Really nasty infection

Here’s a clinical case to test your knowledge of nasty infections, courtesy one of the μgnome’s gneighbours.

• A 65 year old woman, with 
• sudden onset of severe left thigh pain
• currently receiving chemotherapy for breast cancer

 On examination:

•  she appears unwell
•  is febrile (T 38.9^oC)
• the left anteromedial thigh is swollen and warm, but not erythematous

  Diagnostic support:

• Plain X-ray is normal, and a ultrasound scan demonstrates only subcutaneous oedema.
• Blood tests show neutropaenia (0.46) and an elevated CRP (110mg/L).

  Clinical progress:

2 hours later, the skin over the thigh has become brown and indurated, there is palpable crepitation under the skin, and she has developed pain and swelling of the right calf.

1. What is the diagnosis?
2. What is the treatment?

 Selected CT views (RM)

kindly provided by Dr Ronan Murray, Perth, WA.

Answers:

1    Endogenous clostridial myonecrosis of the left thigh and right gastrocnemius muscle.

• This is a rare condition that occurs in patients with neutropaenic enterocolitis, or those with known or occult malignancy, particularly colonic malignancy.
•  The most common causes are Clostridium septicum and C. perfringens.
• Clostridium perfringens was cultured form both from blood and from muscle tissue

2   The treatment of choice is unknown, but usually includes a combination of

• early and aggressive surgical debridement
•  anti-clostridial antimicrobial therapy (usually various combinations of penicillin + metronidazole + clindamycin)
•  hyperbaric oxygen therapy
• and organ support.

 Clostridial myonecrosis is a medical and surgical emergency with close to 100% mortality.