A Clinical Study and Short Term Outcome of the Patients Presented with Thyroiditis

Thyroiditis-inflammation of thyroid gland includes a group of individual disorders having many different clinical presentations, aetiopathogenesis and histology. Sometimes they are overlapping on their presentations. Objectives: To see the clinical biochemical profile and to observe a short term outcome of the patients presented with different types of thyroiditis. Materials & methods: 50 cases with clinical suspicion of thyroiditis were randomly selected. Clinical history, Physical examination and serum T3, T4, TSH was done in every patient and FNAC of thyroid gland & TMab (Thyroid microsomal antibody) was estimated in some. They were followed up at three monthly intervals with the measurement of TSH. Results: Cases were subdivided in to 3 groups. Among them subacute thyroiditis were 19 (38%), 26 (52%) were Hashimoto’s thyroiditis and 5(10%) were silent thyroiditis. The subacute group presented with features of hyperthyroidism, negligible RAIU (radioactive iodine uptake) and FNAC ( Fine Needle Aspiration Cytology) showed granulomatous thyroiditis. During follow up (57%) became hypothyroid at 3 months, (26%) euthyroid and (15%) in thyrotoxic state. After 9 months (87%) was hypothyroid and (5.26%) thyrotoxic. At 12 months (94%) was euthyroid and one thyrotoxic. Hashimoto’s group presented in hypothyroid state, RAIU test were variable. FNAC showed lymphocytic infiltration in all patients. They were found 100% hypothyroid after 1 year. Silent Thyroiditis group were in hyperthyroid state with negligible RAIU. After 12 month (60%) became euthyroid and (40%) remain hypothyroid. Conclusion: Thyroiditis has both thyrotoxic and hypothyroid phase but they are self limiting. So before giving specific therapy, thyroiditis must be excluded.


Introduction
Thyroiditis refers to inflammation of thyroid gland.This includes rare acute bacterial infection to rarest Riddles thyroiditis.The relatively common forms are sub acute or De Quervain's Hashimoto's, silent, postpartum and drug induced thyroiditis like amiodarone, interferon. 1,24][5][6][7][8] There are some geographical and seasonal preponderance also. 8,9No symptoms unique to thyroiditis.The clinical course depends on their types.If the thyroiditis causes slow and chronic destruction, this would be a case of Hashimoto's thyroiditis .
During the course of this disease, the cells of the thyroid become insufficient in converting iodine and "compensate" by enlarging.RAIU may be paradoxically high while the patient is hypothyroid because the gland retains the ability to "trap" iodine even after it has lost its ability to produce thyroid hormone.As the disease progresses the TSH increases and the patient becomes hypothyroid.This sequence of events can occur over a relatively short span of a few weeks or may take several years.
In subacute thyroiditis the thyroid gland generally swells rapidly and is very painful and tender.The gland discharges thyroid hormone into the blood and the patients become hyperthyroid; however, the gland quits taking up iodine.RAIU is very low, Patients frequently become ill with fever.Thyroid antibodies are not present in the blood, but the sedimentation rate is very high.Although this type of thyroiditis resembles an infection within the thyroid gland, no infectious agent has ever been identified, hyperthyroid phase lasts for 1-3 months as inflammation continues the gland often becomes depleted of thyroid hormone leading to hypothyroidism which lasts for 9-12 months.Total resolution occurs within 12-18 months. 2,9ilent thyroiditis is the third and least common type of thyroiditis.It was not recognized until the 1970s, although it probably existed and was treated as Graves' disease before that.The blood thyroid test is high and the RAIU is low (like De Quervain's thyroiditis), but there is no pain and needle biopsy resembles Hashimoto's thyroiditis.The majority of patients have been young women following pregnancy which often considered as postpartum thyroiditis.
Antithyroid drugs have no role because thyroid hormone biosynthesis is already low. 9Levothyroxin is indicated during the hypothyroid phase in subacute & silent thyroiditis when they are symptomatic and also in patients with Hashimoto's thyroiditis.

Materials & methods:
This observational study was done on 50 cases with clinical suspicion of thyroiditis on the basis of painful thyroid gland, low RAIU test, patients with thyrotoxicosis or hypothyroidism and FNAC suggestive of thyroiditis.Pregnant and lactating mother and children below 15 years were excluded.Cases were selected from Thyroid clinic at nuclear medicine & ultrasound centre in Khulna Medical College.
Comprehensive clinical history, physical examination and routine serum T3, T4, TSH and RAIU test were done in every patient and FNAC of thyroid gland & TMab also was estimated in some.They were followed up at three monthly intervals with the measurement of TSH.
Therefore, the duration of thyrotoxic phase was between 1-3 months in most of the patients.Then the transient hypothyroid se of 9-12 months was observed.After 1 year 94.73% patients showed complete recovery & 5.26% remain hyperthyroid.
Among and FNAC showed lymphocytic infiltration in all patients.They were followed up at 3 months interval.70% patients were hypothyroid at diagnosis and remain in the same status after 1 year.30% patients were euthyroid at presentation but gradually turned into hypothyroid.So the ultimate outcome was hypothyroidism in all patients.Akira Sato 13 et al showed in his ten year follow up study 66.2% euthyroid and 27% were hypothyroid among 74 patients.My study is not consistent with that study as the numbers of patients were small and the follow up time was only one year (Fig. -2).
Initially all the patients were hyperthyroid then 60% patients showed a period of transient hypothyroidism and became euthyroid within 9-12 months.40% patients with silent thyroiditis had a tendency to remain hypothyroid.Similar results were found in western population 16 .

Conclusion
From the clinical stand point it is essential to differentiate different types of thyroiditis and other thyroidal illness.Subacute and silent thyroiditis have a transient (3-6 month) thyrotoxic phase similar to Grave's disease but has reduced RAIU.So before giving specific therapy to thyrotoxic patient, thyroiditis must be excluded.On the other hand Hashimoto's, subacute and silent variety, all passes through a phase of hypothyroidism.The former usually permanent and needs replacement therapy but the later two are self limiting so differentiation of these types of thyroiditis is also important.

Table - I
Symptoms & signs of patients with subacute thyroiditis Fig.-2 : One year follow up of patients with Hashimoto's thyroiditis Fig.-3:One year follow up of patients with silent thyroiditis