This month, our goal is to learn more about the adrenal gland as part of our series on discovering how our bodies work and trying to find explanations for symptoms we might experience at various points in our lives. Links to extra information on the subject have been provided at the end of this piece. As always, please remember that all medical information should be discussed fully with your health care provider before making decisions.
The adrenal glands
These are two small triangular-shaped organs located on each kidney
Generally, the gland is divided into two main regions: the outer cortex and the inner medulla.
The cortex produces 3 kinds of steroid hormones which play several important roles in our bodies:
a)Mineralcorticoids (e.g. aldosterone)-helps to regulate salt and water contents of the body which influence how high or low a person’s blood pressure is and the number of times one has to urinate.
b)Glucocorticoids (e.g. cortisol)- cortisol has several functions including the following: maintaining blood pressure and cardiovascular function, slowing the immune system’s inflammatory response, and increasing the amount of circulating blood sugar in the body for energy use
c)Gonadocorticoids or sex hormones– these include both male hormones such as testosterone/androgens and female hormones like estrogen. However, the adrenal gland produces only a small fraction of the total body sex hormones when compared to the ovaries or testes.
How they work
The adrenal medulla produces the two ‘stress’ hormones or ‘fright, fight or flight’ hormones. As the pseudo-names suggest, these are the hormones that kick in when you are scared, causing your heart to beat faster. They are also the same hormones that are released when you need a boost of energy to accomplish a goal such as running a race. They do this by:
a) Epinephrine/adrenaline– increasing the heart rate and force of heart contractions, helping blood flow to the muscles and brain, causing relaxation of some of the body’s muscles, and helping with conversion of stored glycogen to glucose in the liver to provide more energy for the body.
b) Norepinephrine/noradrenaline– increasing blood pressure.
Usually, the brain has a tight control on how much of each hormone the adrenal gland produces and when it releases them. However, sometimes problems can occur either in the gland itself or in one of the other systems that regulate it. Discussed briefly below are a couple of the more common diseases or conditions that can occur when things do go wrong.
Cushing’s Syndrome
This condition occurs when too much cortisol is produced, due to tumors in the adrenal gland or pituitary (an organ in the brain that helps control hormone release from the adrenal gland). Certain medications for asthma, rheumatoid arthritis, lupus or other inflammatory diseases can also lead to high cortisol levels. Since cortisol works to help the body deal with stress, it can be elevated in pregnant women during the third trimester or in highly trained athletes.
Some studies have reported high levels in people suffering from depression, alcoholism, malnutrition and panic disorders. In a few rare instances, high cortisol production can be due to an inherited tendency to develop tumors of one or more hormone-producing glands. The list below indicates common symptoms seen in Cushing’s syndrome. However, many of these are seen with other conditions and as such are not exclusive to this particular syndrome:
Upper body obesity
Round face
Increased fat around neck
Thinning arms and legs
Fragile and thin skin
Stretch marks on abdomen, thighs, buttocks, arms, and breasts
Bone and muscle weakness
Severe fatigue
High blood pressure
High blood sugar
Irritability and anxiety
Excess hair growth in women
Irregular or stopped menstrual cycles in women
Reduced sex drive and fertility in men
Diagnosis: Based on medical history, symptoms, physical examination done by your doctor, lab tests (e.g. 24-Hour Urinary Free Cortisol Level or Dexamethasone. Suppression Test) and x-rays (to look for tumors in the adrenal gland or pituitary)
Treatment: Dependent on cause of syndrome. If tumor, sometimes removing the mass can help reduce significant cortisol level. Surgery, radiotherapy, chemotherapy, immunotherapy, or a combination of these could be used. If the problem is caused by medications the patient is currently on, the health care provider may switch to a different drug or reduce the current dose being taken.
