Forty-nine children (23 males) were included in the study with a mean age of 8 years (range 11 mo - 17 y). The median (range) duration of fever prior to presentation 14 (8-60)day. A diagnosis could be established in 43 patients; in 27 the diagnosis was ‘confirmed’ and in 16 it was ‘probable’. Infections were diagnosedin 34 (79%) patients, while 6 (14%) had collagen vascular diseases and 3 had other causes.

The commonest infection was tuberculosis (TB) accounting for 12 cases (Pulmonary TB 6; lymph node TB 4; one each of disseminated and bone TB) Contrast enhanced computed tomography (CECT) emerged as an important diagnostic investigation, picking up findings suggestive of TB in 6 patients who had normal X -rays and ultrasoundscans. The diagnosis was bacteriologically confirmed in six out of 12 TB cases (cultures in 5 and Xpert MTB/Rif in 6). Three cases were rifampicin susceptible while two isolates were multi-drug resistant, and one isolate was extensively drug-resistant. The other infectious causes were viral infections in 8 (18%) (Epstein Barr Virus infection in 2, probable viral infections 6), enteric fever in 7 (16%), bacterial sinusitis in 4 (9%), and rickettsial fever, S. aureus osteomyelitis and atypical pneumonia in oneeach. The collagen vascular disease included systemic onset juvenile rheumatoid arthritis in 2, Kawasaki disease in 2, and reactive arthritis and dermatomyositis in one each. The miscellaneous group included erythema nodosum in one and drug-related hypersensitivity syndrome in two patients. In six cases where the diagnosis could not be established, fever resolved in 3 cases, continued in 2, and 1 patient was lost to follow up. At the end of the study 43 patients were free of fever; there was no mortality.

Tuberculosis emerged as the commonest cause of FUO in our study; in patients presenting with fever lasting for more than 2 weeks half the etiology was TB. This is in agreement with adult studies on FUO from India [2,3]. An interesting finding of our study was bacterial sinusitis as an etiology of FUO in the absence of prominent upper respiratory signs; diagnosis was established by a CT of paranasal sinus in children with FUO and high leukocyte count with no other septic focus.

The study results may not be generalizable as regional infections influence etiology [4]. Asthe study was conducted at a tertiary care center, infections such as malaria, urinary tract infections did not figure in the etiology as they were diagnosed and treated prior to referral. The high prevalence of drug resistance in TB is again possibly due to referral bias. The absence of malignancy as cause of FUO is probably due to the small study size.

The study suggestsCECT as an important diagnostic investigation in patients with FUO. The high prevalence of drug-resistant TB in the study emphasizes the need for establishing a bacteriologic diagnosis of TB and avoiding empirical therapy.

Funding: None; Competing interest: None

1. Palazzi DL. Fever without source and fever of unknown origin. In Cherry JD, Harrison GJ, Kaplan AL, Steinbach WJ, Hotez PJ, editors. Textbook of Pediatric Infectious Diseases, 7th ed. Philadelphia: Elsevier Saunders; 2014.p.837-8.

2. Kejariwal D, Sarkar N, Chakraborti SK, Agarwal V, Roy S. Pyrexia of unknown origin: a prospective study of 100 cases. J Postgrad Med. 2001;47:104.-7.

3. Bandyopadhyay D, Bandyopadhyay R, Paul R, Roy D. Etiological study of fever of unknown origin in patients admitted to medicine ward of a teaching hospital of eastern India. J Glob Infect Dis. 2011;3:329-33.

4. Joshi N, Rajeshwari K, Dubey AP, Singh T, Kaur R. Clinical spectrum of fever of unknown origin among Indian children. Ann Trop Paediatr. 2008;28:261-6.