Nephrogenic systemic fibrosis (NSF), also known as nephrogenic fibrosing dermopathy (NFD), is a rare condition characterized by the tightening and stiffening of the skin on the extremities. The condition is exclusive to patients in moderate to late stage kidney disease and affects men and women of every age and nationality. There are no confirmed cases of the condition noted prior to 1997, with only 300 confirmed cases occurring worldwide. The majority of the cases of NSF/NFD are found in Europe, Asia, and North America.
The origin of the condition is a mystery, with no credible links to ingested medications, kidney dialysis, or any microorganism. In recent years, a connection between cases of NSF/NFD and the injection of a Gadolinium based contrast agent prior to a magnetic resonance imaging (MRI) procedure has been found. In December of 2006, the US Food and Drug Administration (FDA) had received 90 reports of NSF/NFD occurring in the months after the patient had received an injection of a Gadolinium based contrast agent in order to clarify the images produced by an MRI. This prompted the FDA to open an investigation which found that out of the 75 cases that they meticulously reviewed, all of the patients had received a Gadolinium based contrast agent injection, all had undergone an MRI, and all had moderate to late stage kidney disease.
The onset of NSF/NFD is characterized by dark or reddened areas appearing on the skin. Individuals experiencing the condition report an itching or burning feeling underneath the skin that can range in intensity from mild to severe. The skin of the body starts to thicken and swell, most commonly on the extremities but also affecting the trunk of the body in some cases. The surface of the skin begins to look like the peel of an orange and skin lesions that resemble blisters may appear on the areas between the wrist and shoulders or the areas between the ankles and thighs. Patients have also reported significant joint pain and bone pain occurring deep within the ribs and hips.
As NSF/NFD progresses, the individual will start to experience muscle weakness and severe, sharp pains beneath the affected areas of the skin. Medical testing will show that the soft tissue beneath the affected areas has begun calcification, which is a build up of calcium deposits in the soft tissue causing the tissue to harden. The affected areas of the skin will continue to tighten and thicken, causing severe discomfort and limiting the amount of movement that can be performed by the affected limb. Individuals experiencing a severe case of NSF/NFD may lose the ability to stretch or flex their arms, legs, hands, or feet and, in some cases, are unable to walk or perform normal activities. The movement restriction can become so great that attempting movement may cause bone breakage.
NSF/NFD can develop over a period of days or months, with about 5% of cases classified as rapidly progressive. There is no consistently effective treatment method for the condition, although symptoms may be alleviated by a number of medications. The progression of the condition can be arrested by an improvement in renal function, and in some cases, renal function improvement can slowly reverse the effects of NSF/NFD. Research is ongoing as medical professionals attempt to understand and cure this devastating condition.