Treating Lower Extremity Wounds In The Face Of Systemic Disease
Systemic diseases as varied as diabetes, renal failure and rheumatoid arthritis can affect the healing of lower extremity wounds. When it comes to treating chronic wounds, there is an array of testing one can employ to rule out systemic disease as a potential cause. There are also key warning signs that may indicate a possible malignancy. With these issues in mind, our multidisciplinary panel offered the following insights.
Q: What are the most common systemic diseases that manifest themselves as lower extremity wounds?
A: Diabetes is a common finding for Michael S. Miller, DO, Richard Schlanger, MD, and Lawrence Karlock, DPM. Drs. Karlock and Miller also see lower-extremity wounds in patients with sickle cell anemia and rheumatoid arthritis, and Dr. Miller also sees seronegative arthritis in patients.
Dr. Miller also sees conditions including inflammatory bowel disease, hematologic malignancies, autoimmune conditions such as lupus, collagen vascular disease and vasculitis. For Dr. Schlanger, the most common systemic diseases manifesting in lower extremity wounds are vascular conditions like venous disease, peripheral vascular disease and collagen vascular disease. He also sees AIDS, IV drug use and end-stage renal disease. He notes that many of those conditions “meld together in a collage of comorbidities.”
Dr. Karlock adds that he encounters patients with pyoderma gangrenosum and sarcoidosis that manifest as lower extremity wounds.
Q: When patients present with a chronic, non-healing wound, what workup do you perform to rule out a systemic cause?
A: For patients with lower extremity ulcers and non-healing wounds, Dr. Schlanger orders a multi-stage workup. This entails blood work, including CBC, SMA 7, HbA1c, pre-albumin and erythrocyte sedimentation rate testing. As he notes, these basic tests will indicate one or more systemic problems that have caused a derailment in the healing cascade.
Dr. Miller will likewise use a CBC test and also utilizes renal and hepatic function tests, lower intestinal endoscopy and chest X-rays. While noting that no single diagnostic test is definitive, he says the aforementioned tests can be helpful. Dr. Miller will also obtain a bone marrow biopsy. However, for a condition such as pyoderma gangrenosum, Dr. Miller cautions that a biopsy of the wound itself may exacerbate the condition. Therefore, when it comes to patients with suspected pyoderma gangrenosum, he says one would make the diagnosis and exclude other causes by assessing the clinical presentation.
Like Dr. Schlanger, Dr. Karlock will use an HbA1c comprehensive metabolic test, depending on the patient’s clinical picture. If he has any questions about an undiagnosed, underlying systemic cause, he refers patients to an internist for a workup.
To determine a vascular baseline, Dr. Schlanger will use TcPO2 testing, saying he can test without using a wound clinic and can interpret the results immediately. The readings from the TcPO2 test will provide insight into the cutaneous blood flow and possible inflow problems, which may require more invasive testing. He notes Doppler studies can help rule out blockages.
Q: What signs warn you of a possible malignancy in a chronic foot or ankle wound?
A: Taking a biopsy is key to identifying a malignant wound, according to Drs. Miller and Schlanger. However, Dr. Miller notes the trick is knowing when to biopsy. One would biopsy a wound that continues to get worse despite appropriate therapy and also has a negative systemic workup, advises Dr. Miller. Dr. Schlanger says one should biopsy a wound that has not responded after 30 days of treatment. He adds that one should include the lesion and normal skin for a biopsy or else the pathologist is merely considering the inflamed cells of the wound.