Thyroid Disorders

The thyroid gland sits either side of and in front of the trachea (windpipe) low down in the neck. It has a rich blood supply which it needs as it produces large amounts of a hormone called thyroxine. Closely related to the gland are the nerves that supply the muscles that move the vocal cords, the recurrent laryngeal nerves. These nerves are obviously vital in producing a clear voice. The diagram below shows the thyroid gland and the nerves

Thyroid Anatomy and Physiology

The thyroid gland sits either side of and in front of the trachea (windpipe) low down in the neck. It has a rich blood supply which it needs as it produces large amounts of a hormone called thyroxine. Closely related to the gland are the nerves that supply the muscles that move the vocal cords, the recurrent laryngeal nerves. These nerves are obviously vital in producing a clear voice. The diagram below shows the thyroid gland and the nerves:

The thyroid gland is itself made up of cells that form follicles. These cells take up iodine from the blood stream, the iodine comes form your diet. The iodine is then used to make 2 hormones T3 and T4. T4 is otherwise known as thyroxine. The brain regulates the amount of thyroxine produced so that the body has exactly the right amount for its needs. Thyroxine is the engine driver of many body systems and effects just about every cell in the body. If you do not have enough thyroxine then simply all your body systems slow down, and the opposite is also true. See below

Symptoms of Hypothyroidism (Under-active thyroid)

1. Fatigue or weakness (99%)
2. Lethargy (91%)
3. Cold intolerance (89%)
4. Weight gain despite diminished food intake
5. Swelling
6. Joint pain
7. Lower sex drive
8. Headache
9. Hoarse voice
10. Memory loss
11. Constipation
12. Thin dry skin, hair and nails
13. Loss of periods

Symptoms of Hyperthyroidism (Over-active thyroid)

1. Nervousness or alertness
2. Anxiety, Irritability
3. Palpitations (heart racing)
4. Difficulty sleeping
5. Tremor
6. Diarrhoea
7. Sweating
8. Weight Loss
9. Weakness
10. Heat intolerance
11. Loss of periods

Throid Lumps and Goitre

Any enlargement of a thyroid gland can be called a goitre. Goitres can come in all shapes and sizes. Often the goitre affects the whole gland, this was once much more common and occured in areas where the level of iodine in the diet was extremely low (eg Derbyshire). More common nowadays is when the gland is affected by numerous nodules, hence its medical name multi-nodular goitre. Multi-nodular goitres are extremely common and the vast majority need no treatment. Occasionally one of the nodules can produce too much thyroxine. Also occasionally the goitre continues to enlarge and is cosmetically unappealing, or the goitre starts to grow behind the breastbone (retro-sternal goitre). If a retrosternal goitre is left to grow it can cause difficulties with swallowing and breathing as it may cause pressure on the trachea or oesophagus. In these instances it is recommended that the goitre should be removed.

Solitary thyroid nodules are less common than multiple nodules. More than 95% of all thyroid nodules are benign. Occasionally a thyroid nodule can break down and form a cyst. This can occur relatively rapidly and may be the reason for sudden onset of a thyroid swelling.
http://www.endocrineweb.com/nodule.html

If you have a lump on the neck that may be coming from the thyroid you should consult your general practitioner who if he or she feels it appropriate will refer you to a hospital that runs a regular neck lump clinic. At this clinic you should have a careful 'history' taken, ie asking questions about your lump and you, and be examined. If the doctor at the clinic feela that this lump is coming from your thyroid they may order an ultrasound scan and or perform a needle biopsy.

Ultrasound (US) of the Thyroid

The thyroid gland is ideally imaged with the use of high frequency ultrasound. This is exactly the same as the scan pregnant women get, but obviously the neck is scanned rather than the abdomen. It gives excellent detail of the nature of any thyroid swelling, if there is more than one and also can help in directing the needle biopsy. An experienced ultrasonographer can also pick up any suspicious features of a thyroid nodule, for example, one form of thyroid cancer may have a particular pattern which can be seen on the scan. In addition, it may be all that is needed to reassure a patient that all is fine and nothing else needs doing. It is also a useful way in documenting the size of a thyroid or nodule if the patient requires follow up to check for increasing size. One problem is that an US can not assess if a thyroid is passing behind the breatbone.
http://www.webmd.com/a-to-z-guides/Thyroid-and-Parathyroid-Ultrasound

Fine Needle Aspiration Biopsy (FNA)

Fine needle aspiration has revolutionised the management of thyroid nodules. The technique is quick, cheap and no more painful than a blood test. The doctor in the clinic will explain the procedureand a very fine needle is placed into the lump in the thyroid and a number of cells are sucked up into the needle using a syringe. The needles contents are then spread onto a slide and the slide is looked at by a pathologist. As in all tests there are various possible outcomes, the test may not have had enough cells, categorised as Thy 1, these should be repeated. The best result is benign cells (Thy2), normally, patients are seen once more and the test repeated some months later, if still Thy2 they may be discharged. A Thy3 result means that the pathologist has found a tumour but cannot tell if it is benign or malignant, nevertherless the majority (80-90%) of Thy3 results will end up being benign, however, the only way to be absolutely certain is to remove the half of the thyroid gland with the nodule in it. Therefore anyone with a Thy3 result should undergo a hemithyroidectomy (see later), once the specimen has been looked at, in the majority of cases that will be the end of it, however, a small number of people will have a cancer of the thyroid and will need to have more surgery to remove the remaining part of the gland. A Thy4 result is very suspicious of cancer and requires removal of at least half of the thyroid. A Thy5 result means that the patient almost certainly has thyroid cancer and will require a total thyroidectomy and possible removal of any associated lymph nodes (glands)

Very few patients have a Thy4 or Thy5 result.

