The symptoms, references, and risk factors for thyroid disease are shown below, but not everyone with abnormal thyroid hormones gets all of the symptoms. To add further confusion, the symptoms don’t seem to fit everyone, and 10% of people with hyperthyroidism gain rather than lose weight!
Thyroid disorders are diagnosed by testing hormone levels; however, usually, it’s just the TSH and thyroxine (T4) hormones that are tested, but T3 is four times more biologically active than T4. The symptoms below are possibilities rather than definites, and the longer hormones have been abnormal and further from the norm, the worse symptoms usually become.
|
Hypothyroidism |
Hyperthyroidism |
|||
|---|---|---|---|---|
| Subclinical | Overt | Subclinical | Overt | |
| Thyroid stimulating hormone (TSH) | Slightly Raised | Raised
(above 10 mIU/L) |
Normal | Low
(below 0.3 mIU/L) |
| Thyroxine (T4) | Normal | Low | High | High |
| Triiodothyronine (T3) | Normal | Low | High | High |
| Temperature | Intolerance to cold and feel cold | Intolerance to cold and feel cold | Intolerance to heat and feel hot | Intolerance to heat and feel hot a lot |
| Digestion | Constipation | Constipation | Frequent movements, possibly diarrhoea | Frequent movements, possibly diarrhoea |
| Energy | Fatigue | Fatigue | Fatigue | Fatigue |
| Skin | Dry, itchy
Reduced sweating |
Dry, itchy
Reduced sweating |
Increased sweating, itching and hives | Increased sweating, itching and hives |
| Nails | Thin and brittle | Thin and brittle | Thickened | Thickened |
| Hair | Thinning of the outer third of the eyebrows | Thinning of the outer third of the eyebrows | Fine hair that’s thinning and falling out | Fine hair that’s thinning and falling out |
| Emotional | Rapid thoughts
Depression |
Rapid thoughts
Depression |
Anxiety, irritability, moodiness | Anxiety, irritability, moodiness |
| Voice and lungs | Hoarse and breaking | Hoarse and breaking | Difficulty breathing, even at rest | Difficulty breathing, even at rest |
| Fertility | Infertility, abnormal menstrual cycles, reduced libido for men | Infertility, abnormal menstrual cycles, thin endometrium, reduced libido for men | Abnormal menstrual cycles, infertility | Abnormal menstrual cycles, infertility |
| Blood serum | High cholesterol | High cholesterol | ||
| Heart | Low heart rate: below 60 bpm, hypertension | Low heart rate: below 60 bpm, hypertension | Palpitations, increased pulse rate | Palpitations, increased pulse rate |
| Body | Weight gain, poor muscle tone, water retention, muscle cramps, goiter | Weight gain, poor muscle tone, water retention, muscle cramps, carpal tunnel syndrome, goiter | Weight loss, muscle weakness, tremor or shakiness, dizziness, goiter | Weight loss, muscle weakness, tremor or shakiness, dizziness, goiter |
| Sleep | Sleep apnea | Sleep apnea | Insomnia | Insomnia |
Reference ranges
There are variations in the reference guidelines for thyroid tests, but the main ones are:
- For adults, the standard reference range (TSH) is between 0.3 and 3.0 mIU/L i
- The reference range issued by the Association for Clinical Biochemistry in the UK is between 0.4 and 4.5 mIU/L ii
- The American Association of Clinical Endocrinologists (ACEE) revised their reference range in 2012 for women during pregnancy into trimester-specific ranges for TSH with the following upper normal reference ranges recommended: iii
- First trimester: 2.5 mIU/L
- Second trimester: 3.0 mIU/L
- Third trimester: 3.5 mIU/L
The ACEE suggests the first trimester upper limit of 2.5 mIU/L of TSH for women trying for a baby.
Risk factors for thyroid disease
- A family history of thyroid disease
- A personal history of thyroid disease
- The presence of anti-thyroid antibodies
- Autoimmune diseases such as Type 1 Diabetes, pernicious anaemia, primary adrenal failure (Addison’s disease), myasthenia gravis, celiac disease, rheumatoid arthritis, systemic lupus erythematosus
- Surgery or radiation to the head, neck or chest
- Medications include sedatives, iodine, metformin, opiates
- Exposure to stresses of environmental, emotional or physical origin
- Iodine deficiency
- Treated Graves’ disease
