although the extremity can always be immersed in ice cold water for 30 s to induce an attack if confirmation is necessary. Special investigations are mainly directed at the detection of associated disorders: digital pressure and plethysmographic blood flow measurements are more useful as a research tool than for routine clinical use, and arteriography is not necessary in every patient with a clear history, although it can help to distinguish between purely vasospastic Raynaud's syndrome and that with an obstructive element in the digital vessels (Figs. 2 and 3) 320,321. Arch arteriography is particularly useful when a more proximal arterial obstructive element is suspected, such as subclavian stenosis with thromboembolic obstruction of the digital vessels, as the proximal obstruction may be amenable to surgical correction.

Comprehensive investigation of the Raynaud's patient to rule out associated disorders should include radiography of the thoracic outlet to show the presence of a cervical rib; radiographs of the hands may show the joint disruption characteristic of rheumatoid arthritis or the subcutaneous calcinosis and sclerodactyly of scleroderma. Blood tests include a full blood count and an erythrocyte sedimentation rate, which may be elevated in connective tissue disorders. More specific screening tests include rheumatoid factor, antinuclear factor, anti-DNA antibody, serum protein electrophoresis, cryoglobulins, and cold agglutinin assays.

Acrocyanosis is a separate vasospastic disorder of the hands or feet which occurs mainly in women and may be unilateral. The extremity feels cool, may be slightly oedematous, and has a constant blue discoloration which does not resolve in response to warmth (Fig. 6) 324. Peripheral pulses are normal and ischaemic changes do not occur. The condition is due to cutaneous arteriolar vasospasm which is independent of temperature. The condition may respond to vasodilatory drugs used to treat Raynaud's syndrome and sympathectomy can produce good results if symptoms are severe.

Livido reticularis is also caused by cutaneous arteriolar vasospasm with secondary dilatation of associated capillaries and venules but the distribution is patchy and apparently random. There is patchy reddish-blue mottling of the lower legs and feet or occasionally of the arms and hands which persists irrespective of temperature, although it is often worse in the cold. The majority of cases occur in isolation but the disorder has been described in association with polyarteritis nodosa and systemic lupus erythematosus. No treatment is usually necessary other than reassurance and avoidance of cold.

No curative treatment is available for Raynaud's syndrome and the aim is therefore to palliate the symptoms by reducing the frequency and the severity of the attacks. Reassurance that the outlook is generally benign is important, especially in primary Raynaud's syndrome where progression to digital ischaemia and gangrene is extremely rare. The natural history of the syndrome includes long periods of remission, especially over the summer months. The majority of patients can achieve a worthwhile response through the simple avoidance of cold and tobacco smoking. Smoking a cigarette may produce a fall in temperature of 2 to 3°C in the fingertips (Fig. 2) 320 and smoking is absolutely contraindicated in patients with thromboangiitis obliterans, who should be advised that they run a very high risk of amputation if they continue to smoke. Techniques to keep the extremity warm range from advice to wear thick woollen gloves or socks in cold weather to the use of chemically activated handwarmers or electrically heated gloves, Perhaps less practical might be the advice to move to a warmer climate.

While the majority of patients can be managed satisfactorily with these conservative measures a few continue to have frequent or severe attacks or progress to digital ischaemia. For these patients the choice lies between drug therapy or sympathectomy.

A variety of vasodilatory drugs with different modes of action are available and many have been advocated in the treatment of Raynaud's syndrome. Unfortunately the syndrome itself may remit spontaneously and there is also a strong placebo effect on the frequency and severity of attacks, so trials of drug therapy have to be very carefully controlled and the results interpreted with caution. A significant response to the drug is seen in many trials but only 30 to 60 per cent of the patients respond; in many cases the attacks continue and the drug response is only apparent as a reduction in the frequency or severity of the attacks without complete amelioration of the syndrome. Side-effects are common with these drugs and can be unpleasant. Some therapies are only effective when administered by the intravenous route, which requires hospital admission, and these have to be reserved for the most severely affected patients.

Despite these reservations a trial of the different drug therapies to see if one will induce a response is often worthwhile, because the only other alternative is surgery, the results of which are by no means guaranteed. As the outlook of the syndrome is generally benign, there is plenty of time to give drug therapy a reasonable trial, although the overall clinical impression is that marked improvements in symptoms are difficult to detect unless a strict diary of the frequency and severity of attacks is kept to allow comparisons before and after drug therapy to be made.

The best studied oral agents are nifedipine and thymoxamine and effective intravenous agents are iloprost and ketanserin.

Nifedipine is a calcium channel blocking agent that interferes with the inward displacement of calcium ions through the slow channels of active cell membranes. In vascular smooth muscle cells the effect of this interference is a reduction in vascular tone with subsequent vasodilatation. Nifedipine is often used for the treatment of angina and hypertension and is the first choice of many clinicians for the treatment of Raynaud's syndrome. Side-effects are common and include headache, flushing, peripheral oedema, eye pain, and blurred vision.

Thymoxamine acts by competitive antagonism of &agr;-adrenoreceptors and blocks vasoconstriction in the skin. There is a low incidence of side-effects with thymoxamine but only 25 to 30 per cent of patients may notice any subjective improvement in symptoms.

