From our anonymous insider…
We began endocrinology, the study of hormones. Hormones are signaling molecules, namely peptides and cholesterol derivatives, that cause systemic changes in the body. The pea-sized pituitary gland sits in a small alcove at the base of the skull, right behind the nasal cavities near the optic nerve. This master regulator of hormones functions as the interface between the brain and the blood, secreting nine different hormones.
The pituitary is actually two separate organs. The posterior pituitary gland, more recently renamed the neurohypophysis, is a protrusion of neurons in the hypothalamus. These neurons release oxytocin and antidiuretic hormone (ADH) into systemic circulation (the blood). For example, ADH is released in response to an increase in the concentration of solutes in the blood, thus causing the kidneys to concentrate urine by reabsorbing free water into the blood. Other neurohypophysis neurons release oxytocin (a.k.a. the love hormone) during labor causing uterine contractions and also while a baby nurses causing a “let down” (spray) of milk. (New mothers can have excruciating cramps from uterine contractions during nursing because of this oxytocin release).
The anterior pituitary or adenohypophysis is a broken-off extension of the mouth that wraps around the neurohypophysis. These cells also secrete hormones under the control of the hypothalamus. These hormones regulate everything from the thyroid and adrenal glands to the menstrual cycle and milk production. Thyroid issues are some of the most common adult ailments. The thyroid gland, located right under the “Adam’s apple” secretes thyroxine. Thyroxine increases metabolism and “energy”. Our endocrinologist says that many of her patient’s request synthroid (synthetic thyroxine) to help lose weight. Low thyroxine levels can not only be caused by an issue in the thyroid but also by the pituitary. The pituitary secretes thyroid-stimulating hormone (TSH) which tells the thyroid to release thyroxine. Without TSH, there will be no thyroxine even if thyroxine levels are abnormally low.
Our patient case: “Susan”, 22-year-old female presenting with fatigue, blurred vision, transient loss of vision, and a headache. Labs show abnormally low thyroid stimulating hormone (TSH) and low thyroxine and abnormally high prolactin levels for someone not breastfeeding. She was referred for a head MRI.
The MRI revealed a large mass in the pituitary. Susan had a prolactin-secreting adenoma of the adenohypophysis. The mass was squeezing her optic nerve causing the vision problems. She underwent transsphenoidal (through the nasal cavities) surgery to resect (remove) the pituitary gland. Her vision returned to normal, but she will require hormonal supplementation for life.
This presented an enormous challenge for Susan. Susan’s husband was on SSDI. Her children had health insurance through Medicaid. Susan was the only one working and also the only one without health insurance because she didn’t get it through her employer. Hormone supplements are expensive. Unless she withdraws from the workforce and qualifies for SSDI and/or Medicaid, she and her doctor will endure a lifelong struggle to decide what hormones to prioritize. Growth hormone? Synthroid? ADH?
An epidemiologist introduced clinical trial research. We investigated survival metrics and clinical trial studies on mesothelioma, a cancer of connective tissue, most commonly of the pleural membrane surrounding the lungs. Average survival is 12-20 months after diagnosis; five-year survival is less than 5 percent. The largest risk factor for mesothelioma is exposure to asbestos. Production of many industrial products such as paint, brake-pads and ships used to include asbestos fibers. “It isn’t only males who get mesothelioma,” explained the epidemiologist. “When Daddy got home from the shipyard, Mom and Daughter would run to the door and wring out Daddy’s coat. Asbestos was on that coat.”
We got on the subject of whether the National Institutes of Health (NIH) disproportionately funds cancer research. A traditional successful cancer drug trial finds a few months of additional life compared to the current standard of care, but if funded by a pharmaceutical company does not take into account quality of life. For example, a clinical trial for a VEGF inhibitor in the treatment of renal cancer increases median overall survival (OS) from 21.3 to 23.3 months compared to IFN plus placebo. What if the quality of life for those 23.3 months is miserable compared to the quality of life for the 21.3 months under the current standard of care? “Patient-reported outcomes is the big buzz word in clinical trial research. Double-blind trials are essential for these subjective metrics.”
The whole school is abuzz about Trump’s seven-country immigration ban. Classmates post on Facebook about their immigrant roots (mostly grandparents or farther back in the family tree). One classmate posted a link instructing what to do if a “Customs” officer comes knocking on your door. The reply: “Did you mean immigration officer?”
Statistics for the week… Study: 25 hours. Sleep: 8 hours/night; Fun: 1 night. Example fun: class bbq followed by classmate’s performance at local coffeeshop! They performed a now class-favorite Twistin and Groovin from Leon Bridge’s Tiny Desk Concert.
“Man Made: A Memoir” by Ken Baker is a fascinating autobiography of a person with the same condition as Susan, but diagnosed later in life, and what it took to be a “traditional” male with this debilitating condition. Highly recommended.
This is becoming less an expose on med school, and more a basic introduction to human physiology. I wish it was illustrated!