Thyroid dysfunction highly prevalent in Cushing’s syndrome

Central hypothyroidism is prevalent in about 1 in 2 adults with Cushing’s syndrome, and thyroid function can be restored after curative surgery for most patients, according to study findings.

“Our study findings have confirmed and greatly extended previous smaller studies that suggested a link between hypercortisolism and thyroid dysfunction but were inconclusive due to smaller sample size and short follow-up,” Skand Shekhar, MD, an endocrinologist and clinical investigator in the reproductive physiology and pathophysiology group at the National Institute of Environmental Health Sciences, NIH, told Healio. “Due to our large sample and longer follow-up, we firmly established a significant negative correlation between hypercortisolemia measures — serum and urinary cortisol, serum adrenocorticotropic hormone — and thyroid hormones triiodothyronine, free thyroxine and thyrotropin.”

Shekhar and colleagues conducted a retrospective review of two groups of adults aged 18 to 60 years with Cushing’s syndrome. The first group was evaluated at the NIH Clinical Center from 2005 to 2018 (n = 68; mean age, 43.8 years; 62% white), and the second group was evaluated from 1985 to 1994 (n = 55; mean age, 37.2 years; 89% white). The first cohort was followed for 6 to 12 months to observe the pattern of thyroid hormone changes after surgical cure of adrenocorticotropic hormone-dependent Cushing’s syndrome. The second group underwent diurnal thyroid-stimulating hormone evaluation before treatment and during remission for some cases.

Urinary free cortisol and morning thyroid hormone levels were collected for all participants. In the second group, researchers evaluated diurnal patterns of TSH concentrations with hourly measurements from 3 to 7 p.m. and midnight to 4 p.m. In the first group, adrenocorticotropic hormone and serum cortisol were measured.

In the first cohort, seven participants were receiving levothyroxine for previously diagnosed primary or central hypothyroidism. Of the remaining 61 adults, 32 had untreated central hypothyroidism. Thirteen participants had free T4 at the lower limit of normal, and 19 had subnormal levels. There were 29 adults with subnormal levels of T3 and seven with subnormal TSH.

Before surgery, 36 participants in the first group had central hypothyroidism. Six months after surgery, central hypothyroidism remained for 10 participants. After 12 months, the number of adults with central hypothyroidism dropped to six. Preoperative T3 and TSH levels were negatively associated with morning and midnight cortisol, adrenocorticotropic hormone and urinary free cortisol. In post hoc analysis, a baseline urinary free cortisol of more than 1,000 g per day was adversely associated with baseline and 6-month T3 and free T4 levels.

In the second group, there were 51 participants not on thyroid-modifying drugs who had a thyroid function test 6 or 12 months after surgery. Before surgery, free Tlevels were subnormal in 17 participants, T3 levels were subnormal in 22, and TSH levels were in the lower half of the reference range or below in all but one participant.

After surgery, two participants had below normal free T4, one had subnormal T3, and TSH levels were in the lower half of the reference range or below in 23 of 48 participants. Before surgery, there was no difference in mean TSH between daytime and nighttime. A mean 8 months after surgery, the second group had a normal nocturnal TSH surge from 1.3 mIU/L during the day to 2.17 mIU/L at night (P = .01). The nocturnal TSH increase persisted as long as 3 years in participants who had follow-up evaluations.

“We found a very high prevalence of thyroid hormone deficiency that appears to start at the level of the hypothalamus-pituitary gland and extend to the tissue level,” Shekhar said. “Some of these patients may experience thyroid hormone deficiency symptoms, such as fatigue, depression, cold intolerance, weight gain, etc, as a result of systematic and tissue-level thyroid hormone deficiency. We also noted a strong correlation between hypothyroidism and hypogonadism, which implies that hypothyroid patients are also likely to suffer adverse reproductive effects. Thus, it is imperative to perform thorough thyroid hormone assessment in patients with Cushing’s syndrome, and thyroid hormone supplementation should be considered for these patients unless cure of Cushing’s syndrome is imminent.”

