Pituitary Gland Disorders — MCQs
A child has serum osmolality of 270 mOsm/kg and urine osmolality of 1200 mOsm/kg. What is the most probable diagnosis?
A middle-aged female presents with increasing visual loss, breast enlargement, and irregular menses. What is the most appropriate investigation to diagnose the underlying condition?
A 26 year old female after her delivery develops features of headache, nausea, visual complaints, fatigue. What is the most probable diagnosis?
A patient with a known brain tumor learns that his pituitary stalk has been affected. Secretion of which of the following hormones is increased after the sectioning of the pituitary stalk?
Which is the most common functioning tumour of pituitary?
In which of the following conditions is blood osmolality increased?
Derivative of Rathke's pouch is which one of the following?
Most common cause of Cushing's syndrome is what?
Which of the following conditions is least likely to be associated with normal pressure spontaneous cerebrospinal fluid (CSF) leaks?
A 17 years old girl who was evaluated for short height was found to have an enlarged pituitary gland. Her T4 was low and TSH was increased. Which of the following is the most likely diagnosis?
Pituitary Gland Disorders Indian Medical PG Practice Questions and MCQs
Question 1: A child has serum osmolality of 270 mOsm/kg and urine osmolality of 1200 mOsm/kg. What is the most probable diagnosis?
- A. Nephrogenic diabetes insipidus
- B. Water deprivation
- C. Central diabetes insipidus
- D. SIADH (Correct Answer)
Explanation: SIADH - In SIADH (Syndrome of Inappropriate Antidiuretic Hormone), there is excessive ADH secretion, leading to water retention, low serum osmolality (dilute blood), and concentrated urine. [1] - The serum osmolality of 270 mOsm/kg is low-normal/mildly low [3], while the urine osmolality of 1200 mOsm/kg is very high [1], indicating the kidneys are inappropriately conserving water and concentrating urine despite diluted plasma. Nephrogenic diabetes insipidus - This condition involves the kidneys being unable to respond to ADH [2], leading to the excretion of large volumes of dilute urine despite dehydration. - While serum osmolality might be high due to dehydration, urine osmolality would be low (dilute), contrary to the given values. Water deprivation - In water deprivation, the body compensates by releasing ADH, which leads to concentrated urine to conserve water and a high serum osmolality. - Here, the serum osmolality is low-normal, which does not align with the expected high serum osmolality seen in water deprivation. Central diabetes insipidus - Characterized by the lack of ADH production by the pituitary gland [2], resulting in the excretion of large volumes of dilute urine. - Patients with central DI would typically have high serum osmolality (due to water loss) and low urine osmolality (dilute urine), which is the opposite of the given values.
Question 2: A middle-aged female presents with increasing visual loss, breast enlargement, and irregular menses. What is the most appropriate investigation to diagnose the underlying condition?
- A. S. calcitonin
- B. S. prolactin (Correct Answer)
- C. S. hemoglobin concentration
- D. S. calcium
Explanation: ***S. prolactin*** - **Hyperprolactinemia** is the most likely cause of the presented symptoms: **galactorrhea** (**breast enlargement** with milk production), **amenorrhea** (**irregular menses**), and **visual field defects** due to a pituitary tumor compressing the optic chiasm [1]. - Measuring serum prolactin levels directly confirms or rules out **hyperprolactinemia**, guiding further management, including imaging of the pituitary gland if elevated [1]. *S. calcitonin* - **Calcitonin** is a hormone primarily involved in **calcium regulation** and is typically elevated in medullary thyroid carcinoma. - The presented symptoms (visual loss, breast enlargement, irregular menses) are not characteristic of elevated calcitonin levels or a **medullary thyroid carcinoma**. *S. hemoglobin concentration* - **Hemoglobin concentration** measures the amount of oxygen-carrying protein in red blood cells and is used to diagnose **anemia** or polycythemia. - While general labs might include this, it is not directly relevant to the specific constellation of symptoms pointing towards an **endocrine or pituitary issue**. *S. calcium* - **Serum calcium** levels are checked for disorders of calcium metabolism, such as **hyperparathyroidism** or hypocalcemia. - Though calcium is regulated by hormones, the symptoms of **visual loss**, **breast enlargement**, and **menstrual irregularities** are not typically associated with primary disturbances in calcium levels.
