A 54-year-old male presents to the emergency department with complaints of episodic palpitations and lightheadedness. On examination, his heart rate is 150 bpm, consistent with narrow-complex tachycardia on ECG. Vagal maneuvers such as bearing down fail to terminate the rhythm. After ensuring no carotid bruits or contraindications such as recent stroke or carotid artery disease, a carotid sinus massage is performed on the right side while monitoring the ECG. Which of the following mechanisms underlie the effectiveness of carotid sinus massage?
A 54 year-old male comes to the emergency room with fever, chills, weakness, chest pain and abdominal pain. He does not report shortness of breath or abdominal bloating or swelling in the legs, ankles and feet or weight loss or cough or headaches or weakness in extremities. Auscultation of lungs and heart is normal. He has no murmurs. His chest radiograph is normal but echocardiogram shows vegetations on the mitral valve. Blood cultures show predominance of streptococcus bovis bacteria. After initial endocarditis treatment, this patient should undergo which of the following evaluations?
A 32 year-old woman comes to your office because she is concerned about a mole in her right thumb. She has had it for over three months. It is growing in size and changing in colors. In the physical examination, you notice a lesion under the nail. It involved the proximal nail fold. This is referred to as
In a 32 year-old immigrant from Japan of Thai descent you diagnosed gout and decided to start him on allopurinol. Which of the following tests is recommended before he starts taking Allopurinol?
A 57 year-old male patient is brought to the emergency room by his daughter because he has been ‘vomiting non stop’ since this morning and not responding to her questions appropriately. He developed a slurred speech and she can’t understand what he has been saying. His daughter reports that the patient has been having problems with his vision lately and probably could have taken tablets which belong to his son, who is on treatment for tuberculosis and takes isoniazid and rifampin daily. His temperature is 100.7 ⁰ F, heart rate is 84 beats per minute, respiratory rate is 7 breaths per minute, and blood pressure is 90/64 mm Hg. As you listen to his lungs, he developed a tonic-clonic seizure. Which of the following is a true statement regarding isoniazid overdose?
A 32 year-old male comes to your ophthalmology clinic complaining of increasingly blurry vision and headaches. His wife reports that his gait became clumsy, his speech became slurred. On review of systems, you discover that he has difficulty swallowing, and having frequent headaches. Patient reports that some of his relatives also have similar medical problems. On physical examination, you notice a sweaty, anxious looking male. Cardiac exam is significant for palpitations. In retinal exam, you find dilation and tortuosity of retinal vessels, angiomatous lesions with hemorrhages and exudates in both eyes. Suspecting a systemic disorder, you order some investigative studies, which reveal hemangioblastomas in the cerebellum, two nodules in the pancreas and a large tumor in the kidney. The lesions have a striking appearance of a cyst with a nodule contained in its wall, and angiography demonstrates the highly vascular nature of the nodules. The laboratory tests reveal elevated plasma free fractionated metanephrines, and elevated red blood cells, white blood cells and platelets. The erythrocytosis in this patient is most likely due to which of the following?
