> For the complete documentation index, see [llms.txt](https://thisispiggy.gitbook.io/my-wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://thisispiggy.gitbook.io/my-wiki/01-step-1/endocrinology/08-pituitary-pathology.md). # 08 Pituitary Pathology ## Anterior Pituitary Pathology ### Pituitary Adenoma [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/anterior%20pituitary%20adenoma%20are/README.md) ![](https://f001.backblazeb2.com/file/wikiFiles/bVXTqGu.jpg).. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Nonfunctional%20anterior%20pituitary%20adenoma%20symptoms/README.md)Symptoms ![](https://f001.backblazeb2.com/file/wikiFiles/lUOMTUT.jpg)., #### Bitemporal hemianopsia [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Bitemporal%20hemianopsia%20pathogenesis/README.md)Pathogenesis: ![](https://f001.backblazeb2.com/file/wikiFiles/fkUWeJQ.jpg)., * Pituitary is next to optic chiasm. Enlargement of pituitary can cause vision problems. ![](https://f001.backblazeb2.com/file/wikiFiles/7DSnF27.jpg) [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/anterior%20pituitary%20adenomas%20include/README.md)Include: * Prolactinoma: common * GH adenoma * ACTH adenoma: Cushings * TSH, LH, FSH: rare., #### Prolactinoma [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Prolactinoma%20is,%20symptoms/README.md) * Benign tumor of lactotroph. Inhibits GnRH, thus LH/FSH * Male: no breast lobular unit for milk ![](https://f001.backblazeb2.com/file/wikiFiles/K4SoVlK.jpg)., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Prolactinoma%20drug%20cause/README.md)Dopamine antagonists such as the antipsychotic **risperidone** and **haloperidol**. Antiemetics, **metoclopramide**. All of these block D2 receptors.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Prolactinoma%20treatment/README.md)Treatment * Dopamine agonists: **bromocriptine or cabergoline** to shrink tumor * Surgery., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/bromocriptine,%20carbergoline%20are/README.md)Dopamine agonists drugs., #### GH Excess [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/GH%20excess%20causes/README.md)Causes are usually due to tumor. Presentation can be different depending on where the tumor is. If the tumor secretes GHRH and is in the **hypothalamus** or **the sytem**, there would be a high GHRH level. If the tumor is in the **anterior pituitary**, there would be a **low GHRH and high somatostatin** level. ![](https://f001.backblazeb2.com/file/wikiFiles/UxD3qsg.jpg) ., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/GH%20excess%20symptoms/README.md)Symptoms ![](https://f001.backblazeb2.com/file/wikiFiles/XgWcqMs.jpg) ., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/GH%20Excess%20diagnosis/README.md)Diagnosis ![](https://f001.backblazeb2.com/file/wikiFiles/y9E7Frh.jpg) ., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/GH%20Excess%20Treatment/README.md)Treatment * **pegvisomant**: a GH receptor antagonist that effectively blocks IGF-1 production ![](https://f001.backblazeb2.com/file/wikiFiles/GehNtNq.jpg).. #### Acromegaly [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Acromegaly%20symptoms/README.md) * Insidious onset, 12 yrs average: difficult to diagnose * Enlarged features * jaw, corse faces (enlarged nose, frontal bones) * tongue * hands and feet (rings no longer fit) * larynx (voice deepens) * Enlarged visceral organs * **Cardiac failure** * Enlarged joints: joint pain * **Secondary diabetes** from GH induced liver gluconeogenesis * Increased risk of **colon cancer** ![](https://f001.backblazeb2.com/file/wikiFiles/3tv4c5u.jpg) ![](https://f001.backblazeb2.com/file/wikiFiles/hPjI2HB.jpg) ., ## Hypopituitarism [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Hypopituitarism%20is/README.md)Describes the **insufficient secretion of pituitary hormones resulting from diseases of the hypothalamus or the pituitary**. ., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Hypopituitarism%20causes/README.md)The majority of cases are secondary to destructive processes directly involving the anterior pituitary. This includes: * Tumors, such as **nonfunctional pituitary adenomas** (adnomas not producing hormones) or **craniopharyngiomas**(exert pressure on adjacent pituitary cells) * **Pituitary surgery or radiation** * **Traumatic brain injury** and **subarachnoid hemorrhage** * **Pituitary apoplexy** (sudden hemorrhage into the pituitary gland) * **Sheehan syndrome** (postpartum necrosis of the anterior pituitary secondary to infarction precipitated by obstetric hemorrhage or shock) * **Empty sella syndrome** (presence of an enlarged, empty sella turcica due to a condition that partially or totally destroys the pituitary gland; classically affects obese women with a history of multiple pregnancies). ![](https://f001.backblazeb2.com/file/wikiFiles/9A3yz68.jpg).. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Hypopituitarism%20symptoms/README.md)The clinical manifestation of hypopituitarism depends on the *specific hormone(s) that are lacking*. For example, a deficiency of melanocyte stimulating hormone (MSH) may manifest as **hypopigmentation, due to MSH's stimulatory effects on melanocytes**. ![](https://f001.backblazeb2.com/file/wikiFiles/5Y6Bgge.jpg) Aldosterone part of RAAS system, not adrenal system... [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Hypopituitarism%20treatment/README.md)The treatment for hypopituitarism includes hormone replacement therapy, including: * **Corticosteroid** * **T4 (thyroxine)** * **Sex steroids** * **Human growth hormone** * **Pulsatile GnRH** (for patients that desire fertility).. ### Empty Sella Syndrome [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Empty%20Sella%20Pathogenesis/README.md) ![](https://f001.backblazeb2.com/file/wikiFiles/xeZZoD3.jpg) * Arachnid and dura matter around sella. Pia matter around pituitary * Herniation of arachnoid and CSF into sella compresses and destroys pituitary: hypopituitarism * Sella filled with CSF, which is clear on imaging.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Empty%20Sella%20Syndrome%20Demographics/README.md) ![](https://f001.backblazeb2.com/file/wikiFiles/Uck4pd4.jpg)., ### Pituitary Apoplexy [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Pituitary%20Apoplexy%20is,%20risk,%20symptoms/README.md) ![](https://f001.backblazeb2.com/file/wikiFiles/04dzGzp.jpg) ., ### Sheehan's Syndrome \[\_]\(Sheehan's syndrome pathogenesis)Pituitary gland enlarged in preglancy as result of increased prolactin. However, the blood supply is not increased. In postpartum hemorrhage, pituitary is at risk of infarct from hypotension. .. \[\_]\(Sheehan's syndrome symptoms)Can present as shock after delivery from low cortisol levels if severe. If not severe, present as failure to lactate from loss of prolactin ![](https://f001.backblazeb2.com/file/wikiFiles/mYQoYjT.jpg) Other symptoms: * Absent menstruation from low FSH/LH * **Loss of pubic and axillary hair** from low FSH/LH * Cold intolerance from low TSH * Fatigue from low GH * Anorexia ., ## Posterior Pituitary Pathology ### DI [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Diabetes%20insipidus%202%20types/README.md)Is due to: * Central DI: a **lack of antidiuretic hormone** (ADH) * Nephrogenic DI: a **lack of ADH functionality** in the collecting tubules.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Diabetes%20Insipidus/README.md)Is characterized by: * **Dilute urine** (even after water restriction) * **Intense thirst** * **Polyuria**., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/DI%20labs/README.md)Labs: * hypernatremia * **Urine specific gravity < 1.006** * **Serum osmolarity > 290 mOsm/L**.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/DI%20diagnosis/README.md)A water restriction test is used to diagnose central and nephrogenc DI: 1. Water intake is restricted for 2-3 hours, and urine volume, urine osmolality, plasma Na+ concentration, and plasma osmolality are measured hourly. 2. In healthy individuals, water deprivation leads to a urine osmolality 2-4 times greater than plasma osmolality. 3. In patients with central or nephrogenic DI, **urine osmolality will be less than 300 mOsm/kg after water deprivation**.