Severe Functional Loss of the Hand due to Necrotizing Fasciitis with Underlying Vasculitis Neuropathy

Abstract

A 72-year-old man presented with an erythematous, painful, swollen, and blistering left hand associated with a systemic fever. The patient was diagnosed with microscopic polyangiitis and was receiving steroid therapy from a year before the incident. Based on a clinical diagnosis of necrotizing fasciitis, emergency surgery was performed within 2 days after the onset. β-Hemolytic Streptococcus group A was isolated from a culture of the blood and wound. Radical debridement and high-dose penicillin and clindamycin therapy successfully saved the patient's life and affected limb except for the second finger on his left hand, which was completely necrotic. However, the function of the left hand was seriously decreased and did not recover. The important point to note in this case was the preexisting vasculitis neuropathy due to microscopic polyangiitis. The severe postoperative dysfunction of the hand was considered to be due to ischemic neuropathy that was aggravated by compartmental syndrome and microvascular thrombosis. In conclusion, necrotizing fasciitis of an extremity with underlying vasculitis neuropathy can lead to a poor functional prognosis of the limb.

Introduction

Necrotizing fasciitis (NF) is a life-threatening infection of the skin and soft tissue characterized by progressing necrosis along the soft tissue planes. The mortality rate remains high, ranging between 15 and 52%. 1 2 3 4 5 6 The key to effective treatment includes prompt diagnosis and immediate and aggressive debridement of the infected necrotic tissue. When NF occurs in an extremity, quickly performing the correct procedure may help avoid the need for major amputation of the affected limb. However, the salvaged limb often has a dramatically decreased function due to compartmental syndrome, surgical damage, or contracture.

We herein report a case of NF with underlying dysfunction of the peripheral nerves and circulatory system that had a poor functional prognosis of the affected limb despite appropriate treatment being applied.

Case Report

A 72-year-old man presented with an erythematous, painful, swollen, and blistering left hand associated with a systemic fever lasting 10 hours ( Fig. 1 ). He was followed and treated for bullous pemphigoid and was also receiving steroid therapy for 3 years. Oral methylprednisolone (10 mg/day) was administered at a maintenance dose. The patient was also diagnosed with microscopic polyangiitis (MPA) and was receiving steroid pulse therapy from 1 year before the incident. He also had preexisting bilateral hand paresthesia in the areas served by the median and ulnar nerves, with a bilaterally weakened grip strength score of 3+ on the manual muscle test (MMT). A previous biopsy of the left sural nerve showed mild atrophy. Nerve conduction velocity studies indicated a mixed axonal and demyelinating sensorimotor neuropathy of left median, ulnar, radial, and bilateral sural nerves. The patient also suffered skin ulcer of the fifth finger of the left hand due to a circulatory disorder for several months . Computed tomographic (CT) angiography showed multiple stenosis of the ulnar and digital arteries ( Fig. 2 ). All these findings and functional disorders of the hands were explained as symptoms of MPA and accompanying mononeuropathy multiplex .

Fig. 1.

Clinical findings 24 hours after the onset of necrotizing fasciitis. Purpuric skin lesions partially forming blisters can be seen.

Fig. 2.

The clinical status before the onset. (A) Historical findings. A biopsy of the left sural nerve. Minor atrophy of the nerve fibers is observed (periodic acid–Schiff stain, original magnification ×100, bar = 100 µm). (B) A motor nerve conduction study of the left median and ulnar nerves shows decreased compound muscle action potential (1.39 and 0.38 µV) and nerve conduction velocity (43.8 and 32.3 m/s) (above). A sensory nerve conduction study shows decreased sensory nerve action potential (6 and 2.2 µV) and nerve conduction velocity (38.9 and 41.7 m/s) (below). (C) Computed tomographic angiography of the left hand. The arrows indicate stenoses of the ulnar and digital arteries.

Having been diagnosed with acute cellulitis by a primary physician , the patient underwent emergency hospitalization on the date of the occurrence, and empirical administration of tazobactam/piperacillin was started. Within 10 hours after admission , the left hand developed fulminant purpura on both the dorsal and palmar sides. The purpura rapidly extended to the forearm with increasing blisters by the hour . A significant decline in the grip and extension strength was noted. The second finger became necrotic within 1 day after admission. Within 18 hours of the onset, the systolic blood pressure dropped by around 60 mm Hg. Vasopressor therapy by noradrenaline barely kept the systolic blood pressure in the 80 mm Hg range. The C-reactive protein level increased up to 326 mg/L, along with an increased white blood cell count up to 1.83 × 10 ¹⁰ /L. Gram-stained Streptococcus was confirmed by a microscopic examination of the wound exudate. CT showed infiltration of the subcutaneous fat layer, muscle and fascial edema, and tenosynovitis of flexor tendon sheathes. There was no presence of gas ( Fig. 3 ). Finally, the correct diagnosis of NF was confirmed the day after admission. The patient was referred to the department of plastic surgery, and emergency surgery was performed immediately .

Fig. 3.

Preoperative findings on computed tomography. Infiltration of the subcutaneous fat layer, muscle and fascial edema, and tenosynovitis of flexor tendon sheathes (arrow) are indicated. There is no presence of gas.

