Evaluation of Subacute Thyroiditis: Frequency, Clinical Manifestation and Laboratory Findings

Introduction: Subacute thyroiditis (SAT) is a type of viral thyroiditis, which is often a self-limiting illness, but it causes diagnostic mistakes due to a number of clinical symptoms and leads to inappropriate treatment. In this study, clinical, laboratory and demographic ndings of patients have been investigated Methods: This descriptive cross-sectional study was performed on 40 patients (27 female-13 male) with subacute thyroiditis during one year. Data included age, sex, clinical symptoms (fever, sore throat, otalgia, fatigue, sweating ...) and laboratory ndings. (ESR, CRP, TSH, T4 and WBC). Their les were extracted and analyzed with SPSS. Results: In this study, 67% of the patients were women with the mean age of 38.48 ± 8.7. Female to male ratio was 2.7 to 1. The most common clinical symptoms were fever (57.5%) and sore throat (55%). Laboratory ndings: ESR, TSH,T4 and WBC with average of 67.32, 0.283, 15.368 and 12.456, respectively. CRP positive in 80% of patients who underwent this test. 80 percent of the patients responded to the treatment. The recurrence rate was estimated 42% and 11% for those who received NSAIDs and Prednisolone, respectively Conclusion: In this study, SAT was most prevalent in women in their fourth decade of life. Clinical symptoms were consistent with most studies in terms of prevalence and incidence. There was no signicant association between the age and sex of the patients and their clinical manifestations and laboratory results from laboratory considerations, low concentrations of TSH, high levels of ESR and positive CRP were found to be helpful in diagnosis. Prednisolone proved to be more effective in treating SAT.

Laboratory ndings: ESR, TSH,T4 and WBC with average of 67.32, 0.283, 15.368 and 12.456, respectively. CRP positive in 80% of patients who underwent this test. 80 percent of the patients responded to the treatment. The recurrence rate was estimated 42% and 11% for those who received NSAIDs and Prednisolone, respectively Conclusion: In this study, SAT was most prevalent in women in their fourth decade of life. Clinical symptoms were consistent with most studies in terms of prevalence and incidence. There was no signi cant association between the age and sex of the patients and their clinical manifestations and laboratory results from laboratory considerations, low concentrations of TSH, high levels of ESR and positive CRP were found to be helpful in diagnosis. Prednisolone proved to be more effective in treating SAT.

Background:
Subacute thyroiditis (SAT) also known as Quervain's thyroiditis, the most common cause of pain of the thyroid gland is mostly caused by the viral infections of the upper respiratory tract. SAT, mostly occurring during the 4th and 5th decades of life is more frequent in females, with a female-to-male ratio of 3-5:1(1 & 2 ) Symptoms mostly include neck pain, malaise, low grade fever and myalgia (3.). Diagnosis of subacute thyroiditis is made by combining the patients' clinical ndings with the laboratory tests results such as Thyroid function test, WBC, ESR and CRP (4). SAT initially manifests with Hyperthyroidism due to the cell destruction and the release of pre-made enzymes followed by hypothyroidism as a result of total depletion of the enzymes (5,6,7 ). Treatment includes Non-Steroidal Antiin ammatory Drugs for mild to moderate SAT and corticosteroids for the severe cases (8,9,10). This cross-sectional study aimed to determine the frequency of the clinical and laboratory ndings with regards to the gender and age, the rate of improvement as well as recurrence in patients with subacute thyroiditis in Bushehr City in Iran, year of 2018. Based on the results, the most common symptoms were fever (57.5%), and neck pain (55%) at the time of consultation. Other symptoms such as malaise, otalgia, weakness and perspiration were also seen.
Otalgia (27%) and perspiration (10%) had the lowest frequencies among the reported symptoms. Figure 1 Table 2 shows the relationship between the clinical symptoms of the patients with subactue thyroiditis and the age of these patients As shown in Table 2, there was no signi cant relationship between the age of the patients and their symptoms We also investigated the association between the patients' gender and their symptoms and the results showed no signi cant relationship between these two, as seen in Table 3. with that nding in the rst phase of the disease. This was accompanied with mild leukocytosis and also mild increase in erythrocyte sedimentation rate, expected on the onset of the disease.
As seen in the Table 4, there was no signi cant relationship between the age of the patients and their symptoms Subacute thyroiditis has been reported more frequently in women in the previous studies (11,12,13)). The majority of the patients in the current study were female (67.5%) and the ratio of femal to male was approximately 2.07: 1 Subacute thyroiditis followed by a viral infection may result in misdiagnosis of viral pharyngitis (14).
Sore throat (76.8%) has also been reported as the most common symptom (15). Fever (57.5%) and sore throat (55%) as the most common symptoms shown in our results supported their report. However, in some studies, fever has been reported in minority of patients (16) In addition to fever, otalgia and transient hematuria were found in patients with subacute thyroiditis (17)Our patients showed no signs and symptoms of hematuria and only 27.5% of them complained of otalgia.
Different reports has been done on sings of thyrotoxicity in more than 60% of their population (16,18).
On the other hand we witnessed changes in the thyroid function test of all of our patients. This was in accordance with the ndings of these investigations. Hyperthyroidism in this phase can be explained by the release of pre-made thyroid hormones in the serum of the patients. This differences can be due to the time of consultation, as some patients may show normal ndings. Mild increase in WBC and ESR indicates the benign Leukosytosis and in ammatory process occurring in SAT. We also evaluated the association of the patients' age with their laboratories ndings. There were no evident signi cant association between these two.
Our results showed the superiority of prednisolone as the choice of treatment for subacute thyroiditis. 80 percent of the patients responded to the treatment. The recurrence rate was estimated 42% and 11% for those who received NSAIDs and Prednisolone, respectively. Similarly, based on comparison studies done in china (2013-2016), and also in Japan (2017), prednisolone manifested higher e cacy in treating patients with subacute thyroiditis (19,20). However, some investigations have reported a 20% rate of recurrence in their patients treated with Prednisolone in 2013 in Japan (21).

Conclusions:
As shown in the results, most of the patients with subacute thyroiditis are in the 4th decade of their lives and in accordance with resent studies, SAT is more frequent if females. The most common symptoms are fever, sore throat and malaise, therefore SAT should be taken into consideration as a differential diagnosis in the presence of these symptoms. The change of thyroid function test in favor of hyperthyroidity are expected which indicated the thyroxicicity phase of SAT and should be differentiated from other causes of thyroid disease.
There was no signi cant association between the patients' age and gender and their clinical symptoms and also no evident relationship between their age and paraclinical ndings. Lastly, the response to treatment is considerable with prednisolone and NSAIDS, however prednisolone proved to be superior in the treatment of subacute thyroiditis.