Question 3: A 26 year old female after her delivery develops features of headache, nausea, visual complaints, fatigue. What is the most probable diagnosis?
- A. Sheehan's syndrome (Correct Answer)
- B. Waterhouse-Friderichsen syndrome
- C. Hyperprolactinemia
- D. Pituitary adenoma
Explanation: ***Sheehan's syndrome*** - This syndrome is caused by **ischemic necrosis of the pituitary gland** due to severe postpartum hemorrhage or hypovolemic shock, leading to **pituitary dysfunction** [1]. - Symptoms like **headache, nausea, visual complaints, and fatigue** are consistent with panhypopituitarism developing after delivery, often presenting in the postpartum period due to the large, vulnerable pregnancy-enlarged pituitary [1]. *Waterhouse-Friderichsen syndrome* - This is a rare, life-threatening condition caused by overwhelming **bacterial infection (often meningococcal)**, leading to **adrenal gland hemorrhage** and acute adrenal insufficiency. - It presents with rapid onset of fever, petechial rash, hypotension, and shock, which are not described in the patient's symptoms. *Hyperprolactinemia* - While hyperprolactinemia can cause headaches and visual disturbances (if due to a pituitary tumor) [1], it typically presents with **galactorrhea**, **amenorrhea**, or **oligomenorrhea**, and is not directly linked to the postpartum period unless caused by a new or existing pituitary adenoma. - It does not account for the widespread pituitary failure implied by the patient's general fatigue and other symptoms after delivery, which is more characteristic of Sheehan's [2]. *Pituitary adenoma* - A pituitary adenoma can cause headaches, visual disturbances (due to **mass effect on the optic chiasm**) [1], and hormone deficiencies or excesses, but its onset is not specifically tied to the postpartum period like Sheehan's syndrome. - While it's a possibility for these symptoms, the history of recent delivery strongly points to Sheehan's syndrome over a newly symptomatic or pre-existing pituitary adenoma without specific features like galactorrhea or Cushing's symptoms that would hint at a specific type of adenoma.
Question 4: A patient with a known brain tumor learns that his pituitary stalk has been affected. Secretion of which of the following hormones is increased after the sectioning of the pituitary stalk?
- A. FSH
- B. Prolactin (Correct Answer)
- C. TSH
- D. ACTH
Explanation: ***Prolactin*** - Prolactin is **unique** among anterior pituitary hormones as it is under **tonic inhibitory control** by dopamine from the hypothalamus. - Sectioning of the pituitary stalk disrupts dopamine delivery via the hypothalamic-hypophyseal portal system. - This leads to a **loss of tonic inhibition**, causing an **increase in prolactin secretion** from the anterior pituitary. - This phenomenon is known as the **"stalk effect"** or **hyperprolactinemia due to stalk section**. *FSH* - **Follicle-stimulating hormone (FSH)** secretion is regulated by **gonadotropin-releasing hormone (GnRH)** from the hypothalamus, which is **stimulatory**. - Stalk section interrupts GnRH delivery via the portal system, leading to a **decrease** in FSH secretion. *TSH* - **Thyroid-stimulating hormone (TSH)** secretion is positively regulated by **thyrotropin-releasing hormone (TRH)** from the hypothalamus. - Interruption of the pituitary stalk reduces TRH delivery, causing a **decrease** in TSH secretion. *ACTH* - **Adrenocorticotropic hormone (ACTH)** secretion is positively regulated by **corticotropin-releasing hormone (CRH)** from the hypothalamus. - Damage to the pituitary stalk diminishes CRH stimulation, resulting in a **decrease** in ACTH secretion.
Question 5: Which is the most common functioning tumour of pituitary?
