Streptococcus intermedius as Causative Agent of Perianal Abscess and Metastatic Brain Abscess

A29-year-old male presented to our emergency department (ED) for discharge from a long-standing left perianal fistula; the wound was irrigated and the patient was discharged to take oral clarithromycin. Two days later, he returned with a one-hour history of global aphasia, right hemiplaresis and temperature of 38°C. Neuroimaging revealed a 5.3 cm left fronto-temporal abscess with surrounding edema (Fig. 1). Brain abscess (BA) was extirpated through craniotomy and the patient improved. A subsequent MRI of the pelvis documented a perianal abscess communicating with the cutaneous fistulous tract (Fig. 2); a pigtail catheter was inserted retrieving purulent material. Streptococcus intermedius was cultured from both perianal and brain abscesses.

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FIG. 1.

Magnetic resonance image of brain abscess (coronal view).

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FIG. 2.

Pelvic magnetic resonance image showing presacral abscess (within the circle).

Perianal fistula is a common chronic lesion, which usually ensues from a closed abscess. Local pulsating pain and leakage from a de novo cutaneous orifice are the most common clinical presentations. Brain abscess represents a rare complication of perianal disease (fistula or abscess), as only four cases have been reported in the pertinent world literature [1–4]. Of note, aphasia was the first manifestation experienced by two of these patients [1,2]. Acquired immunodeficiency syndrome (AIDS), in particular in men who have sex with men, is an important risk factor for the development of this condition (two patients described) [3,4]; in our case, the patient was human immunodeficiency virus (HIV)-seronegative and immunocompetent. Given the absence of cardiac or pulmonary foci, the vertebral venous system (also known as Batson venous plexus) is the most likely pathway for the cerebral dissemination of perianal infections as well as of pelvic tumors [5].