The infratemporal fossa is described as a skull base space bounded superiorly by the greater wing of sphenoid and temporal fossa; anteriorly by the posterior wall of the maxillary sinus; medially by the lateral pterygoid plate; laterally by the mandibular ramus; and posteriorly by the deep lobe of the parotid gland; it opens inferiorly into the parapharyngeal space. Infections in this space have been found following maxillary sinusitis, maxillary sinus fracture, temporomandibular arthroscopy, dental infection and tooth extraction. Temporal fossa abscess is a rare and challenging condition to diagnose and manage. We experienced a temporal fossa abscess caused by an apical periodontitis.
2. Case Report
A 79-year-old woman was referred to our department complaining of a painful swelling at the left side of the temporal region and trismus. The medical history was osteoporosis, however she did not take any medication. The family history was unremarkable.
Extraoral examination showed a diffuse, elastic soft, and painful swelling at the left side of the temporal region (Figure 1(a)). Intraoral finding, the left side of upper second molar showed percussion pain and gingival tenderness of apical area (Figure 1(b)). Panoramic and dental X-ray exhibited transmission image at the upper left side of the second molar (Figure 1(c)). The leukocytes and c-reactive protein (CRP) were increased up to 10,300/µl and 11mg/dl respectively on blood test. The biochemical examination showed a decrease in albumin for difficult food intake by trismus (Table 1). Computed tomography showed low density area range from pterygomandibular region to temporal region, and abscess formation suspected (Figure 2). We diagnosed that the temporal fossa abscess due to the periapical periodontitis of the upper left side of the second molar. The patient was hospitalized immediately for anti-inflammatory treatment. We performed drainage treatment and the incision line was designed at temporal skin while paying attention to the temporal branch of the facial nerve on day 1. Fusobacterium species was detected in pus. ABPC 3 g/day was administrated for intravenous from day 1 to day 4. Since the drainage amount was reduced, ABPC was diminished to 2 g/day on day 5. The leukocytes and CRP were decreased 5500/µl and 0.5 mg/dl respectively on day 9. The mouth opening training performed and the inter-incisal distance was improved from 5 mm to 20 mm.
Figure 1. (a) Extra-oral finding at the first visit. (b) Intra-oral findings at the first visit. (c) Dental X-ray confirmed a transmission image at apical of the upper left side of the second molar.
Figure 2. CT images showed low density area at the left side of the temporal area.
Table 1. The summary of blood and biochemical examination.
We performed the extraction of the upper left side of the second molar on day 12. The patient recovered satisfactory and left hospital on day 15 (Figure 3). The patient continues to mouth opening training in the outpatient.
The background to be triggered the severe odontogenic infection, there are the sparse connective tissue spaces which an inflammation is likely to spread in the head and neck area  . The inflammation that occurred in apical area of the maxillary molar was extended through buccinator muscle, pterygomandibular space, temporal space, pterygopalatine fossa, masticatory muscles space, and
Figure 3. Summary of the clinical course.
spread to the temporal muscle in this case   . As the case of infratemporal fossa abscess, Kasahara et al.  reported developing after extraction of a maxillary molar, and D Leventhal et al.  reported complication of dental injection. The spreading of a periapical infection into adjacent and/or remote connective tissue may, rarely, result in serious or even life-threatening complications.
There were the Streptococcus milleri group in aerobic bacteria and the Fusobacterium, Peptstreptcoccus, and Prevotella in anaerobic bacteria as main causative bacteria of odontgetic infections   . Our case also detected Fusobacterium species by a bacteriological examination. Odonogenic infection is caused by polymicrobial infection, so it is necessary to administer susceptible drug against to causative bacteria. ABPC was a sensitivity for Fusobacterium species and choice of antibiotic which was used this time was appropriate  . Because there is also a decrease in liver and renal function, it has to be careful to the emergence of side effect by administration of antibiotics in elderly patients. In our case, it was not confirmed abnormal systemic matter which confirmed by regular blood test.
The development of antibiotics, odontogenic infection associated with severe case is rare  . However, there are extensive severe infection cases that reach the mediastinum and the base of the skull under various conditions. Even odontogenic infection, the appropriate diagnosis and treatment may not have been performed at the beginning of the inflammation, and the administration of inappropriate antibiotics have been made, the inflammation proceeds through the surrounding tissue and causes severe symptoms. We performed precision diagnosis and appropriate treatment by antibiotics and drainage treatment, so the inflammation healed without serious complication and she recovered completely.
We reported a case of temporal fossa abscess caused by periapical periodontitis at the upper left side of the second molar in a 79-year-old woman.
 Kasahara, K., Ogawa, C., Matsuzaka, K., Yamamura, T., Takano, M., Saitou, C. and Shibahara, T. (2015) A Case of Infratemporal Fossa Abscess with Signs of Chronic Maxillary Osteomyelitis. The Bulletin of Tokyo Dental College, 56, 121-129.
 Leventhal, D. and Schwartz, D.N. (2008) Infratemporal Fossa Abscess: Complication of Dental Injection. Archives of Otolaryngology—Head & Neck Surgery, 134, 551-553.
 Lewis, M.A.O., MacFarlane, T.W. and McGowan, D.A. (1986) Quantitative Bacteriology of Acute Dento-Alveolar Abscesses. Journal of Medical Microbiology, 21, 101-104.
 Brook, I., Frazier, E.H. and Gher, M.E. (1991) Aerobic and Anaerobic Microbiology of Periapical Abscess. Oral Microbiology and Immunology, 6, 123-125.