- A. GH secreting tumor
- B. ACTH producing adenoma
- C. Prolactinoma (Correct Answer)
- D. Oncocytoma
Explanation: ***Prolactinoma*** - Prolactinomas are the **most common type of functioning pituitary tumor**, accounting for approximately 40-50% of all pituitary adenomas [1]. - They lead to **hyperprolactinemia**, causing symptoms such as galactorrhea, amenorrhea, and infertility in women, and hypogonadism and erectile dysfunction in men [1]. *GH secreting tumor* - Growth hormone (GH) secreting tumors cause **acromegaly** in adults and **gigantism** in children [2]. - While significant, they are less common than prolactinomas, typically representing about 15-20% of functioning pituitary tumors. *ACTH producing adenoma* - ACTH producing adenomas lead to **Cushing's disease** via excessive cortisol production [3]. - These tumors are less frequent than prolactinomas, accounting for about 10-15% of functioning pituitary adenomas. *Oncocytoma* - Oncocytomas are a **histological classification** of tumors, not typically defined by specific hormone secretion. - Most pituitary oncocytomas are **non-functioning** and detected due to mass effect rather than hormonal excess.
Question 6: In which of the following conditions is blood osmolality increased?
- A. SIADH
- B. Psychogenic polydipsia
- C. Diarrhea (Correct Answer)
- D. Cerebral toxoplasmosis
Explanation: ***Diarrhea*** - Diarrhea leads to a significant loss of **water and electrolytes** from the body, primarily from the extracellular fluid compartment. - This imbalance causes **hemoconcentration** and an increase in the concentration of solutes in the blood, thereby raising blood osmolality. *SIADH* - **Syndrome of Inappropriate Antidiuretic Hormone (SIADH)** is characterized by excessive secretion of ADH, leading to **dilutional hyponatremia**. - The excess water retention dilutes the blood, resulting in **decreased serum osmolality**. *Psychogenic polydipsia* - This condition involves excessive water intake due to psychological factors, which causes **dilution of body fluids**. - The increased water volume without a proportional increase in solutes leads to **decreased plasma osmolality**. *Cerebral toxoplasmosis* - **Cerebral toxoplasmosis** is an opportunistic infection of the brain, typically seen in immunocompromised individuals. - It primarily causes neurological symptoms and **does not directly impact blood osmolality** unless complicated by other factors like dehydration or SIADH (which is not a primary effect).
Question 7: Derivative of Rathke's pouch is which one of the following?
- A. Anterior pituitary gland (Correct Answer)
- B. Neurohypophysis
- C. Superior parathyroid gland
- D. Inferior parathyroid gland
Explanation: ***Anterior pituitary gland*** - **Rathke's pouch** is an **ectodermal evagination** from the roof of the primitive oral cavity (stomodeum). [1] - It develops into the **adenohypophysis**, which is the anterior lobe of the pituitary gland, responsible for producing various hormones. [2] *Neurohypophysis* - The **neurohypophysis** (posterior pituitary) develops from a **downward extension of the diencephalon** (neuroectoderm), not Rathke's pouch. [1] - It stores and releases **oxytocin** and **vasopressin** produced by the hypothalamus. [1] *Superior parathyroid gland* - The superior parathyroid glands develop from the **fourth pharyngeal pouch**. - They are primarily involved in **calcium homeostasis** by producing parathyroid hormone. *Inferior parathyroid gland* - The inferior parathyroid glands originate from the **third pharyngeal pouch**, along with the thymus. - Their embryological origin is distinct from Rathke's pouch and the pituitary gland.
Question 8: Most common cause of Cushing's syndrome is what?
