WORK UP OF A PATIENT WITH THYROID ENLARGEMENT
Patient of thyroid enlargement or goitre can have a primary presentation with the swelling in the neck and associated effects of that swelling or may be associated with thyroid dysfunction also. The swelling of the gland can be as a result of variety of aetiology and that must be at the back of the mind of clinician while dealing with a patient of goitre.
HISTORY
geographical area
COURSE / DURATION:
PAIN: Significantly pain from the very onset favours the possibility of thyroiditis. In all other lesions of thyroid, pain is either absent or late to come.
LOCAL PRESSURE EFFECTS: Patient occasionally has chief presentation with local pressure effects. Superior mediastinal syndrome in retrosternal goitres or extensions is troublesome. Hoarseness of voice or dysphasia often indicate malignancy though uncommonly can occur in benign goitres with complications like infection and haemorrhage.
FEATURES OF DYSFUNCTION: Patient can have goitre presentation along with hype- or hypothyroidism. A goitre with clinical hypothyroidism raises largely the possibility of Hashimoto's thyroiditis while hyperthyroidism may be associated with Graves disease, Plummer's disease or toxic adenoma. Other causes of hyperthyroidism e.g., struma ovari, toxicosis fictitia, etc. do not have enlargement of gland.
CAUSES OF HYPERTHYROIDISM
Common causes
1. Diffuse toxic goitre (Primary = Graves'disease)
2. Toxic nodular goitre (Secondary = Plummer's disease)
3. Toxic Nodule = Toxic adenoma
Other causes
4. Thyrotoxicosis Factitia
5. Jod-Basedow thyrotoxicosis
6. Thyrotoxicosis due to thyroiditis (de Quervain's particularly)
7. Functioning thyroid carcinoma (both primary and secondary)
8. Neonatal thyrotoxicosis
9. Apudomas
10. Ectopic thyroid tissue - Struma ovary
EXAMINATIONS
Thyroid enlargement (a swelling moving up on deglutition and anterior in neck) is one situation where a thorough examination would often establish a diagnosis correlatable to great extent with investigations. Clinical suspicions often turn true on investigations. The gland should be examined both from front and behind systematically. Superior pole, body, inferior pole of both the lobes and isthmus must be palpated. It must be noted whether enlargement is smooth or nodular and, if latter, number of nodules, consistency, etc. Cervical lymph nodes must be examined in all cases carefully. Sometimes the only indication of malignant change in otherwise benign looking goitre may be a culprit looking lymph node. Lahey's method of examination is useful when the gland enlargement is minimal and asymmetrical. (Gr1/gr oh). Berry's sign (carotid artery pulse) in all cases and Pizello's method of making gland prominent in short and obese persons is useful and mobility of gland in neck be determined in all cases . Fixity to trachea and Indirect laryngoscopy to see involvement of vocal cords are important in all goitres. Sometimes infections and haemorrhage within the gland can produce these effects besides, of course, malignancy.
FUNCTION: It is not necessary to go in details of signs but clinically the patient must be evaluated for any dysfunction.
WAYNE'S INDEX: is useful but the significance attached to thyromegaly (+++++) may not apply to Indian geography of disease.
APPROACH
After above history taking and physical examination, following clinical situations can emerge:
A: Goitre without dysfunction
1. Patient has diffuse hyperplasia, no pain, smooth bilateral, symmetrical enlargement, grade often I/II, age is young, often below teens, often female, or women who are menstruating, lactating or pregnant. The diagnosis is physiological goitre.
2. Patient comes from endemic area. There are multiple nodules of long standing, soft to firm but sometimes calcified, no fixity in neck and no pressure effects - Multinodular goitre.
3. There is a solitary nodule of variable duration. Endemicity not elicitable, often painless, mobile, no pressure effects, only nodule is palpable, rest of the gland is not enlarged -An adonoma of thyroid.
4. Solitary nodule as above but along with smooth enlargement of rest of the gland - solitary nodular goitre (Endemicity +) or clinical solitary nodule in an endemic adonoparenchymatous goitre. Distinction between 3 and 4 may not be easy and also not significant as the term "Solitary thyroid noduld' is acceptable.
5. The gland is enlarged for short duration, it is hard or there is a recent rapid enlargement. Effects on recurrent nerve, trachea, oesophagus may be present. Presence of suspicious cervical node and fixity to trachea or obliteration of carotid pulses leaves no doubt about the possibility of thyroid malignancy. If not detected earlier on clinical examination, the sites for secondary deposits in neck, bones, liver and lungs must be examined again.
MALIGNANCY OF THYROID
Primary
A. Epithelial = Carcinoma
1. From thyroid epithelium
a) Differentiated
Papillary
Follicular
Papillary-Follicular
Other variants of above
Hurthle cell Ca
b) Undifferentiated = anaplastic carcinoma
2. From non-thyroidal cells
Medullary carcinoma
Mesenmchymal = Sarcoma, lymphoma
Secondary
1. Local infiltration from carcinoma esophagus, larynx, etc.
2. Metastatic (blood borne) from kidney, brain, prostate, parotid, etc.
SOLITARY THYROID NODULE
Solitary thyroid nodules are important especially as they harbour 30x chances of malignancy. These cannot be left uninvestigated for this single the most important reason. It is not prudent to put them on suppressive therapy without conducting that the nodule is not malignant . In all cases a radionuclide scan be done and the nodule will fall in one of the following categories :
HOT: Can be managed conservatively after evaluation of thyroid function. FNAC is optional.
WARM & COLD: Must undergo FNAC.
FNAC reveals benign - Trial Suppressive Hormone therapy: Nodule must disappear in six months or else surgery must be done.
FNAC - Malignant - Surgery outright. The minimum surgery for any nodule (including benign or suspicious malignant) is Lobectomy+ isthmusectomy. Nodule excision alone has no place, If carcinoma is diagnosed with certainty on FNAC, depending on type more radical surgery is to be done. In differentiated carcinoma, total 1 near total thyroidectomy is a must.
B: GOITRES WITH DYSFUNCTION
I. With hyperthyroidism
a. Primary toxic goitre (Graves' disease):
The goitre is smooth and toxic manifestation + enlargement starts together.
b. Secondary toxic goitre (Plummer's disease): The toxicosis supervenes on top of a previously enlarged gland, usually a muitinodular goitre.
c. Toxic adenoma: A solitary nodule that overfunctions. Clinical toxicosis is used in nuclear medicine for all hyperactive thyroid nodules.
II. In goitre with Hypothyroidism: Hashimoto’s disease- a distinct possibility.
THE WORK UP
Having achieved a clinical diagnosis from foregoing, every patient should have assessment of thyroid function and morphology. A percentage of clinically euthyroid patients have a disturbed serum biochemistry. For function, out of all the tests, T3/T4/TSH/FT4/FT3 in serum suffice. TRH (or Domperidone) stimulated TSH level seems to be least interfered or most representative thyroid function test. For morphology, radionudide scan Tc or I-131 is still preferable as its gives idea of not only morphology but also function of each individual part. Toxic adenoma can be diagnosed only by this investigation. U/S Scan and CT have no special advantage except that in malignancy CT may give better idea of tissue plane infiltration. Imprint Smear: can be a good substitute for Frozen section.
