Diagnosis of hyperthyroidism can be made by taking proper history of the patient and by clinical signs and symptoms. Blood test and other radiological test aid the diagnosis.
How do know I have diabetes is a question people usually ask a doctor.
Here are some clinical tests that a doctor will perform to know whether you have any thyroid abnormalities.
Palpation of thyroid gland for diagnosis of hyperthyroidism
- – Patient be sitting in a stool.
- – The examiner will stand behind the patient.
- – Patient is asked to flex/bend the neck slightly.
- – Examiners thumb are placed behind the neck and the four fingers are placed over each lobe.
- – The thyroid is palpated entirely the lobes, isthmus.
Pizzillo’s method of palpation of thyroid gland
In people who have short neck or in obese individual it is difficult to palpate the thyroid gland by above method in such cases the doctor might use pizzillo’s method for palpation.
- – Patient is sitting on the stool.
- – Patient is asked to keep both hands behind the head.
- – And now asked to push the head backwards towards the clasped hands.
- – This methods will make any swelling prominent and easier for inspection and palpation.
Lahey’s method of palpation of lobes of thyroid gland
Lobes of thyroid gland are best palpated by this method.
- – Patient is sitting on the stool.
- – Examiner standing infront of the patient.
- – To palpate the right lobe examiner uses his right hand and pushes the thyroid gland towards the right.
- – This will make the right lobe more prominent than left lobe and makes it easier for palpation.
Crile’s method for palpation of thyroid gland
To appreciate even slight enlargement of thyroid gland or any nodules in the substance of the gland examiner will place thumb on the thyroid gland and will ask patient to swallow.
Movement of thyroid gland on deglutition (swallowing)
When patient is asked to swallow the thyroid gland will move upwards.
This is most important physical sign of a thyroid swelling.
This occurs because the thyroid gland is attached to larynx and moves with upward movement of larynx.
Sternocleidomastoid contraction test for diagnosis of hyperthyroidism
- This test is performed when only one lobe is enlarged.
- It is done to determine whether the swelling which is there is deep or superficial to sternocleidomastoid muscle.
- Patient is sitting.
- Examiner stands infront of the patient, and keeps his hand on the side of the chin, opposite to the side of enlarged lobe.
- Then patient is asked to turn his head towards the examiners hand.
- If the swelling is deep to the sternocleidomastoid muscle, like that of a thyroid swelling it will become less prominent when this test is performed.
Chin test (neck fixation test)
- This test is done classically in multinodular goiter when both the lobes of thyroid are enlarged.
- Patient sitting on the stool.
- Examiner keeps one hand under the chin.
- Now asks patient to look downwards against the resistance.
- In this test as both the sternocleidomastoid and strap muscles of neck are contracted it makes the swelling less prominent.
Kocher’s test to see for obstruction of trachea
- An enlarged thyroid gland may press on the vital structure around it and causes certain sings and symptoms related to which organ is compressed.
- When pressure is applied to the lateral lobes of the gland it produces stridor (noisy breathing).
- This indicates that the gland is causing compression of trachea.
Test to check for retrosternal goiter
- Retrosternal goiter is a type of goiter in which more than 50% of the goiter mass is inside the mediastinum or the one which has descended into thoracic inlet .
- It is an abnormally located goiter.
- When there occurs a thyroid swelling it is possible to palpate the lower border of the swelling by getting below the thyroid swelling.
- In case of a retrosternal goiter where in the lower part of the thyroid swelling is inside the mediastinum palpation of lower border is not possible.
- In some cases when the patient is asked to swallow the lower border can be seen as the thyroid swelling moves up with deglutition.
- In patients with a retrosternal goiter there occurs obstruction of the major vessels at the thoracic inlet which leads to engorgement of the subcutaneous veins on the upper portion of the thorax anteriorly.
- – Patient is asked to raise both arms above head until they touch the ears.
- – Ask the patient to hold this position for a while.
- – In case of retrosternal goiter with engorged veins there also occurs congestion of the face and distress .
