Imaging in Rheumatic Immune-related Adverse Events.

Since their introduction, immune checkpoint inhibitors have revolutionized cancer treatment by harnessing the body's own immune system as a defense against tumor growth. The downside of activating the immune system is the development of immune-related adverse events (irAEs), which mimic autoimmune disease of various organ systems. The musculoskeletal system is an uncommon, but substantial one for patients and can lead to long-term pain and disability that affects their quality of life. This review summarizes recent literature on imaging forms utilized for diagnosis and assessing treatment response in rheumatic irAEs.

A 73-Year-Old Man with an Incidental Diagnosis of Deltoid Intramuscular Myxoma Following a History of Trauma.

BACKGROUND Intramuscular myxomas are rare and benign soft-tissue tumors of uncertain differentiation. Predisposing or precipitating factors have not yet been reported. Activating mutation in GNAS (exons 8 and 9) is detected in >90% of sporadic cases. The role of chronic myopathy, tendinopathy, or trauma to muscles in the etiology of these neoplasms is not known. We report an unusual case of a deltoid mass found following longstanding rotator cuff tendinopathy and a recent fall, later confirmed to be an intramuscular myxoma on biopsy. CASE REPORT A 73-year-old man with a 5-year history of left shoulder pain and rotator cuff tear presented with intractable pain in his left shoulder after a recent fall at home. Physical examination was suggestive of a rotator cuff injury and magnetic resonance imaging (MRI) of the left shoulder revealed a 2.7×2.5×3.7cm T1 hypo- and T2 hyperintense oblong mass-like signal abnormality with heterogeneous, predominantly peripheral enhancement within the deltoid muscle concerning for a malignant mass. Surgical resection was carried out along with left reverse total shoulder replacement, and histopathology revealed findings consistent with an intramuscular myxoma. CONCLUSIONS Intramuscular myxomas are rare, benign tumors. This case report presents one such myxoma incidentally found in a patient with longstanding rotator cuff tendinopathy and a recent fall. Although this co-occurrence is likely incidental, further research and case series review of similar presentations may influence postulations of the pathophysiology of myxomas.

Rapidly Progressive Granulomatous Amoebic Encephalitis in a Diabetic Individual.

We present a case of rapidly progressive granulomatous amoebic encephalitis caused by Balamuthia mandrillaris in an individual with diabetes mellitus. Our patient presented with occipital headache, blurry vision, confusion, and gait imbalance of one week's duration. Brain imaging revealed numerous peripheral ring-enhancing lesions concerning malignancy. Brain biopsy was consistent with Balamuthia mandrillaris infection. He passed away 45 days after presentation despite being treated with a five-drug regimen. This case highlights the importance of considering amoebic brain infections, especially with ring-enhancing lesions on imaging. There are opportunities to design modalities for rapid diagnosis and better treatment.

A Case of Osmotic Demyelination Syndrome in a Chronic Alcoholic With Moderate Hyponatremia.

Osmotic demyelination syndrome (ODS) is a clinical syndrome seen following aggressive correction of severe hyponatremia. Chronic alcohol use, malnutrition, and electrolyte derangement are additional risk factors promoting the demyelination in ODS. A 49-year-old female with a history of untreated mood disorder, hypertension, alcohol, and tobacco abuse presented to the emergency department (ED) with a three-month history of generalized body weakness. She also had a history of recurrent falls, difficulty walking, inadequate food and water intake, progressively worsening jaundice, and confusion which started about the same time. Her vital signs were normal; some of the significant physical examination findings were: sclera icterus, abdominal distension, bilateral pedal edema, hand tremors, rotary nystagmus, paraparesis, 1+ bilateral knee jerk, and absent bilateral ankle jerk. She had moderate hyponatremia, mild hypokalemia, deranged liver function test with a cholestatic pattern and transaminitis, hypoalbuminemia, elevated ammonia, lipase, in keeping with alcoholic liver disease and acute pancreatitis. In the ED, she received a normal saline infusion, and her serum sodium rose by just 6 mmol/L within the first 24 hours. She had drainage of her ascitic fluid and treatment with thiamine, folic acid, prednisone, lactulose, rifaximin, furosemide, spironolactone, and Ceftriaxone with improvement in clinical and laboratory abnormalities. Her lower extremity weakness persisted despite physical therapy, prompting neurologic evaluation. MRI of the lumbar spine showed an old compression fracture and lumbar spinal stenosis, while MRI brain findings were consistent with Osmotic demyelination. At the time of discharge to a rehabilitation facility, her serum sodium was 132 mmol/L, but her leg weakness persisted. Although rare, ODS can occur in the setting of moderate hyponatremia if there are additional risk factors that lower the threshold for demyelination.

Sustained Ventricular Tachycardia as a Harbinger of Cardiac Amyloidosis.

BACKGROUND Cardiac amyloidosis is an infiltrative cardiomyopathy caused by the extracellular deposition of insoluble precursor protein amyloid fibrils. These depositions of protein amyloid fibrils are found on the atria and ventricles and can cause a wide array of arrhythmias; however, sustained ventricular arrhythmias are quite uncommon. CASE REPORT A 71-year-old man with a history of hypertension developed a sudden onset of shortness of breath, profuse diaphoresis, lightheadedness, and presyncope. Upon emergency medical services' arrival, an initial electrocardiogram revealed wide complex tachycardia with a heart rate of 220 to 230 beats per min. He was subsequently given, in succession, magnesium, adenosine, and amiodarone with no change in heart rate or rhythm. Due to ongoing symptoms of diaphoresis and the development of dyspnea, he underwent direct current cardioversion and was converted from ventricular tachycardia to atrial fibrillation at controlled rates. A transthoracic echocardiogram and cardiac magnetic resonance imaging showed features suspicious for cardiac amyloidosis. A subsequent 99m technetium pyrophosphate single-photon emission computerized tomography scan revealed a grade 3 visual uptake and a heart-to-contralateral lung ratio of 1.92, consistent with transthyretin amyloidosis. The patient was treated with tafamidis and an implantable cardioverter-defibrillator for secondary prevention of ventricular arrhythmia. CONCLUSIONS This case highlights the need to consider cardiac amyloidosis in the differential diagnoses of patients with persistent ventricular arrhythmia and no prior history of heart disease.