Researchers said providers should routinely screen for hypothyroidism in adults with Cushing’s syndrome. Even after thyroid function is restored, regular follow-up should also be conducted.

Further research is needed to investigate thyroid dysfunction in iatrogenic Cushing’s syndrome and the impact of these findings on euthyroid sick syndrome, Shekhar said.

For more information:

Skand Shekhar, MD, can be reached at skand.shekhar@nih.gov.

From https://www.healio.com/news/endocrinology/20210208/thyroid-dysfunction-highly-prevalent-in-cushings-syndrome

Measuring TSH Levels Could Improve Diagnosis for Cushing’s Syndrome

Measuring the variation in thyroid stimulating hormone blood levels between midnight and morning may be better for diagnosing Cushing’s syndrome than current approaches, a study suggests. 

The study, “TSH ratio as a novel diagnostic method for Cushing’s syndrome,” was published in the Endocrine Journal

Cushing’s syndrome (CS) is a condition characterized by excess cortisol in the blood, which can lead to a variety of issues, including obesity, high blood pressure, abnormal lipid levels, osteoporosis, depression, and cognitive impairments.

In some cases, patients have high cortisol levels, but lack the typical physical features of Cushing’s syndrome. These patients are considered to have subclinical Cushing’s syndrome (SCS), and are at higher risk for cardiovascular disease.

Being able to properly diagnose CS and SCS is of utmost importance for proper intervention and treatment of these patients.

Current methods of diagnosis rely on dexamethasone suppressing tests or late-night salivary and blood cortisol tests, as well as measurements of cortisol in urine. However, because cortisol is a stress-hormone, it can be elevated in cases of mental or physical stress, leading to false positive results on these tests. 

Researchers in this study examined if another hormone, called the thyroid stimulating hormone (TSH), could be used to diagnose Cushing’s syndrome with better accuracy.

TSH is a hormone that stimulates the thyroid gland and whose secretion is affected by the body’s circadian rhythm. Its highest levels in the blood are usually seen in the late evening or early morning. However, patients with CS or SCS lack this nocturnal increase in TSH levels, which could be useful as a new diagnostic approach.

The study recruited 142 patients with suspected CS and SCS, and 21 patients with depression, being treated at the Osaka University Hospital in Japan.

Patients received the ordinal screening tests for Cushing’s syndrome, along with measurements of their midnight-to-morning TSH levels.

After taking the tests, only 20 patients were diagnosed as having Cushing’s, including 12 with over (normal) Cushing’s syndrome and 10 with subclinical Cushing’s syndrome.

Patients with Cushing’s had significantly lower midnight TSH levels than non-Cushing’s patients. No differences were seen in morning levels between the groups. Of note, TSH ratio was maintained in patients with depression, suggesting TSH levels could be used to diagnose Cushing’s in patients with depression.

Researchers observed that serum TSH ratio had powerful diagnostic accuracy. Among patients identified as having Cushing’s, 90% actually had the disease. And among patients excluded for Cushing’s, 95% did not have the condition. These sensitivity and specificity rates were better than with current diagnostic approaches.

However, when considering this test, patients with a severe TSH deficiency must be taken into account.

Overall, these results suggest that the midnight-to-morning serum TSH ratio is a potential new way to diagnose both CS and SCS with a higher specificity than the current diagnostic methods

“The strength of our current survey is its prospective design and the evaluation of not only overt CS but also SCS. The limitation is the relatively small number of CS group patients, especially overt CD,” the researchers wrote.

“New prospective studies will be needed with a larger number of patients in order to further clarify the optimal TSH ratio in the diagnosis of CS,” the study concluded. 

From https://cushingsdiseasenews.com/2018/06/28/measuring-tsh-levels-may-improve-cushings-syndrome-diagnosis-study/

Pituitary Issues: Irregular Periods

Q: I am 28 years old and I have not yet started my periods naturally. I have to take medicine for periods — Novelon. The doctors say that there is some problem with my hormones in the pituitary gland. Please advise me how to get normal and natural periods, because after taking the medicine I get my period, but without medicines I don’t.

