Dronedarone-induced digoxin toxicity: new drug, new interactions.

Dronedarone is a relatively new antiarrhythmic drug approved for paroxysmal or persistent atrial fibrillation. Dronedarone can inhibit P-glycoprotein-mediated digoxin clearance and increase steady-state digoxin level 2.5 times. It is important to closely monitor plasma digoxin levels or administer a lower loading dose of digoxin in patients taking dronedarone concomitantly. We report a case of digoxin toxicity in a patient taking concomitant dronedarone as a result of interaction between digoxin and dronedarone.

Disseminated tuberculosis secondary to adalimumab.

A 62-year-old woman with rheumatoid arthritis presented with fever (T-103.9°F). Vital signs and physical examination were normal. She was taking adalimumab, methotrexate, and prednisone for the past 9 months. Blood and urine cultures, human immunodeficiency virus, rapid plasma reagin, purified protein derivative, and cerebrospinal fluid test findings were negative. Computed tomography showed scattered 0.2-cm nodules in the lungs and innumerable subcentimeter lesions in the liver and spleen. Broad-spectrum antibiotics were started empirically. Liver biopsy findings revealed necrotizing granulomas and were negative for acid fast bacilli and fungi on staining. As the patient was persistently febrile despite antibiotics, the antibiotics were discontinued, and an antituberculous regimen including INH, ethambutol, and pyrazinamide was initiated empirically on day 40 of hospitalization. Fourteen days after liver biopsy, acid-fast bacilli grew in the tissue culture. Disseminated tuberculosis (TB) was diagnosed. Fever subsided after 1 week of anti-TB treatment. Antitumor necrosis factor alpha therapy in rheumatoid arthritis increases the risk of TB 5-fold. This is mostly as a result of reactivation of latent TB and commonly presents as disseminated TB. It usually occurs in the early stage of treatment. In our patient, the screening test results for TB before initiation of Adalimumab could have been falsely negative due to immunosuppression secondary to steroids. Our case emphasizes that current screening tests can miss latent TB especially in immunosuppressed patients. As it is difficult to diagnose TB with polymerase chain reaction and culture, histopathology should be sought early. Patients on antitumor necrosis factor alpha therapy presenting with fever of unknown origin should be considered for empirical anti-TB treatment regardless of microbiological and tissue diagnosis.

Complete heart block following a blow on the chest by a soccer ball: a rare manifestation of commotio cordis.

Commotio cordis is a rare type of blunt cardiac injury in which low impact chest trauma causes sudden cardiac arrest, usually occurs from being struck by a projectile during sports. The most common arrhythmia during commotio cordis is ventricular fibrillation, although complete heart block and an idioventricular rhythm have also been reported. We describe a case of a young patient who presented with a persistent third-degree atrioventricular block and a left bundle branch block, following blunt chest trauma, as a result of blow by soccer ball and subsequently needed a permanent pacemaker.

Protothecal olecranon bursitis: an unusual algal infection.

Prototheca is an achlorophyllic alga which rarely causes infections in humans and protothecal olecranon bursitis is remarkably rare. We report a case of a 76-year-old immunocompetent man presenting with pain and swelling of the right elbow secondary to protothecal infection. Initial cultures of the olecranon bursal aspirate revealed no growth; however, repeat aspiration after 2 months grew prototheca species on culture. Prototheca wickerhamii and Prototheca zopfii are the only 2 protothecal species known to cause human infections. Protothecal infection can manifest as skin infections, extremity infections, bursitis and very rarely as systemic infections. Treatment of protothecal infections remains controversial. Amphoterecin B, ketoconazole and fluconazole have been reported to yield a successful outcome. More recently, itraconazole has been found to be curative. Surgical excision of the bursa remains the definitive treatment. Our patient was treated with itraconazole with a favorable response.

Repetitive monomorphic ventricular tachycardia as a manifestation of suboptimally treated thyrotoxicosis.

Monomorphic ventricular tachycardia (VT) is a unique manifestation of hyperthyroidism. We present the case of a 41-year-old male with a history of hyperthyroidism presenting with palpitations secondary to non-sustained episodes of monomorphic VT. Cardiac arrhythmias due to thyrotoxicosis are perpetually supraventricular in origin. Monomorphic VT in the setting of thyrotoxicosis in the absence of structural heart disease is exceedingly rare. After starting propranolol and increasing the dose of methimazole, the patient had no further episodes of VT. It is important to recognize repetitive monomorphic VT as an understated but important manifestation of thyrotoxicosis. Propranolol is associated with an excellent response in these patients and anti-thyroid medications such as methimazole effectively reverse thyrotoxicity.