Thromboangiitis obliterans

Thromboangiitis obliterans (TAO, Buerger disease) is an inflammatory, non-atherosclerotic, vaso-occlusive disease of both small and medium-sized arteries as well as veins in the upper and lower limbs. TAO most commonly affects adult males with a significant history of cigarette smoking. In susceptible individuals, smoking causes inflammation of the tunica intima of small vessels by an unknown mechanism, which results in thrombotic occlusion of the vessel. Patients initially present with a classic triad of intermittent claudication, Raynaud phenomenon, and migratory thrombophlebitis. Eventually, critical limb ischemia develops and the patient presents with rest pain, absent pulse in the extremities, and/or digital gangrene. Ultrasonography and arteriography are used to localize the site of occlusion and differentiate TAO from other causes of peripheral artery disease. The most important therapeutic measure is the complete cessation of smoking. Additionally, prostaglandin analogs (e.g., iloprost) may be used to improve blood flow and decrease rest pain. Patients with TAO who develop digital gangrene require amputation.

• Prevalence: up to 20 cases per 100,000 individuals ^[1]
• Sex: : ♂ > ♀ (3:1)
• Age of onset: before the age of 45 years ^[2]

Epidemiological data refers to the US, unless otherwise specified.

• Definition: an inflammatory, nonatherosclerotic vasculitic disease that affects both small and medium-sized arteries as well as the veins.
• Etiology: Smoking is the single most important risk factor for TAO.
• Stages of TAO ^[3]
  • Inflammation of the tunica intima with neutrophilic infiltration and microabscess formation (endarteritis) → inflammation may also spread to the tunica media but the internal elastic lamina usually remains intact. Unlike in other forms of vasculitis, the rest of the vessel wall is usually relatively spared → development of cell-rich, inflammatory thrombi in the lumen → occlusion of the vessel
  • Mononuclear cells, fibroblasts, and giant cells replace neutrophils
  • Reorganization of the thrombus and perivascular fibrosis
  • Contiguous extension of the inflammatory process to the adjacent vein and nerve, resulting in the encasement of the artery, vein, and nerve in a fibrous sheath
• Disease localization: distal arteries of the upper and lower extremities

Patients may present with acute limb ischemia and/or symptoms of chronic peripheral artery disease (see “Clinical features” in “Peripheral artery disease”).

• Early manifestations
  • Superficial thrombophlebitis; (which is often migratory) with tender nodules along the course of the vein
  • Intermittent claudication
  • Raynaud phenomenon
  Late manifestations
  • Rest pain
  • Cool peripheral extremities
  • Trophic nail changes
  • Ulceration and/or gangrene of fingertips and/or toes (digits may autoamputate)
  • Normal brachial and popliteal pulses but poor/absent radial, ulnar, anterior tibial, posterior tibial, and/or dorsal pedis pulsations

• Laboratory findings
  • ESR and CRP are within normal limits.
  • Autoantibodies (e.g., ANA, RF) are absent and a hypercoagulability screen is normal.
• Ankle-brachial index: decreased
• Imaging ^[4]
  • Doppler ultrasound: initial imaging
  • Arteriography
    • Imaging modality of choice
    • Shows non-atherosclerotic, smooth, tapering, segmental lesions that occlude distal vessels of extremities with corkscrew-shaped collateral vessels around the site of occlusion
• Biopsy: Although confirmation of the diagnosis requires excisional skin biopsy, biopsies are rarely performed.

ESR and CRP remain within normal limits.

See “Differential diagnoses” in “Peripheral artery disease.”

The differential diagnoses listed here are not exhaustive.

• General measures
  • Complete cessation of smoking and the use of tobacco products is the single most important therapeutic measure.
  • Protection of fingers and toes from cold to prevent Raynaud phenomenon
• Medical therapy ^[3][4]
  • Iloprost
  • Calcium channel blockers (nifedipine, amlodipine)
  • Hyperbaric oxygen therapy
• Surgical therapy ^[3][4]
  • Revascularization procedures (e.g., bypass grafting, angioplasty) usually cannot be performed because, typically, distal small and medium-sized arteries are involved.
  • Patients with ulcers may require debridement and treatment with antibiotics.
  • Patients who develop gangrene in the extremities will require amputation.