Adrenal Gland Function Test are conditions that interfere with the normal functioning of the adrenal glands. Adrenal disorders may cause hyperfunction or hypofunction, and may be congenital or acquired.
The adrenal gland produces hormones that affects growth, development and stress, and also helps to regulate kidney function. There are two parts of the adrenal glands, the adrenal cortex and the adrenal medulla. The adrenal cortex produces mineralocorticoids, which regulate salt and water balance within the body, glucocorticoids (including cortisol) which have a wide number of roles within the body, and androgens, hormones with testosterone-like function.The adrenal medulla produces epinephrine (adrenaline) and norepinephrine(noradrenaline).Disorders of the adrenal gland may affect the production of one or more of these hormones.
Types of Adrenal Gland Function Test
There are three major types of adrenal insufficiency.
Primary adrenal insufficiency – is due to impairment of the adrenal glands.
- 80% are due to an autoimmune disease called Addison’s disease or autoimmune adrenalitis.
- One subtype is called idiopathic, meaning of unknown cause.
- Other cases are due to congenital adrenal hyperplasia or an adenoma (tumor) of the adrenal gland.
Secondary adrenal insufficiency – is caused by impairment of the pituitary gland or hypothalamus.Its principal causes include pituitary adenoma (which can suppress production of adrenocorticotropic hormone (ACTH) and lead to adrenal deficiency unless the endogenous hormones are replaced); and Sheehan’s syndrome, which is associated with impairment of only the pituitary gland.
Tertiary adrenal insufficiency – is due to hypothalamic disease and a decrease in the release of corticotropin releasing hormone (CRH).Causes can include brain tumors and sudden withdrawal from long-term exogenous steroid use (which is the most common cause overall).
Corticosteroids of Adrenal Gland Function Test
Corticosteroids are a group of steroid hormones produced from the cortex of the adrenal gland, from which they are named. Corticosteroids are named according to their actions:
- Mineralocorticoids such as aldosterone regulate salt (“mineral”) balance and blood volume.
- Glucocorticoids such as cortisol influence metabolism rates of proteins, fats and sugars (“glucose”).
The adrenal gland produces aldosterone, a mineralocorticoid, which is important in the regulation of salt (“mineral”) balance and blood volume. In the kidneys, aldosterone acts on the distal convoluted tubules and the collecting ducts by increasing the reabsorption of sodium and the excretion of both potassium and hydrogen ions.Aldosterone is responsible for the reabsorption of about 2% of filtered glomerular filtration rates.Sodium retention is also a response of the distal colon and sweat glands to aldosterone receptor stimulation. Angiotensin II and extracellular potassium are the two main regulators of aldosterone production.The amount of sodium present in the body affects the extracellular volume, which in turn influences blood pressure. Therefore, the effects of aldosterone in sodium retention are important for the regulation of blood pressure.
Cortisol is the main glucocorticoid in humans. In species that do not create cortisol, this role is played by corticosterone instead. Glucocorticoids have many effects on metabolism. As their name suggests, they increase the circulating level of glucose. This is the result of an increase in the mobilization of amino acids from protein and the stimulation of synthesis of glucose from these amino acids in the liver. In addition, they increase the levels of free fatty acids, which cells can use as an alternative to glucose to obtain energy. Glucocorticoids also have effects unrelated to the regulation of blood sugar levels, including the suppression of the immune system and a potent anti-inflammatory effect. Cortisol reduces the capacity of osteoblasts to produce new bone tissue and decreases the absorption of calcium in the gastrointestinal tract.
Blood cortisol is one of the basic tests used to assess adrenal gland function. Cortisol levels rise and fall throughout the day, so a single blood sample may not be effective at diagnosing a deficiency or overproduction. As a result, multiple samples may be taken. Cortisol levels can also be measured before or after stimulation of the adrenal gland to get a better sense of adrenal function.
Adrenocorticotropin hormone, or ACTH, is a hormone made by the pituitary gland that stimulates the adrenal glands to make cortisol. As a result, it can be measured to assess adrenal function. If the adrenal glands are not working effectively, the pituitary secretes more ACTH to stimulate them to make more cortisol. As a result, people with poorly functioning adrenal glands typically have elevated ACTH levels.
Adrenal Stimulation Test
Another way to more accurately measure adrenal gland function is to measure cortisol levels before and after stimulation of the adrenal glands. For this test, the cortisol level is measured and then the patient is injected with a synthetic form of ACTH called cosyntropin. After 45 minutes, the blood cortisol level is measured again to see if the adrenal glands produced more cortisol in response to the cosyntropin. Failure of the blood cortisol levels to rise suggests adrenal gland malfunction.
The corticotropin-releasing hormone test can also be used to test adrenal gland function. First, baseline levels of ACTH and cortisol are measured. Then, corticotropin-releasing hormone a chemical that stimulates the release of ACTH — is injected. Cortisol and ACTH levels are measured every 15 minutes. Typically, ACTH levels peak after 15 to 30 minutes, and cortisol levels peak 30 to 40 minutes after the injection of corticotropin-releasing hormone. Failure of cortisol levels to rise after an increase in ACTH suggests adrenal failure.
