Thomas Nguyen

Positron emission tomography scanning in anti-neutrophil cytoplasmic antibodies-associated vasculitis

AbstractTools for evaluation of disease activity in patients with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) include scoring clinical manifestations, determination of biochemical parameters of inflammation, and obtaining tissue biopsies. These tools, however, are sometimes inconclusive. 2-deoxy-2-[18F]-fluoro-D-glucose (FDG) positron emission tomography (PET) scans are commonly used to detect inflammatory or malignant lesions. Our objective is to explore the ability of PET scanning to assess the extent of disease activity in patients with AAV.Consecutive PET scans made between December 2006 and March 2014 in Maastricht (MUMC) and between July 2008 and June 2013 in Brussels (EUH) to assess disease activity in patients with AAV were retrospectively included. Scans were re-examined and quantitatively scored using maximum standard uptake values (SUVmax). PET findings were compared with C-reactive protein (CRP) and ANCA positivity at the time of scanning.Forty-four scans were performed in 33 patients during a period of suspected active disease. All but 2 scans showed PET-positive sites, most commonly the nasopharynx (n = 22) and the lung (n = 22). Forty-one clinically occult lesions were found, including the thyroid gland (n = 4 patients), aorta (n = 8), and bone marrow (n = 7). The amount of hotspots, but not the highest observed SUVmax value, was higher if CRP levels were elevated. Seventeen follow-up scans were made in 13 patients and showed decreased SUVmax values.FDG PET scans in AAV patients with active disease show positive findings in multiple sites of the body even when biochemical parameters are inconclusive, including sites clinically unsuspected and difficult to assess otherwise.

Pachymeningitis and Aortitis in a Patient With Antineutrophil Cytoplasmic Antibody–Associated Vasculitis

FIGURE. A, FDG-PET/CT fusion image with aortic and cervical hypermetabolism. B, Sagittal view of cervical magnetic resonance image with pachymeningitis (arrow). From the Department of Internal Medicine, Erasme University Hospital, Brussels, Belgium. A 64-year-old woman presented with cervical and shoulder pain with elevated C-reactive protein. The workup revealed an antimyeloperoxidase antineutrophil cytoplasmic antibody-associated vasculitis (AAV), proven by biopsy. Aortic hypermetabolism was demonstrated on F-18 fluorodeoxyglucose positron emission tomography/ computed tomodensitometry (FDG-PET/ CT) performed because of the initial suspicion of giant cell arteritis. The patient was treated with methotrexate and steroids. During follow-up, an FDG-PET/CT showed persistent aortic as well as cervical spine hypermetabolism (Figure, A). The latter was shown to be cervical pachymeningitis by magnetic resonance imaging (Figure, B), although the patient did not experience any neurological symptoms (Supplemental Figures 1, 2, and 3, available online at http://www.mayoclinicproceedings.org). The finding of hypermetabolism in a large vessel such as the aorta is quite unexpected in the setting of AAV, which mainly involves small vessels, but this finding has been described. In contrast, cervical pachymeningitis in the setting of AAV has, to the best of our knowledge, never been found by FDG-PET/CT, notably in 2 recently published case series on the clinical value of FDG-PET/CT in AAV. This exceptional case brings additional data to the concept that FDG-PET/CT may identify more organ involvement than usual organ screening identifies.

Increased risk of ventricular fibrillation associated with RYTHMIQ™: lessons learned

A 52-year-old woman with a history of non-ischemic left ventricular dysfunction (EF of 40 %) was brought to the hospital for cardiac arrest. The patient was found at home in ventricular fibrillation and was shocked three times with return of spontaneous circulation. Mild hypokalemia (3.2 mEq/L) was the only contributing factor. She was known for intermittent third-degree AV block and Mobitz type II second-degree AV block but never experienced any syncope. The patient was implanted 5 months before with a dual-chamber pacemaker in another center (Boston Scientific AccoladeTM MRI EL) in DDDR mode with a lower rate limit of 30 bpm and RYTHMIQTM algorithm on. Pacemaker interrogation revealed short-long-short intervals (Fig. 1) preceding ventricular tachycardia then degenerating to ventricular fibrillation (Fig. 2). The RYTHMIQTM algorithm was switched off and the AV search + algorithm was switched on. The patient was upgraded to an ICD and did not experience any recurrence of malignant arrhythmias. 2 Discussion

A lucky car accident

A 30-year-old male was admitted to our institution after a high-speed motor vehicle collision. The patient had remained hemodynamically stable and conscious throughout. He had a traffic pole perforating his left thigh (Figure 1 and Figure 2), but distal pulses were present and sensation was normal in all dermatomes. The patient also had multiple facial abrasions and a scalp laceration. Full-body computed tomography (CT) was performed. The scan showed a steel rod perforating the left thigh, revealing no other significant injury (Figure 3). Surprisingly, and despite the close proximity of the steel rod to the femoral vessels, no vascular lesions were observed on a contrast-enhanced CT scan. Emergency surgery was performed to remove the rod, and no major arterial or