Nervous System Tumors in Dogs: Symptoms, Types, Risk and Treatment

Nervous system tumors in dogs are abnormal and uncontrolled tissue growth in the nervous system, which comprises the brain, spinal cord, and associated nerves. Abnormal and uncontrolled tissue growth is known as neoplasia. 

Nervous system tumors in dogs include astrocytomas in the brain or spinal cord, glioblastomas in the cells that support nerve cells, meningiomas in the membrane that covers the brain, and neuroblastomas in the nerve tissue. Neoplasia occurs in any part of the nervous system and causes neurological signs in dogs, including vision loss, loss of sense of smell, and paralysis. Nervous system tumors increase the risk of permanent damage to the underlying nervous system structures. 

Symptoms of nervous system tumors or neoplastic disease are a wobbly gait, circling, twitching, head tilting, and abnormal behaviors, such as being irritable, withdrawn, or lost learned behaviors.

The treatment for nervous system tumors depends on the extent of tissue damage, tumor location, and surgical accessibility. Surgical resection, radiation therapy, and chemotherapy are types of treatments for neoplasia in dogs.

What is Neoplasia in Dogs?

Neoplasia in dogs is abnormal and uncontrolled cell growth. The nervous system comprises the brain, the spinal cord, and the associated nerves, which control involuntary and voluntary bodily processes. 

Malignant nervous system tumors infiltrate, damage, and compress the underlying structures of the nervous system, leading to vision loss, loss of sense of smell, paralysis, and behavioral abnormalities. The tumors grow exponentially over time or metastasize into surrounding structures. 

Benign neoplasms grow slowly with less risk of invading the surrounding tissues and other body parts. 

How do Dogs have Neoplasia?

Dogs have neoplasia through diet, environment, genetics, chemical exposure, viruses, trauma, and immune system function. The definitive cause of neoplasia in dogs is unknown. “Gene changes that cause some rare inherited syndromes (like neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome, and von Hippel-Lindau syndrome) that increase the risk of developing some brain and spinal cord tumors” in humans, according to the American Cancer Society. 

Neoplasia is used interchangeably with cancer; however, only malignant neoplasia is cancer. A common misconception about neoplasia is that death is inevitable. Swift veterinarian care and diagnosis cure some types of neoplasia while others  managed to reduce the spread and prolong a dog's life. 

How does Neoplasia Differ from Cancer in Dogs?

Neoplasia differs from cancer in dogs because neoplasia is any abnormal and uncontrolled overgrowth of cells, while cancer is an overgrowth of cells that  spread to other organs. Metastatic neoplasia, known as “Mets,” is cancer that has spread to other body parts from its original site. Metastatic neoplasias are one of the types of cancer in dogs that are harder to treat.

Benign neoplasia grows into a large mass. Benign neoplasia is not cancerous because it does not spread to other organs. 

What are the Common Types of Neoplasia Found in Dogs?

The common types of neoplasia found in dogs are listed below.

• Astrocytoma: Astrocytomas are the most common brain tumor in dogs. They are neoplastic cells that resemble astrocytes. Brachycephalic adult dogs are predisposed to Astrocytoma, which occurs in any dog breed. Signs of astrocytoma in dogs include an abnormal pupillary light reflex, seizures, anorexia, and loss of appetite. 
• Gangliocytoma: Gangliocytomas are rare intracranial tumors in dogs that contain neuroblast-like cells. The tumors primarily affect the cerebellum, cranial nerve roots, eyes, and cervical ganglion. Signs of gangliocytoma are loss of muscle control, paralysis, and vision changes. 
• Meningioma: A meningioma is a tumor that grows inward from the meninges of the skull. It is typically benign and well-visualized with diagnostic imaging, making it suitable for surgical resection. Meningioma symptoms in dogs include walking in circles, vision loss, and incoordination.
• Pituitary adenoma: Pituitary adenomas are abnormal growths in the cells of the pituitary gland. The pituitary gland is responsible for hormonal changes that regulate important bodily processes like appetite and thirst. Dogs with pituitary adenomas have too much cortisol, which leads to hyperadrenocorticism or Cushing’s disease. The symptoms of pituitary adenoma are increased appetite and thirst, increased urination, hair loss, obesity, and a pot-bellied appearance.
• Spinal cord tumors: Spinal cord tumors are uncommon tumors in dogs. Clinical signs of spinal cord tumors are sudden onset of spinal pain, lameness in limbs or regions, and progressive neurological deficits.

What are the Typical Signs and symptoms of neoplasia in dogs?

The typical signs and symptoms of neoplasia in dogs are listed below.

• Ataxia: Ataxia is the loss of balance manifesting in an abnormal gait. The dog looks wobbly and unstable as it walks or runs. Loss of balance is a sign of a hindbrain tumor that affects the cerebellum, which leads to incoordination. 
• Seizures: Seizures are uncontrollable episodes of electrical surges in the brain and a sign of neoplasia in dogs. Seizures cause short-term spasms of uncontrolled body movements and changes in behavior. Dogs with seizures experience loss of awareness, change in emotion, shaking, and muscle control. Tumors cause seizures by affecting surrounding tissue or an imbalance in chemicals in the brain.
• Head and neck abnormalities: Head tilting occurs when the dog leans towards or falls onto one side. It is primarily a sign of dysfunction of the vestibular system. The vestibulocochlear nerve (cranial nerve VIII) and its receptor in the inner ear, brainstem, and cerebellum are structures affected by neoplasia in dogs. 
• Episodes of rage: Brain tumors interfere with the center for emotions in dogs. A study involving 97 dogs showed that rage episodes were among the highest percentage (45%) of clinical signs exhibited by dogs with neoplasms. Rage episodes are potentially exacerbated by feelings of confusion and discomfort that factor into aggressive behavior. 
• Muscle spasms: Neve injuries to the motor nerves trigger muscle spasms and twitching. The spasms occur sporadically but are consistent throughout the day and are a symptom of neoplasia in dogs. Muscle spasms look like small to moderate involuntary movements. 

