This case was a patient with long-term sneezing symptoms who was finally diagnosed with an oral-nasal fistula. Oral-nasal fistula is the abnormal fistula formed between the oral and nasal cavities. Common causes include trauma, periodontal disease, tumor, congenital dysplasia, etc. Its clinical symptoms include frequent sneezing and chronic, unilateral serous or mucopurulent nasal fluid. The early oral-nasal fistula is very limited in diagnosing and evaluating oral-nasal diseases because the clinical symptoms are not obvious or because the head tissue overlaps significantly and the contrast is poor. At the same time, computed tomography (CT) provides more possibilities for diagnosing head diseases. It is especially suitable for the evaluation and differential diagnosis of oral and nasal disorders. In this case, CT diagnosis revealed multiple canine periodontitis complicated with oral-nasal fistula and nasal obstruction. The effectiveness and comprehensiveness of CT diagnosis were significantly superior to X-ray. Once diagnosed, periodontitis and oral-nasal fistula should be treated with ultrasonic tooth cleaning, tooth extraction, and oral-nasal fistula repair as soon as possible. However, periodontitis is a preventable disease. Daily brushing and oral care products should be used to keep oral teeth clean and prevent the occurrence of periodontitis and its complications.
Keywords: Canine, periodontitis, Oral-nasal fistula, diagnosis
Name: LAI FU
Sex: male (castrated)
Age: 11.5 years old
Body weight: 11.2 kg
Complete vaccination and deworming, virus infection when he was young.
The owner fed him at home, ate dog food, and brushed his teeth occasionally. The time brushing their teeth was nearly one year ago. 2 months ago, the patient presented with increasing snot from the right nasal, and reverse sneezing was found occasionally. In the last two weeks, the dog’s appetite decreased, the patient’s body weight had reduced from 11.8kg to 11.2 kg, he was found the more frequently increasing sneezing and reverse sneezing, slightly cloudy nasal discharge from the right nostril, occasionally bloodshot. So decided to take him to the hospital. Vaccinate history is completed, and deworming is this year.
Body weight 11.2kg, temperature 38.4℃, respiratory rate was 25/min, heart rate：110 beats/min.No prominent murmurs in breathing and cardiophony. Mouth mucosa was pink, capillary refill time（CRT）<2s, and body condition score（BCS）was 5/9, which can touch the ribs in palpation. The patient was presented with a highly depressing situation—dry coat and nose. Abdominal palpation was found to be nothing evident abnormal. Poor smelling from the month with breathing, moderate to severe calculi in premolar and molar teeth, local gingival atrophy, a small amount of yellowish discharge in the right nostril, bilateral nostril ventilation tests showed significantly less airflow in the right nostril. The dehydration was evaluated at 5%. Palpation, the rate of the femoral artery, was equal to the heart rate.
Complete Blood Count (CBC) examination
Interpretation: There was a mild increase in the WBC and OTHER%. Most were the increase of neutrophils and monocyte in the blood smear. Red blood cell count and HCT are average, but the physical examination indicated a possibility of dehydration with a low liquid volume.
Idexx Catalyst biochemistry CHEM17
Interpretation: No apparent abnormalities in biochemical indicators. The diagnosis should be analyzed with the other examinations.
The result of the CRP testing
Interpretation: The result of CRP was typical. The inflammation might be a chronic process combined with the development of CBC.
The radiography of X-ray examination of the head
Picture 1. Markedly Decreasing the density around the roots of several premolars and slight loss of alveolar bone were seen, but no obvious abnormality was observed in the septum and adjacent nasal tissues. （VD radiograph）
Picture 2. Markedly Decreasing density around the roots of several premolars and slight loss of alveolar bone were seen, suggesting periodontal disease of this patient -Right lateral radiograph
The radiography of CT of the nose
Due to the decreasing airway volume in the right nasal cavity and obvious reverse sneezing, nasal obstruction was suspected, so a CT examination was recommended. The CT image showed that alveolar bone osteolysis was observed in teeth 106, 107, and 108, and the tooth root communicated with the nasal cavity (indicated by the white arrow). The ipsilateral nasal cavity was full of substances with soft tissue density shadow, and the enhancement signal was not noticeable. There was no apparent space-occupying mass. CT results suggested oral-nasal fistula and right nasal obstruction, which may be a tumor, inflammatory substances, or foreign bodies.
