In many cases, the neurologic manifestations occur in conjunction with the systemic features of thyroid disease and may be noted only incidentally. However, symptoms and signs of neurologic dysfunction may be the presenting feature in some patients and can contribute significant disability. Most of these complications are partially or fully responsive to thyroid replacement therapy in the majority of cases but for some Thyroid dysfunction related neuropathy can become a life long struggle.
Hyperthyroidism and Nerve Pain:
What Thyroid Cancer Survivors Should Know
Thyroid hormones are important at a cellular level, affecting nearly every type of tissue in the body, these hormones functions as controllers of the pace of all of the processes in the body. This pace is called metabolism. If there is too much thyroid hormone, every function of the body tends to speed up. It is therefore not surprising that some of the symptoms of hyperthyroidism are nervousness, irritability, increased perspiration, heart racing, hand tremors, anxiety, difficulty sleeping, thinning of the skin, fine brittle hair, and muscular weakness—especially in the upper arms and thighs. More frequent bowel movements may occur, but diarrhea is uncommon.
Thyroid hormone is critical to normal function of cells. In excess, it both overstimulates metabolism and exacerbates the effect of the sympathetic nervous system, causing "speeding up" of various body systems and symptoms resembling an overdose of epinephrine (adrenaline). These include fast heart beat and symptoms of palpitations, nervous system tremor such as of the hands and anxiety symptoms, digestive system hypermotility (diarrhea), considerable weight loss and unusually low lipid panel (cholesterol) levels as indicated by a blood test.
Hyperthyroidism usually begins slowly. At first, the symptoms may be mistaken for simple nervousness due to stress. If one has been trying to lose weight by dieting, one may be pleased with weight loss success until the hyperthyroidism, which has quickened the weight loss, causes other problems.
Thyroid Related Neuropathy Symptoms
Neuropathy symptoms include those having to do with nerve functions throughout the body. Common neurological symptoms include headaches, numbness or tingling in the hands and/or feet (peripheral neuropathy), abnormal reflexes and muscle weakness and spasms. Thyroid disease is an endocrine gland disorder (hormone related) and all disorders in this category, including diabetes have potential to cause neurological symptoms. In the case of thyroid disease, the hormones produced by this endocrine gland regulate the metabolism in every cell of the body, including those related to nerve function. When a disorder affecting thyroid hormone balance develops or they thyroid gland is surgically removed, the function of the nervous system can be sped-up or slowed down, resulting in nerve-related symptoms.
Treating Thyroid Hormone Imbalances
Hypothyroidism is a condition in which thyroid hormone levels drop below normal. This results in all bodily functions slowing down (hypo-metabolism), including brain-nerve signals (motor responses). It also causes fluid build up in tissues of the body or what is referred to as “myxedema”, which can cause pressure on nerves, resulting in additional symptoms of neuropathy, such as numbness and tingling in the extremities. When thyroid hormones are brought back up to correct levels, these type symptoms improve, as well as myxedema in body tissues affecting nerve signals.
[Hypothyroidism is a common and growing medical condition in the general population that often goes undiagnosed or misdiagnosed for many reasons. Common systemic manifestations include fatigue, constipation, cold intolerance, weight gain, hair loss, dry skin, and hoarseness which are often discussed in blogs and other forums. An often overlooked and more important discussion is a variety of central and peripheral nervous system manifestations common in patients with hypothyroidism and hyperthyroidism.]
Hyperthyroidism is a condition of abnormally high thyroid hormone levels, which causes all bodily functions to become sped up (hyper-metabolism). Muscle reflexes are hyper-reactive, meaning there is abnormal muscle tension in response to brain-nerve signals. This can result in the adverse effect following physical activity, of severe muscle weakness. Some patients may also experience episodes of muscle paralysis and/or muscle deterioration. Neurological symptoms that accompany hyperthyroid conditions are sometimes referred to as “thyrotoxic myopathy” but will improve significantly with treatment to reduce thyroid hormone levels and treatment for symptoms of an overactive metabolism via anti-thyroid drugs and beta-blockers.
Thyroid cancer survivors can have fluctuations in their thyroid hormone levels ranging from high to low (hyper / hypothyroidism) as a result of the surgical removal of the thyroid gland and how well they respond to hormone replacement therapy, synthetic hormone absorbtion and other individual factors such as co-existing disorders or medical conditions that require the use of other medications among other things. It is also important to remember that thyroid cancer patients are normally required to remain slightly hyperthyroid to prevent thyroid cancer recurrence.
Thyroid Antibodies: The thyroid hormone imbalances caused by the surgical removal of the thyroid gland and other thyroid diseases are an obvious cause of neurological symptoms but what role does “thyroid autoimmunity” play in these type symptoms? Autoimmune-caused hypothyroidism is called Hashimoto’s thyroiditis and autoimmune-caused hyperthyroidism is called Graves’ disease. Medical research conclusions on studies of thyroid patients has shown that the disease process itself may contribute to neurological symptoms in some thyroid patients in spite of correcting abnormal thyroid hormone levels.
