Background and purpose: Fever of unknown origin is a frequent disorder in pediatric age.The aim of this study was to determine the causes of Fever of unknown origin and; to evaluate diagnostic tests.Materials and Methods: Cases were identified by reviewing the medical records of all patients with FUO which were admitted in three medical centers in Tehran during March 1994- 99.Results: Infection was the most frequent cause of Fever of unknown origin. Neoplastic disorders occurred in children older than one year. Abdominal ultrasonography was performed in 71 patients (61%) and was helpful in diagnosis of 15% of the cases.Conclusion: The improvement in diagnostic procedures has conditioned a change of spectrum of the diseases. In most cases the etiological diagnosis can be made with a limited number of laboratory and/ or imaging investigations bases upon a careful clinical evaluation.

Primary cardiac tumors are rare and occur in 1 per 1000 to 1 per 100000 individual in unselected autopsy series at tertiary heart centers .Approximately 75% of cardiac tumors are histologically benign and malignanat cardiac tumors are reminder of them. We describe a rare form of complicated benign cardiac mass in 46 years old man.

A 52-year-old man referred with Fever for 40 days. On examination, he had no abnormal finding except for a slightly enlarged thyroid gland. Thyroid function tests demonstrated a thyrotoxic state with reduced uptake of radioiodine (RAI-U) compatible with subacute thyroiditis (SAT). He had leukocytosis, raised ESR and a painless nontender thyroid gland.

Patients with subacute or glaucomatous thyroiditis usually come to the physician with Fever, Anterior cervical pain and they show tenderness in palpation during physical examination. Occasionally, clinical presentation is atypical and it is possible that it is taken as systemic or malignant diseases wrongfully.Here, we reported a 27 years old girl with FUO that the final diagnosis was subacute thyroiditis. The diagnosis was done through abnormal thyroid function tests, thyroid scan, suppressed radio - iodine uptake and excellent response to Aspirin.

Background: Fever of unknown origin (FUO) is a perplexing medical problem. The causes for FUO are more than 200 diseases. The aim of the study was to present human clinical cases of Coxiella burnetii infection debuting as FUO. Methods: The following methods were conducted in the study: literature search, laboratory, imaging, and statistical methods. Criteria of Durack and Street were applied for FUO definition. For the etiological diagnosis indirect immunoenzyme assay (ELISA) for antibodies detection against Coxiella burnetii was used (cut-off = 0. 481– 0. 519). Results: From 2008 until 2015, nine patients with FUO caused by C. burnetii were hospitalized at the Military Medical Academy of Sofia. Male gender was predominant (male/female – 77. 8% /22. 2%), mean age was 48. 78± 14. 52 years (range: 26– 67), hospital stay was 9. 78± 2. 95 days (range: 5– 15), Fever duration was 54. 33± 56. 23 days (range: 21– 180). Laboratory investigations estimated the elevation of erythrocyte sedimentation rate 49. 11± 31. 74mm/h (95%CI = 13. 09– 111. 31), C-reactive protein 37. 68± 37. 62mg/L (95% CI = 36. 07– 111. 42) and fibrinogen 5. 69± 1. 59g/L (95% CI=2. 57– 8. 81). The mean values of liver enzymes were in reference range. Among imaging tests, abdominal ultrasound and X-ray demonstrated 33. 3% contribution to the final diagnosis. Transthoracic echocardiography found 22. 2% contribution. Serological methods presented 100% contribution. Conclusion: C. burnetii infection was accepted as a final diagnosis among 9 patients with FUO based on the integrated information from the applied methods. Active search and establishment of this pathogen among FUO should lead to avoiding potential complications and consequences in case of untreated patients infected with C. burnetii.

Background: The etiology of Fever of unknown origin (FUO) may differ from different countries. This study was conducted to evaluate the etiology of FUO in patients attending SKIMS, a tertiary care teaching hospital, at Srinagar, Kashmir, India.Methods: From July 2010 to September 2012, this study was done to examine the profile of patients with FUO. The classic FUO was defined as three outpatient visits or three days in the hospital without elucidation of cause of Fever. Infectious agents, collagen vascular diseases and hematological malignancies as well as other etiologies were investigated when appropriate. The data were collected and analyzed.Results: A total of 91 cases (62 males and 29 females), with age ranging from 16 to 80 years were investigated. The mean duration of Fever before hospitalization was 26±4 days. The etiology of FUO was delineated in (66%) of cases, whereas, (25%) remained undiagnosed. Most common group of FUO was that of infectious diseases (44%) followed by collagen vascular diseases and malignancies (12 % each). Amongst the infection group, brucellosis and salmonellosis comprised the majority of cases (25% each).Conclusion: Infections are the most common cause of FUO followed by collagen vascular diseases in our region.

Background: Fever of unknown origin (FUO) is defined as temperatures of >38/3°c and duration of Fever of > 3 weeks with failure to reach a diagnosis despite 1 week of inpatient investigation. Case report: A 20 year-old man presented with FUO and skin rash from 3 weeks ago. Physical examination revealed cervical adenopathy, decreased sound of heart, splenomegaly with generalized maculopapular rash. Echocardiography study revealed pericarditis. In abdominal sonography, splenomegaly and in laboratory test leukocytosis with CRP3+, increased liver function test, increased ferritin and other serologic study was normal. In this case with above findings, Adult onset still disease was diagnosed.Conclusion: Although rare, Adult onset still disease can manifest as Fever of unknown origin and if diagnosed rapidly, it would be possible to prevent joint deformity.