Pituitary Gland: Normal Function and Assessment

Posted on July 23, 2016 by MaryO

Abstract

This computer-based, interactive module introduces preclinical medical students to normal pituitary function and outlines its assessment. Solid understanding of these topics is requisite to learning clinical disorders of the pituitary.

Existing resources largely target learners at earlier or later stages of training; thus, we created this resource to address needs of medical students during a first- or second-year endocrine course. A module format was selected to promote interactive, independent learning.

Two cohorts of medical students completed the 40-minute module: 172 second-year students who had completed a year of basic sciences in the traditional curriculum and 180 foundation-phase students in a three-semester combined basic and clinical sciences curriculum (due to a change in the medical school curriculum at our institution). In both instances, the module was completed before start of clinical pituitary content. A static set of PowerPoint slides accompanied the module to facilitate note taking.

Test Your Knowledge slides were inserted to ensure grasp of key terms/concepts before moving to subsequent slides. A short question-and-answer session was held following module completion to clarify points of confusion. Students rated effectiveness of the module as 4.6 out of 5, commenting on its clarity, organization, high-yield nature, and utility in preparing for clinical material.

Faculty noted greater understanding of foundational pituitary principles and more engaging discussions. The percentage of pituitary-related questions answered correctly on the midterm exam increased.

Finally, success of the pituitary module prompted development of adrenal, thyroid, and parathyroid modules that now comprise the Endocrine Organs Introduction Series in our curriculum.

Citation

Kirk D, Smith KW. Pituitary gland: normal function and assessment. MedEdPORTAL Publications. 2016;12:10430. http://dx.doi.org/10.15766/mep_2374-8265.10430

Educational Objectives

After completing this module, the learner will be able to:

  1. Describe the normal function and regulation of the pituitary gland, including names and actions of the anterior and posterior pituitary hormones.
  2. Understand the basic approach to laboratory assessment of the pituitary.
  3. Differentiate between anterior and posterior pituitary origin, function, and regulation.
  4. List the hormones produced by the pituitary gland.
  5. Discuss for each pituitary hormone: hypothalamic stimulating/inhibiting factors and their clinical uses, basic physiologic function, and regulation (feedback loop).
  6. Describe factors that affect growth hormone levels.
  7. Understand the tests for growth hormone excess and deficiency.
  8. Define a primary versus secondary endocrine disorder.

Keywords

  • Endocrine, Endocrinology, Pituitary, Module, Preclinical Medical Education

More information at https://www.mededportal.org/publication/10430

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GH therapy increases fracture risk in patients previously treated for acromegaly

Posted on July 16, 2016 by MaryO

van Varsseveld NC, et al. Pituitary. 2016;doi:10.1007/s11102-016-0716-3.

Adult patients with severe growth hormone deficiency previously treated for acromegaly saw an increased fracture risk after 6 years of growth hormone replacement therapy, whereas those previously treated for Cushing’s disease did not experience the same risk, according to a recent observational study.

Nadege C. van Varsseveld, MD, of the department of internal medicine at VU University Medical Center in Amsterdam, and colleagues analyzed data from 1,028 patients with previous nonfunctioning pituitary adenoma (NFPA; n = 783), acromegaly (n = 65) and Cushing’s disease (n = 180), identified through the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide, long-term surveillance study in patients with severe GH deficiency. Data were collected biannually from medical records through 2009. Baseline DXA measurements were available for 414 patients; 71 (17.1%) had osteoporosis at one or more of the measured sites; 147 (35.5%) had osteopenia.

During a mean follow-up of 5.2 years, researchers found that 166 of patients with previous NFPA were prescribed osteoporosis medications (21.3%), as were 69 patients with previous Cushing’s disease (38.5%) and 22 patients with previous acromegaly (33.4%). During follow-up, 39 patients experienced fractures (3.8%; 32 experiencing one fracture), including 26 patients in the previous NFPA group, eight patients in the previous Cushing’s disease group and five patients in the previous acromegaly group. The median time between baseline and first fracture was 2.4 years (mean age, 59 years).

Researchers found that fracture risk did not differ between groups before 6 years’ follow-up. Fracture risk increased in patients with previous acromegaly after 6 years’ follow-up, but not for those with previous Cushing’s disease vs. patients with NFPA. Results persisted after adjustment for multiple factors, including sex, age, fracture history and the extent of pituitary insufficiency.

The researchers noted that patients with previous Cushing’s disease were younger and more often women and had a greater history of osteopenia or osteoporosis, whereas patients with acromegaly had a longer duration between tumor treatment and the start of GH therapy and were treated more often with radiotherapy.

“During active acromegaly, increased bone turnover has been observed, but reported effects on [bone mineral density] are heterogeneous,” the researchers wrote. “It is postulated that cortical BMD increases, whereas trabecular BMD decreases or remains unaffected.