Disorders of hormone over/under-production
- Addison’s disease – also known as primary adrenal insufficiency, a disease in which the adrenal glands do not produce sufficient glucocorticoids (sometimes also mineralocorticoids) for a reason directly related to the adrenal gland itself, such as auto-immune damage to the adrenal gland or adrenal gland atrophy due to medication use
- Adrenal crisis – a life-threatening medical emergency resulting from insufficient levels of cortisol
- Adrenal insufficiency – a condition in which the adrenal glands do not produce sufficient glucocorticoids (or sometimes mineralocorticoids. This is often due to another adrenal disorder, such as Addison’s Disease or Congenital Adrenal Hyperplasia, however it may also result from a problem elsewhere in the body (such as the hypothalamus or pituitary gland) that leads to abnormalities in the production of hormones regulating adrenal function
- Congenital Adrenal Hyperplasia – a hereditary disorder in which one of the enzymes involved in cortisol synthesis does not function properly. This disorder is also often associated with an over-production of androgen hormones.
- Cushing’s disease – a disorder in which cortisol levels are abnormally high
- Hyperaldosteronism – (including Conn’s syndrome), a condition in which aldosterone is over-produced
- Hypoaldosteronism – a condition in which aldosterone is under-produced
- Allergies – Both food and environmental allergies can be a sign that your adrenal glands are stressed. If you’re unable to go through normal seasonal changes without sneezing or getting sick or if you’re sensitive to certain foods, your adrenal glands may need a tune-up.
- Dizzy standing up quickly – This problem, known as orthostatic hypotension, occurs when your blood pressure drops when you stand up too quickly. No, the way to alleviate this problem is not to stand up more slowly, but deal with the hormonal stress so your blood pressure can be regulated immediately no matter what your positional movement is.
- Bright lights and loud noises – If you’re sensitive to bright lights, such as you can’t go from a dark space to a bright space without being temporarily blinded, then that’s an adrenal issue as your pupils are slow to constrict and stay constricted. If you often need to wear sunglasses especially on overcast days then that’s a sure sign of adrenal gland problems too. Ideally a healthy person should not need to wear sunglasses even on a sunny day unless the sun is directly in the eyes. If you’re overly startled by loud noises, such as if someone drops something on the ground creating a loud bang, most likely your adrenal glands are too stressed.
- Hangnails – Getting hangnails or brittle fingernails can often be a sign of fatigued adrenal glands. They can be from thyroid problems too.
- Sleep issues -Most sleep issues are at least somewhat tied into adrenal gland problems whether due to the adrenal-pineal link or due to the adrenal-pancreas-liver relationship in controlling blood sugar. Both of these will be discussed in Part III.
- Craving salt – If you crave salt then your adrenal glands are most likely fatigued as you’re losing too much sodium in your sweat and urine. Yeah, if you crave potato chips and pretzels then it’s probably because of the salt.
- Low energy, especially in the evening – Typically people with adrenal gland problems have lower energy as the day goes on and they crash around 4-7pm but then get their second wind later at night and tend to be night owls. Often they feel the need to drink coffee or some other caffeinated beverage throughout the morning to get them going and then they may need to resort to alcohol at night to calm them back down; it’s a classic adrenal-dysfunction pattern.
- Low Sex and Athletic Performance -If your sex drive is low and if you can’t perform, then the adrenals may be to blame. The same goes for performance out of the bedroom, as in athletic performance. Athletes who are suffering performance problems, especially if they have chronic nagging injuries, often have adrenal gland problems.
- Sick often – Those who seem to get sick often and catch multiple infections throughout the year may have a suppressed immune system from the adrenals constantly secreting high levels of cortisol. This is similar to when someone is prescribed a corticosteroid such as Prednisone to help lower inflammation via suppressing the immune system, as is often the treatment with auto-immune diseases.
- Pain – especially pelvis, knee, foot, and ankle – The adrenal glands have a strong muscle relationship with the muscles which support the inside of the knee as well as the lower legs (calf muscles). Therefore, if you’re suffering from knee pain, especially on the inside or outside of the knee, or if you have problems with plantar fasciitis, shin splints, or Achilles tendonitis, then your adrenal glands may be partly or fully to blame. Back pain can also be due to adrenal gland problems due to the impact of the glands on the muscles which connect the pelvis to the knees.
|Underlying causes||Abrupt steroid withdrawal, Tumor of the hypothalamus (adenoma), antibodies, environment (i.e. toxins), head injury||Tumor of the pituitary (adenoma), antibodies, environment, head injury, surgical removal6, Sheehan’s syndrome||Tumor of the adrenal (adenoma), stress, antibodies, environment, Addison’s disease, trauma, surgical removal (resection), miliary tuberculosis of the adrenal|
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