Guselkumab, a Novel Monoclonal Antibody Inhibitor of the p19 Subunit of IL-23, for Psoriatic Arthritis and Plaque Psoriasis: A Review of Its Mechanism, Use, and Clinical Effectiveness.

Psoriatic arthritis and plaque psoriasis are autoimmune conditions affecting multiple organs, including the skin. The pathophysiology and etiology of these conditions are not fully understood; however, numerous factors are believed to play a critical role, including genetics and environmental risk factors. Furthermore, research suggests the IL-23/IL-17 pathway partially mediates these diseases. Once the IL-23 receptor is bound and activated, two subunits, p19, and p40, act through different signaling pathways. Ultimately, inflammation is produced through the effector molecule, IL-17, other cytokines, and tumor necrosis factor (TNF). Traditionally, these chronic conditions have been treated with TNF-α inhibitors and methotrexate, a dihydrofolate reductase inhibitor. Although successful in inhibiting the immune system, these drugs can have many adverse effects due to their broad targets. In recent years, more targeted therapy has become popular. Guselkumab is a monoclonal antibody that inhibits the p19 subunit of IL-23. It has been FDA-approved to treat both plaque psoriasis and psoriatic arthritis. Clinical trials showing guselkumab's efficacy have been promising, even showing improvement in symptoms of plaque psoriasis patients resistant to adalimumab, a TNF-α inhibitor. Guselkumab has also been shown to be well tolerated with a similar safety profile as other biologics inhibiting the immune system. In addition to its efficacy in treating plaque psoriasis and psoriatic arthritis, the mechanism of action offers a targeted approach that may minimize the broad immunosuppressive effects often associated with traditional therapies, providing a potential advantage in the long-term management of these autoimmune conditions.

Six-year history of intermittent symptomatic bilateral vertebral artery stenosis: Imaging and therapeutic intervention.

A 66-year-old man was evaluated for a 6-year history of disabling symptoms of typical intermittent vertebrobasilar (VB) insufficiency. Duplex scanning was "normal," but computed tomographic angiography (CTA) revealed significant bilateral proximal vertebral artery (VA) disease. Angiography with stent placement with the proximal right VA resulted in resolution of symptoms. Symptoms of VB insufficiency may occur from bilateral VA disease, most often involving both proximal segments. Duplex ultrasound has high specificity but relatively low sensitivity for finding hemodynamically significant VA disease. Further imaging with CTA or magnetic resonance angiography (MRA) will help in identification of disease. As with this patient, invasive angiography with percutaneous stenting of the most significantly stenosed VA often results in resolution of symptoms of VB insufficiency.

Cutis marmorata in decompression sickness is associated with a patent foramen ovale.

A 39-year-old male commercial diver developed cutis marmorata after a dive. He had a full recovery after therapy in a hyperbaric oxygen chamber. Transthoracic echocardiography revealed an atrial septal aneurysm and a large shunt during normal respirations. This form of decompression sickness may progress to type II DCS, thus is important to identify and treat. Cutis marmorata as a result of diving is highly associated with an atrial septal defect or a large patent foramen ovale. It is particularly important to assess these patients for a right-to-left shunt as part of a medical evaluation prior to returning to diving.

Carotid artery fibromuscular dysplasia: Ultrasound and CT imaging.

An asymptomatic 54-year-old Caucasian female was found to have a right carotid bruit located high in the cervical region. Carotid duplex ultrasound revealed carotid intimal disease with increased Doppler flow in the mid-distal right internal carotid artery (RICA) with color Doppler turbulence in the distal RICA. Computed tomography angiography (CTA) revealed a typical "string-of-beads" sign in both distal internal carotid artery (ICAs), diagnostic of fibromuscular dysplasia (FMD). While often not diagnostic, carotid duplex ultrasound may yield clues as to diagnosis of FMD with elevated Doppler velocity in the distal carotid, turbulent distal carotid flow, and possibly a "string-of-beads" sign. An "S-curve" distal ICA is associated with FMD and may warrant further evaluation. Magnetic resonance angiography and CTA appear to be better for diagnosis of carotid FMD. The typical "string-of-beads" may be readily identified. While invasive angiography is considered the "gold standard" for diagnosis of carotid FMD, it is infrequently required. Generally, invasive angiography is performed in symptomatic patients in planning for interventional therapy.