A 53-year-old right-handed man complained of acute-onset right-sided weakness and paresthesia. He was reportedly healthy with no chronic or infectious diseases. The patient could not control the movement of his right-sided limbs very well. Loss of proprioception in the right limbs was also noted. His vital signs were stable and he had no fever. General physical examination was normal. However, neurologic examination revealed left-sided and right-sided confusion (difficulty in distinguishing the directions right and left), right-sided limb apraxia, impairment of light touch, impaired pinprick sensation and proprioception on the right side, as well as dyscalculia and dysgraphia. Muscle strength on the right side was grade 3 out of 5 on the Medical Research Council scale (indicating that active movement against gravity is possible). The initial impression was of a cerebrovascular accident because of the acute onset and focal deficits. There were no obvious risk factors for stroke, nor any symptoms or signs of increased intracranial pressure.
Hematologic investigations and chest x-ray were normal. Cranial computed tomography (CT) showed a brain mass with edema of the peripheral white matter in the left parietal lobe (Figure 1A). Magnetic resonance imaging of the brain revealed a mass in the left parietal lobe with irregular central necrosis and edema of the peripheral white matter (Figure 1B). A metastatic tumor or brain abscess was suspected. Alpha-fetoprotein, carcinoembryonic antigen, cancer antigen 15-3, prostate-specific antigen, cancer antigen 125, and carbohydrate antigen 19-9 were all within normal limits. Other laboratory examinations, including aspartate transaminase, alanine aminotransferase, gamma-glutamyl transferase, bilirubin, and alkaline phosphatase, were normal. Intravenous dexamethasone 4 mg every eight hours was prescribed in the emergency room due to the severe brain edema found on CT.
The patient's neurologic status deteriorated into right hemiplegia two days after admission. His muscle strength on the right side deteriorated from grade 3 to 0 out of 5. A subsequent cranial CT scan showed that the brain mass had increased in size, with ring-like enhancement and more severe edema of the peripheral white matter (Figure 1C). The findings favored a brain abscess rather than a metastatic lesion. Stereotactic surgery was performed to obtain a tissue diagnosis and decompression of the mass effect. During the operation, approximately 6 mL of pus was aspirated. The pathology report showed predominantly neutrophils with necrotic tissue and no caseation or granuloma tissue, which was compatible with a brain abscess (Figure 2A). Ziehl-Neelsen staining of the pus revealed that acid-fast bacilli were present (Figure 2B). Serial cultures of pus from the abscess were conducted, which showed the Mycobacterium tuberculosis complex. Microbiologic analysis demonstrated sensitivity to ethambutol, pyrazinamide, rifampin, and isoniazid. Human immunodeficiency virus serology was negative.
Pulmonary tuberculosis in this patient was unlikely due to the absence of cough or other respiratory symptoms during his clinical course. The initial and follow-up chest x-ray at 12 months were unremarkable, so we did not perform a CT chest after consultation with a chest specialist. Instead of performing a conventional sputum culture, we arranged a sputum polymerase chain reaction examination which was negative.
The criteria for diagnosis of a tuberculous brain abscess include presence of a brain abscess and acid-fast bacilli in pus and absence of caseation and formation of granuloma. This case met all these criteria, so was diagnosed as a primary tuberculous brain abscess. The patient received antituberculous chemotherapy consisting of oral ethambutol 1200 mg/day, pyrazinamide 1500 mg/day, rifampin 600 mg/day, and isoniazid 300 mg/day. His muscle strength on the right side gradually recovered (from grade 3 to 0 out of 5) after aspiration of the abscess and antituberculous chemotherapy. Dexamethasone was continued during admission and then changed to an oral formulation after one month. Dexamethasone was suspected to be helpful for the cerebral edema causing his focal neurologic signs.
The patient was transferred to our physical medicine and rehabilitation ward for further rehabilitation. Initially, upon arrival for rehabilitation, he could only walk with the use of a walker. Severe left-right confusion, right-sided apraxia, dyscalculia, and dysgraphia were noted. He needed moderate assistance in most activities of daily living. His functional independence measure score was 65. The patient was diagnosed as having a tuberculous brain abscess in the left parietal lobe with Gerstmann's syndrome and right-sided apraxia. Physical therapy, occupational therapy, and speech therapy were arranged. In addition, to regain somatic sensation and motor control of the right side of his body, training was focused on the right-left confusion and apraxia. The sensory rehabilitation program addressed various perception deficits and impairment of hand-eye coordination. The motor training program included limb and trunk motion, posture, and balance training, which finally progressed to ambulation training. Speech therapy included writing and cognitive training. After antituberculous chemotherapy and rehabilitation, the patient was able to walk without assistance and had almost recovered normalcy at four months. His left-right confusion, right-sided apraxia, dyscalculia, and dysgraphia improved significantly.
He continued to receive antituberculous chemotherapy for a total of 18 months. We repeated the chest x-ray several times over the course of 12 months and all were normal. Subsequent magnetic resonance imaging showed that the previous brain abscess had almost completely resolved.