Rare Manifestation of Neurobrucellosis as Disseminated Craniospinal Subdural Abscess: The Diagnostic Dilemma and Management

Sir, Brucellosis is a multisystem disease caused by a gram-negative coccobacillus of the genus Brucella. It is transmitted by either direct transmission through cuts/abrasions, inhalation of aerosols, consumption of raw meat, or unpasteurized milk of an infected animal.[1] The most common causative species are Brucella melitensis and Brucella abortus.[1] Neurobrucellosis is a less common manifestation (0.5%–25% cases)[1] mostly presents as meningoencephalitis, and rarely with myeloradiculopathy, peripheral neuritis, Guillain–Barre syndrome, spondylodiscitis, or parenchymal abscess.[2] Only four such cases of simultaneously occurring cranial and spinal subdural abscess are reported.[3–6] These patients present with sudden onset and rapidly deteriorating neurological deficits. Such cases require urgent surgical evacuation and prolonged antibiotic treatment based on culture reports.[3] Here, we present an atypical case of concurrent craniospinal subdural abscess with rapidly progressive neurodeficits caused by Brucella. We also highlight the diagnostic dilemma and the importance of clinical (especially occupational) history in the current case along with a short review of previously reported similar cases. A 38-year-old abattoir worker presented with complaints of progressive suboccipital and neck pain of 6 months with intermittent fever. He developed acute onset quadriparesis (lower limbs more than upper limbs) with the bladder retention 5 days before presentation. On examination, he had a fever with neck stiffness; his uvula was deviated to right and a poor gag reflex. Power in his upper limbs was MRC grade 3/5, and 0 in the lower limbs, with spasticity and hyperreflexia. There was a graded sensory loss below D4. His serum showed neutrophils predominant leucocytosis (14,000/mm3) and was negative for HIV. The magnetic resonance imaging (MRI) brain and spine showed intradural abscess involving retro-clival, cervical (C3-C5), and dorsal (D2 level) spine with T2 hyperintense cord changes and mass effect on the cervicomedullary junction and cervical cord [Figure 1a and c].Figure 1: The contrast MRI of the patient. (a) Axial section at the C1 level shows loculated, peripherally enhancing lesion anteriorly which is compressing and pushing the cord posteriorly. (b) Post-op axial image following laminectomy showing good evacuation of the abscess and decompression of the cord. (c) Sagittal contrast images showing multiple abscess pockets starting from retro-clival region, compressing cervical and dorsal spine. (d) Post-op image after abscess evacuation, the pressure on the cord is relievedEmpirical IV antibiotics (as per the hospital protocol) were started and an informed consent was taken for urgent surgical abscess evacuation. With the patient in prone position a midline suboccipital and cervical incisions were made. A suboccipital craniotomy and “Y” shaped durotomy was done for the evacuation of the retroclival/premedullary abscess. Skip C3-C4 partial and D2 laminectomies with linear durotomies were done with evacuation of a thick, greenish abscess and debridement of the granulation tissue. Intradural saline lavage was done before dural closure. The wounds were closed with a vacuum assist drain. Following surgery, his lower limbs power improved to 3/5 but the LCN weakness persisted. Ryle’s tube feeds, limb physiotherapy, and Deep vein thrombosis (DVT) prophylaxis were started from POD-1. There was no cerebrospinal fluid (CSF) leak from the wound site, and the drain removed on POD-2. The Gram and ZN stain of the pus, as well as the bacterial and AFB cultures were negative. The histopathology of the granulation tissue showed dense lymphoplasmacytic infiltrate with occasional histiocytes, eosinophils, and polymorphs. Many Russel bodies with areas of focal necrosis were seen. On immunohistochemistry, the inflammatory infiltrate had CD138+ plasma cells, CD20+ B, and CD3+ T lymphocytes [Figure 2]. The pathologists advised a differential diagnosis of Tubercular versus Brucella abscess. CSF cartridge-based nucleic acid amplification test (CB-NAAT) was negative for tuberculosis. The titers for anti-Brucella abortus (ABA) by standard tube agglutination test (STAT) in serum and CSF were 1:320 and 1:640, respectively [Figure 3a and b] and also by Indirect ELISA. The patient was started with oral doxycycline 100 mg BD, rifampicin 600 mg OD, and IV