Steroid-responsive meningitis-arteritis with spontaneous echocardiographic contrast and elevated cardiac troponin I in a dog

Steroid-responsive meningitis-arteritis: What have we learned since 2010? A narrative review

Steroid-responsive meningitis-arteritis (SRMA) occurs as an immune-mediated, inflammatory, and non-infectious disorder of juvenile and young-adult dogs. In principle, SRMA is divided into two clinical courses: during the typical acute form, dogs are presented with fever, cervical hyperaesthesia, and reluctance to move. The more protracted form most probably emerges after insufficient immunosuppressive treatment or relapses, with additional neurologic deficits localized in the cervical and thoracolumbar spinal cord or multifocally. The trigger leading to SRMA still remains an unsolved riddle for immunologists and clinical neurologists. In the past, many attempts have been made to clarify the etiology of this disease without success. The purpose of writing this narrative review about SRMA is to summarize new insights on the pathogenesis of SRMA with a focus on immunologic dysregulation. Furthermore, unusual manifestations of the disease, new diagnostic approaches using possible laboratory biomarkers or diagnostic imaging tools, and potential innovative treatment strategies are discussed.

Development of Spontaneous Echocardiographic Contrast After Transarterial Occlusion of a Patent Ductus Arteriosus in an Adult Dog With Concurrent Pulmonary Hypertension

An 8-year-old intact female Chihuahua was presented for evaluation and possible occlusion of a previously diagnosed patent ductus arteriosus (PDA). Transthoracic echocardiography revealed left ventricular and left atrial enlargement, enlargement of the main pulmonary artery, and a PDA with bidirectional shunting. Tricuspid regurgitant velocities suggested moderate pulmonary hypertension. The PDA was occluded with an Amplatz® Canine Duct Occluder using a transarterial approach on the following day. No immediate complications were observed other than an acute decrease in left ventricular systolic function. One day after the PDA occlusion transthoracic echocardiography revealed no residual ductal flow, but there was spontaneous echocardiographic contrast in the left ventricle. The patient was discharged with sildenafil, pimobendan, and clopidogrel. Five weeks later when the patient was presented for a recheck examination, the previously documented spontaneous echocardiographic contrast was no longer present. Finding spontaneous echocardiographic contrast in the dog has not previously been reported in association with PDA occlusion.

Cardiac Troponins in Dogs and Cats

Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.