Trigeminal nerve sheath tumor

sv penchevDr Svetoslav Penchev

United  Veterinary Clinic

Varna, Bulgaria

 

 

The nerve sheath is a layer of myelin and connective tissue that surrounds and insulates fibers in the peripheral nerves. A nerve sheath tumor is an abnormal growth within the cells of this covering. Nerve sheath tumors include schwannomas, neurilemmomas, and neurofibromas. The trigeminal nerve is the most frequently affected cranial nerve. This results in unilateral atrophy of the temporalis and masseter muscles and facial dysesthesia or anesthesia. Eventually, brain-stem compression can develop.

 

 

Signalmen: 12 years old, female, castrated Labrador retriever

 

History:  The owner noticed that dog`s head has not normal shape.

 

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Case presenting signs:  Chronic right trigeminal nerve deficit with atrophy of the temporalis and masseter muscles. Reduced facial sensation, absent palpebral reflex with normal menace response reaction and reduced right corneal sensation and enophtalmus.

 

Clinical examination: The overall condition of the dog was normal with normal appetite, good muscle and body condition except the right temporalis and masseter muscles.  Internal body temperature 38,8 ; Normal respiratory and heart rate; Color of mucous membranes – pink; CRT – 1,5 sec.

 

Neurological examination:

Mentation and behavior- Normal

Posture- Normal

Gait – Normal

Cranial nerves – right trigeminal nerve deficit

There was no change in conscious proprioception and bladder function was normal.

Spinal reflexes were normal.

 

Neuroanatomic localization: R Trigeminal nerve

 

Differential diagnosis:

Idiopatic/Inflammatory/Trauma/Metabolic/Neoplastic

 

Case work-up:  CBC – without changes; Biochemistry – Elevation of Liver enzymes (ASAT 69 IU/L; ALAT 90 IU/L)

Contrast MRI study of the head was performed with GE MRI 1.5 Tesla.

 

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MRI     findings:

There is a large extra-axial T1 hypointense, T2 hyperintense tubular mass that arises at the origin of the right trigeminal nerve and extends rostrally through the trigeminal canal of the temporal bone. The right oval foramen is enlarged because of involving the mandibular branch. Atrophy and denervation of the masticatory muscles (temporalis, masseter and pterygoid muscles) is present with T1-, T2-hyperintesity, reduction of the muscle mass and replacement by fatty tissue. Post contrast images shows marked contrast enhancement of the right trigeminal nerve compared with the left (mild enhancement of the left trigeminal nerve is physiologic).

 

Diagnosis:

Right Trigeminal nerve sheath tumor

 

Intracranial peripheral nerve sheath tumors are relatively uncommon tumors in dogs. Clinically, dogs with intracranial PNST have one or more of the following clinical signs: ipsilateral masticatory muscle atrophy, loss of facial sensation, and Horner’s syndrome. Signs from intracranial brainstem compression can also occur. Radiation therapy is a commonly used modality in the treatment of intracranial PNST. Stereotactic radiation therapy (SRT) is one method used to deliver a curative dose of external beam radiation therapy. This precise and conformal treatment directly targets the radiation at the tumor with rapid dose drop-off, which allows for very high doses of radiation to be administered without increasing toxicity to adjacent normal tissues.

Paradoxical Vestibular Syndrome

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Dr Svetoslav Penchev

Dr Svetoslav Penchev

United Veterinary Clinic

Varna, Bulgaria

 

 

 

Paradoxical Vestibular Syndrome is a condition that affects flocculonodular lobe or the caudal cerebellar peduncle of the cerebellum and causes vestibular signs. These parts of the cerebellum participate in central components of vestibular apparatus and are responsible for the maintenance of equilibrium and coordination of head and eye movements;
This syndrome is called paradoxical vestibular disease because the head tilt and circling occur contralateral to the lesion. There is usually some evidence of cerebellar disease on neurological examination, such as ipsilateral dysmetria and head tremor.

Signalment: 8 years old, male, not castrated French bulldog

History: The owner noticed that the head of his dog is not in normal position and is tilt to the left. The dog was carried to its personal doctor, and the doctor had doubts that the dog was having problem with the inner ear . The doctor refer the dog to me for computer tomography, and for approval of the diagnosis.

Case presenting signs: Left head tilt, progressive vestibular signs

Clinical examination: Internal body temperature 38,1 ; Respiratory rate: 36 breaths per minute ; Color of mucous membranes – pink; CRT – 1,5 sec.
Puls 110 bpm ; The overall condition of the dog was normal and there was no no signs of pain.