A by Dr Sharmaine Mitchell: The problem you have with your menstrual period being irregular is most likely due to overproduction of the hormone prolactin by the pituitary gland in the brain. The pituitary gland can sometimes enlarge and cause an overproduction of prolactin and this can result in inappropriate milk production in the breasts (white nipple discharge), irregular menstruation or absent menstrual periods, headaches and blurred vision. The blurred vision occurs as a result of compression of the optic nerve which supplies the eyes, by the enlarged brain tumour in the pituitary gland.

You should get a magnetic resonance imaging (MRI) or CT scan of the brain and pituitary gland done. You should also test your prolactin levels to determine the extent of overproduction of the hormone.

Other investigations should include a thyroid function test (TSH), follicle stimulating hormone (FSH) and leutinizing hormone (LH), and baseline testosterone level tests.

Abnormalities in the production of thyroid hormones can also cause menstrual irregularities and this should be ruled out.

Polycystic ovarian disease can also cause irregular menstrual periods and checking the level of FSH, LH and testosterone will help to rule out this diagnosis. This condition is usually associated with excessive weight gain, abnormal male pattern distribution on the face, chest and abdomen and an increased risk for diabetes mellitus. A pelvic ultrasound to look at the structure of the ovaries and to rule out polycystic ovaries is essential.

If the pituitary gland is enlarged, then medication can be prescribed to shrink it. Bromocriptine or Norprolac are commonly used drugs which work well in reducing the prolactin levels and establishing regular menstrual cycles. The use of these drugs will also help to establish ovulation and improve your fertility.

In some cases it may become necessary to have surgery done if the tumour in the pituitary gland is large and does not respond to the usual medications prescribed to shrink the pituitary gland. The MRI of the brain and pituitary gland will give an idea as to the size of the gland and help to determine if there is a need for you to see the neurosurgeon.

In most cases medical management with drugs will work well and there is no need for surgical intervention. This is a problem that can recur, so it may be necessary to take treatment intermittently for a long period of time, especially if fertility is desired.

Consult your doctor who will advise you further. Best wishes.

Dr Sharmaine Mitchell is an obstetrician and gynaecologist. Send questions via e-mail to allwoman@jamaicaobserver.com; write to All Woman, 40-42 1/2 Beechwood Ave, Kingston 5; or fax to 968-2025. All responses are published. Dr Mitchell cannot provide personal responses.

DISCLAIMER:

The contents of this article are for informational purposes only and must not be relied upon as an alternative to medical advice or treatment from your own doctor.

From http://www.jamaicaobserver.com/magazines/allwoman/Still-no-normal-period-at-28_87596

The Pituitary Gland: Small But Mighty

The pituitary gland works hard to keep you healthy, doing everything from ensuring proper bone and muscle growth to helping nursing mothers produce milk for their babies. Its functionality is even more remarkable when you consider the gland is the size of a pea.

“The pituitary is commonly referred to as the ‘master’ gland because it does so many important jobs in the body,” says Karen Frankwich, MD, a board-certified endocrinologist at Mission Hospital. “Not only does the pituitary make its own hormones, but it also triggers hormone production in other glands. The pituitary is aided in its job by the hypothalamus. This part of the brain is situated above the pituitary, and sends messages to the gland on when to release or stimulate production of necessary hormones.”

