USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 38-year-old woman comes to the emergency department because of a severe headache, vomiting, and lethargy for the past few hours. She has had increasingly worse "tunnel-vision" for the past few months. She has also had fatigue, constipation, dehydration, and a stoppage of her menstrual periods. Her temperature is 37.0°C (98.6°F), pulse is 58/min, respirations are 8/min, and blood pressure is 92/64 mm Hg. Physical examination shows a lethargic female complaining of severe pain. Laboratory studies show hypernatremia and hypoglycemia. Head magnetic resonance imaging is shown below. Which of the following is the most likely diagnosis?
The pituitary is a pea-sized gland, hanging by a stalk from the base of the brain.
The second largest cell group are the corticotrophs which secrete adrenocorticotropic hormone, or ACTH, which stimulates the adrenal glands to secrete cortisol, a hormone that controls the stress response, blood pressure, and metabolic regulation.
A smaller cell group are the lactotrophs which secrete prolactin.
There are also thyrotrophs which are cells that secrete thyroid stimulating hormone, or TSH, that stimulate the thyroid gland.
And finally, there are the gonadotrophs which secrete two gonadotropic hormones - luteinizing hormone, or LH, and follicle-stimulating hormone, or FSH, both of which go on to stimulate the ovaries or testes.
ADH acts on the kidneys to decrease the amount of water lost in the urine.
Because the pituitary exists within the very confined space of the sella turcica, it’s very sensitive to changes in that space. Even the slightest bit of compression can interfere with the pituitary’s hormone production.
Hypopituitarism can also be due to pituitary apoplexy, which is a disorder where there is either severe bleeding such as a hemorrhage, or a loss of blood flow to the pituitary gland, known as infarction. The more common way is a hemorrhage.
Larger tumors demand more blood, and increased blood flow means increased pressure in the vessels, eventually causing them to rupture and bleed.
- "Robbins Basic Pathology" Elsevier (2017)
- "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
- "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
- "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
- "Harrison's Endocrinology, 4E" McGraw-Hill Education / Medical (2016)
- "Management of Hypopituitarism" Journal of Clinical Medicine (2019)
- "Hypopituitarism After Traumatic Brain Injury" Cureus (2019)