ceftriaxone 2 g BD. At 12-week follow-up, the patient’s motor function improved (4/5), and his swallow and gag reflexes were better. Follow-up MRI showed resolution of the abscess, but a persisting diffuse lepto-meningeal enhancement [Figure 1b and d]. The cord signal changes decreased when compared to the pre-op scan. There was a decrease in the serum antibody titers from 1:320 to 1:160 by STAT [Figure 3c].Figure 2: Inflammatory infiltrate composed of polymorphs, lymphocytes, plasma cells, and histiocytes (a, H and E, ×40; b, H and E, ×200). Special stains for acid-fast bacilli (c, Ziehl Neelsen, ×100) and fungi (d, periodic acid Schiff, ×100 and e, Gomori methenamine silver, ×100) were negative. H and E: hematoxylin and eosinFigure 3: Standard agglutination tests. The last tube in all images is the negative control. (a) Serum samples showing agglutination up to titer 1:320. (b) Serum follow-up samples— agglutination up to 1:160. (c) CSF sample—agglutination up to titer 1:640Subdural abscess or empyema is a neurosurgical emergency. Brucella causing a cranial or spinal abscess is very rare and only few cases of spinal subdural abscess are reported.[1,2] The most common species involved in transmission are Brucella melitensis and Brucella abortus.[7] Recent animal studies show that anti-GM1 ganglioside antibodies induced by surface antigens of B. melitensis can cause neuronal damage. Any untreated subdural abscess can subsequently spread along the CSF pathways without barriers causing a disseminated disease.[2] The cord can undergo ischemic necrosis and demyelination, resulting in higher residual morbidity and mortality. The diagnosis of neurobrucellosis is one of exclusions, where clinical history (occupational exposure) is very important. Imaging features of neurobrucellosis are frequently nonspecific, with MRI showing features of basal meningitis, demyelination, rarely parenchymal or subdural abscess with ring enhancement. Central nervous system tuberculosis is an important differential diagnosis for neurobrucellosis.[8] CSF examination shows pleocytosis with hypoglycorrhachia, while cultures are usually sterile. The presence of infection is confirmed with the detection of ABAs in serum and/or CSF.[1,2] The histopathology of the abscess wall shows a picture of chronic granulomatous inflammation compared to tubercular abscess or tuberculoma.[2] To the best of our knowledge, this is the only reported case of neurobrucellosis presenting with simultaneous infratentorial and spinal subdural abscess. Only four cases of simultaneous cranial and spinal abscess are reported previously [Table 1].[3–6]Table 1: Previously reported cases of simultaneous cranial and spinal abscess. Clinical and treatment profile of the patients described hereIV antibiotics and steroids with urgent surgical evacuation usually manage a multi-site cranial and spinal abscess.[3,9] As in our case, there were multiple levels of loculated pus pockets causing neural compression, so different levels of exposure, and decompression was done. The patient’s myelopathic and radicular symptoms improved following surgery. WHO guidelines recommend prolonged antibiotics therapy (minimum 6–8 weeks) with ceftriaxone based combination therapy, of doxycycline and rifampicin.[10] As seen in our case, there was a clinical improvement with resolution of the abscess on MRI and 8 weeks of iv therapy. However, a diffuse meningeal enhancement persisted, suggestive of indolent meningeal inflammation, which requires prolonged antibiotics. Fall in ABAs titer after antibiotics also suggest disease response. Neurobrucellosis has a varied prognosis with self-limiting meningitis, carrying a good prognosis, while subdural empyema lies on the other extreme with higher morbidity and functional dependence. Atypical clinical and radiological presentation of neurobrucellosis can cause a diagnostic dilemma. This is the first report of craniospinal empyema caused by Brucella. A negative culture report delayed the identification of the organism in our case; however, clinical history (occupational exposure) and the histopathology of the granulation tissue prompted us to look for Brucellosis. The serological and CSF investigations ultimately clinched the diagnosis. Prompt surgical evacuation and IV antibiotics result in good outcomes. Consent The patient’s kin signed an informed consent to treatment which included a consent to use anonymized data for scientific purposes. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.