Pyoderma Gangrenosum after Minor Trauma in a Pregnant Woman,Mistaken for Necrotizing Fasciitis: Report of a Case and Literature Review

Case Report

A 27-year old nurse in the second trimester of pregnancy with no past medical history had a left pretibial laceration after falling on a rough surface during a walk. Within days, the skin around the wound became red and warm despite daily disinfection with iodine. Ten days after the fall, she went to the hospital. There, local infection was suspected. Empiric oral antibiotic treatment with amoxicillin-clavulinic acid was started. No cultures were taken at this stage. However, two days later, the wound became more painful and purulent, and the erythema progressed. She had no fever. A limited surgical debridement was performed (Fig. 1). Antibiotics were switched to meropenem and clindamycin.

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FIG. 1.

Wound after limited surgical debridement.

Necrotizing fasciitis was suspected two days later when the course became fulminant. Physical examination of the wound showed greyish fascia. The muscles below the fascia were swollen and showed no contraction, suggestive of necrotic tissue. Laboratory values revealed increased C-reactive protein (CRP; 226 mg/dL), increased leucocytes (21,000 per mm³), decreased hemoglobin (10.5 g/dL), slightly decreased sodium (134 mmol/L) and creatinine (0.43 mg/dL), and normal glucose (77 mg/dL). Extensive debridement of the necrotic tissue of the proximal lower leg (Fig. 2) was performed. Antibiotics were switched to piperacillin-tazobactam and clindamycine. Intravenous immunoglobulin also was given.

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FIG. 2.

Wound after extensive debridement of the necrotic tissue of the proximal lower leg.

When no response to these treatments was observed and the patient developed a high fever (39.7°C [103.5°F]), she was transferred to our hospital. Further debridement of the lower and upper leg was performed consisting of removal of fascia and muscles. Vancomycin was added to the antibiotic treatment. However, on day 3 in our hospital, she developed septic shock. At this moment, she had further increased leukocytosis (48,000 per mm³) and CRP (330 mg/dL). The cultures of the previous operation were negative and the biopsy showed necrosis of muscle tissue. Magnetic resonance imaging at this stage showed edema of the psoas, gluteal, and paravertebral muscles. Further debridement of the leg and gluteal region was performed (Fig. 3). Intraoperatively, yellowish liquid was observed but no pus. During this procedure, intrauterine fetal demise occurred and vaginal evacuation of the fetus was performed. Examination of the placenta and fetus showed no signs of infection. Within two weeks, four further operations were performed where more fascia and muscles were removed. In every debridement, the fascia and muscles were greyish and swollen. Despite these repeated debridements, the patient remained in septic shock. Leukocytes and CRP remained high, peaking at 77,000/mm³ and 363 mg/dL, respectively. All cultures of fascia and muscle samples taken from every debridement remained negative. As she developed renal insufficiency, systemic corticosteroid therapy was started. This led to favorable outcome. She became afebrile for the first time in two weeks. Her leukocyte count and CRP decreased to their lowest levels at 41,000/mm³ and 84 mg/dL, respectively. Due to this favorable response, no new debridement was performed. However, when corticosteroids were stopped five days later, the patient became febrile (39.2°C [102.6° F]). The leukocyte count and CRP increased (66,000/mm³ and 345 mg/dL, respectively). The differential diagnosis was then re-evaluated. Pyoderma gangrenosum was suspected because repeated debridements paradoxically worsened the condition of the patient and because all bacteriologic cultures were negative. Systemic corticosteroids were restarted and improvement occurred within 24 h. C-reactive protein normalized within three weeks. Skin grafting to close wound defects was performed. Except for aesthetic considerations and some weakness of the lower left limb, she had no sequelae of the pyoderma gangraenosum (Fig. 4, A-D). She was completely weight-bearing and became pregnant again. After an uneventful pregnancy, she gave birth to a healthy baby 18 mos after the diagnosis of pyoderma gangrenosum.

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FIG. 3.

The site after extended debridement of the leg and gluteal region.

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FIG. 4.

(A–D) Patient's left leg 18 mos after the diagnosis of pyoderma gangrenosum.

Discussion

Pyoderma gangrenosum is a rare, non-infectious skin disease [2,3]. The appearance of the lesions varies, from erythema with edema to necrotic ulceration. These lesions have a predilection for the pretibial areas [4] and usually are painful. Pyoderma gangrenosum can affect people of all ages but occurs mainly between the ages of 20 and 50 years [5]. The pathogenesis is unknown. Defects in immune mechanisms, including immune complex-mediated neutrophilic vascular reactions, have been proposed as the underlying mechanisms of the disease [5]. It often affects patients with underlying systemic disease, such as inflammatory bowel disease, arthritis, and hematologic malignant tumors [2,5].