As with all tests the results are not 100% accurate and occasionally surgery is recommended even with benign results.
http://www.thyroidmanager.org/FunctionTests/fnabiopsy-text.htm

Blood Tests

Many people have their thyroid hormone levels at some time during their life. The blood test checks the level of thyroxine (T4) in the body as well as checking TSH (thyroid stimulating hormone) which is low if you have too much thyroxine ie have an overactive thyroid, and high if you need more thyroxine, ie underactive thyroid. This makes sense as TSH comes from the brain to stimulate the thyroid gland.

These 2 tests alone are by far the most important blood tests
http://www.patient.co.uk/showdoc/40000930/

Thyroid Cancers

Thyroid cancer is uncommon. In the UK only 1,400 people per year are dianosed with thyroid cancer. It is more common in middle aged and older people and more common in women than men. One of the less agressive forms (papillary cancer) can occur in younger people.

2 forms of cancer are often relatively slow growing in their development and respond extremely well to treatment. Most patients will be cured long term

Papillary
Follicular

The other forms are more aggressive and the chance of long term cure is lower:

Medullary - this may run in families and can be associated with other tumours
Anaplastic - this is a very unpleasant cancer that usually occurs in elderly people, it is very aggressive and very few patients survive this condition.

One final form of thyroid cancer is lymhoma of the thyroid, which is different from the other forms of thyroid cancer as it affects the lymphoid tissue of the thyroid. This form of cancer usually responds well to treatment.

Treatment of Thyroid Cancer

Largely speaking most thyroid cancers should be treated by surgical removal of the whole thyroid (thyroidectomy), followed up by radio-iodine treatment ( a form of radioactive treatment that kills all thyroid tissue cancerous or otherwise in the body).

Anaplastic cancer is often too advanced to offer surgery as a potential cure, and palliative radiotherapy may be offered

Lymphoma responds very well to treatment by radiotherapy and or chemotherapy.

http://www.cancerbackup.org.uk/Cancertype/Thyroid/General/Thyroidcancer

Thyroid Surgery

There are only 2 operations that should currently performed on the thyroid gland, namely a thyroid lobectomy (hemi-thyroidectomy) or a total thyroidectomy. This is the advise that nearly all endocrine and head and neck surgeons recommend. In the past general surgeons would perform a paritial thyroidectomy for 2 reasons: one, it is technically easier as you do not have to identify the recurrent laryngeal nerve, and two, it was felt that the remnant of thyroid tissue may be enough to mean that the patient doesn't require thyroxine medication. In surgery for thyroid cancer the leftover thyroid tissue makes the post-operative radio-iodine treatment more difficult as well as making checking for recurrent disease harder. In simple goitre surgery, the remnant was often not enough anyway to keep the patient off thyoid tablets, and in addition often regrew making difficult revision surgery necessary. In experienced hands, the more complete operations do not have increased incidences in the known complications. Overall, there is a roughly 1% risk of permanent damage to the recurrent nerve, however, initially 2% of patients might be hoarse with half recovering. The incidence of needing lifelong calcium is around the 5% level in patients having total thyroidectomy. All of these complications increase in cancer cases or in revision cases.

The surgery is performed under general anaesthetic. An incision is made low in the neck, the strap muscles of the neck are separated and the thyroid gland taken off the laryngeal nerve and trachea, leaving the important parathyroid glands behind (they are important in calcium regulation).

In the majority of cases patients of mine who have only half the thyroid removed do not have a surgical drain (a plastic tube in the wound to collect blood) placed at the end of the procedure. This is more comfortable than having a drain and ensures early discharge from hospital, indeed recently some patients have been able to have their surgery as a day case (ie no overnight stay in hospital).

The wound is closed with skin clips (metal staples) and steristrips (paper butterfly stitches). I have found removing the staples 48 hours after the operation and the steristrips after 7 days produces excellent cosmetic results.

Recent Advances, Minimally Invasive Thyroid Surgery

Recently, a technique has been developed using endoscopes and video technology to remove thyroid glands through extremely small incisions, often as little 1.5 or 2 centimetres. This technique is suitable for removal of small thyroid nodules or tumours and for parathyroid surgery.

I am hoping to introduce this service in the very near future

http://www.llu.edu/lluhc/ent/thyroid.html
http://video.google.com/videoplay?docid=5099115877287143814