The prostanoids prostaglandin E&sub1; and prostacyclin are potent vasodilators and inhibit platelet aggregation; they are effective in severe Raynaud's syndrome but their rapid metabolism may limit their therapeutic potential. Iloprost is a more stable prostacyclin analogue, with a half-life 10 times longer than that of prostacyclin. Iloprost is administered as a 6-h intravenous infusion at a dose of 2 ng/kg.min on three consecutive days. The dose is reduced in 0.5 ng/kg.min increments if side-effects, which may include severe headache, dizziness, vomiting, and diarrhoea, occur. Studies in patients with severe secondary Raynaud's syndrome due to scleroderma report a 30 per cent reduction in the frequency of attacks and a 20 per cent reduction in their severity. Digital ischaemic lesions can heal after iloprost infusion but healing may not necessarily be significantly better than after placebo infusions. No orally effective prostanoid preparation is currently available and the severity of side-effects confines the use of intravenous preparations to hospital inpatients. Although the effects of iloprost on vasodilatation and platelet adhesion disappear almost as soon as the infusion is stopped, the clinical improvement may last for up to 6 weeks and repeated infusions may be given.

Ketanserin is a serotonin receptor antagonist that antagonizes serotonin-induced vasoconstriction and platelet aggregation and inhibits the amplification by serotonin of vasoconstriction and platelet aggregation by other agents. Intravenous ketanserin improves finger blood flow and relieves ischaemic symptoms in severe secondary Raynaud's syndrome, but the effect is short-lived and wears off after the infusion is stopped. Oral ketanserin is also available and although it can improve finger blood flow, many studies have shown no subjective clinical improvement in Raynaud's symptoms over placebo.

Reserpine is a rauwolfia alkaloid which depletes noradrenaline from sympathetic nerve terminals. Guanethidine has a similar effect and also prevents noradrenaline release from post-ganglionic neurones. Reserpine has been used orally to treat Raynaud's syndrome but the high incidence of side-effects associated with long-term use has made it an unpopular choice. Both reserpine and guanethidine may be administered intravenously into an affected extremity distal to a blood pressure cuff which is kept inflated above systolic pressure for 20 to 30 min during and after the injection. This so-called chemical sympathectomy does not produce lasting relief and is not effective in patients with advanced digital vessel obstruction, but may give short-term relief of severe symptoms in patients with predominantly vasospastic disease.

The mainstay of surgical treatment in Raynaud's syndrome is sympathectomy, although surgery may also be required when the syndrome is secondary to proximal vascular disease. In the latter cases it may be necessary to resect a cervical rib or band to relieve thoracic outlet compression, although first rib resection has also been advocated. Occasionally the subclavian stenosis and poststenotic dilatation are so severe that local excision and vein graft replacement of the artery are required. The transaxillary approach to first rib resection is best avoided in this latter group of patients where the supraclavicular approach gives better proximal control of the artery.

Atherosclerotic disease in the brachial artery is rare but it is possible to bypass severely stenosed or occluded segments with a vein graft if the symptoms warrant it. The majority of patients with severely ischaemic digits due to Raynaud's syndrome have intact distal pulses and tolerate local amputation to control severe ischaemic pain or gangrene well. In many instances the middle or proximal phalanges can be preserved and primary closure of the amputation stump gives good healing. In severe cases digits may require amputation over a period of time as the disease progresses, particularly in patients with scleroderma. The more that can be preserved of each digit therefore, the better the long-term functional result.

The results of sympathectomy for Raynaud's syndrome are variable and there is considerable doubt over its long-term efficacy. Subjective clinical improvement is noted in 60 to 70 per cent of patients immediately after sympathectomy but 10 years later only 30 to 40 per cent of patients are still improved, which is not a statistically significant result compared to non-operated patients.

Good results from sympathectomy may be expected in patients with primary Raynaud's syndrome and in those patients whose secondary Raynaud's syndrome is due to embolic, traumatic, or atherosclerotic obstruction. Good results may also be obtained in patients with thromboangiitis obliterans but results have been uniformly poor in patients with connective tissue disorders. With the exception of the connective tissue disorders, where sympathectomy is usually best avoided, it is generally agreed that sympathectomy should be reserved for patients with recurrent ulceration of the fingertips or those who are severely incapacitated by vasospastic phenomena in spite of adequate medical management.

Lumbar sympathectomy may be performed either operatively or by percutaneous injection of phenol solution. An operative lumbar sympathectomy is performed through a small transverse muscle-splitting incision just above the level of the umbilicus and lateral to the rectus muscle. The sympathetic chain is approached retroperitoneally. Percutaneous sympathetic blockade is much more difficult in the cervical region and hand symptoms therefore require operative cervical sympathectomy. This operation is technically much easier through the transaxillary route than via the supraclavicular approach. Both approaches carry the risk of damage to the stellate ganglion resulting in a Horner's syndrome with ptosis, pupillary constriction, and facial flushing and dryness on the affected side. Resection of the second, third, and fourth thoracic ganglia appears in practice to produce effective sympathetic denervation of the arm and axilla without risking damage to the stellate ganglion. More recently cervical sympathectomy has been performed successfully endoscopically and this seems likely to become the routine approach to this procedure. Although abolished initially after sympathectomy, the vasomotor and sudomotor reflexes may return to the hand a year or more after surgery. Whether this return represents regeneration of nervous fibres or the gradual assumption of a greater role of residual sympathetic pathways is not known, but the phenomenon may account for the variable long-term results of sympathectomy in Raynaud's syndrome.

Most patients with Raynaud's syndrome can be managed with advice to stop smoking and to keep the extremity warm. Failure of these simple measures in patients without digital ischaemia is an indication for oral drug therapy with nifedipine or thymoxamine. The onset of digital ischaemia, especially in the connective tissue disorders, justifies a trial of intravenous iloprost therapy. Continued severe symptoms or ischaemia despite full medical treatment warrants consideration for sympathectomy. Local digital amputation may be the eventual outcome of severe ischaemic damage.

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