August 2000

Editor: Gregg Kortz, DVM, DACVIM, (NEUROL)

Background   Physical Examination   Neurology Examination Results   Tests Performed   Imaging   Diagnosis and Summary

Background

Signalment

Dog, male, 11 months old, yellow Labrador retriever.

History

Progressively worsening ataxia in all four limbs for past four months.

Past Medical History

No history of previous trauma or illness was reported by the owners.

Medications

None at this time.

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Physical Examination

 Rectal temperature: 102.2;

 Heart rate: 90/m;

 Rhythm: regular with femoral pulses equal and synchronous.

 Respiratory rate: 32/m,

 Eupneic and mucous membranes: pink,

 Capillary refill time: < 2 sec.

 General appearance: Alert and responsive, body condition score 5 / 9

 Integument: Minor ulcers and encrusted areas were present on the dorsum of most digits of the thoracic limbs.

 Eyes, ears, nose and throat: No abnormalities noted.

 Cardiopulmonary, abdominal cavity, musculoskeletal, lymph nodes: No abnormalities noted.

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Neurological Examination Results

 Consciousness: Alert, responsive.

 Posture: N

 Falling, rolling: Absent

 Righting reactions: N

 Head Tilt: None

 Tremor: None

 Circling: None observed

 Gait: Moderate paresis, all four limbs, more severe in forelegs.

 Proprioceptive placing
thoracic limbs, very depressed;
pelvic limbs: depressed.

 Hopping, hemistand/walk ("wheelbarrowing"):
thoracic limbs, very depressed;
pelvic limbs, depressed.

 Spinal (segmental) reflexes: (N=normal; D= depressed; A= Absent; I= increased;)

 Forelimbs:
Tendon Reflexes: Extensor Carpi: N: Biceps brachii: N; Triceps brachii: N
Flexion Reflexes: N
Crossed Extensor Reflexes: Absent clinically

 Pelvic limbs:
Tendon Reflexes:Quadriceps: N; Gastroc/Dig. flexors: N.
Crossed Extensor Reflexes: Absent clinically

 Perineal Reflexes: N

 Cutaneous Trunci Reflexes: Present in all normal segmental levels.

 Painful Stimulation: Normal withdrawal responses.

Cranial Nerves

 I: Not tested

 II: Vision apparently normal.

 III, IV, VI: Pupils equal, normal direct and indirect pupillary light reflexes. Normal ocular positions and movements.

 V: Normal

 VII: Normal

 VIII: Righting reactions: N; Physiological Nystagmus: N; Spontaneous nystagmus: absent; Positional nystagmus: absent. Audition apparently normal.

 IX, X, XI: Normal swallowing action in response to stimulation.

 XII: Tongue: position, symmetry, normal movements.

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Tests Performed

Hematology, Chemistry and Urinalysis

General Clinical Chemistry Panel

Hemogram Results

Urinalysis

Cerebrospinal Fluid Studies

Cerebrospinal Fluid: Total and Differential Cell Counts; Total Protein

Fluid from: Lumbar region
Gross appearance: Clear, yellow
Refractive index: 1.3350

Total Protein: 21 mg/liter

Total erythrocytes: 66/microliter
Total nucleated cells: >1/microliter

Differential Nucleated Cell Counts:

Smear type: Cytofuge
Neutrophils: 0%
Small mononuclear cells: 39%
Large mononuclear cells: 61%
Eosinophils: 0%
Microscopic evaluation: There are unremarkable large and small CSF mononuclear cells and a few erythrocytes.

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Imaging

Survey Radiographs

Note: the lowermost two are enlarged views of the atlanto-occipital region made with differing degrees of rotation of the head on the neck.

Click on an image to see a larger view

Myelography

Please note: there are five views on this page; the last two are ventrodorsal views.

Click on an image to see a larger view

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Diagnosis and Summary

The signalment, clinical signs, imaging studies and histopathology in this case were all consistent with a diagnosis of calcinosis circumscripta (also referred to as tumoral calcinosis).

Calcinosis circumscripta is an idiopathic condition which occurs as single or multiple ectopic areas of mineralization and deposition of calcium salts in periarticular connective tissue. It occurs most commonly in young, large-breed dogs, with an apparently higher incidence in German shepherd dogs. A frequent location is at the dorsal aspect of the first and second cervical vertebrae; however other locations have been reported.^1-3 Neurological signs depend on the location of the mass and result from spinal cord and nerve root compression by the expanding mass. Diagnosis is made on the basis of radiographs; myelography will usually demonstrate an extradural compressive lesion. Computed tomography or magnetic resonance imaging may further delineate the lesion and be valuable in planning surgery. Complete surgical resection of the mass often results in a cure (see movie of post-operative gait in this case). Histopathology demonstrates the typical changes described with calcinosis circumscripta (for example, see histopathology in De Risio and Olby¹).

See video   

De Risio and Olby, Tumoral Calcinosis

Click on an image to see a larger view

Figure 4. Histologic section of the surgically resected tissue mass (hematoxylin and eosin stain X 180). The lesion consists of lakes of mineral deposits (large arrow) surrounded by zones of granulomatous inflammation, often containing multinucleate giant cells (arrow head) and other zones of thick fibrous tissue (small arrow).

For additional information on calcinosis circumscripta, its diagnosis and treatment please see the references.

References

1.  De Risio, L., Olby, N., Tumoral Calcinosis of the Thoracic Spine: A case report and literature review. Veterinary Neurology and Neurosurgery 2000

2.  Lewis, DG., Kelly, DF., Calcinosis circumscripta in dogs as a cause of spinal ataxia. Journal of Small Animal Practice, 1990, 31, 36-38.

3.  Bichsel, P., Lang, J., Vandevelde, M., et al. Solitary cartilaginous exostoses associated with spinal cord compression in three large breed dogs. Journal American Animal Hospital Association, 1985, 21, 619.

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