Pituitary Lab Questions

Question 1

A 45-year-old man seeks evaluation for weakness, fatigue, decrease of libido and loss of body weight. Laboratory tests reveal low plasma levels of ACTH and TSH. What is the most likely diagnosis and which laboratory tests would be the most appropriate for the
patient?

Answer 1

• Low Libido: FSH/LH↓ → Testosterone+Sperm↓
• Weakness and Fatigue:ACTH/TSH↓→Cortisol/T3↓
• MRI: Adenoma Pressing Pituitray

Complex Stimulatory Tests: Giving hormones​​​

• GnRH - checking if FSH/LH↑
• TRH - checking if TSH↑
• Insulin - checking if Glucose↓→ GH↑

Treatment: Hormones and Surgical Removal of Adenoma if Present -Probably Panhypopituitarism

Question 2

In a 29-year-old woman complaining of amenorrhea, plasma PL is found elevated in association with low FSH and LH levels. Estrogen excretion is decreased. GnRH stimulation test was performed on three consecutive days. The first two tests were negative but after the third test a normal response was detected in plasma FSH and LH.

How do you interpret the result of the test and what is the most likely diagnosis?

Answer 2

• Amenorrhea can be Primary or Secondary
• Prolactin↑:GnRH↓→FSH/LH↓→Estrogen↓
• Possible Result: Downregulation of GnRH-R
• MRI -Prolactinoma (40% of Pitu. Tumors)
• Visual Field Test: Bitemporal Hemianopsia by Pitu. Tumers (normaly micro and irrelevent)
• TSH/T3/4 ↑ : Could Increase Prolactin
• ​Treatment: Surgical Removal or Bromocriptine (Dopamine Agonist)

Question 3

Other than Panhypopituitarism, what other possible causes are there for this pateint:

A 45-year-old man seeks evaluation for weakness, fatigue, decrease of libido and loss of body weight. Laboratory tests reveal low plasma levels of ACTH and TSH. What is the most likely diagnosis and which laboratory tests would be the most appropriate for the
patient?

Answer 3

• Vascular Lesions: Sheehan/Simmond’s Syndrome
• Causes: Infection/Trauma/Surgary/Irradiation
• Empty Sella/Syndrome - Pituitray Fltans, Sella is full of CSF - Rarely hormonal consequences
• Hypovolemic Lesions
• Developmental Abnormalities + Perinatal Aphyxia
• Usual Progression of Hormone Loss: GH→FSH/LH→ACTH→TSH→PRL→ADH

Question 4

A 44-year-old man complains of impotence and galactorrhea. He has gynecomasty. Plasma PL is very high, FSH and LH are lower than normal. Plasma testosterone and urinary 17-ketosteroid excretion are decreased. After TRH or chlorpromazine stimulation
there is only a minimal increase in plasma PL.

What is the most likely diagnosis and what
other tests would you perform?

Answer 4

• Glactorrhea+Gynecomastia =Hyperprolactnemia
• Impotance(Testo↓): PRL↑→GnRH↓→FSH/LH↓​
• TRH/Chlorpromazine: Dopamine Atagonism test tells us if Extra-Pituitary Source.
• Most Likely - Prolactinoma
• ​Treatment: Surgical Removal or Bromocriptine (Dopamine Agonist)​

Question 5

A 51-year-old man seeks evaluation for blurring of vision and headache. He has coarse facial features and enlarged extremities.

The determination of which hormone would be the most straightforward in the patient?

What other diagnostic procedure(s) would you
order?

Answer 5

• Check IGF-1 (more accurate than GH - Pulsetile)
• Blurring of Vision/Headache→GH-Secreting Adenoma Compressing Optic Chaism and Increasing pressure in Sella Tursica.
• GH Suppression Test: Glucose causes drop of GH (through Insulin) normally, no drop/increase.
• Check: MRI, Hormones and Bilateral Hemianopsia
• Treatment: Surgical removal / Bromocriptine (Dopamine Agonists) / SST Analogues

Question 6

In a 35-year-old woman, after the third delivery, lactation fails to start. She complains of loss of body weight and amenorrhea. Low voltage is found in her EKG tracing. Plasma levels of anterior pituitary hormones are very low. FT4 and FT3 are low. After TRH stimulation test neither TSH nor PL increase. Serum cholesterol level: 8.6 mmol/l.

Is the problem primary, secondary or tertiary?

Answer 6

• No Positive Response to TRH → Secondary Endocrine Disorder (Pituitary based)
• Amenorrhea +Ant. Pituit↓→Panhyppituitarism
• 3rd Birth+Failed Lactation→Sheehan’s Syn. (Postpartum Pituitary Infarction)
• Weight Loss: Hypoglycemia→No Insulin Antag.
• No TSH→T3↓→Pericardial Myxedma→Low ECG
• T3↓→Less Lipolysis and Less LDLR→Cholesterol↑

Question 7

A 37-year-old man complains of intense thirst (anadipsia) which commenced 7 days before. He drinks 5–6 l water a day, preferentially chilled water. His urine output is 6 l/24 h, the density is 1.004 kg/l. He is subjected to a water deprivation test with a duration of 8 h. During the test period he voids 4 l urine and the density does not exceed 1.005 in any of the collected fractions.

What is the most likely diagnosis and which test
would be the most effective in the differential diagnosis?

Answer 7

• Sudden Polyuria but Low glucose means not DM.
• OGTT
• Water Deprevation results in High Density and Lower Volume Urine → Diabetes Insipidus
• No Resopnse to ADH Injection→ Nephrogenic DI
• Responds to ADH Injection → Central DI
• For Central Checking: MRI → Hypothalamic Tumor
• Surgary or Diuretics Depanding on Type

Question 8

A 50-year-old woman complains of polyuria. She drinks 6–8 l water a day. Serum Na+: 138 mmol/l, urine output: 8 l/24 h, density: 1.004 kg/l. After salt loading urine volume
decreases and the density increases.

What is the most likely diagnosis?

Answer 8

• Na+↑ → ADH↑, so No DI
• Primary Psychogenic Polydypsia
• (ADH measurment not Accurate)