The patient, a 58-year-old man, was referred for evaluation and management of the left jaw joint during hospitalization in the Division of Otolaryngology due to an outbreak of malignant external otitis on November 6, 2012. He began treatment in otolaryngology mainly due to running ears. However, since his condition did not improve, incision and drainage of the left jaw joint were performed after hospitalization. Later, as the patient’s condition threatened to deteriorate after pharmacological treatment at another ENT hospital, he was sent to our tertiary care hospital for treatment. His medical history included diabetes that had resulted in diabetic neuropathy.
Clinical examination of the patient revealed pain in the left jaw and mouth-opening deflection to the left. The maximum active mouth opening was measured to about 27 mm, which limitation was due to continuous pain. Tender points in the left temporalis muscle and left jaw joint were noted.
Panoramic radiographs revealed bone resorption patterns in the left condyle (Fig. 1). CT scans and cone beam computed tomography (CBCT) of the temporal bone showed the same patterns (Figs. 2 and 3). MRI findings revealed the left temporomandibular joint to be surrounded by thickened soft tissue (Fig. 4); T2-weighted imaging, meanwhile, showed effusion in the left mastoid air cell (Fig. 5). Based on the thickening of the external auditory canal epithelium (Fig. 6a, b), contrast-media imaging of diffusion with increased patterns around the thickening region, as well as discharge in the mastoid process, the patient was provisionally diagnosed with malignant external otitis, mastoiditis, and arthritis of the left temporomandibular joint. After treatment of the lesion by incision and drainage of the left jaw joint in the Department of Otorhinolaryngology, arthrocentesis and occlusal stabilization appliance therapy were carried out. Due to severe inflammation in the joint space, the arthrocentesis with lavage was performed twice. According to the results of a culture of the bacteria in the external auditory canal, carried out prior to incision and drainage, pseudomonas aeruginosa was detected; but according to the results of a bacterial culture implemented later, no bacteria were detected. After the arthrocentesis with lavage, the extent of active mouth opening was increased to 40 mm, and pain in the left jaw joint was alleviated.
Approximately 1 month after the first arthrocentesis with lavage was performed, an occlusal stabilization appliance was employed, which effectively eliminated the pain in the left temporomandibular joint. The extent of active mouth opening was further increased, from 40 to 45 mm (Fig. 7). Then, close observation with regular examination and pharmacological treatment with quinolones such as ciprofloxacin were performed in our otorhinolaryngology clinic. Panoramic and CBCT images taken 1 year and 5 months after surgery confirmed that the bone resorption patterns in the left condyle had been significantly reduced (Figs. 8 and 9). Now, the patient, still pain-free in the left temporomandibular joint, currently is undergoing implantation treatment (Fig. 10).
Discussion
Skull-base osteomyelitis arises mainly through secondary infection of malignant external otitis. Although skull-base osteomyelitis and malignant external otitis are considered to be identical concepts in many studies, it is more appropriate to conceive of and think about skull-base osteomyelitis with basal bone involvement in pathophysiological terms [3].
Important skull-base osteomyelitis risk factors include immunosuppression, diabetes, chronic mastoiditis, sinusitis, malignant external otitis, infectious disease treated poorly with antibiotics, and decreased immunity due to the use of steroids or infection with human immunodeficiency virus [7]. The most common disease associated with patients hospitalized due to skull-base osteomyelitis is diabetes [8]. Skull-base osteomyelitis most typically infects the diabetic elderly; accordingly, infection caused by chronic external otitis occurs secondarily in connection with temporal bone [9]. However, atypical skull-base osteomyelitis, which arises in the absence of any history of external otitis, has only rarely been reported [10]. Skull-base osteomyelitis is an often fatal disease, with mortality rates ranging from 28 to 60 % along with cranial nerve palsy in cases of delayed diagnosis and treatment [11]. Pseudomonas aeruginosa is the most common (99.2 %) cause of skull-base osteomyelitis, whereas fungal skull-base osteomyelitis, caused by aspergilus and candida, is very rarely observed [12].
The most important consideration in the treatment of malignant external otitis is the control of diabetes and its complications. The excision of lesions is not generally recommended, though there is a need to remove locally inflamed tissues and bacteria. Generally, treatment is performed with antibiotic-mediated therapy using penicillin, ciprofloxacin and third-generation cephalosporin, which approach helps to reduce the mortality rate by 0–15 % [13]. In cases where the middle cranial fossa and foramen magnum are contracted, aspergilus infection occurs, from which poor-prognosis facial paralysis arises [14, 15].
According to the literature, surgical removal of the temporomandibular joint remains controversial. Long-term antibiotic therapy might affect the same results, even without other surgical procedures, and non-invasive treatment such as arthrocentesis with lavage also is recommended [16]. However, surgical treatment is recommended in cases where an abscess has formed in the joint space, or where extensive bone destruction of the glenoid and condyle is observed [17].
As for typical cases, conservative treatment primarily is performed when malignant external otitis affects the temporomandibular joint. However, in the present investigation, panoramic images showed cortical erosion of the upper mandibular condyle, and an MRI revealed condylar locking, mouth-opening limitation, and inflammation within the joint space. For this patient, arthrocentesis with lavage was performed.