“The increased fracture risk in the present study may be a long-term effect of impaired skeletal health due to previous GH excess, even though this was not reflected by an increased occurrence of osteopenia or osteoporosis in the medical history,” the researchers wrote. – by Regina Schaffer

Disclosure: One researcher reports receiving consultancy fees from Novartis and Pfizer.

From http://www.healio.com/endocrinology/hormone-therapy/news/online/%7B92a67ad7-3bd5-46f0-b999-0a8e3486edab%7D/gh-therapy-increases-fracture-risk-in-patients-previously-treated-for-acromegaly

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Elevated late-night salivary cortisol may indicate recurrent Cushing’s disease

Posted on July 15, 2016 by MaryO

Carroll TB, et al. Endocr Pract. 2016;doi:10.4158/EP161380.OR.

 

Elevated late-night salivary cortisol may serve as an early biochemical marker of recurrent Cushing’s disease, and prompt intervention may result in clinical benefits for people with Cushing’s disease, according to recent study findings.

According to the researchers, late-night salivary cortisol level is more sensitive for detecting Cushing’s disease recurrence compared with urinary free cortisol or a dexamethasone suppression test.

Ty B. Carroll, MD, assistant professor at the Medical College of Wisconsin Endocrinology Center and Clinics in Menomonee Falls, and colleagues evaluated 15 patients (14 women; mean age, 49.1 years) with postsurgical recurrent Cushing’s disease (mean time to recurrence, 3.3 years) after initial remission to determine the performance of urinary free cortisol and late-night salivary cortisol measurements for detecting recurrent Cushing’s disease.

Participants were identified as having Cushing’s disease between 2008 and 2013; there was no standard for follow-up, but after remission confirmation participants were followed at least every 6 months after surgery for 2 years and then annually thereafter. Late-night salivary cortisol was the primary biochemical test to screen for recurrence, and follow-up tests with a dexamethasone suppression test, urinary free cortisol or other tests were performed if late-night salivary results were abnormal or if suspicion of recurrence was high.

Of the cohort, 80% had normal urinary free cortisol (< 45 µg/24 hours) at recurrence. Primary transphenoidal adenoma resection was performed in all participants. Evidence of pituitary adenoma on MRI at the time of recurrence was present in seven of 12 participants with normal urinary free cortisol and two of three participants with abnormal urinary free cortisol. Normal renal function was present in all participants, and 14 underwent testing with late-night salivary cortisol, dexamethasone suppression test and urinary free cortisol.

Of participants with normal urinary free cortisol at recurrence, nine had an abnormal dexamethasone suppression test (cortisol 1.8 µg/dL), and all had at least one elevated late-night salivary cortisol measurement (> 4.3 nmol/L). Mean late-night salivary cortisol was 10.2 nmol/L, and mean urinary free cortisol was 19.9 µg/24 hours.

Therapy for recurrent Cushing’s disease was administered in 11 of the 12 participants with abnormal urinary free cortisol. Adrenocorticotropic hormone (ACTH)-staining pituitary adenoma was confirmed in three participants who underwent repeat transphenoidal adenoma resection. Pharmacotherapy was administered to seven participants with normal urinary free cortisol, and two additional participants underwent bilateral adrenalectomy.

Abnormal dexamethasone suppression test was found in two participants with elevated urinary free cortisol at the time of recurrence, and two participants had confirmed abnormal late-night salivary cortisol. All three participants with elevated urinary free cortisol at the time of recurrence underwent therapy.

“This study has shown potential clinical benefit of either surgical or medical therapy in recurrent [Cushing’s disease] patients with elevations of [late-night salivary cortisol] and normal [urinary free cortisol],” the researchers wrote. “We believe that the outcomes observed in this retrospective case series suggest that the risk/benefit ratio of early treatment needs to undergo a more rigorous prospective evaluation utilizing [late-night salivary cortisol] elevation as an early biochemical marker of recurrent [Cushing’s disease].” – by Amber Cox

Disclosure: Carroll reports being a consultant for Corcept Therapeutics. Please see the full study for a list of all other authors’ relevant financial disclosures.

From http://www.healio.com/endocrinology/adrenal/news/online/%7B9ea4e4ed-6428-49b8-9b2a-11462cb21349%7D/elevated-late-night-salivary-cortisol-may-indicate-recurrent-cushings-disease

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Cushing’s syndrome: Pituitary surgery alone is the preferred treatment to improve survival

Posted on July 8, 2016 by MaryO

Background

No agreement has been reached on the long-term survival prospects for patients with Cushing’s disease. We studied life expectancy in patients who had received curative treatment and whose hypercortisolism remained in remission for more than 10 years, and identified factors determining their survival.

