A 55-year-old man presented to the emergency room with a three week history of throbbing and persistent right occipital headaches radiating to his frontal region. The headaches were not associated with any aura, photophobia, nausea or vomiting. The patient also had recurrent complaints of fevers and nocturnal diaphoresis. After presenting to a walk-in clinic and diagnosed with a presumptive viral infection. No antibiotic medication was prescribed.
His past medical history included smoking and gastro-esophageal reflux disease. There was no history of any prior headaches, tuberculosis or exposure, positive tubercullin skin tests, syphilis, gonorrhea, chlamydia, human immunodeficiency virus (HIV), malignancies, hepatitis, recent surgeries, workplace exposure or recent travel.
His physical examination showed a healthy appearing man, hemodynamically stable with a high grade fever of 39.5  C. His neurological exam, cardiac exam, respiratory exam and abdominal exam were all normal.
Investigations revealed white blood cell count of 13.1 x 109/L (with 87% polymorphonuclear cells, 4% monocytes, and 9% lymphocytes), hemoglobin 136 g/L, platelet count 367 x 109/L and a normal serum chemistry panel including transaminases. His absolute CD4 count was 449 x 10 (6)/L and his HIV serology was non-reactive. Chest radiograph however revealed wedge-shaped nodular opacity measuring 3.1 x 3.25 cm in the left upper lobe adjacent to the pleura (Fig. 1). A lumbar puncture showed 3065 x 106/L of white blood cells (normal 0-5 x 106/L), 1.1 mmol/L of glucose (normal 2.2-3.9 mmol/L) and 1.90 g/L of total protein (normal 0.12-0.6 mmol/L). Preliminary CSF cultures did not grow any organism. The patient was then started on ceftriaxone, vancomycin and ampicillin.
A computed tomography (CT) of the chest and abdomen with intravenous contrast revealed a large spiculated 2.8 x 4.5 x 3.7 cm subpleural mass in the lateral aspect of the left upper lung lobe and a smaller spiculated and eccentrically cavitary 1.4 cm nodule in the posterior and subpleural aspect of the left lower lobe (Fig. 2). There was no hilar or mediastinal lymphadenopathy. Initial computed tomography of the head was normal but a follow up Multisequence Multiplanar Unenhanced Magnetic Resonance Image (MRI) of the head with gadolinium showed a T2 hypointense lesion involving the left head of the caudate nucleus with perifocal edema suspicious for a fungal abscess (Fig. 3).
The patient's headaches and fever continued to persist so a computed tomographic guided biopsy of the large spiculated subpleural mass of the left upper lobe was performed as well as repeat lumbar puncture. Both the lung tissue biopsy and the repeated CSF fluid cultures grew beaded branching gram positive bacill. Molecular studies using the Multi-Locus sequence analysis (MLSA) identified the species as Nocarida farcinica. Further susceptibility testing showed the organism was susceptible to amoxicillin/clavulanic acid, imipenem, linezolid, moxifloxacin and trimethoprim/sulfamethoxazole (TMP-SMX) but resistant to ceftriaxone (Fig. 4).
Ceftriaxone, vancomycin and ampicillin were discontinued and the patient was treated initially with imipenem for six weeks followed by TMP-SMX for one year.