Sheehan's syndrome

Sheehan's syndrome
Other namesSimmond's syndrome, postpartum hypopituitarism, postpartum pituitary gland necrosis
Anatomy of normal pituitary gland and surrounding structures
Empty sella turcica on MRI as seen in severe cases of Sheehan's syndrome
SpecialtyEndocrinology, obstetrics and gynaecology Edit this on Wikidata

Sheehan's syndrome, also known as postpartum pituitary gland necrosis, occurs when the pituitary gland is damaged due to significant blood loss and hypovolemic shock (ischemic necrosis) or stroke, originally described during or after childbirth leading to decreased functioning of the pituitary gland (hypopituitarism).[1] Classically, in the milder partial form, the mother is unable to breastfeed her baby, due to failure of the pituitary to secrete the hormone prolactin, and also has no more periods, because FSH (Follicle Stimulating Hormone) and LH (Luteinising Hormone) are not secreted. Although postmenopausal, the mother with this milder form of Sheehan's syndrome does not experience hot flushes, because the pituitary fails to secrete FSH (high levels of FSH, secreted by the pituitary in healthy postmenopausal women is an attempt to trigger ovulation, and these high levels of FSH cause hot the flushes). The failure to breastfeed and amenorrhea no more periods, were seen as the syndrome (a collection of symptoms), but we now view Sheehan's as the pituitary failing to secrete 1-5 of the 9 hormones that it normally produces (the anterior (front) lobe of the pituitary produces FSH, LH, prolactin, ACTH (Adreno-cortico-trophic hormone),TSH (Thyroid Stimulating Hormone) and GH (Growth Hormone); the posterior (the lobe at the back) pituitary produces ADH (Anti-Diuretic Hormone) and Oxytocin, i.e. the pituitary is involved in the regulation of many hormones. It is very important to recognise Sheehan' stroke as, the ACTH deficiency Sheehan's in the presence of the stress of a bacterial infection, such as a urine infection, will result in death of the mother from Addisonian crisis. [2][3] This gland is located on the under-surface of the brain, the shape of a cherry and the size of a chickpea and sits in a pit or depression of the sphenoid bone known as the sella turcica (the Turk's saddle).[4] The pituitary gland works in conjunction with the hypothalamus, and other endocrine organs to modulate numerous bodily functions including growth, metabolism, menstruation, lactation, and even the "fight-or-flight" response.[3] These endocrine organs, (like the thyroid gland in the neck, or adrenals on the upper pole of the kidneys), release hormones in very specific pathways, known as hormonal axes. For example, the release of a hormone in the hypothalamus will target the pituitary to trigger the release thyroid stimulating hormone (TSH), and the pituitary's released hormone (TSH) will target the next organ in the pathway i.e. the thyroid to release thyroxin. [3] Hence, damage to the pituitary gland can have downstream effects on any of the aforementioned bodily functions.

  1. ^ Kaufman MS, Stead LG (2011). First aid for the obstetrics & gynecology clerkship. McGraw-Hill Professional. ISBN 9780071634199. OCLC 768527672.
  2. ^ PubMed.gov 'Sheehan's in modern times: Retrospective study Iceland 2011'. |2011 Mar;164(3):349-54. doi: 10.1530/EJE-10-1004. (In the severe form of Sheehan's, with full destruction of the pituitary, mum can have polydypsia (thirst) and polyuria (excess urination) and uncontrolled lactation, with headache Ref 13.). Epub 2010 Dec 23.
  3. ^ a b c Hammer G, McPhee S (2019). "Disorders of the Hypothalamus & Pituitary Gland". Pathophysiology of Disease: An Introduction to Clinical Medicine (8th ed.). New York, NY: McGraw-Hill Education. ISBN 978-1-260-02650-4.
  4. ^ Chapman PR, Singhal A, Gaddamanugu S, Prattipati V (November 2020). "Neuroimaging of the Pituitary Gland: Practical Anatomy and Pathology". Radiologic Clinics of North America. 58 (6): 1115–1133. doi:10.1016/j.rcl.2020.07.009. PMID 33040852. S2CID 222299889.