Oral and nasal fistula in canine periodontitis
According to the history, clinical examination, and auxiliary examination of the dog, the preliminary diagnosis was periodontitis complicated with oral-nasal fistula, and inflammatory rhinitis or nasal tumor was suspected. After extracting 108 teeth during the anesthesia operation, it was found that the dissolved alveolar bone cavity and the nasal cavity were filled with a large amount of bean curd residue with a small amount of hair. After removing these substances, blood flowed out of the right nostril, and the nasal cavity was patented, indicating that the importance filled with soft tissue density in the nasal cavity in the CT image was not issued. A mixture of food debris and inflammatory exudation enters the nasal cavity through an oral-nasal fistula. Cytological examination of the nasal mucosa and subsequent blood examination of the case indicated chronic rhinitis, and no tumor lesions were found.
1. Surgical remove the teeth
2. Metronidazole 7.5mg q12h p.o q12h
3. Amoxicillin clavulanic acid 20mg/kg s.c q12h
All the premolars and molars of the right upper jaw were extracted due to periodontitis and gingival atrophy in teeth 105, 107, and 110. As a result, the occlusal surface of the right jaw was missing to avoid postoperative damage of mandibular teeth to the gums and hard palate. Therefore, the premolars and molars of the lower jaw were also extracted. After cleaning and disinfecting, the separated gingival flap was closed with a 4-0 monofilament suture. For oral-nasal fistulas at teeth 106, 108, and 109, the gingival flap-free repair was performed, inflammatory granulation tissue in the fistulas was removed, fresh wounds were made on the palatal side, and labial side and the single labial mucosal free flap was separated. Oral-nasal fistulas were repaired without tension nodule sutures.
After 24 hours of fasting, soft or fluid food was gradually given, and the mouth was cleaned after eating to avoid food residue remaining on the wound and affecting wound healing. Antibiotics (sun sol + metronidazole) were given for one week. After two weeks of postoperative visits, the pet reported good wound healing, normal mental appetite, significantly reduced sneezing, and clean nostrils.
Oral-nasal fistula is the abnormal passage between the oral cavity and nasal cavity caused by trauma or other diseases. It can occur in animals of any breed and gender. Congenital oral-nasal fistula can be seen, but it is usually secondary to periodontal diseases, trauma, and tumors in middle-aged and elderly animals, also known as an acquired oral-nasal fistula. Acquired oral-nasal fistula, the most common cause of which is periodontitis, occurs in 80-85% of canine, feline patients over 2-3 years of age, according to a comprehensive review of the literature. It most commonly occurs on the palatal side of the maxillary canine. Other teeth that may be involved in forming an oral-nasal fistula are:
- The incisor.
- The first and second maxillary premolars.
- The mesial root of the third premolar.
The formation of fistulas between the oral cavity and maxillary recess may be associated with late periodontitis in the distal roots of the third premolar, fourth premolar, and first molar. The typical clinical symptoms of oral-nasal fistula, such as runny nose, epistaxis, sneezing, dyspnea, snoring, panting, etc., when the patient has the above clinical signs in addition to oral-nasal fistula, it is still necessary to identify and diagnose rhinitis, nasal tumors, nasal foreign bodies, especially in cases that have caused nasal congestion, which may lead to no epistaxis in periodontal exploration and missed oral-nasal fistula. The nasal cavity is a 3D spatial structure mainly surrounded by bone tissue, and the lesions of the oral-nasal fistula are usually located on the side of the palate. Therefore, 2D X-ray imaging has certain limitations in diagnosing nasal diseases, and CT or MRI tomography is better than traditional X-ray imaging diagnosis. CT is easy to diagnose oral and nasal conditions and can provide a lot of diagnostic information regarding lesion location, scope, nature, relationship with surrounding tissues, and invasion degree.
