Case Presentation:

This is a 65–year–old caucasian woman admitted after developing purple discoloration, pain, swelling, and loss of sensation of her right thumb. Her medical history was significant for mechanical mitral valve replacement six years prior to admission with appropriate warfarin anticoagulation subsequently. Her initial examination was significant for easily palpable bilateral radial pulses. Her right thumb on the palmar aspect was purple in color and cool. Sensation in this area was diminished. A similar area 5 cm wide was present on the right lateral wrist/forearm also. The left arm was unremarkable. Laboratory analysis was significant for a normal CBC and serum chemistries, and an INR of 3.5. She was admitted to the Vascular Surgery service and started on an unfractionated heparin infusion due to suspicion of an embolic event. Angiography of the right upper extremity did not show any evidence of embolic/thrombotic phenomena, but instead showed a “string of beads” appearance of the right brachial artery consistent with FMD. Also, multiple interdigital vessels, particularly the princeps pollicis artery, showed narrowing and irregularity. Distal vessels of the right thumb were not seen on delayed images and appeared to taper away. MRI of the left upper extremity showed nearly the same appearance, despite that hand being asymptomatic. MRI of the brain and CT angiography of the abdomen/pelvis showed no evidence of other vascular bed involvement. The patient was transferred to the Medicine service and started on amlodipine. Dramatic improvement in perfusion of the right hand was seen, with near resolution of the discoloration, paresthesias, pain, and coolness. The patient was discharged on warfarin, amlodipine (10 mg daily) and other chronic medications. After discharge, she continues to have mild intermittent paresthesias but is otherwise asymptomatic on amlodipine.

Discussion:

Fibromuscular dysplasia (FMD) affects arteries of nearly every vascular bed. Renal and carotid arteries are commonly affected. Involvement of the media, or medial fibroplasia, is the most common lesion, manifested angiographically by a “string of beads appearance.” Isolated brachial artery involvement is rare. Only four cases of FMD affecting bilateral brachial arteries have been reported to date in the literature.

Conclusions:

Isolated FMD of the bilateral brachial arteries is extremely rare. We describe the fifth reported case of this clinical entity, and the first successful treatment of ischemia due to this entity with amlodipine.

Figure 1Angiogram of right upper extremity with “string of beads” appearance of the brachial artery (lower left).

Figure 2Angiogram of right hand.