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Monday, October 20, 2014

Mucormycosis of the skin in a diabetic woman


Mucormycosis is a very rare but nasty and often deadly infection caused by fungi in the order Mucorales, such as Mucor or Rhizopus species. It is more common in people whose immune systems don't work properly - AIDS sufferers, cancer patients, folks receiving immunosuppressive treatment after organ transplantation... High doses of steroids and uncontrolled diabetes mellitus are risk factors too, for precisely the same reason - they weaken the body's natural defenses, making it easier for these opportunistic fungi to strike. 

Mucormycosis is an infection with many faces. It often involves the sinuses, brain or lungs; other affected areas include the gastrointestinal tract and skin, especially after injuries. Fungal invasion of blood vessels leads to blood clot formation, so that blood supply is lost in the affected body parts, causing tissue necrosis. If the infection has attacked the lungs, symptoms include difficulty breathing and a persistent cough; if the skin is affected, it becomes red and swollen at first, with a significant amount of pain, then turns black. Without an early diagnosis, the outcome can be dismal. Treatment involves amphotericin B therapy and, frequently, surgery to remove the affected tissue - often resulting in significant disfigurement or limb amputation. In cases of disseminated mucormycosis, where the fungi have attacked the entire body, mortality reaches 90% (in AIDS patients, the mortality rate is almost 100%).

Ahmadinejad et al. describe a case of mucormycosis that occurred in Iran in September 2011. A 63-year-old lady with poorly controlled diabetes (she was on oral medication - Metformin - but apparently it didn't help much) who had fallen from a vehicle and dislocated her wrist. She had been treated by an alternative practitioner who applied a poultice made of herbs, egg, flour and turmeric and bandaged her hand. Four days later, she was still in severe pain, so her family removed the dressing and found out that the hand and forearm were now swollen and turning black.

 Necrosis of the skin and soft tissues of the hand and forearm in a female diabetic patient with mucormycosis.


The woman was admitted to the Imam Khomeini hospital in Tehran. Apart from the excruciating pain, edema and discoloration in her left hand, she was found to have a low-grade fever (38 degrees Celsius), but her laboratory findings were more or less normal. The skin on her left hand and forearm was already necrotic, and the range in wrist motion had become limited. She was initially treated with antibiotics. Ultrasonography showed fluid collection inside her wrist. A diagnosis of tenosynovitis was made, and an operation was performed, but the patient was still suffering from pain and fever after 24 hours. Thrombosis of arterial vessels in her hand was diagnosed; the antibiotics were changed and heparin was added to treat the blood clotting, but to no avail. On the 10th day after admission, mucormycosis was finally suspected and the patient was put on amphotericin B. A smear and tissue biopsy showed fungal hyphae, and a tissue culture finally made it possible to identify the "criminal" - a fungus from the genus Rhizopus:



Unfortunately, it was too late to save the hand; the necrosis had spread to the palm area and to the fifth finger. 18 days after admission, limb gangrene was diagnosed, so the hand and forearm had to be amputated below the elbow. The patient received amphotericin B for 9 more days. Six months later, she was alive and well. 

Take a look again at the chain of events that led to the amputation: diabetes, a fall from a vehicle, a herbal dressing applied by an alternative medicine practitioner (it was probably very unwise on the patient's part to rely on traditional medicine instead of seeing a doctor right after her injury) and a delayed diagnosis. One wonders whether the outcome would have been different if the doctors in the hospital had decided to use amphotericin B earlier, instead of trying several different antibiotics in vain.


Literature:

Ahmadinejad Z, (2013)  Cutaneous Mucormycosis in a Diabetic Patient following Traditional Dressing. Case Rep Dermatol Med. 2013: 894927.

Wikipedia: Mucormycosis





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