DIAGNOSIS

3.1. Clinical signs

Clinical signs may include hypersalivation, inappetence, dysphagia, halitosis, unilateral ocular changes (discharge, chemosis, conjunctival erythema), lethargy/depression, weight loss and mandibular, facial and periorbital swell­ing.

3.2. Examination

Thorough oral examination in macropods requires anaesthesia. The face and mandibles should be observed and palpated for symmetry and swelling. Halitosis com­monly develops as the disease progresses and can be a useful clinical indicator. Oral lesions may include gingi­val hyperaemia and recession, purulent exudate, draining sinuses, mandibular/maxillary swelling and tooth mobil­ity (note that some lateral splay of the lower incisors is normal and rostral molar mobility/loss is a normal fea­ture of molar progression; see section 2.2.4). Spread of oral pathogens to systemic sites (e.g. lung, liver, brain) can occur and should be considered.

3.3 Clinical pathology

Haematological and biochemical parameters may be unremarkable or variably include neutrophilia, mono­cytosis, hyperglobulinaemia and elevations in fibrino­gen, CK, AST and ALT (Hawkey et al. 1982; Vogelnest and Portas 2008; Kane et al. 2017). Cytological evalua­tion for toxic changes in neutrophils is generally more sensitive for inflammatory demand than neutrophil count in macropods. Ventral tail hair cortisol, reflect­ing chronic stress, was significantly higher in eastern grey kangaroos with MPPD than in healthy animals; there was no difference in plasma cortisol, reflecting the acute stress of handling (Sotohira et al. 2017). Sotohira et al. (2016) used an automated hand-held system to measure plasma endotoxin activity in eastern grey kan­garoos with and without ‘lumpy jaw’, reporting 80% sensitivity and specificity with a cut-off of >0.22 endo­toxin units/mL.

Cytological examination of material along the gingival margin or between teeth is useful to differentiate inflam­matory exudate in early stage disease from incidental food impaction.

3.4 Radiography

Imaging is recommended for all cases. Oblique skull and intraoral dental radiographs will aid in identifying affected teeth and the extent of bone involvement (Fiani 2015; Hulst et al. 2015) (Figs 32.2-32.6). Oblique extraoral projections with the mouth open are useful to isolate the quadrant of interest and increase sensitivity for bone pathology (Vogel- nest and Allen 2015). Computed tomography, including 3D reconstructions, avoids superimposition and provides greater detail (Lee et al. 2011; Hulst et al. 2015; Vogelnest and Allen 2015; Kane et al. 2017) (Figs 32.3 and 32.5). Serial imaging allows tracking of progression during treatment and determining resolution (Figs 32.5 and 32.6).

3.5. Culture

Many laboratories do not routinely identify cultured anaerobes nor determine their antimicrobial susceptibili­ties (which are generally predictable). Given the limita­tions of culture in polymicrobial disease (Antiabong et al. 2014), it may be more appropriate to base antimicrobial protocols on current understanding of the microbial community changes associated with disease, rather than culture results.

In advanced disease, with osteomyelitis, the bacterial community becomes less diverse and less stable (Antiabong

Fig. 32.4. Yellow-footed rock-wallaby (Petrogalexanthopus) with macropod progressive periodontal disease, intraoral dental radiograph, right mandible. The 1st molar had been extracted and the gingiva healed with apparent narrowing of the space between 3rd premolar and 2nd molar (arrowhead). The atrophic remnant of the caudal root of the 1st molar is present. Lucency is evident around the atrophic roots of the 2nd and 3rd molars (arrows). On examination, both teeth were stable and there was only a small focus of gingivitis on the lateral aspect of the 2nd molar.

Fig. 32.5. Tammar wallaby (Notamacropus eugenii) with macropod progressive periodontal disease. (a) Oblique skull radiograph demonstrating alveolar lucency around the left mandibular incisor and 1st molar with associated osteomyelitis and bony fragments (arrowhead); the premolar had been extracted. The wallaby had been treated with florfenicol 25 mg/kg IM q 3 d for 6 wk. (b-g) Comparison of diagnostic imaging modalities 3 mo after extraction of the mandibular incisor, 1st molar and fragments of osteomyelitic bone, and treatment with ceftiofur crystalline free acid 6.6 mg/kg q 4 d and periodic application of metronidazole in poloxamer gel into the affected site. Gingival tissues had completely healed and there was no significant soft tissue swelling. A focus of bony sequestra, subsequently removed surgically, is present at the rostral end of the remaining left mandible (arrow), though not obvious in all images; viable bone immediately caudal to this could be mistaken for a sequestrum on the radiographs (arrowhead). (b) Ventrodorsal intraoral dental radiograph. (c) Axial CT scan. (d) Dorsal oblique radiograph. (e) Ventral oblique radiograph. (f) Saggital CT scan. (g) Left lateral aspect of 3D reconstruction of CT scans.

Fig. 32.6. Yellow-footed rock wallaby (Petrogalexanthopus) with macropod progressive periodontal disease, oblique skull radiographs to isolate left mandible. (a) 4 wk after initial presentation and extraction of left 1st-3rd mandibular molars. A retained tooth root is evident, with associated osteomyelitis and mandibular fracture (arrow). The right mandibular 1st molar displays fracture of the caudal root with associated atrophy, possibly consequent to molar drift and progression (the tooth was extracted) (arrowhead). (b) 6 wk after initial presentation. Sequestrum evident in ventral mandible (arrow). There is atrophy of the right maxillary 1st molar tooth roots, though the tooth remained stable (arrowhead). (c) 8.5 wk after initial presentation, confirming extraction of sequestrum (arrow). The lesion subsequently healed well. Percutaneous injection of 40% poloxamer gel with 1% doxycycline to the site of mandibular osteomyelitis was performed on three occasions over the course of treatment.

et al. 2013d). This could potentially allow facultative and aerobic pathogens, for which susceptibility patterns are less predictable, to proliferate. Hence, culture of extra-oral sites may have value in some cases.

3.