The CT image characteristics of periodontitis complicated with oral-nasal fistula are that the fistula leading from the maxillary root to the nasal cavity can be found, and the local alveolar osteolysis can be observed in the periodontal region. Meanwhile, because oral-nasal fistula is often secondary to chronic rhinitis, liquid accumulation, soft tissue density, dissolution, and destruction of turbinate bone or ethmoid plate in the nasal passage near the fistula can also be seen frequently, and abnormal images can be dispersed throughout the nasal cavity or locally. Periodontitis lesions may affect the frontal sinuses, maxillary recesses, and the bones that make up the nasal cavity. In CT images, abnormal soft tissue images in the frontal sinuses and maxillary recesses, non-specific thickening of the mucosa on the surface of the nasal bone, and irregular soft tissue images in the facial sinuses and behind the eyeballs can be seen. Soft tissue density imaging is usually uneven and not evident on enhanced CT. When the homogeneous soft tissue density mass, extensive destruction of turbinate and related bone, destruction of the nasal septum, frontal sinus, or ethmoid plate, involvement of the nasopharynx or the retrobulbar area, uneven enhancement of the soft tissue density mass after enhancement, and high and low mixed (mottled) density shadow, the possibility of a tumor should be considered first, although rhinitis, nasal tumor, and nasal foreign body have different CT findings, there are still many cases of actual cases of CT image findings make doctors feel ambiguous, most patients with tumors will also be accompanied by inflammation, and some instances of severe rhinitis can also see soft tissue density mass, so the diagnosis should be based on histopathology as the gold standard, and CT signs have a solid suggestive role.
The key to surgical treatment of this disease is to choose single or double mucosal flap repair to repair the oral-nasal fistula according to the size of the fistula. Most oral-nasal fistula repairs can be successful if the mucosal flap has no tension and a good blood supply: postoperative routine anti-infection and analgesic treatment, feeding liquid diet, soft diet for about one week. Keep your mouth clean and hygienic. Use oral care gel or mouthwash to aid rehabilitation.
In the retrospective study of CT diagnosis of 29 cases of canine nose diseases by DR.Cai et al., College of Veterinary Medicine, China Agricultural University, the results showed that 19 cases were malignant tumors (65.9% (19/29), 5 cases were rhinitis secondary to periodontitis (17.2% (5/29), and 4 cases were inflammatory rhinitis (13.7% (4/29). One case was foreign body rhinitis (3.4%, 1/29). Dr.Mei et al. from the College of Veterinary Medicine of Nanjing Agricultural University conducted a retrospective study on CT diagnosis of 19 cases of canine nose bleeding, and the results showed that the number of cases caused by oral and nasal fistula was the largest, accounting for 26.3% (5/19), nasal tumors accounted for 15.8% (3/19), and nasal infection and trauma accounted for 10.5% (2/19), respectively. Foreign body and granuloma in the nasal cavity accounted for 5.3% (1/19), respectively, and undetermined etiology accounted for 26.3% (5-19) . It can be seen from the data statistics that the proportion of nasal diseases caused by periodontitis is still relatively high, which requires special attention from clinical veterinarians and good education of pet owners. Because periodontitis and its complications are preventable, good home care, consistent daily brushing, and control of plaque and stones can effectively prevent the occurrence of periodontitis. Studies have shown that brushing every other day is not enough to maintain clinical dental health in dogs, so it is essential to stick to daily brushing. The correct way to brush is to hold the toothbrush at a 45-degree angle so that the tip of the toothbrush goes deep into the gingival groove and around the teeth to ensure that the teeth are clean. Oral care products such as mouthwash, mouth gel, and bite gel can also aid effectively. The use of products certified by the Veterinary Oral Health Council VOHC is recommended.