Evaluation of an infant with a variety of congenital abnormalities reveals hypocalcemia due to a lack of parathyroid hormone. On x-ray, the thymic shadow is absent. A failure of development and differentiation of which of the following embryonic structures would most likely be responsible for the observed presentation?
An endocrinologist examines a patient suspected of having Riedel thyroiditis. Which of the following findings on physical examination would best help confirm the diagnosis?
A 55-year-old male with hypertension and a past medical history of myocardial infarction is prescribed atenolol. This medication will lower his blood pressure by
A 20-year-old woman presents to the emergency room in labor. She has had no prenatal care. The patient is noted to be very restless, with fever, profuse sweating, marked tachycardia, and a marked tremor. Over the next hour, she develops delirium, nausea, vomiting and abdominal pain between contractions. This potentially fatal condition is most likely related to which of the following thyroid diseases?
A patient with familial hypercholesterolemia undergoes a detailed serum lipid and lipoprotein analysis. Studies demonstrate elevated cholesterol in the form of increased LDL without elevation of other lipids. This patient's hyperlipidemia is best classified as which of the following types?
A research physiologist is performing an experiment in which he stimulates sympathetic cholinergic neurons. Which of the following responses is expected?
A 30-year-old man is found to have a mass in his left anterior neck. Chest x-ray films are normal. A CT scan of the thorax and abdomen shows a hemorrhagic right adrenal mass. Serum electrolytes are remarkable for decreased calcium levels. Which of the following neoplasms is most likely responsible for the depression of calcium levels in this patient?
Deficiency in which of the following usually predisposes to thrombosis rather than bleeding?
A newborn infant has multiple, hemorrhagic, cutaneous lesions and does not respond to sound. Head CT scan shows periventricular calcifications. Which of the following infectious agents is the most likely cause of this child's presentation?
A strict vegetarian is not getting sufficient vitamin D in his diet, and he develops osteomalacia. This disease is characterized by which of the following changes in his bones?