Misdiagnosed draining fistula in a pregnant patient: A case report

Discussion

Cutaneous dental fistulas are not a common dermatological subject, which is why it is misdiagnosed by dermatologist and surgeons, thus submitting the patient to unnecessary antibiotic treatments, biopsies, resections, and even radiotherapy, with a not so favorable outcome and a recurrence of the fistula. Initially, microorganisms such as Fusobacterium nucleatum sp. Vicentii, Porphyromonas gingivalis, Veillonella parvula, Enterococcus faecalis, Campylobacter gracellis and Neisseria mucosa invade the tooth through the enamel and dentin, infecting the pulp causing necrosis, periodontitis and formation of the periapical abscess, rich in anaerobic bacteria. Usually this process is acute and renders the patient to seek medical attention. At this point, the purulent material finds a way out through an abnormal canal that connects the alveolar abscess with an orifice in the interior of the mouth (intraoral sinus tract), or into the skin (extraoral sinus tract). Based on a recent report, extraoral fistulas are more common in women and adults and intraoral fistulas are usually found in children. The draining pathway depends on the length of the root and the exposition of the apex, in relation to the muscle union to the bone.

The purulent material tries to find a way out through a place that presents less resistance, in order to relieve the pain and the edema.

The purulent material does this by passing through the periodontal ligament, bone and soft tissue right into the epidermis, creating abscess or cellulites of the skin, which leads to a hole in the skin. Besides caries being the most common cause of periapical infection, there can be other causes such as trauma and root retentions. Clinically, there can be a soft nodule on the skin, symmetric, erythematous, or covered with scab tissue, the skin can be retracted because of a fibrous tissue that joins the jugal mucosa with the gingival tissue, which if it is palpated may produce the exit of purulent material. The most common fistulas are associated with mandibular teeth. Topically, they are localized in the angles of the mandible, chin and cheeks, and most of the times it can be predicted where the fistula will drain, depending on what tooth is affected: the mandibular premolars and molars will drain into the submandibular regions and some into the cheek of the affected side. The diagnosis of a fistula requires a well taken medical history and adequate physical and oral examination. Past inflammatory process and dental work should be asked about. The panoramic or periapical x-ray may show some radiolucent areas, traces with gutta percha on the sinus tract (radiopaque material is put into the fistula and then the x-ray is taken to determine the source of infection). If there is purulent material it is best to take samples for cultures, in 60% of the cases it may be caused by anaerobic bacteria. Treatment consists of the elimination of the infectious agent through endodontic work if the tooth can be saved. If it cannot, it is best to remove it. Patient should be under a cover of systemic antibiotics. Once the infection is treated, the sinus tract heals in 5-14 days and closes by secondary intention. The esthetic results, however, are determined by the size. Small sized fistulas heal on their own. In medium and big sized fistulas, the results are not so favorable; patients present with scaring and depressions of the skin. Hence, the medium sized ones should be sutured, while big sized ones should be surgically removed.

Conclusion

An initial dental consultation would have avoided this patient an unnecessary dermatology visit, and instead she could be directly referred to dentist. General physicians and dermatologists must be made aware of this overlapping condition. Emergency treatment should be considered in acute conditions and final treatment must be postponed till acute condition subsides. It is best to have all consents and physicians approvals in place, especially in compromised patients and states like pregnancy.

A stitch in time saves nine, so right diagnosis at right time is crucial.

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