The diagnosis of pyoderma gangrenosum is difficult to make and the differential diagnosis is extensive (e.g., infections, neoplasm, and vascular ulceration) [2]. There are no specific histopathologic findings for pyoderma gangrenosum. The diagnosis can be confirmed after exclusion of other possible diagnoses [3]. Problems arise when necrotizing fasciitis is one of the differential diagnoses. Necrotizing fasciitis is a life-threatening infective condition and therefore considered a surgical emergency; urgent debridement should be performed based on clinical suspicion rather than on established diagnosis [1]. On the other hand, surgery can lead to worsening of ulceration of pyoderma gangrenosum—the so called pathergic phenomenon [3].

Our case exemplifies the diagnostic dilemmas faced when pyoderma gangrenosum is mistaken for necrotizing fasciitis. In a search of the published surgical literature, we found only a few articles on pyoderma gangrenosum where necrotizing fasciitis was the initial working diagnosis [4,6–8]. In two reports, the patients were older than 60 years of age [6,7] and in the others, between 30 and 40 years old [4,8]. The affected areas varied: A wound on the hip after total hip replacement [6], abdomen post-laparoscopic cholecystectomy [8], arm [7], and leg [4]. Only in one case [6] was pyoderma gangrenosum also considered initially and corticosteroids given. In the other cases, debridement was performed. In all cases, improvement was shown within 48 h.

Compared with the aforementioned published cases, our case is unique because the patient endured only a minor injury (fall on a rough surface) and was pregnant. These two conditions could trigger pyoderma gangrenosum [2,9]. Learning from our case and published cases, several differences in the characteristics of pyoderma gangrenosum and necrotizing fasciitis could help in preventing mistreatment of either condition. The following characteristics lean more toward the diagnosis of pyoderma gangrenosum: The presence of associated systemic disease, slow progression (days instead of hours), multiple lesions, worsening after surgery or disinfection with iodine-containing solutions, absence of fever, negative bacteriologic cultures, poor response to antibiotics, and rapid response to corticosteroids [4,8]. Pyoderma gangrenosum also is described typically as a cutaneous lesion whereas necrotizing fasciitis is described as deep tissue necrosis. However, we found in our case that the deep tissue (fascia and muscles) also was necrotic.

It is noteworthy to mention that even when pyoderma gangrenosum is considered, it must be a diagnosis of exclusion and should be included in the initial differential diagnosis of necrotizing fasciitis. To help distinguish necrotizing fasciitis from other soft tissue infection, the laboratory risk-indicator for necrotizing fasciitis (LRINEC) score can be used. This scoring system considers the laboratory values of CRP, leukocytes count, hemoglobin, sodium, creatinine, and glucose [10]. In retrospect, the LRINEC score for our patient was 9: 4 for having CRP ≥150 mg/dL, 1 for having a leukocyte count between 15,000 and 25,000/mm³, 2 for having hemogloblin <11 g/dL, and 2 for having sodium <135 mmol/L. This score, which is ≥6, indeed would have supported our clinical suspicion of necrotizing fasciitis.

Management of pyoderma gangrenosum consists of topical or systemic treatment and treatment of the underlying disease. In localized superficial pyoderma gangrenosum, topical treatment such as corticosteroid or tacrolimus may be sufficient [2,5]. Additionally, local wound care is needed to prevent and treat possible secondary bacterial infections. When pyoderma gangrenosum extends to deeper structures such as tendons or muscles, systemic treatment should be given. Systemic treatment also should be given to induce remission. High doses prednisolone (60 to 120 mg) is the first choice; reduction in pain and erythema will usually occur within 24 to 72 h. Corticosteroids should be continued until the disease is under control as indicated by healing of the ulcers. Another immunosupressive agent that can be used is cyclosporine [2,5]. Response to cyclosporine is normally shown within three weeks.

Surgery in pyoderma gangrenosum is not needed and could paradoxically lead to further tissue destruction (pathergic phenomenon), resulting in a vicious cycle of surgical debridements [2]. Skin grafting may be performed in the quiescent stage of the disorder [11]. If surgery for other causes has to be performed, atraumatic skin closure with subcuticular sutures is recommended [12]. Planned operation in patients with pyoderma gangrenosum should be performed in the remission stage of the primary disease; preoperative treatment with methylprednisolon is recommended for 2–3 d [12].

In conclusion, we presented here a case of pyoderma gangrenosum after a minor trauma mistaken for necrotizing fasciitis. Retrospectively, the presence of risk the factors trauma and pregnancy, lesions in predilection area, slow progression (days), worsening after disinfection and repeated debridements, negative bacteriological cultures, and poor response to antibiotics could have guided us earlier to the diagnosis of pyoderma gangrenosum. The diagnosis was confirmed after rapid response to corticosteroids. As this disorder could be precipitated by trauma or operation, the patient might initially consult a surgeon. Awareness and early suspicion of pyoderma gangrenosum could prevent unnecessary treatment that can lead to tissue defect.

Author Disclosure Statement

No competing financial interests exist.