Case of Subacute Thyroiditis Presenting as the Cause of Pyrexia of Unknown Origin

Abstract

Pyrexia of unknown origin (PUO) is not infrequently a diagnostic dilemma for clinicians. Endocrine causes of PUO are rare. The endocrine disorder likely to present as PUO is subacute thyroiditis. Subacute thyroiditis usually occurs in middle-aged women as viral prodrome, classic symptoms of thyrotoxicosis, and an elevated erythrocyte sedimentation rate. The patient may have abrupt onset of fever and chills with complaints of thyroid pain, or only low-grade fever with poorly characterized anterior neck pain. We present a case of PUO in a 40-year-old male who had fever for more than two month. Despite an extensive evaluation, the patient had persistent fever and no cause was found, with the exception of subacute thyroiditis. The fever resolved from the fifth day of treatment with low-dose steroid (Prednisolone, 10mg per day). This case illustrates that subacute thyroiditis should be considered in cases of FUO. HOW TO CITE THIS ARTICLE:

Fever of Unknown Origin as a Sole Presentation of Subacute Thyroiditis in an Elderly Patient: A Case Report with Literature Review

“…There is no established guideline regarding the dose or duration of prednisone therapy; however most of the existing literature suggest a starting dose of 40 mg daily and titrating down the lowest possible dose controlling the symptoms [ 1 , 4 , 12 ]. Low dose steroids (Prednisone 10 mg daily) have also been used in many reported cases with significant improvement in symptoms [ 11 , 13 , 14 ]. Our patient responded well to prednisolone 40 mg daily.…”

Subacute Thyroiditis: An Unusual Presentation of Fever of Unknown Origin Following Upper Respiratory Tract Infection

“…Thyroid diseases are considered among the rare causes of FUO. After searching the literature, we found a number reported cases of subacute thyroiditis, mainly published after the year 2000, where patients presented with FUO [9][10][11][12][13][14][15][16][17]. Table 2 shows the main clinical and biochemical features and outcomes of the 8 cases.…”

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“…[12][13][14] Further, lower doses of 10 mg/day would be used in other reports with relieving the symptoms of the cases. 15,16 Because we can recently get the results of thyroid function immediately due to the laboratory development, the management for subacute thyroiditis would be safer and easier with less doses of steroid administration. 15,16 After the relieving condition of subacute thyroiditis, the patients seem to reveal overt or subclinical hypothyroidism in about 20 -30% of the cases.…”

“…15,16 Because we can recently get the results of thyroid function immediately due to the laboratory development, the management for subacute thyroiditis would be safer and easier with less doses of steroid administration. 15,16 After the relieving condition of subacute thyroiditis, the patients seem to reveal overt or subclinical hypothyroidism in about 20 -30% of the cases. 2,5 Those thyroid function may vary in the cases with a variety of latency period.…”