Methods

We did a multicentre, multinational, retrospective cohort study using individual case records from specialist referral centres in the UK, Denmark, the Netherlands, and New Zealand. Inclusion criteria for participants, who had all been in studies reported previously in peer-reviewed publications, were diagnosis and treatment of Cushing’s disease, being cured of hypercortisolism for a minimum of 10 years at study entry, and continuing to be cured with no relapses until the database was frozen or death. We identified the number and type of treatments used to achieve cure, and used mortality as our primary endpoint. We compared mortality rates between patients with Cushing’s disease and the general population, and expressed them as standardised mortality ratios (SMRs). We analysed survival data with multivariate analysis (Cox regression) with no corrections for multiple testing.

Read more at http://www.univadis.com/viewarticle/cushing-s-syndrome-pituitary-surgery-alone-is-the-preferred-treatment-to-improve-survival-421761

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Hypopituitarism – Deficiency in Pituitary Hormone Production

Posted on June 30, 2016 by MaryO

By Yolanda Smith, BPharm

Hypopituitarism is a health condition in which there is a reduction in the production of hormones by the pituitary gland.

The pituitary gland is located at the base of the brain and is responsible for the production of several hormones, including:

  • Adrenocorticotropic hormone (ACTH), which controls the production of the vital stress hormones cortisol and dehydroepiandrosterone (DHEA) in the adrenal gland
  • Thyroid stimulating hormone (TSH), which controls the production of hormones by the thyroid gland
  • Luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which control the secretion of the primary sex hormones and affect fertility
  • Growth hormone (GH), which regulates the growth processes in childhood and other metabolic processes throughout life
  • Prolactin (PRL), which facilitates the production of breast milk
  • Oxytocin, which is crucial during labor, childbirth and lactation
  • Antidiuretic hormone (ADH), also known as vasopressin, which regulates the retention of water and the blood pressure

An individual with hypopituitarism shows a deficiency in one or more of these hormones. This inevitably leads to abnormal body function, as an effect of the low levels of the hormone in the body, and may result in symptoms.

Causes

Hypopituitarism is most commonly due to the destruction, compression or inflammation of pituitary tissue by a brain tumor in that region. Other causes include:

  • Head injury
  • Infections such as tuberculosis
  • Ischemic or infarct injury
  • Radiation injury
  • Congenital and genetic causes
  • Infiltrative diseases such as sarcoidosis

Symptoms

General symptoms that are associated with pituitary hormone deficiency include:

  • Weakness and fatigue
  • Decreased appetite
  • Weight loss
  • Sensitivity to cold
  • Swollen facial features or body

There are also likely to be more specific symptoms according to the type of pituitary hormone deficiency, such as:

  • ACTH deficiency:
    • abdominal pain
    • low blood pressure
    • low serum sodium levels
    • skin pallor
  • TSH deficiency:
    • generalized body puffiness
    • sensitivity to cold
    • constipation
    • impaired memory and concentration
    • dry skin
    • anemia
  • LH and FSH deficiency:
    • reduction in libido
    • erectile dysfunction in men
    • abnormal menstrual periods
    • vaginal dryness in women
    • difficulty in conceiving
    • infertility.
  • GH deficiency:
    • slow growth
    • short height
    • an increase in body fat

Treatment

The first step in the treatment of hypopituitarism is to identify the cause of the condition.

Secondly, the hormones that are deficient must be identified. From this point, the appropriate treatment decisions can be made to promote optimal patient outcomes.

Hormone replacement therapy is the most common type of treatment for a patient with hypopituitarism.

This may involve supplementation of one or more hormones that are deficient, to reduce or correct the impact of the deficiency.

Follow Up

As hormone replacement therapy is expected to continue on a lifelong basis, it is important that patients have a good understanding of the therapy.

It is especially important to educate patients on what to do in case of particular circumstances that may change their hormone requirements.

For example, during periods of high stress, the demand for many hormones is increased, and the dose of hormone replacement may need to be adjusted accordingly.

It is recommended that patients have regular blood tests to monitor their hormone levels and ensure that they are in the normal range.

Patients should also carry medical identification, such as a medical bracelet or necklace, to show that they are affected by hypopituitarism and inform others about their hormone replacement needs and current treatment. This can help to meet their medical needs in case of any emergency.

Epidemiology

Hypopituitarism is a rare disorder that affects less than 200,000 individuals in the United States, with an incidence of 4.2 cases per 100,000 people per year.

The incidence is expected to be higher in certain subsets of the population, such as those that have suffered from a brain injury. Statistics in reference to these population groups have not yet been determined.

Reviewed by Dr Liji Thomas, MD.

References

From http://www.news-medical.net/health/Hypopituitarism-Deficiency-in-Pituitary-Hormone-Production.aspx

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