Conn’s syndrome
This disease is generally two times more common in women than in men and tends to occur between ages 30-60. It is characterized by increased aldosterone secretion from the adrenal glands which can result from a benign tumor of one adrenal gland, called an adenoma, or an enlargement of both adrenal glands, called bilateral hyperplasia. Typically, it causes:
a)Hypertension (which untreated over the course of many years can lead to heart disease (e.g., coronary artery disease, congestive heart failure), stroke, and intracerebral hemorrhage (bleeding in the brain due to very high blood pressures) b) Hypokalemia (which is low blood potassium levels. This can cause your heart to beat in a weird rhythm called a cardiac arrhythmia and can be fatal.)
Other associated symptoms include: numbness, frequent urination, nighttime urination, headache, and excessive thirst, pins and needles sensation in body, visual disturbances, temporary paralysis, muscle twitching and cramps. (of note, many of these are commonly associated with other diseases such as diabetes mellitus and as such, cannot be used exclusively to make a diagnosis of Conn’s syndrome).
Diagnosis: made by measuring the blood levels of potassium, aldosterone and renin (a hormone made by the kidney that stimulates adrenal glands to produce aldosterone). A CT scan of the abdomen to visualize the adrenal glands is helpful to rule out a tumor or identify an infection of any of the glands.
Treatment: If tumor or enlargement of gland is present, surgical removal of the adrenal gland is recommended.
Summary of other adrenal gland related diseases
Addison’s disease/Adrenal Insufficiency
This occurs usually when too little cortisol is produced by the adrenal glands. However, in some situations, low aldosterone levels can cause this disease too. Rarely tuberculosis infection (TB) can destroy the adrenal glands and lead to Addison’s disease. Symptoms include chronic tiredness, muscle weakness, loss of appetite, weight loss, nausea, vomiting, diarrhea, low blood pressure (which can cause fainting or dizziness), hyperpigmentation of skin (darkening of skin color especially around the knuckles, elbows, lips and old scars), depression, irritability, low blood sugar and craving for salty foods.
Virilization
The adrenal gland makes both male and female sex hormones. Actually, both hormones occur in all individuals regardless of sex. However, normally, more female hormones (estrogen) are made in women by the ovaries while there are more male hormones (androgen/testosterone) in men made by the testes. These hormones play a role in creating some of the features we use to classify the genders into their respective groups.
Virilization occurs when too much male hormones are produced in a woman due to dysfunction of the adrenal gland (or ovaries). As such, one notices excess facial and body hair, baldness, acne, deepening of the voice, increased muscularity, enlargement of the clitoris, decreased breast size and an increased sex drive (testosterone is largely responsible for boosting sex drive). Mild forms of virilization can be corrected with drugs but usually, surgery is required to remove any tumors that might be present. Of note, virilization can also be seen in female athletes who take androgen supplements (anabolic steroids) to increase their muscle bulk or improve performance.
Pheochromocytoma
These are tumors that cause significant increases in epinephrine/adrenaline. Given that these hormones cause your heart to beast faster and increase blood supply to your muscles and brain, it is not surprising that an excess amount leads to rapid heart rate, chest pain, high blood pressure, severe short-lasting headaches, lots of sweating, stomach pain, shaking/tremors of the hands, feeling of anxiety or extreme fright, pale skin and sleeping difficulties. Like the other conditions talked about earlier, treatment is mainly by removing the tumor or using drugs to control the effects in mild cases.
As stated earlier, many of the symptoms associated with adrenal gland dysfunction can occur in other diseases or be caused by medications you might be on (e.g. water pills /diuretics can cause loss of potassium leading to hypokalemia). As such, please do talk to your doctor if you notice any of the above symptoms or have questions related to your health.
Resources for more information
a) Cushing’s disease: http://familydoctor.org/online/famdocen/home/common/hormone/623.html
b) Conn’s disease: http://www.cushings-help.com/conns_syndrome.htm
c) Virilization: http://www.ecureme.com/emyhealth/data/Virilization.asp
d) Addison’s disease: http://www.endocrine.niddk.nih.gov/pubs/addison/addison.htm
e) Pheochromocytoma: http://www.endocrineweb.com/pheo.html