Signs and Symptoms of Hyperthyroidism

Hyperthyroidism—also known as overactive thyroid—is a condition that occurs when your body is producing too much thyroid hormone. Thyroid hormone is secreted by the thyroid gland, which is a small organ in the front of the neck. Your body needs thyroid hormone for several functions, such as managing your metabolism and regulating your body temperature and heart rate.

Too much thyroid hormone, however, can cause a host of symptoms that affect several organs in your body. Hyperthyroidism can sometimes be hard to diagnose, especially because symptoms can mimic symptoms of other health conditions. But, knowing the signs of hyperthyroidism may encourage you to visit your healthcare provider and get a proper diagnosis if you begin to experience symptoms.

Neurologic and Cognitive Symptoms

Hyperthyroidism can cause neurologic and cognitive symptoms—or symptoms that affect the functioning of your brain and nervous system. As a result, you may experience a variety of symptoms including:

• Fatigue or extreme exhaustion
• Tremors or shaking 
• Anxious or racing thoughts 
• Irritability
• Restlessness
• Mood swings
• Difficulty sleeping 
• Trouble concentrating or remembering things

In severe cases, you may also experience depressive moods or psychosis. While all of these symptoms may seem frustrating or worrisome, the good news is that treatment can drastically improve your condition and reduce symptoms.

Skin Symptoms

With your condition, you might also experience changes to your skin, hair, and nails. Hyperthyroidism can commonly cause:

• Flushed skin 
• Feeling warm or hot to the touch 
• Increased sweating
• Soft or brittle nails 
• Onycholysis, or separation between your nails and nail beds 
• Hyperpigmentation or dark spots on the skin 
• Hair thinning and loss

It’s important to note that Graves’ disease is the most common cause of hyperthyroidism. Graves’ disease can produce its own unique skin symptoms, such as areas of thick and darkened skin over the shins that mimic the texture of an orange peel. This is clinically known as a symptom called infiltrative dermopathy or pretibial myxedema.

Cardiovascular Symptoms

The cardiovascular system—or the part of your body that controls your heart and blood vessels—is also sensitive to changes relating to your thyroid hormone levels. Hyperthyroidism can lead to heart disease and worsen an underlying heart condition. Having an overactive thyroid also increases your risk of heart failure and atrial fibrillation—a condition that causes arrhythmias, or a rapid heartbeat. 

Hyperthyroidism can cause one or more of the following heart-related symptoms:

• Elevated heart rate
• Heart palpitations, or a rapid and irregular heartbeat
• Trouble keeping up with exercises that raise your heart rate (e.g., running or biking)

Musculoskeletal Symptoms

Excess levels of thyroid hormone can also affect your muscles, joints, and bones—which make up your musculoskeletal system. Hyperthyroidism can lead to:

• Joint pain
• Muscle weakness 
• An increased risk of bone fractures or bone loss 

In rare cases, people with hyperthyroidism can experience thyrotoxic periodic paralysis—a condition that causes sudden episodes of severe muscle weakness or paralysis that usually lasts for a few hours. Sometimes, exercise and eating a meal high in carbohydrates and salt can trigger symptoms. Between episodes, however, you may not experience any symptoms at all.

Respiratory Symptoms

Excess thyroid hormone increases metabolism, so the condition can cause your lungs to bring in more oxygen and breathe off of carbon dioxide. As a result, you might experience shortness of breath or feel very tired easily after physical activity.

Hyperthyroidism can also cause goiter—or an enlarged thyroid. Goiter can obstruct your airways and make it difficult to breathe as you would normally. 

Gastrointestinal Symptoms

Hyperthyroidism is also known to affect your gastrointestinal tract—or, the passageway that runs through your digestive system from your mouth to your anus. This can affect the function of your digestive organs and cause the following symptoms:

• Diarrhea
• The need to use the bathroom more often 
• Feeling hungry or having an increased appetite
• Weight loss
• Nausea and vomiting

While this is rare, if you have a large goiter, you might also experience difficulty swallowing your food properly. 

Eye Symptoms

In some cases, hyperthyroidism can cause what is known as lid lag or “thyroid stare.” Lid lag occurs when your eyelids are open more than usual. In lid lag, you can see the white of the eye that’s normally covered by the eyelid, even when you’re looking down.

Graves’ disease may also cause some eye-related symptoms due to inflammation around the eyes. Aside from lid lag, you might also experience:

• Swelling or redness in your eyes
• Eye bulging 
• Blurry vision
• A gritty or sandy feeling in your eyes 
• Pain and pressure
• Puffy eyelids 
• Light sensitivity 

Sex-Specific Symptoms

Thyroid hormone is also involved in the function of your sex glands and sex hormone production. Hyperthyroidism can cause abnormalities in estrogen and testosterone levels, which manifests in various ways. 

Sex-related symptoms include:

• Light or short menstrual periods
• Irregular or missed menstrual periods
• Infertility 
• An increased risk of losing pregnancy 
• Growth of breast tissue
• Erectile dysfunction
• Abnormal sperm production 

Symptoms in Children

The symptoms discussed above can occur at any age, even in children. However, children who receive a diagnosis for hyperthyroidism may also notice signs of:

• Body maturing and growing too quickly 
• Bedwetting
• Delayed puberty
• Behavioral changes and decreased attention span
• Decline in school performance

If your child receives a diagnosis of hyperthyroidism at birth or early in infancy, you may also notice some delays in their cognitive functioning and development.

When to See a Healthcare Provider

If you have symptoms of hyperthyroidism or have a family history of thyroid disease, it’s a good idea to visit your healthcare provider. Keep in mind: do your best to not delay care, because untreated hyperthyroidism can result in serious complications. 

Your healthcare provider can give you an accurate diagnosis by using your medical history, a physical exam, and the results of a blood test. The good news is that there are several effective treatments on the market that can reduce symptoms and improve your overall quality of life. 

If you’ve already received a diagnosis for a thyroid disorder, it’s especially important to stay in contact with your healthcare provider so you can get regular thyroid checks and make any adjustments to treatment if needed.