Gadolinium (Gd)-based contrast agents are frequently used in health care for enhancing magnetic resonance image (MRI) signals at low concentrations. Contrary to popular opinion, this widely used heavy metal is not biologically inert. Once notable for its safety profile, there is mounting evidence for Gd deposition in various organ systems of the body, even in those with normal renal function. A large knowledge gap remains concerning the potential harms of Gd deposition and the factors determining its elimination from the body. However, the findings of deposited Gd throughout various organs and their intracellular compartments even years after the initial exposure have been established. Here, we describe a case of a Vietnam-era veteran whose presentation, clinical, and laboratory findings were consistent within the spectrum of Gd deposition disease.
Case Presentation
A Vietnam-era veteran aged > 70 years presented for evaluation of Gd-based contrast agent–induced chronic multisymptomatic illness His medical history was significant for chronic low back pain, chronic hypertension, type 2 diabetes mellitus, and hypogonadism. Surgical history was notable for back surgery (24 years prior), laminectomy (2 years prior), shoulder replacement (2 years prior), and an epidural complicated by a hematoma (1 year prior). His presenting concerns included a painful and pruritic rash that worsened with showering, pain originating at the right Achilles tendon with migration to the knee, and shoulder pain. His symptoms started shortly after receiving multiple exposures to Gd-based contrast agents to enhance MRIs during his clinical care (Omniscan 20 mL, Omniscan 20 mL, and Gadovist 10 mL, administered 578, 565, and 496 days prior to the clinic visit, respectively). New onset headaches coincided with the timeline of symptom onset, in addition to hoarseness and liberation of an “oily substance” from the skin. More than one year prior to this clinic visit, he was considered for having polymyalgia rheumatica given the ambiguity of symptoms. Functional status remained impaired despite treatment with prednisone and methotrexate.
The patient’s military service was in the mid-1960s. He was deployed to Japan and had no knowledge of an Agent Orange exposure. His tobacco history was distant, and he reported no tattoos, prior transfusions, or occupational metal exposure (he was never stationed at Camp Lejeune or other bases with potential toxicants in the drinking water). Family history was significant for lung cancer in his mother (smoker) and his father died aged > 90 years. One sister had fibromyalgia. The patient’s children were healthy.
Clinical Findings
The patient was afebrile, normotensive (146/88 mmHg), and normocardic. His weight was 100 kg. He was well nourished and in no acute distress. The thought process was attentive, and his affect pleasant. Ocular examination was notable for arcus senilus. The fundoscopic examination was limited on the left, but there was no neovascularization on the right. Jugular venous pulsation was normal at 8 cm. Right ventricular impulse was slightly hyperdynamic, the rhythm was regular, and there was no abnormal splitting of S2. A soft-grade I/VI crescendo/decrescendo murmur was auscultated along the apex. Radial pulses were 2/2. He was not in respiratory distress, with equally resonant fields bilaterally. Lung sounds were clear bilaterally. A papular, erythematous rash was present in a general distribution over the chest, with few telangiectasias and some varicosity along his left arm. The skin had normal elasticity, although the skin of the hands and legs was papyraceous.
Gd levels were measured in the blood and urine (Table 1). Gd was detectable in the skin (0.2 µg/g) nearly 400 days after the last exposure. Gd was still detectable in the patient’s blood and urine (0.2 ng/mL and 0.5 µg/24 h, respectively) more than 3 years after his last exposure.
Discussion
In the United States, there are 40.44 MRI units per million people and 40 million MRIs are conducted annually. From 30 to 50% of these are enhanced with Gd-based contrast agents. In the past 30 years, there have been > 450 million contrast-enhanced MRI procedures.1
Gd is a rare earth metal. Among commercially available elements Gd has exceptional properties for enhancing MRI signals at low concentrations.1 The nonphysiologic metal is detoxified by chelation with proprietary multidentate formulations that enhance (primarily renal) elimination while retaining the paramagnetic and chemical properties for imaging. Gd exposure was found to be associated to iatrogenic nephrogenic systemic fibrosis in 2006 and later confirmed via multiple systematic reviews.2 Gd is retained in every vital organ after exposure.3 Gd-based contrast agents stimulate bone marrow–derived fibrocytes in mediating fibrosis, and bone marrow develop a memory of prior contrast exposure (Figure 1).4-6 Systemic fibrosis is mediated by the monocyte chemoattractant protein 1/C-C chemokine receptor 2.6,7 Even in the setting of normal renal function, Gd-based contrast induces the formation of Gd-rich nanoparticles in the skin and kidney.7,8 Far from being inert, Gd-based contrast agents induce systemic metabolic changes such as hypertriglyceridemia, elevations in low-density lipoprotein cholesterol, insulin resistance, and the Warburg effect (glycolytic/energy switching) in the renal cortex concomitant with profound mitochondrial abnormalities.8
We have discovered that the rate of Gd-enhanced procedures has increased immensely within the Veterans Health Administration (VHA) system in a subset of patients with designated kidney disease (Table 2). Although a substantial number of procedures are dedicated to head and brain imaging within the VHA, the indications for Gd-enhanced diagnoses (eg, cardiac) are increasing (Figure 2).