Clinical utility of 18 Fluorodeoxyglucose (FDG)-PET/CT scans in patients with suspect ocular tuberculosis
A 58-year-old female patient presented with a history of persistent pain, redness accompanied by bilateral visual loss since the past one and one half years. Previous significant medical history included surgery for pituitary macroadenoma 26 years ago. Previous investigations included a mantoux test that had been reported as “positive” but the patient had declined to start antitubercular therapy.\nHer best corrected visual acuity was counting fingers at 6/12 in the right eye and 6/36 in her left eye. Slit lamp examination of her right eye revealed multiple fresh nongranulomatous keratic precipitates with a severe anterior chamber reaction (cells 2+, flare 2+). The anterior chamber had a normal depth but there were extensive posterior synechiae with a complicated cataract. similar findings were seen in the left eye.\nThe disc and the retina were normal in either eye. The intraocular pressure was 10 and 12 mmHg.\nSystemic evaluation revealed palpable cervical and axillary lymph nodes. A repeat mantoux test showed an induration of 22× ×25 mm. Her total and differential blood counts, tests for serum creatinine, serum calcium, serum angiotensin converting enzyme and serological tests to detect human immunodeficiency virus (HIV) infection were normal.\nA 18 FDG-PET scan revealed several metabolically active, bilateral level 5 lymph nodes in the neck, the largest on the left side measuring 1.6 ×1.8 cm with SUV max 5.5 and the largest on the right measuring 1.4 cm with a SUV max 5.2. The lungs and mediastinum were clear. Several metabolically inactive nodes were seen bilaterally in the axilla.\nShe underwent an ultrasound guided biopsy of a right posterior cervical lymph node suggested by the PET/CT scan. The microscopic examination revealed several medium sized epithelioid granulomas with occasional central necrosis suggestive of tuberculosis.\nShe was started on standard four drug therapy along with topical and periocular corticosteroids. Two months later there was a marked reduction of clinical anterior chamber activity.