Thromboangiitis Obliterans (Buerger's Disease)

Thromboangiitis obliterans, or Buerger's disease, is a non-atherosclerotic, segmental, inflammatory occlusive disease of the small and medium arteries and veins of the extremities. It is a disease of tobacco: it occurs almost exclusively in smokers, and substantial tobacco exposure is essential both to the disease and to its activity.

Who. A young adult, with onset usually before about 45-50, classically a man though increasingly a woman. Nearly all are tobacco users, whether of cigarettes or of other forms.

The lesion. The occluding thrombus is highly cellular and inflammatory, and it characteristically spares the vessel-wall architecture, usually without atheroma. That wall-sparing is what distinguishes Buerger's disease from atherosclerosis and from a destructive necrotising vasculitis.

Histopathology. The appearance changes as the lesion ages, and the diagnostic features belong to the first phase alone:

• Acute - an occlusive, highly cellular inflammatory thrombus with intraluminal microabscesses (neutrophil collections) and multinucleated giant cells. The inflammation involves all wall layers, but the internal elastic lamina and the overall wall architecture are preserved, the pathognomonic wall-sparing feature.
• Subacute (intermediate) - progressive organisation of the thrombus, with persistent but less florid inflammation
• Chronic (end-stage) - an organised, recanalised thrombus with perivascular fibrosis, non-specific and indistinguishable from other end-stage vasculopathy

Why biopsy is rarely done. The microabscesses and giant cells are seen only in the acute phase, and excising an artery from an already ischaemic limb risks the limb. The diagnosis therefore stays clinical and angiographic rather than histological.

Telling a patient that stopping tobacco "arrests the disease" is the right message delivered slightly too absolutely. The largest long-term series puts numbers to both halves of the truth.

The natural history. A multicentre retrospective cohort of 224 patients (median age at diagnosis 38.5 years, 23.8% female) was followed for a mean of 5.7 years. A vascular event occurred in 58.9% and an amputation in 21.4%. Amputation-free survival was 85% at 5 years, 74% at 10 and 66% at 15, so roughly a third of patients lose tissue within 15 years of diagnosis.

It takes digits and limbs, not usually life. Mortality in the same cohort was only 1.4%.

What predicts losing the limb. The strongest independent factor for amputation was limb infection at diagnosis, with a hazard ratio of 12.1 (95% CI 3.5 to 42.1), far larger than anything else measured. Non-white ethnicity predicted vascular events (hazard ratio 2.35). Patients who stopped tobacco had a significantly lower amputation risk than those who continued, so the two things that change the outcome are stopping tobacco and treating infection early and aggressively.

Distal ischaemia. The disease shows itself at the ends of the limbs: claudication of the foot (instep) or of the forearm and hand, ischaemic rest pain, and digital ulceration and gangrene of the fingers and toes. Upper and lower limbs may both be involved.

The rest of the picture. Alongside the ischaemia come migratory superficial thrombophlebitis and Raynaud's phenomenon.

Pulses. Because the disease is distal and segmental, proximal pulses are usually preserved while the digital arteries are occluded. Allen's test is often abnormal, from involvement of both forearm arteries or the palmar arch.

There is no single confirmatory test. The diagnosis is clinical: the right patient with the right distal pattern, plus rigorous exclusion of the mimics.

The patient. A young smoker with the distal picture above and no or limited atherosclerotic risk factors.

Angiography. Segmental occlusions of the distal vessels, bridged by corkscrew (tortuous 'tree-root') collaterals, with normal proximal arteries free of atheroma. In the right clinical setting these appearances support the diagnosis.

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Exclude the mimics.

• Atherosclerosis and its risk factors
• Diabetes
• An embolic source - echocardiography; a proximal aneurysm
• Autoimmune or connective-tissue disease - autoantibodies and inflammatory markers
• Hypercoagulable states

Shionoya's criteria. Five criteria, and meeting all five supports the diagnosis:

1. A smoking history
2. Onset before age 50
3. Infrapopliteal arterial occlusive disease
4. Either upper-limb involvement or migratory phlebitis
5. Absence of atherosclerotic risk factors other than smoking

Olin's approach. An exclusion-based clinical definition: a young current or recent tobacco user with distal-extremity ischaemia (claudication, rest pain, ulcers or gangrene) confirmed non-invasively, consistent arteriography, and exclusion of autoimmune or connective-tissue disease, a hypercoagulable state, diabetes and a proximal embolic source on echocardiography or proximal imaging. Both sets formalise the same idea, criteria plus exclusion.

Stop all tobacco. Complete, permanent cessation of all tobacco is the only disease-modifying treatment, and it is worth every effort. Deliver the message unambiguously and support it actively with counselling and pharmacotherapy. Continued tobacco drives progression and amputation.

Treat infection early. Limb infection at diagnosis is the largest amputation risk measured, so an infected ischaemic digit warrants prompt antimicrobial therapy and debridement rather than watchful wound care. It is not a wound-care problem to review in a fortnight.

Supportive care. Meticulous care of the foot and hand, and analgesia for ischaemic rest pain and for the pain of ulcers and gangrene. Where appropriate, vasodilators and prostanoids such as iloprost may help rest pain and ulcer healing. Sympathectomy and other adjuncts have a limited, selective role.

Revascularisation. The distal, segmental pattern leaves poor distal targets, so surgical or endovascular revascularisation, including palmar-arch angioplasty in the hand, is reserved for selected critical ischaemia with suitable anatomy. It is a supportive limb-salvage measure, not a cure, and it often fails or only delays tissue loss.

What revascularisation buys. Minor amputations remain frequent even after revascularisation, but major amputation can often be avoided. In the small upper-limb series reported, minor amputations were still needed in most of the nine patients, though none lost a limb.

Amputation. At the most distal level that will heal, for established gangrene or intractable pain. It is far more likely if the patient continues to smoke.