Neurological examination:
Mentation and behavior-normal; Posture – Left head tilt; Gait – Vestibular ataxia, increase muscle tone and dysmetria of right fore and hind limbs The dog react with cranial and spinal normoreflexia. Menace response reaction of right eye was a little bit reduced. There was no change in conscious proprioception and bladder function was normal. The owners report for intention tremor of the head when the dog is waiting to be fed.

Neuroanatomic localisation: Central Vestibular ; Right Cerebellar Flocculonodular lobe; Paradoxical Vestibular Syndrome

Differential diagnosis:

Neoplastic/Degenerative

Case work-up:
CBC and Biochemistry were normal. Magnetic resonance of the head was performed with GE MRI 1.5 Tesla.

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MRI findings :
A single oval T1-hypo and T2, T2 FLAIR-hyperintensive intra-axial mass is observed, leading out of the cerebellar vermis and affecting the both cerebellar hemispheres. The mass is well circumscribed by the surrounding tissues, with extracapsular expansion and diffuse infiltration into the the gray matter. There is a significant mass effect that reveals compression of the flocculonodular lobe and reveals obstruction to the flow of cerebrospinal fluid with secondary dilatation of the quarter ventricle and central canal with subsequent syringohydromyelia.
Diagnosis: Cerebellar neoplasia
Treatment:
The clinical condition of the dog did improved after i.v
infusion with Mannitol (0.25g/kg bolus 3 times over 20 minutes) , Harmann`s solution 20ml/kg and Prednisolone p.o 0.5mg/kg – 2 times daily – for 3 days . Next 10 days the dog take Prednisolone 0.5 mg/kg 2 times daily at home.
Control visiting on the 14th day -https://www.youtube.com/watch?v=XRyp9sgqCjE

All of previous clinical signs were more severe present. There was no more improvement with this therapy and the owners chose to euthanize the dog.
With both central and peripheral Vestibular syndorme, the head tilt, circling and nystagmus typically occur ipsilateral to the side of the lesion. Less frequently, lesions affecting the caudal cerebellar peduncle, the fastigial nucleus, or the flocculonodular lobes of the cerebellum can cause central Vestibular disease with a resulting paradoxical head tilt. Bilateral Vestibular disease is characterized by head sway from side to side, loss of balance on both sides and symmetrical ataxia with a wide-based stance.  A physiological nystagmus usually cannot be elicited and a head tilt is not observed.

Cerebrovascular accidents in dog

 

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Dr Svetoslav Penchev

United Veterinary Clinic

Varna,Bulgaria

 

 

Stroke or cerebrovascular accident (CVA) is the most common clinical manifestation of cerebrovascular disease, and can be broadly divided into ischemic stroke and hemorrhagic stroke. CVA are characterized clinically by a per acute or acute onset of focal, asymmetrical and non-progressive brain dysfunction. Next cases show the both type of CVA in dogs.

1st case is about 9 years old female boxer. The dog was referring to the clinic with acute onset of seizures. The results of CBC and Biochemistry were normal and MRI was performed.

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MRI findings: Intra-axial right piriform lobe and hippocampus lesion with impression of moderate swelling of these portions is present. The cerebral falx is only mildly displaced to the left. There is corresponding low T1 signal intensity in these sections of the brain suggesting edema. There is no enhancement of the lesion after contrast administration. The findings suggest that there is a non-hemorrhagic cerebrovascular accident in right forebrain of the dog.

 

The 2nd case is about  a 8 years old male Cane corso. The dog was present in the clinic with unilateral fore brain deficits and history of epileptic seizures. Biochemistry and CBC were normal and MRI was performed.

 

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MRI findings : There is a well‐delineated T1 iso- to hypointense  and T2 hypointense  mass lesion with surrounding brain edema in right piriform lobe with a thin peripheral rim of contrast enhancement. There is a mass effect, displacement of the right lateral ventricle and midline shift to the left. This imaging feature is consistent with an acute to subacute intracranial hemorrhage.

 

Conclusion:

MRI features of Hemorrhagic infarction in dogs may not be distinguishable from hematoma caused by vascular disruption. Imaging characteristics will vary depending on the size, location, and chronicity ofthe hematoma.

Hyperacute – 24 hours   T1 isointense ; T2 hyperintense

Acute         1-3 days  T1 iso- to hypointense  ; T2 hyperintense

Early subacute   >3 days  T1 hyperintense  ; T2 hypointense

Late subacute    >7 days  T1 hyperintense ; T2 hyperintense

Chronic              > 14 days   T1 hypointense ; T2 hypointense

Secondary  features :  mass effect, surrounding edema, midline shift , ventricular displacement and compression .

