Restricted jaw mobility in a 3 year old female Golden Retriever
Contributed by Drs. Robert Runde and Ronald Lyman
Animal Emergency and Referral Center
Ft. Pierce, FL
Clinical History
This 3 year old female intact Golden Retriever presented for a several day history of restricted jaw mobility. Clinical signs occurred while the owners were out of town. Referral blood tests were consistent with renal azotemia (high BUN, creatinine and proteinuria with a urine specific gravity of 1.004). A 2M antibody titer submitted by the referring veterinarian was borderline at 1:100. No other problems were noted by the owner and vaccinations were current.
Physical and Neurological Examination
The only abnormality identified on physical and neurological examinations was restricted jaw mobility (Figure 1A shows the limitation to range of motion). The jaw could open just enough for eating soft food (Figure 1B).
Figure 1A
Figure 1B
Diagnostic Tests
CBC – HCT 32.8% (37.0-55.0), HGB 11.4 g/dL (12.0-18.0) with normal MCHC
Serum chemistry profile – BUN 24 mg/dL (7-27), creatine 1.8 mg/dL (0.5-1.8), cholesterol 514 mg/dL (110-320), creatine kinase (CK) 219 U/L (10-200)
Urinalysis – Urine SG 1.014, cocci and rods noted. Urine culture confirmed a urinary tract infection with E. coli (4+) and K. pneumonia (3+).
Thryoid panel – T4 <0.2 µg/dL (1.0-4.0), TSH level 1.61 ng/ml (0.0-0.60), and Free T4 by equilibrium dialysis <2 pmol/L (8-40). These results were consistent with severe hypothyroidism.
Abdominal ultrasound – Left kidney asymmetric in shape with mild pelvic dilatation.
Assessment and Further Diagnostics
Electromyography and tissue biopsies were performed under anesthesia at the time the dog was spayed. Spontaneous insertional activity, positive sharp waves and rare fibrillation potentials were found in the temporalis muscles bilaterally and in the flexor muscles of the digits. A kidney biopsy confirmed severe and chronic granulomatous pyelonephritis. Biopsies from the digastricus and temporalis muscles were not abnormal. Mild lymphocytic cellular infiltrations were observed in the biopsy from the epaxial muscle. While under general anesthesia swelling of the tongue occurred which necessitated the mandible to be manually separated.
Outcome
Based on all the diagnostic information, this 3 year old dog was affected with severe pyelonephritis, severe hypothyroidism and mild inflammatory myopathy (myositis). Treatment was initiated with L-thyroxine (0.8 mg twice daily), clindamycin (450 mg twice daily), clavamox (500 mg twice daily), and prenisolone (80 mg once daily). The owner was also instructed to manually open the jaw every 2-4 hours daily. On reexamination one week later, the owner reported that the dog was "acting like a new dog" Jaw mobility was markedly improved (Figure 2) A post-pill T4 was 5.2 µg/dL. Thyroid hormone therapy was continued and the prednisone dosage was decreased.
Note: Complications resulting from tongue position during anesthesia has been previously reported in dogs with restricted jaw mobility due to masticatory muscle myositis (Nanai B et al. Life threatening complication associated with anesthesia in a dog with masticatory muscle myositis. Vet Surg 2009;38:645-649).