For those patients whose neuropathies do not fully resolve with treatment for thyroid hormone imbalance, another factor in causing symptoms that should be considered is the disease process of thyroid autoimmunity itself. The auto-antibodies sent from the immune system to attack the thyroid gland may also exert negative effects on the peripheral nervous system. Some of this may be the result of inflammation in the body that begins to effect nerve function. With “Hashimoto’s Encephalopathy” for example, which can result from Hashimoto’s thyroiditis in very rare cases, severe and even life-threatening neurological symptoms can develop. It would seem obvious that neuropathies may manifest in Hashimoto’s patients to lesser degrees as well.
Other medical research studies have found that some autoimmune thyroid disease patients have other auto-antibodies present as well, that can directly affect the nervous system. This includes studies that have found mild manifestations of other autoimmune diseases present in thyroid patients including symptoms of Myasthenia Gravis. There is no cure for auto-antibodies but keeping thyroid hormone disorders well-treated can help and some research suggests that supplementing patients with selenium may help to reduce thyroid antibody levels.
Side Effects of Neuropathy
It is important to understand that neuropathy exists in two forms, autonomic and peripheral.
- Autonomic neuropathy involves damage to nerves that control involuntary functions, such as heart rate, blood pressure perspiration and digestion, states MayoClinic.com.
- Peripheral neuropathy is nerve damage in motor and sensory nerves that leads to pain, numbness and weakness. Many different conditions, infections, poisonous substances and forms of trauma can cause neuropathy. A patient should be aware of the side effects of neuropathy and know when to seek treatment.
1. Dizziness and Fainting
MayoClinic.com states that dizziness and fainting are side effects associated with neuropathy. Specifically, damage to autonomic nerves that control blood vessels are affected. Because these nerves are damaged, blood vessels cannot contract and expand to control blood pressure. A patient with an autonomic neuropathy that controls blood vessels may experience dizziness and fainting when standing from a sitting or laying position. This occurs because blood vessels in the lower body do not effectively constrict, or shrink in response to the increase in blood pressure in the lower extremity. This causes blood to pool in the legs, which reduces blood pressure in the brain. Because blood pressure in the brain is reduced, a patient may begin to feel dizzy or faint.
MedlinePlus states that a peripheral neuropathy may cause a loss of sensation. This occurs because damage to sensory nerves result in numbness and an inability to determine joint position, which can cause incoordination. A patient may notice sensory loss that begins in the hands or toes that progressively affects the arms or legs. Sensory loss is a serious medical condition because patients, particularly diabetic patients, may not be able to feet a sore or ulcer developing in the feet. The open sore or ulcer can get infected, which may lead to serious complications. Thus, a patient with a sensory loss should not hesitate to schedule an appointment with the physician so the cause of sensory loss can be determined.
2. Movement Difficulties
Neuropathy may affect nerves that control muscles, states MedlinePlus. Specifically, advanced peripheral neuropathy may affect motor nerves in the hands, arms, feet or legs that results in difficulty moving. In addition, a patient may experience cramps, difficulty breathing, difficulty swallowing, joint instability, lack of coordination and loss of muscle tissue. Peripheral neuropathy should be diagnosed and treated early to avoid further decrease in motor function.
What About When the Pain Doesn't Go Away?
Typically, neuropathy symptoms do usually resolve with proper treatment of your thyroid condition. When muscle and joint pain does not go away with proper thyroid treatment, however, it's time to ask yourself and your doctor several questions.
- If you are hypothyroid, are you getting sufficient and proper treatment? Insufficient thyroid hormone replacement, or a need for the additional hormone T3, may be required to resolve muscle and joint pain.
- If you are receiving optimal thyroid treatment, and still suffering joint and muscle problems, should you get a referral to a rheumatologist, for further evaluation and possible treatment? In many cases a well trained rheumatologist can provide a more thorough evaluation of unexplained muscle aches and pains that does not respond to pain medication. *Rheumatologists are experts in joint and muscle problems, and treat arthritis, some autoimmune conditions, various musculoskeletal pain disorders, fibromyalgia and tendonitis.
*To find a rheumatologist in your area, check the American College of Rheumatology's Doctor Directory
Interestingly, on the subject of fibromyalgia, some practitioners actually believe that fibromyalgia is actually a manifestation of hypothyroidism. Fibromyalgia is a syndrome that features specific tender points in the body, with widespread weakness and fatigue.
- Is it time to look into alternative therapies? Some patients with chronic joint and muscle pain related to their thyroid conditions have had success with therapies such as massage, acupuncture, bio-feedback, myofascial and nutritional supplement therapies.