Severe Upper Limb Complications from Parenteral Abuse of Subutex®
Case 1
A 55-year-old male presented with a large thenar abscess. His entire thenar eminence was intensely swollen, extremely tender, red and warm. There were 3 other indurated subcutaneous swellings on his forearm along the line of his cephalic vein (Fig. 1). During surgical debridement, a large, multiloculated abscess was found within the thenar muscles, which were gangrenous and required complete excision. Cultures grew Staphylococcus aureus, and he was treated with intravenous cloxacillin followed by oral augmentin. He initially denied, but later admitted to being a chronic intravenous drug abuser, and having injected Subutex® into his left thenar eminence. As all his thenar muscles were excised, he has lost palmar abduction and opposition of the thumb, impairing his ability to pinch and grasp. He declined further reconstructive surgery.
Case 2
A 48-year-old male on an opiate cessation programme injected Subutex® twice into his radial artery at the right wrist. He presented 12 hours later with an intensely swollen, ischaemic hand (Fig. 2). There were injection marks at the right wrist overlying the radial artery. The radial pulse was palpable proximal to the wrist crease but not beyond. The ulnar pulse was palpable, but Allen’s test showed markedly delayed capillary refill from both radial and ulnar arteries. He was treated with intravenous dextran, oral pentoxifylline, nifedipine and aspirin. An axillary brachial plexus block with marcain was given for vasodilation and pain relief. The thenar and first dorsal interosseous muscle compartments were decompressed with fasciotomies. The colour and capillary return of the hand initially improved over 3 days and he was discharged on oral medications. However, his thumb, index, middle and ring fingers gradually turned gangrenous over the next month (Fig. 3). These were amputated once the gangrene had fully demarcated – the fingers at the proximal interphalangeal joint and the thumb at the interphalangeal joint.
Case 3
A 23-year-old male presented initially with severe unilateral left upper limb oedema with no history of trauma. he was treated with warfarin. He presented 2 months later with ischaemia distal to the mid-forearm and dry gangrene of all the digits of the left hand (Fig. 4). He admitted to having injected a Subutex® solution into his brachial artery because he could not find a vein. He initially refused amputation and absconded, but presented again 3 months later with sepsis and wet gangrene of the digits. All digits on his left hand were amputated at the level of the proximal phalanx. Following this, he again injected Subutex® into his left brachial artery, resulting in worsening ischaemia from the level of the mid-forearm distally. He was given intravenous iloprostol and prophylactic antibiotics, but his forearm turned gangrenous, requiring a below-elbow amputation.
Case 4
A 22-year-old male with a history of intravenous heroin abuse presented a month after attempting to inject dissolved Subutex® into a volar vein in his left wrist. He had burning pain, paraesthesia and numbness of the thumb, index and middle fingers. He later developed paralysis of the thenar muscles. Examination showed a complete loss of sensation of the thumb, index and middle fingers and severe atrophy of the thenar muscles. Nerve conduction studies and electromyography showed denervation of the thenar muscles and no conduction across the median nerve at the wrist and carpal tunnel. He had not recovered sensation or thenar motor function after 2 months. Surgical exploration revealed scarring of the median nerve proximal to the carpal tunnel. One month after undergoing microsurgical neurolysis, he continues to have neuralgic pain, numbness and thenar weakness.
Discussion (abridged):
- Upper limb complications from parenteral abuse of intravenous or oral formulations of drugs such as heroin, benzodiazepines and methadone are well documented in the literature. These consist of infections of varying severity,7 vascular complications including superficial thrombophlebitis, deep venous thrombosis and critical limb ischaemia8 and compartment syndrome.9 In previously reported series, patients tended to be chronic intravenous drug abusers, usually in their 20s to 30s. In this series, patients were also chronic intravenous drug abusers, but on average were older, with 2 patients above 45 years old.
- Limb ischaemia occurs when a large artery is injected, either deliberately or inadvertently. The drug itself or other constituents of the tablet causes inflammation, severe vasospasm, and thrombosis. Incompletely dissolved constituents form micro-emboli, which lodge in the microcirculation, causing widespread scattered end-organ ischaemia. Venospasm and venous thrombosis result in outflow obstruction and acute compartment syndrome.9 Intermittent decrease in the arterial vasospasm and opening of collateral vessels may result in reperfusion injury, which can also cause significant swelling and compartment syndrome. Treatment with antiplatelet agents, vasodilators, anticoagulation, corticosteroids, intravenous dextran-40,8 intravenous iloprost (a prostaglandin analog),10,11 thrombolysis,12,13 thrombectomy, and hyperbaric oxygen therapy14 have all been tried. A fasciotomy may be required to relieve compartment pressure. There is a high failure rate of about 25% in one large series.8 However, numerous individual case reports or small case series have documented successful revascularisation with more aggressive methods including thrombolysis and thrombectomy.10-13 Reasons for failure may include delayed presentation and widespread damage to the microcirculation from micro-emboli. In the absence of infection, amputation should be delayed until the level of dry gangrene is fully demarcated. Onset of infection (wet gangrene) requires immediate amputation to a level above the infection.
- Inadvertent damage to the median nerve is a rare complication of parenteral drug abuse that has not been previously reported. This may be due to direct trauma or extravasation of the injected solution. Varying degrees of nerve injury ranging from temporary neuropraxia to fibrosis or destruction of nerve fibres may potentially occur. In the case described, there was total loss of nerve function due to perineurial and intraneurial scarring. This was probably caused by an inflammatory reaction to Subutex® injected around and into the nerve. In the absence of recovery on close follow-up with serial clinical examination and neurophysiological studies, surgical exploration and neurolysis may be required, as in the case described. Reconstruction with nerve grafts may be required if there is no recovery following neurolysis, or in the presence of more severe nerve injury.
.Life...