 

MRI features of Nonhemorrhagic Infarction in dogs include mildly T1 hypointense and T2 hyperintense  lesion with minimal  mass effect involving both gray and white matter on unenhanced MR images. These changes seen in ischemic parenchyma rely on an increase in tissue water content. Gradually, during the acute stage, the T2-weighted image becomes more hyperintense in the ischemic region, particularly over the first 24 hours. These signal changes seen in the first 24-hours are best appreciated in grey matter and are well visualized in deep grey matter structures such as the thalamus or basal ganglia, in addition to cortical grey matter. Gadolinium enhances infarcts because of vascular rupture but does not enhance ischemia or edema.

 

Broncholithiasis in cats

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Dr Svetoslav Penchev

Unites Veterinary Clinic

Varna, Bulgaria

 

 

 

 

 

 

3 years old male, not castrated British shorthair cat with history of tetraparesis was referred to the clinic for Computed Tomography. Mineral-attenuating endobronchial lesions were detected in Thorax as accidental finings in spinal CT. The finding is specific for broncholitiasis.

CT  :

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CT features: Multifocal mineral-attenuating endobronchial lesions in cranial and middle right and cranial left lung lobe are present. There is mild generalized thickening of the bronchial walls and consolidation of right middle lung lob with regional bronchiectasis

 

 

 

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X-rays

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X-ray features: Multiple mineral opacity nodules with irregular margins are present within left and right cranial and right middle lung lobe. The largest of which lies within the right middle lung lobe and interstitial patter in this region is present.

 

 

 

Broncholithiasis is very rare condition in cats and is defined as the presence of calcified or ossified material within the bronchial lumen. Only four cases of broncholithiasis in cats have been reported in the veterinary literature. Normal this condition is associated with lower airway inflammation, but in this case the owner does not report for respiratory problems. Broncholithiasis is an uncommon condition, which should be considered as a differential diagnosis for cats with chronic respiratory disease. Affected cats may develop broncholithiasis secondary to a diffuse inflammatory lower airway disease with mineralisation of secretions in the airways.

 

 

 

 

 

 

Meningocele and meningoencephalocele in a dog

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Dr Svetoslav Penchev

United Veterinary Clinic

Varna, Bulgaria

 

8 mounts ,female dog with congenital meningocele and hydrocephalus . The dog is with normal behavior and without neurological deficits.1113

Meningocele and meningoencephalocele of the skull are congenital deformities. These deformities, which are observed as cyst-like swellings in the median part of the skull cap, occur very rarely. The intracranial material protrudes through a spontaneous cavity, such as the anterior fontanelle , and they are classified as encephalocele, meningocele, or meningoencephalocele according to the cranial bifida.111 1122

C2 FRACTURE AND CENTRAL CORD SYNDROME

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Dr Svetoslav Penchev

United Veterinary Clinic 

Varna, Bulgaria

 

 

 

 

Case is about a 6 months , male  cocker spaniel named  Michael.Michael was brought in the clinic from another city in very bad candition.The owners report for a trauma in cervical region.Radiography and neurological examinations were made. Results revealed –Tetraplegie and atalnto-axial instability.It was made a CBCT on cervical region.The image show C2-Fracture .3

 

 

 

 

 

 

 

 

Michael C2 fr et CCS 9Michael C2 fr et CCS 5Michael C2 fr et CCS 6Michael C2 fr et CCS 4Michael C2 fr et CCS 2It was maked a surgary to stabilize  cervical spine. Ten days after surgery Michael starts moving the pelvic limbs first and tries to stand on them. Twenty one days after surgary Micheal start to moving and thoracic limb  , but  have ataxia and destroys proprioception on his  four leg. Michael`s  recovery begin first with the hind limbs and then with the thoracic limbs .In human literature, the symptom in which the thoracic limb is in a dysfunctional state with minimal to no deficit in the pelvic limbs has been referred to as CCS (Central Cord Syndrome ). The spinal cords that travel to the pelvic limbs are minimally affected because the lesion is centralized in the cervical region, which only affects the thoracic limbs. In general, CCS has a good prognosis for functional recovery and its common etiology is traumatic disease in human medicine. CCS treatments with nonsurgical management include cervical spine restriction with a neck collar, rehabilitation followed by physical therapy and occupational therapy. Surgical management is provided for patients who cannot be treated by conservative management alone.

 

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