Thyroid Disorders
The thyroid gland sits in the lower part of the front of the neck, in front of the windpipe. It is often described as a “butterfly” shaped gland. The thyroid gland is important in the regulation of the body’s metabolism (similar to the way a thermostat controls a heater / air conditioner). It does this by producing the thyroid hormones, T4 and T3. An overproduction of thyroid hormone is called thyrotoxicosis or hyperthyroidism; an underproduction of thyroid hormone is called hypothyroidism.
Sometimes the gland can become enlarged, this is called a goitre. A goitre can be due to a number of reasons. A goitre may or may not be associated with a change in the gland’s function - that is , the thyroid hormone levels may be normal or abnormal.
Thyroid Nodules
Thyroid nodules are very common, particularly in inland areas , such as the New England locality. Often they are found coincidentally , and may not cause any problems. There may be one nodule , or multiple nodules. Most thyroid nodules are benign (95%). Nodules are often found when a lump is detected in the neck. Sometimes the nodule/s may cause pressure on the windpipe or oesophagus, leading to problems breathing or swallowing, or persistent coughing.
The initial investigation is usually an ultrasound. This will determine the size of the gland, how many nodules are present and whether they are on one side of the gland or both. It will determine the size of the nodules. It may also detect changes in the nodule that are suggestive of a thyroid cancer, rather than a benign nodule.
If you have a very large thyroid gland , or if you are having symptoms such as shortness of breath, coughing, or difficulty swallowing, it may be useful to have a CT scan of the neck. This can detect compression of the windpipe or the oesophagus, and can also detect if the thyroid gland is extending into the chest .
If one or more nodules have some changes on ultrasound that are associated with the development of a thyroid cancer, a Fine Needle Biopsy may be needed. A fine needle is introduced into the nodule under ultrasound guidance and a sample of the cells in the nodule is taken. This will be sent to the pathology lab for testing.
Sometimes surgery is needed to remove an enlarged gland, or to determine whether a nodule is cancerous or not.
Thyroid Cancer
There are four main types of thyroid cancers - they are called papillary, follicular, medullary and anaplastic. The most common type of thyroid cancer is the papillary form. Anaplastic is the rarest form of thyroid cancer. Luckily, the most common type, papillary, has a very good prognosis overall after treatment . Treatment usually involves surgery to remove the thyroid, and is often followed by radioactive iodine (which can be given in Tamworth). More aggressive forms of thyroid cancer are best managed under the guidance of a multidisciplinary team of surgeons / oncologists / endocrinologists and nuclear physicians. Dr Sardelic participates in the Thyroid Cancer MDT held at John Hunter Hospital.
The Parathyroid Glands and Hyperparathyroidism
The parathyroid glands are usually situated close to (or even inside) the thyroid gland. There are usually four, and they are very small, often only a few millimetres in size ( about the size of a grain of rice). Despite their tiny size, they are very important in maintaining a safe level of calcium in your blood, due to their production of Parathyroid hormone (or PTH for short).
Sometimes one or more glands can develop a benign tumour, or adenoma, which can then produce too much parathyroid hormone. Sometimes all the parathyroid glands can become enlarged (this is called hyperplasia), and can produce too much parathyroid hormone. Having too much parathyroid hormone is called hyperparathyroidism.
Having too much parathyroid hormone produced by the parathyroid glands can cause too much calcium in the blood (called hypercalcaemia) due to the effects of the parathyroid hormone on the bones and kidneys.
This can lead to kidney stones and osteoporosis; the osteoporosis can in turn lead to an increased risk of fractures, sometimes after minimal trauma. It can also cause a number of other, less specific symptoms, such as persistent thirst, passing more urine more frequently, constipation, tiredness, poor concentration, muscle aches, low mood, and confusion. A very high calcium level in the blood can lead to dehydration and kidney failure, and require the patient to be admitted to hospital for rehydration.
Hyperparathyroidism is usually suspected after a routine blood test, when an elevated calcium level is found. It is confirmed by checking the parathyroid hormone and calcium levels in the blood.
Apart from blood tests, other investigations include an ultrasound of the thyroid and the neck, a Nuclear Scan called a Parathyroid / Sestamibi scan, and sometimes a 4D CT scan.
The ultrasound looks for one or more enlarged parathyroid glands, as well as checking for thyroid nodules, which can make it harder to interpret the other scans. The Parathyroid scan looks for an enlarged parathyroid, and is most helpful when it finds a single enlarged gland. Sometimes the Parathyroid scan is not helpful, and a 4D CT scan may be needed. A 4D CT scan is best done at a major centre which has a lot of experience in reporting this very specialised scan.
There is no treatment for hyperparathyroidism except for surgery . The aim of surgery is to find and remove any enlarged gland. If the scans have shown a single enlarged gland , it can sometimes be removed through a very small incision. If the scans have not been able to find a single enlarged gland, a larger incision is made, and all four glands will be searched for. Their positions can be very variable - they can be high in the neck, close to the jawbone, down in the chest, or anywhere between.