A 17-year-old female was admitted to the hospital for the evaluation and treatment of acute cellulitis and deep vein thrombosis of the right lower extremity. The history of her problem began 11 days earlier when she awoke with pain in her right lower extremity between her ankle and calf. She also experienced an undocumented, subjective fever that day. The next morning, she noted some erythema and swelling, and she was taken to a local ED for evaluation. She was found to have a deep vein thrombosis in the right leg and admitted for treatment of this, as well as for presumed cellulitis, with coumadin (Warfarin, Bristol Myers Squibb) and a combination of antibiotics: vancomycin, gentamicin, levofloxacin and caspofungin (Cancidas, Merck). During the next 10 days, she had occasional low-grade fever and no improvement in the appearance of her leg. She had a bone scan that was normal, but magnetic resonance imaging of her lower extremity could not be performed because she was morbidly obese. She was then transferred to our facility for further management. Except for her coagulation studies and mild elevation of the inflammatory markers (CRP and ESR) the rest of her lab tests at the referring hospital were normal.
Her past medical history is complicated by morbid obesity, but otherwise, it is unremarkable. There has been no trauma and her immunizations are up to date. There are some social stressors with her parents, but the patient denies drug use or sexual activity.
Examination revealed a female whose vital signs are normal, but who weighs more than 500 pounds. Her right lower extremity is markedly swollen with brawny edema, pain and erythema and skin breakdown with a serosanguineous discharge as shown in figures 1 through 3 with her left leg shown in figure 4.
Her lab tests on arrival included a normal complete blood count and metabolic profile. Her ESR = 49 and C-reactive protein = 67. All blood cultures and wound stains and cultures for bacteria, fungi and acid-fast organisms at the referring hospital and at our lab are negative.
A skin biopsy revealed “Full thickness inflammation with hyperplastic epidermis, papillary dermal edema, vascular proliferation typical of stasis throughout and dense scarring extending into the subcutaneous fat with some fat necrosis. Small foci of fibrin and some blood are present and there are macrophages with hemosiderin pigment. Gomori methenamine silver and tissue Gram stains are negative. An immunostain for HHV8 [human herpesvirus 8] is negative.”
Discussion
This turned out to be lipodermatosclerosis, confirmed by the skin biopsy.
Lipodermatosclerosis is more common in females and in patients who are obese, and is a direct consequence of venous insufficiency of the lower extremities. The deep vein thrombosis (DVT) in this patient no doubt contributed to this problem developing.
Histological studies suggest that lipodermatosclerosis appears to be caused by damage to the venous walls of the lower extremities caused by elevated venous pressure. This results in an inflammatory response, which includes activated macrophages and results in the destruction of adipose tissue (panniculitis). This results in fat appearing in the extracellular matrix, which in turn, stimulates more macrophages and activates fibroblasts, maintaining a vicious cycle of worsening inflammation (Vignale R, Panucio A, Saralegui P, et al. Histological studies in LDS associated with venous hypertension. Medicina Cutánea. 2004;32:111-116). The clinical manifestations typically include induration of the soft tissue to the point of wood-like hardening, erythema and in many, an inverted coke bottle shape of the leg above the ankle. Although, this feature may not be seen in those who are obese.
The treatment of lipodermatosclerosis should be in cooperation with various consultants, such as a wound management team, which may include compression therapy and ultrasound therapy; a hematologist if there’s a DVT to help tend to with low molecular weight heparin; and the services of a vascular surgeon may be needed. But, most important, the patients need to resolve the underlying contributing factors, such as weight reduction and increased activity.
As with the case presented, many of these patients are thought to have cellulitis initially, and usually have been treated with a variety of antimicrobials before arriving at the correct diagnosis. The clues in this case were that there were no organisms identified by the numerous stains, cultures or through biopsy during the hospitalization, and no improvement on the various antimicrobials used. The appearance of cellulitis may be very similar (figure 5), but the swelling of cellulitis is not likely to be hard (brawny). Sometimes, soft-tissue infections may have an unusual appearance as shown in figures 6 and 7, a patient with erysipelas of the leg that included some blistering.
There should not be much confusion between lipodermatosclerosis and an infected pressure ulcer. With a pressure ulcer, the infection is likely to be draining through the sore with minimal erythema and swelling around the ulcer, as shown in figure 8, a patient with a deep, infected pressure ulcer, including underlying osteomyelitis. Yet the soft tissue around it is minimally involved. Also, it would be highly unlikely that a pressure ulcer would appear in the lower extremity in that location. There are no “pressure points” in that location.
Lastly, necrotizing fasciitis is a rapidly progressive, severe infection of the deep tissues that ultimately results in a necrosis of the deep tissue and the overlying skin as shown in figures 9 and 10 (before and after surgical debridement). It is frequently caused by group A streptococcal infection, and often associated with varicella. Clearly, this is not what the patient had.
Source: Infectious Diseases in Children, 11/08
