Sheehan's syndrome. Why there is no deficiency in posterior pituitary hormones?

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In summary, Sheehan's syndrome can result in the loss of all hormones, including those in the posterior pituitary, due to its different blood supply and vulnerability to hypoxic damage. The transient polyuria associated with this condition suggests a deficiency in ADH, but the damage is usually transient and recovers. Hypertrophy and hyperplasia of lactotrophs during pregnancy can also lead to enlargement of the anterior pituitary, without a corresponding increase in blood supply, making it vulnerable to ischaemia during major hemorrhage or hypotension. However, the posterior pituitary is usually not affected due to its direct arterial supply. It is unclear if Sheehan's syndrome causes bitemporal hemianopia
  • #1
sameeralord
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Hello everyone,

Why is that in sheehan's syndrome there is no deficiency of posterior pituitary hormones. Ok they are synthesized in hypothalamus, but they are stored in posterior pituitary. So if the gland is damaged how are they secreted? Also there seems to be a trasient polyurea associatd with this condition, this means ADH must be deficient? Also I don't understand why TRH increases in this conditin. Help would be appreciated. Thanks :smile:
 
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  • #2
sameeralord said:
Hello everyone,

Why is that in sheehan's syndrome there is no deficiency of posterior pituitary hormones. Ok they are synthesized in hypothalamus, but they are stored in posterior pituitary. So if the gland is damaged how are they secreted? :

Sheehan's syndrome results in the loss of all hormones including the posterior pituitary (even if DAMAGED it is usually transient or subnormal). This is because the development of posterior pituitary is slightly different, which gives it a separate blood supply and suffers less hypoxic damage during an acute episode .

Also there seems to be a transient poly urea associated with this condition, this means ADH must be deficient?

usually the damage is transient because of the initial insult, but recovers.

Hypertrophy and hyperplasia of lactotrophs during pregnancy results in the enlargement of the anterior pituitary, without a corresponding increase in blood supply.

Secondly, the anterior pituitary is supplied by a low pressure portal venous system.[3]

These vulnerabilities, when affected by major hemorrhage or hypotension during the peripartum period, can result in ischaemia of the affected pituitary regions leading to necrosis.

The posterior pituitary is usually not affected due to its direct arterial supply.

http://en.wikipedia.org/wiki/Sheehan%27s_syndrome" [Broken]
 
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  • #3
Were you ever in hypovolmia, that is, a state of decreased blood volume, primarily plasma?
 
  • #4
mugaliens said:
Were you ever in hypovolmia, that is, a state of decreased blood volume, primarily plasma?

Haven't had such an incident yet.

@Cosmos: Thanks for the answer :smile: I somehow missed it when I read wiki. Do you or anyone know if this syndrome causes bitemporal hemianopia?
 
  • #5
sameeralord said:
Haven't had such an incident yet.

@Cosmos: Thanks for the answer :smile: I somehow missed it when I read wiki. Do you or anyone know if this syndrome causes bitemporal hemianopia?

are you researching on this subject or a med student ?
 
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1. What is Sheehan's syndrome?

Sheehan's syndrome is a condition that occurs when the pituitary gland does not receive enough blood during childbirth, leading to damage and loss of function in the gland.

2. What are the symptoms of Sheehan's syndrome?

The symptoms of Sheehan's syndrome can vary, but commonly include fatigue, low blood pressure, irregular or absent periods, and difficulty producing breast milk.

3. How is Sheehan's syndrome diagnosed?

Sheehan's syndrome is typically diagnosed through blood tests to check hormone levels, as well as imaging tests such as MRI or CT scans to evaluate the pituitary gland.

4. Why is there no deficiency in posterior pituitary hormones in Sheehan's syndrome?

The posterior pituitary gland is responsible for storing and releasing two hormones, oxytocin and vasopressin, which are not produced by the gland itself. Therefore, damage to the pituitary gland does not affect the production of these hormones.

5. Can Sheehan's syndrome be treated?

Yes, Sheehan's syndrome can be treated with hormone replacement therapy to supplement the hormones that are not being produced by the damaged pituitary gland. Other treatments may also be necessary to manage specific symptoms, such as medication for low blood pressure.

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