Mr. X, a 51-year-old gentleman, who is a known case of Diabetes mellitus, systemic hypertension and dyslipidemia on regular treatment and follow up, presented with history of High-grade fever with chills for 7 days, along with minimal flu-like symptoms. He had no history of significant weight loss, night sweats, respiratory, urinary or gastrointestinal symptoms. No history of any recent travel. He denied any livestock exposure or sick contacts. He received a course of oral antibiotic cefuroxime in an OPD basis. Despite which the fever failed to resolve; hence the patient was admitted for further evaluation.
Conscious, oriented, febrile, moderately built and nourished. No pallor, no icterus, no cyanosis, no clubbing, no generalized lymphadenopathy, no pedal edema. There was no hepatosplenomegaly, and the oropharyngeal exam was normal. CVS- S1 S2 +; RS- BAE+ No added sounds; P/A- soft, non-tender, BS+; CNS- NFND.
VITALS: BP- 126/84 mmHg; PR-110/min; RR- 20/min; SpO2- 98% in RA; Temp- 100.8 F
INITIAL INVESTIGATIONS: HB-11.9; Hct-34.2; WBC-14720; Plt-2.38L;CRP-76; RFT and LFT within normal limits, Urine routine normal. TSH levels were very low.
CT CHEST and CT ABDOMEN: No significant abnormality, no features suggestive of infective etiology.
During the hospital stay, he only had a low-grade fever, with a pattern of evening rise of temperature. Blood culture and urine cultures were done but showed no growth. No evidence of endocarditis on Echocardiography. He was clinically treated as enteric fever with ceftriaxone during the admission period. Patient had a resolution of fever after one week of admission. He was discharged fever free.
Following a short fever free period of two days, he again presented with fever spikes to the OPD, not responding to treatment. He was put on Meropenem and Azithromycin to cover atypical organisms, but fever failed to improve
A whole-body PET CT scan was done to look for the source of infection, which was suggestive of an active infective/inflammatory process in the thyroid gland- features suggestive of thyroiditis. On further examination of the patient, a small goiter was palpable but only minimal tenderness was present.
His thyroid function showed TSH-7.84; Free T3-66.3; Free T4-3.93. A thyroid antibody (anti thyroid peroxidase antibody) screen was done and their levels were markedly elevated. An ultrasound of the thyroid showed that both lobes of the gland, with the isthmus, were enlarged with heterogeneous texture of the thyroid gland.
The patient was treated with Carbimazole 10 mg twice a day with propranolol for 2 weeks. Following which he was treated with 25 mg once a day for 1 week, followed by 20 mg per day and steroid was gradually tapered. Following this his pain and fever subsided.
Fever of unknown origin (FUO) is one of the most difficult medical problems encountered in medicine. Three criteria define this condition: (i) an illness lasting more than 3 weeks, (ii) fever >101°F on several occasions, and (iii) no diagnosis established after 1 week of investigations. Infections, malignancies and autoimmune disorders are the most common causes of FUO, although the etiology remains idiopathic in many cases. Endocrine causes of FUO are rare. Fever is common in a few endocrine disorders (e.g. Subacute thyroiditis, thyroid storm, adrenal crisis, and pheochromocytoma).
Subacute thyroiditis, while classic symptoms include neck pain, tenderness, and sometimes fever, subacute thyroiditis can, in some cases, present as FUO, especially if the neck pain is absent or subtle.
Histopathology of subacute thyroiditis (A) Thyroid tissue infiltration with neutrophils, lymphocytes, histiocytes and giant cells, masses of colloid, and necrosis of thyroid follicular cells as pointed by the black arrow; (B) on higher magnification showing numerous foreign body giant cells as pointed by the black arrow
There are no universal guidelines on the management of SAT. Usually, nonsteroidal anti-inflammatory agents (NSAIDS) are used as first-line management for pain. If the symptoms persist despite the use of NSAIDs or if there are severe symptoms, corticosteroids are used. Acute suppurative thyroiditis should be excluded before starting steroids. Therapy with corticosteroids generally provides rapid relief of symptoms within 24–48 hours.
1) https://pubmed.ncbi.nlm.nih.gov/1763224/
2) Weiss BM, Hepburn MJ, Mong DP. Subacute thyroiditis manifesting as fever of unknown origin. South Med J. 2000 Sep;93(9):926-9. PMID: 11005359.
3) https://pmc.ncbi.nlm.nih.gov/articles/ PMC10643017/#:~:text=Subacute %20thyroiditis%20(SAT) %20is%20a, specific %20left%2 Dsided%20neck%20pain.
4) https://pmc.ncbi.nlm.nih.gov/articles/ PMC6297584/
5) HARRISON’S TEXTBOOK OF INTERNAL MEDICINE 21ST EDITION
Dr. S. Sivaram Kannan Clinical Lead and Chief Consultant Physician Kauvery Hospital, Chennai
Dr. N. Roseline Sweety Jebapriya DNB General Medicine 1st year Resident Kauvery Hospital, Chennai