- – This sign is called the Pemberton’s sign.
LABORATORY DIAGNOSIS OF HYPERTHYROIDISM
Serum thyroxin (T4)-ROLE IN DIAGNOSIS OF HYPERTHYROIDISM
- Thyroxin in plasma is present in the bound form.
- Thyroxin is bound to thyroxin binding globulin (TBG) and thyroxin binding prealbumin.
- Therefore measurement of serum thyroxin is more difficult.
- Se.thyroxine can be measured by radio-immunoassasy or by competitive protein binding.
- Normal levels – 3.0-7.5microgram per 100 ml.
Total serum tri-iodothyronine (T3)
- It is very difficult to measure and it can only be measured by radio-immunoassasy method.
- It is important only in those cases where in the hyperthyroidism is causes due to increased serum T3 levels without any increase in se T4 levels.
Free thyroxin (FT4) index
- Considered as best single test available.
- It is calculated by a formula : serum T4 x T3 uptake percent.
- The values correlates closely to the free T4 in serum.
- These values accurately reflects the thyroid status.
- Normal values: 3.5-8
Thyroid stimulating hormone level (TSH)-most important for diagnosis of hyperthyroidism.
- Serum concentration of TSH (Thyroid stimulating hormone) Is measured by immunoassay.
- In hyperthyroidism the TSH levels will be low or sometimes undetectable.
- Normal value: ≥ 1 microgram/ml
- As there is reverse cholesterol transport that is increase in thyroid levels causes decrease in the cholesterol levels.
- Low cholesterol is said to be a sign of an increased metabolic rate.
- Its effect is same as that of seen in cholesterol.
- Here also increase in thyroid hormone causes reduction of triglyceride levels.
Radiological tests for diagnosis of hyperthyroidism
Thyroid scan and uptake
- Previously the thyroid scan and radioactive iodine uptake test were 2 different test.
- Now both the tests are clubbed together.
- This test can determine the cause of hyperthyroidism.
- Patient is given a solution containing radioactive iodine 123 (I123) on an empty stomach.
- The uptake of iodine by the thyroid gland is measured with the help of a device called a gamma probe.
- The normally around 15-25% of iodine 123 is taken up by the gland at 24hours.
- The iodine uptake is high in patients with grave’s disease, toxic adenoma, toxic multinodular goiter.
- Uptake is low if patient has hyperthyroidism due to thyroiditis.
It is possible to differentiate the causes of hyperthyroidism on the bases of the distribution of the radioactive iodine in the gland.
- Grave’s disease- homogenous distribution.
- Toxic adenoma-iodine 123 is concentrated at one spot.
- Toxic multinodular goiter- iodine 123 is concentrated at multiple spots.
Used to visualize the thyroid gland and see if there is presence of any non palpable nodules in the gland.
CT scan and MRI
- CT and MRI do not have any use in diagnosing hyperthyroidism.
- It can be used to visualize brain to see for any tumors of pituitary gland which is one of the cause of hyperthyroidism.
- May sometimes be used to see for a retrosternal goiter.
Xrays/radiography diagnosis of hyperthyroidism
- Xrays are helpful in cases of of retrosternal goiter.
- Xray may show if there is any deviation or narrowing of trachea.
- Barium swallow radiograph help to see compression of esophagus.
- PIZZILLO’S METHOD
- LAHEY’S METHOD
- CRILE’S METHOD
- MOVEMENT OF THYROID GLAND ON DEGLUTITION
- STERNOCLEIDOMASTOID CONTRACTION TEST
- CHIN TEST
- SERUM THYROXIN (T4)
- TOTAL SERUM TRI-IODOTHYRONINE (T3)
- FREE THYROXIN (FT4) INDEX
- THYROID STIMULATING HORMONE LEVEL (TSH)
- CHOLESTEROL TEST
- TRIGLYCERIDE TEST
- THYROID SCAN AND UPTAKE
- CT SCAN AND MRI