The operation was performed under general anesthesia. The second finger showed complete necrosis and was therefore amputated at the level of the metacarpal head. The fifth finger was treated with partial debridement as it was still viable and the infection was localized. The purpuric skin lesion of the dorsum and palm was resected along with a thrombosed vein and necrotic subcutaneous fat tissue. The dorsal fascia and palmar aponeurosis that became grayish and were no longer adherent to the underlying layer were also debrided. The carpal tunnel, the hypothenar space, and the midpalmar space were opened and found to be filled with “dishwater” pus and necrotic areolar tissue, which was irrigated or carefully removed while preserving the flexor tendons, arterial arch, and median nerve ( Fig. 4 ). The exposed spaces were repaired by suturing with an indwelling drain. The first lumbricalis was necrotic and therefore resected. The skin defects were left open with dressings. β-Hemolytic Streptococcus group A was isolated from a culture of the blood and wound. Therefore, massive-dose therapy of penicillin G (24 million units/day) and clindamycin (1,800 mg/day) was started simultaneously with the surgery.

Fig. 4.

Intraoperative findings. Completion of debridement. The carpal tunnel, hypothenar space, and midpalmar space are opened.

Postoperatively, the patient gradually recovered from shock. The inflammatory response values were normalized. However, the mobility of the thumb and fingers was completely lost. Vasopressors were tapered off within seven days after the surgery. On the eighth day after the first surgery, secondary debridement was performed. The extensor digitorum and abductor digiti minimi became necrotic and were removed. On the same day, negative pressure wound therapy was initiated. After satisfactory formation of the granulation tissue, skin grafting on the raw surface was performed. With successful engraftment, the patient was discharged and followed up as an outpatient. He underwent rehabilitation with passive hand exercises and ultrasonic stimulation. Although the passive range of motion of the wrist, metacarpophalangeal (MP), and proximal interphalangeal (PIP) joints were normal, the flexor muscles were atrophic and the motor function of the left hand never recovered (MMT = 1 in grasp and wrist flexion), with numbness remaining except for around the superficial branch of the radial nerve. A motor nerve conduction study of the left median and ulnar nerve failed to induce a significant waveform ( Fig. 5 ).

Fig. 5.

Two years after the surgery. (A) The skin grafts fully took, and the ulcer of the fifth finger healed. (B) Nerve conduction studies did not show a significant waveform.

Discussion

In this case, the patient was suffering from preexisting mononeuropathy multiplex due to MPA . MPA is one of the most common forms of antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis and is characterized by necrotizing small vessel inflammation without granulomatosis. 7 The main symptoms of MPA include rapidly progressive glomerulonephritis, pulmonary hemorrhaging or interstitial pneumonia, purpura, subcutaneous hemorrhaging, gastrointestinal bleeding, and mononeuropathy multiplex. 8 9 Mononeuropathy multiplex is a symptom of vasculitis neuropathy associated with ANCA. The pathogenesis of vasculitis neuropathy is explained as multiple infarction of the nutrient small arteries and arterioles .

NF was initially classified into two groups based on bacteriology. 10 Later, this classification was modified, and NF was divided into four groups. 11 This case was categorized as type II, which is caused by group A Streptococcus , either alone or in combination with other species such as Staphylococcus aureus . Monomicrobial infection is most commonly caused by group A Streptococcus . 12 13 The risk factors contributing to the development of NF include immunocompromising conditions, such as malignancy, malnutrition, obesity, immunosuppressant use, and renal failure. 1

NF typically only affects the skin and superficial fascia and stops short of the deep fascia. However, intense edema produced by circumferential NF can give rise to compartmental syndrome and subsequent progressive thrombosis of the small vessels. The intraoperative findings of this case obviously indicated the occurrence of compartmental syndrome. The necrosis of the second finger was likely to have been caused by thrombosis of the metacarpal and/or digital arteries. Adhesion of the tendons and intrinsic muscles induced by infection and surgical damage to the deep palmar spaces may have disturbed the motion of the hand and wrist. However, tonus of the forearm muscles and neuronal action potential was almost completely lost postoperatively. Therefore, the main cause of the hand dysfunction was considered to be ischemic neuropathy aggravated by the compartmental syndrome and microvascular thrombosis. The vasopressor therapy in the acute stage may also have induced ischemic neuropathy. Unfortunately, the patient's hand seemed to have been severely damaged because of the underlying vasculitis neuropathy. In addition, the delayed timing of surgical treatment led to prolonged ischemia. The hand function could have been better preserved and necrosis of the index finger potentially avoided if the diagnosis of NF had been made as soon as blistering or developing purpura had been observed .

There have been some reports of successful preservation of the hand function using free flaps. 14 15 However, the feasibility of free flap coverage depends on the availability of recipient vessels. In addition, the main purpose of reconstruction by flaps is to preserve exposed tissues and prevent scar contracture (the mobility loss in the present case was due to neuropathy rather than contracture). Similarly, dynamic reconstruction, such as free muscle transfer, was not applicable in this case because of the neurologic dysfunction.

As adjunctive therapy, hyperbaric oxygen treatment in the early phase of occurrence may be beneficial for salvaging the limb function. However, the efficacy of hyperbaric oxygen treatment is controversial, and its mechanism is not well understood.

In conclusion, NF of an extremity with underlying vasculitis neuropathy can lead to a poor functional prognosis of the limb. The patient should be well informed when deciding on whether to preserve or amputate the limb in consideration of the physiological reserve, predictable residual function, and therapy duration. Surgeons should not necessarily be insistent on pursuing limb salvage when the diagnosis and first surgical treatment are delayed or when the premorbid function is at a low level .

Conclusion

NF occurred in the upper extremity of an MPA patient. The early diagnosis and immediate aggressive debridement saved the patient's life without the need for major amputation. However, functions of the hand and wrist were severely debilitated. This case suggested that NF of an extremity with underlying vasculitis neuropathy can lead to a poor functional prognosis of the limb. Therefore, surgeons should not necessarily be insistent on pursuing limb salvage in situations of a delayed diagnosis, delayed treatment, or preexisting dysfunction .