A patient meets with an accident with resultant transection of the pituitary stalk; what will NOT Occur –
## Core Concept
The pituitary stalk, also known as the infundibulum, connects the hypothalamus to the pituitary gland and plays a crucial role in the transport of hypothalamic-releasing and inhibiting hormones to the anterior pituitary gland. Transection of the pituitary stalk disrupts this connection, affecting hormone secretion.
## Why the Correct Answer is Right
Transection of the pituitary stalk leads to a decrease in the delivery of hypothalamic-releasing hormones (like TRH, GnRH, CRH) and inhibiting hormones (like somatostatin, dopamine) to the anterior pituitary. This typically results in decreased secretion of anterior pituitary hormones (hypopituitarism), except for prolactin. Prolactin secretion is primarily under tonic inhibitory control by dopamine from the hypothalamus. When the stalk is transected, the level of dopamine reaching the pituitary gland decreases, leading to an increase in prolactin secretion.
## Why Each Wrong Option is Incorrect
- **Option A:** This option is not provided, but generally, we would expect an increase in prolactin levels due to the reasons mentioned above.
- **Option B:** Similarly, not provided, but one might expect decreased ACTH, TSH, LH, FSH, and GH due to reduced stimulation by their respective releasing hormones.
- **Option C:** Without the specific details of option C, we can infer that any option suggesting an increase in hormones that are typically decreased by stalk transection (like ACTH, TSH, GH, LH, FSH) would be incorrect.
- **Option D:** This option is stated as the correct answer but without details; we infer it suggests something that will NOT occur.
## Clinical Pearl / High-Yield Fact
A key clinical pearl is that transection of the pituitary stalk leads to **hyperprolactinemia** due to the loss of inhibitory dopamine effect on prolactin release. This is a critical point for exams and clinical practice, as it helps differentiate between various causes of hypopituitarism and hyperprolactinemia.
## Correct Answer: D. Hyperglycemia due to decreased ACTH.