A 54-year-old woman was admitted to the emergency department with a swollen right leg, fever, and altered mental status. Her family brought her in after finding her confused and lethargic. She was incontinent of stool and urine and complained of a rash with blisters on her right thigh. The patient had noted a pimple in her groin more than 5 days earlier; over the past few days she has been complaining of increasing leg pain. She related to her sisters that she had an appointment with her gynecologist in the next few days to have the lesion drained.
The patient had no fever, chest pain, shortness of breath, nausea, or vomiting. Her medical history included type 2 diabetes mellitus, hypertension, and cortical atrophy with mild mental retardation. She had been living independently in her own apartment, and was last seen by her sisters 6 days before with no apparent complaints. She had been wheelchair-bound for 6 months due to a fractured ankle from which she has not been able to completely rehabilitate.
The medications she was taking included glyburide, raloxifene (Evista), and furosemide (Lasix). Surgical history was significant only for a cholecystectomy. She did not smoke or drink alcohol. Upon presentation to the ED she appeared ill, with a blood pressure of 124/50 mm Hg, pulse 110, respiratory rate 18, and temperature of 102°F. Her fingerstick blood sugar was 573. She was able to answer simple questions but was not oriented to time or place. Her skin was hot and dry. Chest exam revealed clear lungs with tachypnea and a 2/6 systolic murmur. Her abdomen was slightly obese, soft, and nontender with normal bowel sounds and a well-healed right upper quadrant incision. Her genitourinary exam revealed a purulent drainage in the groin near her vulva.
Her right leg was markedly swollen, erythematous, and had a brownish-red discoloration that extended from her groin circumferentially to her knee. The skin had a “woody” feel when palpated and large bullae were present (FIGURE 1).
The decision to obtain x-rays of her pelvis and femur was made to assess the extent of her infection (FIGURES 2 AND 3).
FIGURE 1
Cellulitis in the leg
FIGURE 2
Radiograph of thigh and hip area
FIGURE 3
Radiograph of knee
What is the differential diagnosis for this patient?
What tests might help delineate the extent of her infection?