Panhypopituitarism

Question 1

What are the hypothalamic causes of hypopituitarism?

Answer 1

Tumors

• Craniopharyngioma
• Metastasis from malignant tumors e.g. lung and breast CA

Infarct / Stroke (rare)

Radiation therapy
- Can lead to hypothalamic / pituitary dysfunction or both
Is dose and time-dependent, and may not become apparent until many years s/p treatment
- Hence impt for pt post-therapy to go for regular screening

Infiltrative lesions :

• Marked thickening of infundibulum on MRI is a common finding
• Conditions include Sarcoidosis and Langerhans cell histiocytosis

Infections: TB, Candida, Hanta virus

Traumatic brain injury (TBI)

Question 2

What are the pituitary causes of hypopituitarism?

Answer 2

Mass lessions

• Most commonly by a non-secretory pituitary macroadenoma > 1cm
• Commonly: HG, Prolactinoma, Non-Secreting pituitary tumor

Pituitary surgery – Pituitary function may be better or worse afterwards

Pituitary radiation

Sheehan syndrome

Pituitary apoplexy

Snake bite: Russell viper bites have been shown to cause hemorrhagic necrosis of the pituitary

Hemochromatosis : Gonadotropin deficiency is the most common endocrine abnormality

Question 3

How does non secretory pituitary adenoma present?

Answer 3

Presents with loss of multiple anterior pituitary hormone deficiencies

• GH and gonadotrophins are usually first affected
• TSH and ACTH are usually last to be affected

A/w HYPERPROLACTINAEMIA due to Stalk Compression Syndrome

• Loss of dopaminergic inhibition from hypothalamus
• Don’t confuse this w/ prolactinoma 🡪 will p/w macroadenoma w/ Prolactinaemia >4-5x ULN; whereas in SCS prolactin levels usually 2x ULN

Question 4

What is Sheehan’s syndrome and how does it present?

Answer 4

Infarction after postpartum haemorrhage, often severe as to cause hypotension and require multiple transfusions

In severe hypopituitarism, patient may develop lethargy, anorexia, weight loss, and inability to lactate during the first days/weeks after delivery

In mild hypopituitarism, there may be delay in recognition for many year

Question 5

What is pituitary apoplexy and how does it present?

Answer 5

Sudden haemorrhage into the pituitary gland, often into a pituitary adenoma

This may produce severe headache, double vision and sudden severe visual loss, sometimes followed by acute life-threatening hypopituitarism.

Often pituitary apoplexy can be managed conservatively with replacement of hormones and close monitoring of vision, although if there is a rapid deterioration in visual acuity and fields, surgical decompression of the optic chiasm may be necessary.

Question 6

How does a patient with growth hormone deficiency present?

Answer 6

• Growth Failure (during childhood) -> Dwarfism
• ↓ bone density
• Muscle atrophy & weakness

Question 7

How does a patient with prolactin deficiency present?

Answer 7

Lactation Failure following delivery

Asymptomatic in Males

Question 8

How does a patient with central TSH deficiency present?

Answer 8

• Weight gain
• LOA
• Cold intolerance
• Lethargy
• Constipation
• Dry skin
• Menstrual Change (Oligo/Menorrhagia)

Question 9

How does a patient with 2’ adrenal deficiency present?

Answer 9

• HypoNa
• HypoTN
• Hypoglycaemia
• Lethargy
• Hypoandrogenism (in women)

Question 10

How does a patient with ADH deficiency present?

Answer 10

Central DI 🡪 polyuria, polydipsia

Question 11

How does a patient with oxytocin deficiency present?

Answer 11

No Effect

Question 12

How does a male with 2’ hypogonadism present?

Answer 12

• Testicular Atrophy
• Gynecomastia
  Infertility, Loss of libido
  Menopausal / Andropausal S&S, Osteoporosis, CV S/E

Question 13

How does a female with 2’ hypogonadism present?