These hormones include:

  • Growth hormone, for healthy bone and muscle mass
  • Thyroid-stimulating hormone, which signals the thyroid to produce its hormones that govern metabolism and the body’s nervous system, among others
  • Follicle-stimulating and luteinizing hormones for healthy reproductive systems (including ovarian egg development in women and sperm formation in men, as well as estrogen and testosterone production)
  • Prolactin, for breast milk production in nursing mothers
  • Adrenocorticotropin (ACTH), which prompts the adrenal glands to produce the stress hormone cortisol. The proper amount of cortisol helps the body adapt to stressful situations by affecting the immune and nervous systems, blood sugar levels, blood pressure and metabolism.
  • Antidiuretic (ADH), which helps the kidneys control urine levels
  • Oxytocin, which can stimulate labor in pregnant women

The work of the pituitary gland can be affected by non-cancerous tumors called adenomas. “These tumors can affect hormone production, so you have too little or too much of a certain hormone,” Dr. Frankwich says. “Larger tumors that are more than 1 centimeter, called macroadenomas, can also put pressure on the area surrounding the gland, which can lead to vision problems and headaches. Because symptoms can vary depending on the hormone that is affected by a tumor, or sometimes there are no symptoms, adenomas can be difficult to pinpoint. General symptoms can include nausea, weight loss or gain, sluggishness or weakness, and changes in menstruation for women and sex drive for men.”

If there’s a suspected tumor, a doctor will usually run tests on a patient’s blood and urine, and possibly order a brain-imaging scan. An endocrinologist can help guide a patient on the best course of treatment, which could consist of surgery, medication, radiation therapy or careful monitoring of the tumor if it hasn’t caused major disruption.

“The pituitary gland is integral to a healthy, well-functioning body in so many ways,” Dr. Frankwich says. “It may not be a major organ you think about much, but it’s important to know how it works, and how it touches on so many aspects of your health.”

Learn more about Mission Hospital. Learn more about Dr. Frankwich.

From http://www.stjhs.org/HealthCalling/2016/December/The-Pituitary-Gland-Small-but-Mighty.aspx

Pituitary Dysfunction as a Result of Traumatic Brain Injury

A victim of brain injury can experience many consequences and complications as a result of brain damage. Unfortunately, the problems caused by a traumatic brain injury can extend even beyond what most people think of as the standard symptoms of a brain injury, like mood change and cognitive impairment. One issue which can occur is pituitary dysfunction. If the pituitary gland is damaged due to injury to the brain, the consequences can be dramatic as the pituitary gland works together with the hypothalamus to control every hormonal aspect of a person’s body.

Pituitary dysfunction as a result of a brain injury can be difficult to diagnose, as you may not immediately connect your symptoms to the head injury you experienced. If you did suffer injury to the pituitary gland, you need to know about it so you can get proper treatment. If someone else caused your brain injury to occur, you also want to know about your pituitary dysfunction so you can receive compensation for costs and losses associated with this serious health problem.

The pituitary is a small area of the center of your brain that is about the size of the uvula. The pituitary is surrounded and guarded by bone, but it does hang down.  When it becomes damaged as a result of a brain injury, the damage normally occurs as a result of the fact the pituitary was affected by reduced by reduced blood flow. It can also be harmed directly from the trauma, and only a tiny amount of damage can cause profound consequences.

Many of the important hormones that your body needs are controlled by the pituitary working with the hypothalamus. If the pituitary is damaged, the result can include a deficiency of Human Growth Hormone (HGH). This deficiency can affect your heart and can impact bone development.  Thyroid Stimulating Hormone (TSH) can also be affected, which could result in hypothyroidism. Sex hormones (gonodotropin); Adrenocorticotopic hormone; and many other hormones could be impacted as well, causing fertility problems; muscle loss; sexual dysfunction; kidney problems; fatigue; or even death.

Unfortunately, problems with the pituitary gland may not always be visible on MRIs or other imaging tests because the pituitary is so small. Endocrinologists who handle hormone therapy frequently are not familiar with brain injuries, and may not make the connection that your brain injury was the cause of the problem.

If you begin to experience hormonal issues following an accident, you should be certain to get an accurate diagnosis to determine if your brain injury played a role. If it did, those responsible for causing the accident could be responsible for compensating you for the harm you have experienced to your pituitary and to the body systems which malfunction as a result of your new hormonal issues.

Nelson Blair Langer Engle, PLLC

From http://www.nblelaw.com/posts/pituitary-dysfunction-result-of-traumatic-brain-injury

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