Dr Sudeep Singh Sachdev
Patients with renal insufficiency need to be beware that getting MRI angiography can be dangerous to the internal organs and the skin. It leads to a disease known as ‘Nephrogenic Fibrosing Dermopathy (NFD). NFD, is a disease of fibrosis of the skin and internal organs but distinct from scleroderma or scleromyxedema. It is caused by gadolinium exposure used in imaging in patients who have renal insufficiency.
Epidemiological studies suggest that the incidence of NSF is unrelated to gender, race, or age and it is not thought to have a genetic basis.
In NFD, patients develop large areas of hardened skin with fibrotic nodules and plaques. It may also cause joint contractures resulting in joint pains and limitation in range of motion. In its most severe form, NFD may cause severe systemic fibrosis affecting internal organs including the lungs, heart and liver.
At the microscopic level, NFD resembles scleromyxedema. Both conditions show a proliferation of dermal fibroblasts and dendritic cells, thickened collagen bundles, increased elastic fibers, and deposits of mucin. More recent case reports have described the presence of sclerotic bodies (also known as elastocollagenous balls) in skin biopsies from NFD patients. While not universally present, this finding is believed to be unique to patients exposed to gadolinium, although not necessarily limited to areas involved by NFD.
Nephrogenic systemic fibrosis always occurs (with the exception of one report in 2 transplant patients whose organ donors' histories were not noted) in patients with renal insufficiency who have had imaging studies like magnetic resonance angiography with gadolinium, a contrast agent used in imaging studies.
Gadolinium is a silvery white paramagnetic metal found in earth's crust. Due to its nature of forming trivalent ions it has fluorescent properties which make it useful in Magnetic Resonance imaging. Gadolinium(III) ion occurring in water soluble salts are toxic for the mammals. However the chelated compounds are far less toxic as they carry gadolinium(III) through the kidneys and out of the body before the free ions can be released into the tissues.
The paramagnetic properties make its solution eligible for MRI inspections. Solutions of chelated gadolinium complexes are intravenously administered in MRI based contrast agents. However in renal failure patients, at least four such agents are associated with this rare nodular inflammatory disease NFD.
Evidence to link NFD and Gadolinium, were proven in 13 patients when all developed NFD after exposure to Gadolinium. The mechanism by which this occurs is yet to be found, but it seems to involve a cell termed as ‘circulating Fibrocyte' is stimulated by Gadolinium. Endothelin receptor signaling plays a vital role in the calcification and fibrosis of NFD. Patients with NFD may develop large areas of indurated skin with fibrotic nodules and plaques. Flexion contractures with an accompanying limitation of range of motion also can occur. Although most patients with NFD have undergone hemodialysis for renal failure, some have never undergone dialysis and others have received only peritoneal dialysis. It resembles scleroderma and eosinophilic fasciitis clinically and scleromyxedema histopathologically.
Histopathologically, NFD resembles scleromyxedema in that it manifests with a proliferation of dermal fibroblasts and dendritic cells, thickened collagen bundles, increased elastic fibers, and mucin deposition.
In Medicine, photopheresis or Extracorporeal photopheresis (ECP) is a form of apheresis and photodynamic therapy in which blood is treated with a photosensitizing agent and later irradiated with specified wavelength of light to achieve an effect. WBC and platelets are removed from the blood and treated chemically with 8-methoxypsoralen, then exposed to UV light and returned into the patient.
The author is Nephrologist, Narayana super speciality hospital, Gurugram.
