All except following are caused by accidental transection of pituitary stalk
**Core Concept**
The pituitary stalk, also known as the infundibulum, connects the hypothalamus to the pituitary gland, facilitating the release of hypothalamic-releasing hormones that regulate pituitary function. Transection of the pituitary stalk can disrupt this hormonal axis, leading to various endocrine disturbances.
**Why the Correct Answer is Right**
Accidental transection of the pituitary stalk typically results in **Sheehan syndrome**, characterized by panhypopituitarism due to the loss of hypothalamic-releasing hormones. This is because the pituitary gland is no longer receiving the necessary signals to produce and release hormones. In contrast, other conditions listed in the options may be caused by other types of pituitary dysfunction or disease.
**Why Each Wrong Option is Incorrect**
**Option A:** **Diabetes Insipidus (DI)** may be caused by a lesion affecting the hypothalamus or the posterior pituitary gland, but it is not typically associated with pituitary stalk transection. DI is characterized by an inability to regulate water balance due to a deficiency of antidiuretic hormone (ADH).
**Option B:** **Acromegaly** is a condition caused by excessive growth hormone (GH) secretion, usually due to a pituitary adenoma. Pituitary stalk transection is not a common cause of acromegaly.
**Option C:** **Cushing's disease** is caused by excessive adrenocorticotropic hormone (ACTH) secretion, typically due to a pituitary adenoma. While pituitary stalk lesions can affect ACTH regulation, they are not a typical cause of Cushing's disease.
**Clinical Pearl / High-Yield Fact**
When considering a patient with a pituitary stalk lesion, it's essential to remember that the diagnosis of Sheehan syndrome requires the presence of panhypopituitarism, which can be confirmed by measuring multiple pituitary hormones.
**Correct Answer:** C.