Answer 13

Amenorrhea

Question 14

What is Kallman’s syndrome?

Answer 14

Isolated gonadotrophin (GnRH) deficiency due to mutations in the KAL1 gene on the short arm of X Ch

Characterized by anosmia

Question 15

What is septo- optic dysplasia?

Answer 15

• Congenital syndrome associated with mutations in the HESX1 gene 🡪 resulting in developmental abnormality of the forebrain
• Presents in childhood with a clinical triad of midline forebrain abnormalities, optic nerve hypoplasia and hypopituitarism.

Question 16

What is ‘empty sella’ syndrome?

Answer 16

An ‘empty sella’ on pituitary imaging

This is sometimes due to a defect in the diaphragma and extension of the subarachnoid space (cisternal herniation) OR may follow spontaneous infarction or regression of a pituitary tumour

All or most of the sella turcica is devoid of apparent pituitary tissue, but, despite this, pituitary function is usually normal, the pituitary being eccentrically placed and flattened against the floor or roof of the fossa.

May be associated with a certain degree of decreased pituitary function, causing hypopituitarism

Question 17

What is the investigations performed for GH deficiency?

Answer 17

First measure IGF-1 levels 🡪 will be low

Then perform Insulin tolerance test / glucagon stimulation test

• First, exclude CVD, epilepsy, and patients with severe untreated hypopituitarism
• Involves overnight fast followed by IV insulin 0.15U/kg at time 0
• Caution – must be done with care else may ppt severe neuroglycopenia 🡪 seizure, coma
• Glucose, cortisol and GH levels are measured at 0, 30, 45, 60, 90, 120min
• Is meant to ↑ GH and Cortisol!

Question 18

What is the investigations performed for Gonadotrophin deficiency?

Answer 18

Measure serum LH & FSH

Men: testosterone + SHBG

Women: Estradiol

Females: the presence of regular menstrual cycles effectively rules out gonadotropin deficiency; no further diagnostic test is required.

Question 19

What is the investigations performed for TSH deficiency?

Answer 19

do TFT – showing ↓ T3, ↓ T4, ↓ or normal TSH

Question 20

What is the investigations performed for ACTH deficiency?

Answer 20

Administer an 8am cortisol + ACTH + Synacthen Test showing

• 8am cortisol & ACTH shows Hypocortisolism & low ACTH
• If acute central A-I: optimal rise in cortisol
• If chronic central A-I: suboptimal rise in Cortis

Question 21

What is the investigations performed for prolactin deficiency?

Answer 21

check serum prolactin levels

Question 22

What are the 2 hormones that needs to be replaced in a patient with pan hypopituitarism going for surgery for removal of adenoma?

Answer 22

The 2 main replaced hormones are Cortisol & Thyroxine

• Cortisol, so that pt doesn’t develop Addisonian crisis intra-op
• Thyroxine, so that pt doesn’t develop Myxedema Coma crisis intra-op

Always cortisol before thyroxine b/c:

• Cortisol has a permissive effect on thyroxine
• ↑ Thyroxine activity increases cortisol clearance 🡪 further lowers cortisol levels 🡪 ppt adrenal crisis

Question 23

What are the indications for growth hormone replacement?

Answer 23

Children for growth!

Adults exhibiting excessive tiredness, muscle weakness, weight gain 🡪 improves psychological well being

Question 24

How do you replace sex hormones in a young man?

Answer 24

we give testosterone (IM/Gel) for libido, sexual activity

• ALONE CANNOT BE ENOUGH
• If wants to father a child: give FSH & LH injections for spermatogenesis & testosterone production

Question 25

How do you replace sex hormones in an old man?

Answer 25

We will still give testosterone (IM/Gel) to prevent osteoporosis

Question 26

How do you replace sex hormones in a woman?

Answer 26

Young woman b4 menopause – Give HRT Old woman – DO NOT GIVE HRT