A 29-year-old man with history of unrepaired congenital heart disease was transferred to our hospital for the management of a symptomatic right parietal mass. He had been in his usual state of health until 6 days before presentation when he developed sensory loss in his left foot that persisted for 24 h. He presented to an outside emergency department where he had a normal computed tomography (CT) without contrast of the head and normal CT angiography of the chest, abdomen, and pelvis. Outpatient neurology follow-up was recommended, but his symptoms progressed rapidly during the following days to include complete left-sided body weakness, numbness, and focal convulsions of his left upper and lower extremities. On Day 5, he presented again to the outside hospital, where magnetic resonance imaging (MRI) of the head revealed a right parietal ring-enhancing lesion consistent with cerebral abscess. Antibiotics were held to increase potential yield of abscess drainage culture, and the patient was started on levetiracetam with subsequent reduction in focal convulsions. He was then transferred to our hospital for neurosurgical intervention.
The patient was originally from Pakistan and moved to the United States in 2006. At age 5, he was diagnosed with truncus arteriosus Type II, bicuspid truncal valve, and single ventricular septal defect. He was not a surgical candidate because of progression of disease and subsequently developed Eisenmenger's syndrome with pulmonary hypertension, which was managed with nocturnal oxygen (4 L/min) and sildenafil. He had no recent travel and he last travelled to Pakistan in 2007. He worked as a part-time driver for taxi and fast-food companies and was not involved in any outdoor activities. He denied any sick contacts, personal history of or known exposure to tuberculosis, or incarceration. He had a significant remote history of recurrent dental problems requiring tooth extractions and outpatient oral antibiotic courses. His last visit to the dentist was for routine cleaning one year prior. The patient lived locally with his wife and denied any use of alcohol, tobacco, or other drugs.
On arrival to the emergency department, he had a temperature of 36.7  C, heart rate of 88 beats/minute, respiratory rate of 27 breaths/minute, blood pressure of 120/69 mm Hg, and oxygen saturation of 92% on 4 L nasal cannula. Physical examination revealed a fatigued, thin, but well-nourished man in no acute distress. He was alert and oriented to time, space, and person. On neurologic examination, he had 4/5 strength and a sensory deficit to light touch of his left upper and lower extremities. Tone and reflexes were normal throughout. Head and neck exam did not reveal any sinus tenderness, signs of trauma, otorrhea, Roth spots, oropharyngeal exudate, or palpable cervical lymph nodes. He did have notably poor dentition with visible caries and gingivitis. Cardiovascular examination was remarkable for a known II/VI systolic ejection murmur at the left sternal border and a soft diastolic murmur and he did not have any jugular venous distention. Pulmonary and abdominal examinations were within normal limits. He had clubbing bilaterally but no peripheral stigmata of endocarditis. Extensive review of systems on admission was negative except for what has already been mentioned and frequent gingival bleeding with brushing.
Complete biochemistry and hematology panel on presentation disclosed preserved renal and liver function, absence of leukocytosis, normal differential cell count, increased hemoglobin level of 20.2 mg/dL, and a normal platelet count of 145,000/muL. Other work-up included a negative HIV 4th- generation Ag/Ab test, non-detectable toxoplasma IgG and IgM serum antibodies, and negative blood cultures. Chest X-ray showed a dilated cardiac silhouette and mild pulmonary congestion. A repeat MRI of the head showed a ring-enhancing 3.7 x 3 x 3 cm mass within the right parietal lobe, with perilesional vasogenic edema (Fig. 1, Fig. 2). Lumbar puncture was not attempted due to lack of signs or symptoms of meningitis and potential risk of cerebral herniation. Transthoracic and transesophageal echocardiograms did not show any valvular vegetations.
The patient underwent emergent stereotactic-guided neurosurgical drainage, which yielded 100 cc of purulent material. Postoperatively, he was started on oral trimethoprim-sulfamethoxazole 800-160 mg every 12 h, intravenous metronidazole 500 mg every 12 h, and intravenous vancomycin 1 g every 8 h. Antibiotic management was challenging because of the patient's history of anaphylaxis to penicillin. Unfortunately, the patient was not desensitized to penicillin while under clinical observation, limiting choice of antibiotics. Cultures showed growth of Streptococcus intermedius, A. meyeri, and Parvimonas micra. The first two isolated organisms were susceptible to penicillin, ceftriaxone, vancomycin, clindamycin, and erythromycin. On subsequent complete dental evaluation, the patient was found to have a molar with an abscessed root, for which he underwent extraction. Once culture results were available, trimethoprim-sulfamethoxazole was discontinued and the patient was started on oral doxycycline 100 mg twice daily to cover A. meyeri. Doxycycline was chosen based on this organism's reported antibiotic susceptibility and need for optimal central nervous system (CNS) penetration. He was discharged to an acute rehabilitation facility with oral doxycycline and intravenous vancomycin and metronidazole. Although systemic availability of metronidazole has been shown to be similar following oral and intravenous administration, intravenous administration is often recommended for the treatment of life-threatening infections, at least for initial therapy. We also opted for intravenous metronidazole over oral for ease of administration.
The patient stopped vancomycin prematurely due to reported rash in week 4 which was deemed later to be an infusion-related Red Man's syndrome. An MRI 6 weeks into his antibiotic treatment showed interval signs of improvement with no evidence of abscess but with persistent hemorrhagic fluid, consistent with postoperative state. The patient was switched to oral doxycycline and oral metronidazole, and antiepileptics were stopped after electroencephalography was negative for seizure activity. Five months after his initial presentation, the patient underwent a second follow-up MRI brain examination that showed complete resolution of hemorrhagic fluid and no evidence of residual abscess. His clinical exam revealed stable residual left leg weakness. Metronidazole was stopped, and the patient was continued on doxycycline with a plan for 6 to 12 months based on published experience.