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Differentiate%20between%20central%20and%20nephrogenic%20DI/README.md) * Central: low ADH * Nephrogenic: high ADH DDAVP (desmopressin, an ADH analog) is administered to differentiate between central and nephrogenic DI: * In central DI, DDAVP administration will result in a 50% or greater increase in urine osmolality. * **In nephrogenic DI, DDAVP administration will lead to no change in urine osmolality**.. ### Central Diabetes Insipidus [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Central%20Diabetes%20Insipidus%20cause/README.md) * radiation, surgery, trauma ![](https://f001.backblazeb2.com/file/wikiFiles/ZPWwYkA.jpg) ., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Central%20DI%20treatment/README.md)Treatment: Desmopressin., ### Nephrogenic Diabetes [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Nephrogenic%20DI%20causes/README.md)Is due to the inability of the kidney to respond to ADH. This may be due to an **inherited mutation in the V2 receptor** or secondary to: * **Lithium** (drug-induced nephrogenic DI) * **Demeclocycline** (reduces responsiveness of kidney tubules to ADH) (treats SIADH) * **Hypercalcemia** (causes natriuresis and water loss) * **Hypokalemia** (decreases responsiveness of kidney tubules to ADH) * **Sickle cell disease** (impairs renal response to ADH).. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Nephrogenic%20DI%20treatment/README.md)Treatment involves: * **Adequate hydration** * **Hydrochlorothiazide** (see below) * **Indomethacin** * **Amiloride**., *Why treat a water-wasting disease with a thiazide diuretic?* Thiazides increase renal Na+ excretion, which leads to extracellular fluid volume contraction. This decreased volume will decrease GFR, and increase proximal tubular reabsorption of water and Na+. Therefore, ultimately less water and Na+ are lost as urine. ### SIADH [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Syndrome%20of%20Inappropriate%20ADH%20cause/README.md)Occurs when too much ADH is secreted by the posterior pituitary. Common CNS causes of SIADH include: * Brain infections (encephalitis) * Tumors of the pituitary, or tumors that impinge on the pituitary * Head trauma * Psychiatric illness Non-CNS causes of SIADH include: * Medications (chlorpropamide, carbamazepine, cyclophosphamide and SSRIs) * Ectopic production by lung tumors (**especially small cell carcinoma**) * Pulmonary infection (viral, bacterial or tuberculous pneumonia).. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/SIADH%20symptoms/README.md)Patients will generally present with euvolemic hyponatremia. Total body water is increased, but near-normal blood volume is maintained due to the body's compensatory response (decreased thirst, suppressed aldosterone release). Peripheral edema does not develop., [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/SIADH%20treatment/README.md)If asymptomatic, the treatment of SIADH is free water restriction. Treatment of SIADH includes: * Demeclocycline, an antibiotic (tetracycline) used to treat SIADH because it induces a state of nephrogenic diabetes insipidus by inhibiting the actions of ADH in the kidney. This allows for diuresis and less retention of water. * Vaptans (conivaptan, tolvaptan), which are vasopressin antagonists * Hypertonic (5%) saline should also be administered if severe CNS changes (e.g. seizures) are present. It is important that hyponatremia be corrected slowly. A rapid correction of hyponatremia can lead to **central pontine myelinolysis (aka osmotic demyelination syndrome)**.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/Central%20pontine%20myleinolysis%20pathogenesis/README.md)Damage to the myelin sheath of the pons leads to the patient becoming "locked in", with intact cognitive function but total muscle paralysis, with the exception of eye blinking.. [\_](https://github.com/thisispiggy/my-wiki/tree/601ff771dc2fac1318ae8b59435ac8485628fd81/01%20Step%201/Endocrinology/SIADH%20urine%20vs%20serum%20osmolarity/README.md)In SIADH, urine osmolarity is greater than serum osmolarity..