Jacopo Monticelli1, Roberto Luzzati1, Cristina Maurel1, Chiara Rosin1, Romina Valentinotti1 and Claudio Farina2
1 Unit of Infectious Diseases, University Hospital, Trieste, Italy.
2 Microbiology and Virology Institute, AO "Papa Giovanni XXIII", Bergamo, Italy.
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We report the first case of multiple brain abscesses caused by Nocardia paucivorans in a patient suffering from multiple myeloma on treatment with lenalidomide and dexamethasone. N. paucivorans is a recently described species of the genus Nocardia, which is supposed to have a heightened neurotropism in cases of disseminated infection. Although nocardiosis itself is an uncommon infectious complication in multiple myeloma so far, nocardial brain abscess should be added to the spectrum of adverse effects due to this novel chemotherapy regimen.
A 70-year-old male was transferred to our unit from the intensive
care unit of a nearby hospital. He had had sudden onset
clonic seizures involving the right hemisoma and the assessment of
multiple brain abscesses by computerized tomography (CT) scan. The
patient was receiving empirical treatment with metronidazole and
cefotaxime. His past medical history included a 2-year-history of IgA
myeloma (International Staging System – II). The patient was initially
treated with melphalan plus prednisone plus bortezomib (4 cycles)
according to MPV protocol. Then, he started treatment with lenalidomide
and dexamethasone having completed eleven cycles of such regimen with
partial response. During the chemotherapy regimen the patient did not
receive a trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis and, at
time of admission, we discontinued the chemotherapy regimen for
myeloma. The patient suffered from a 2-month history of subcutaneous
abscess of unknown origin on the left shoulder. The lesion was drained,
and the microbiological analysis was not conclusive because of
mixed bacterial flora. The patient was living in a small rural hamlet.
He was a construction worker, but he retired 10 years before the
present hospital admission.
At hospital presentation, body temperature was 36.5 °C, heart rate was 92/min, blood pressure was 150/90 mmHg and Glasgow Coma Scale was 15/15. The patient was alert, oriented and no abnormal physical findings were shown, except for a painful hypoesthesia in the lateral and anterior sides of the left thigh, in the lateral side of the left leg and, on the dorsal side of the left foot. The subcutaneous abscess on the left shoulder completely resolved with no signs of local inflammation. Laboratory showed the following abnormalities: serum C-reactive protein 96.19 nmol/L (normal values inferior to 71.43 nmol/L), hemoglobin 90 g/L, white blood cells 3.9 x 109/L (51% neutrophil granulocytes). In addition, the analysis of peripheral blood lymphocytes subsets showed CD3+ 742 cells/µL, CD3+CD4+ 420 cells/µL (47%), CD3+CD8+ 241 cells/µL (27%), CD4+/CD8+ ratio 1.70, CD19+ 72 cells/µL. Serum protein electrophoresis showed a relative hypoalbuminemia (55.4%) according to the known monoclonal gammopathy (serum IgA 4490 mg/L, monoclonal component 3 g/L). The chest X-ray revealed a lower right lobe infiltrate associated with bilateral pleural effusion. A brain CT scan (Figure 1) with contrast medium showed 6 focal ring-enhancing lesions of which the largest one had a maximum diameter of 16 mm (left occipital lobe). All the lesions had a minimal perilesional oedema. The right frontal lesions led to a mass effect on the right lateral ventricle. At that time, the patient underwent CT-guided brain biopsy of a parietal lesion. A bioptic sample revealed branching Gram positive nocardioform rods. Then, cultures were incubated aerobically at 35°C for three weeks. All whitish, chalky and wet hay-smelling colonies (Figure 2) yielded on blood agar were stained by partial acid-fast method according to Kinyoun technique modified for nocardioforms (Figure 3).
|Figure 1. Axial brain CT scan post-contrast medium administration. Images obtained before therapy show two ring-enhancing lesions with abundant peripheral oedema in right parietal lobe (a) and one in left parietal lobe at the vertex (b). Images obtained after therapy (c,d) show the complete resolution of the lesions.|
|Figure 2. Whitish chalky colonies of N. paucivorans yielded on blood agar.|
|Figure 3. N. paucivorans hyphae. Staining by partial acid-fast method according to Kinyoun technique modified for nocardioforms. The vegetative hyphae are well developed with irregular branches.|
Contributions, Conflict of Interest and Ethical Statement
We would like to thank doctor Gabriele Bazzocchi, Trieste (Italy), for providing the radiological imaging.