- A. Adrenal adenoma
- B. Adrenal carcinoma
- C. McCune Albright syndrome
- D. Pituitary adenoma (Correct Answer)
Explanation: ***Pituitary adenoma*** - The **most common cause** of Cushing's syndrome, specifically **Cushing's disease**, is excess ACTH production from a pituitary adenoma [1]. - This leads to **overstimulation of the adrenal glands**, resulting in increased cortisol production [1]. *McCune Albright syndrome* - It is a genetic disorder characterized by **fibrous dysplasia**, **café-au-lait spots**, and **endocrine problems**, not primarily Cushing's syndrome. - Though hormone abnormalities may present, it is not the **most common** cause of Cushing's syndrome. *Adrenal carcinoma* - While adrenal carcinoma can cause **Cushing's syndrome**, it is less common compared to the **pituitary adenoma** [1]. - This malignant tumor is rare and typically presents with more aggressive features and higher cortisol levels. *Adrenal adenoma* - Adrenal adenomas are benign tumors that can produce **excess cortisol**, but they are not the leading cause of Cushing's syndrome overall [1]. - They account for a smaller proportion of cases compared to **pituitary adenomas**.
Question 9: Which of the following conditions is least likely to be associated with normal pressure spontaneous cerebrospinal fluid (CSF) leaks?
- A. Pseudo tumor Cerebri (Correct Answer)
- B. Empty Sella Syndrome
- C. Encephalocele
- D. Meningiocele
Explanation: ***Pseudotumor Cerebri*** - Also known as **idiopathic intracranial hypertension**, it is characterized by symptoms of **increased intracranial pressure** but with **normal CSF composition** and **no identifiable intracranial mass** [1]. - CSF leaks, especially spontaneous ones with normal pressure, typically result from **low intracranial pressure (intracranial hypotension)**, which is the opposite of pseudotumor cerebri . *Empty Sella Syndrome* - This condition involves the **sella turcica** (the bony structure housing the pituitary gland) being partially or completely filled with CSF, often due to a **defect in the sellar diaphragm**. - It arises from **idiopathic intracranial hypertension** which is also referred to as **pseudotumor cerebri**, but in some cases, it can be associated with **spontaneous CSF leaks** as the brain sags and pulls on the dura. *Encephalocele* - An **encephalocele** is a rare birth defect where there's a **protrusion of the brain and its meninges** through a defect in the skull. - This can be a source of **spontaneous CSF leaks** if the dura mater or skin covering the encephalocele is compromised. *Meningocele* - A **meningocele** is a type of **spina bifida** where the **meninges protrude through a defect in the vertebral column** forming a sac filled with CSF. - Like encephaloceles, these defects in continuous meningeal coverings can be a source of **spontaneous CSF leaks**.
Question 10: A 17 years old girl who was evaluated for short height was found to have an enlarged pituitary gland. Her T4 was low and TSH was increased. Which of the following is the most likely diagnosis?
- A. Thyroid target receptor insensitivity
- B. TSH-secreting pituitary tumour
- C. Primary hypothyroidism (Correct Answer)
- D. Pituitary adenoma
Explanation: ***Primary hypothyroidism*** - **Primary hypothyroidism** leads to decreased production of thyroid hormones (low T4), which in turn causes the pituitary to produce more TSH (increased TSH) in an attempt to stimulate the thyroid [1], [3]. - The elevated TSH can lead to **pituitary hypertrophy** (enlarged pituitary gland) due to chronic stimulation, as observed in this patient. *Thyroid target receptor insensitivity* - This condition involves resistance to thyroid hormones at the tissue level, leading to elevated T4 or normal T4 and elevated TSH. However, in this case, T4 is low, which contradicts this diagnosis. - While TSH can be elevated, the primary issue is cellular resistance, not a lack of thyroid hormone synthesis. *TSH-secreting pituitary tumour* - A TSH-secreting pituitary tumor would result in **elevated TSH** and **elevated T4** (secondary hyperthyroidism), as the tumor is autonomously producing TSH. - This patient presents with **low T4**, which rules out a TSH-secreting tumor causing hyperthyroidism [2]. *Pituitary adenoma* - While a pituitary adenoma is present, the low T4 and high TSH indicate that the adenoma is a **secondary effect** of chronic TSH stimulation (due to primary hypothyroidism) leading to pituitary enlargement, rather than a primary secreting adenoma causing the thyroid dysfunction. - Non-functional pituitary adenomas can cause mass effects, but this specific hormonal profile points to the pituitary enlargement being a compensatory response.
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