How is Neoplasia Diagnosed in Dogs?

Neoplasia in dogs is diagnosed through history-taking, physical examination, and diagnostic imaging. A complete blood count and blood chemistry evaluation rule out underlying conditions before considering neoplasm in the nervous system. 

Diagnostic imaging with X-rays is useful but inconclusive when the localization is not optimal. Specialized radiographic techniques, such as radionuclide imaging (scintigraphy), CT scans, and MRI, are used to diagnose nervous system tumors. The specialized images detail the tumor's origin, location, shape, pattern, and extent. 

What is neoplasia in dogs treatment?

The neoplasia in dogs' treatment are listed below. 

• Surgical resection:  The best treatment for neoplasia in dogs is surgical removal of the tumor. The success of tumor removal surgery depends on the localization, pattern, visualization, and whether the dog is able to withstand the duration of the procedure. Surgical resection is a viable treatment option for benign neoplasms whereas metastatic neoplasms depend on the location, growth, and extent of the tumor. 
• Radiation: Radiation therapy uses a focused radiation beam to target cancer cells. The goal is to destroy the tumors' cellular makeup, which causes the cancer cells to die. Radiation therapy is combined with other forms of treatment, such as surgery and chemotherapy. The treatment is used in both benign and metastatic neoplasms. 
• Chemotherapy: Intravenous medication targets rapidly dividing cells, such as cancer cells. Chemotherapy is combined with surgical removal to remove residual cancer cells. Chemotherapy increases the risk of organ damage, including the stomach, mouth, and reproductive organs. Chemotherapy is a treatment for benign and metastatic tumors. 
• Palliative care: Palliative care is the conservative treatment for canine neoplasia. Medication is used to control seizures, relieve intracranial pressure and inflammation, and minimize pain, but the prognosis is often poor. Palliative care helps to ease the dog’s discomfort and pain as the disease progresses. 
• Euthanasia: Euthanasia is the procedure of inducing a painless death for a dog that has an incurable disease. Euthanasia is a treatment for dogs with metastatic tumors that are diagnosed late, too extensive, painful, and costly to treat. Euthanasia is indicated in cases where cancer has little to no chance of being treated, and the dog is suffering. 

What are the Risk Factors for Developing Neoplasia in Dogs?

The risk factors for developing neoplasia in dogs are listed below.

• Aged 5 years or above: Dogs with nervous system tumors have “a mean age of 9 years, on a scale between 4 and 13 years, 95% having ages over 5 years”, according to Baba and Câtoi, in “Comparative Oncology,” 2007.
• Breed disposition: Golden Retrievers are prone to cancer, according to a study of 97 dogs. The incidence by breeds was “16% Golden Retriever, 12% mixed breeds, 10% Labrador Retriever, 9% Boxer, 6% Collie. Of all 97 subjects with nervous system tumors”, according to Gavin et al. in “Clinical signs associated with brain tumors in dogs: 97 cases (1992–1997)”, 1999.
• Brachycephalic dogs: Dog breeds such as Boxers, English Bulldogs, and Boston Terriers are cited as having the highest incidence of brain tumors. The breeds have glial tumors and unclassified gliomas.

How can Neoplasia in Dogs Be Effectively Managed?

Neoplasia in dogs can be effectively managed by proactive treatment and management. The veterinarian prescribes medications and regular therapy sessions.

Follow the veterinary-prescribed schedule for radiation, chemotherapy, and other treatments to avoid a recurrence. Regular follow-ups are necessary to avoid complications with therapy. Seizures in dogs are a common clinical sign of nervous system neoplasia and are managed with medication. Supportive therapy minimizes discomfort and pain, and CBD for Dog Mobility helps minimize inflammation and improve mobility. 

How does Neoplasia Affect a Dog’s Quality of Life?

Neoplasia affects a dog’s quality of life by interfering with important bodily functions. The nervous system controls the functions inside a dog’s body. Neoplasias of the central nervous system cause mild to severe clinical signs depending on location, size, metastatic ability, and growth. Dogs with nervous system neoplasia are likely to be more irritable, have uncontrollable movements, seizures, and spasms, have difficulty walking, have poor eyesight, and difficulty breathing, which make daily life difficult. 

Are There Any Preventative Measures That Can Reduce the Risk of Neoplasia in Dogs?

Yes, there are preventative measures that can reduce the risk of neoplasia in dogs. Genetic predisposition is considered a risk factor; do not breed dogs with a history of neoplasia. 

Providing a good-quality and balanced diet, maintaining a healthy weight, regular mental and physical exercises, reducing exposure to toxic chemicals, secondhand smoke, pollutants, and spaying and neutering reduce the risk of certain types of neoplasia in dogs. 

Regular veterinary checkups allow for early detection and reduce the risk of debilitating neoplasia in dogs. A veterinarian assesses the dog for signs of neoplasia that owners do not. Neoplasias grow exponentially in a matter of days, so owners must schedule a veterinary appointment immediately when noticing unusual signs, especially for dogs over 5 years old and a predisposed breed. 

How can Owners Monitor Their Dogs for Signs of Neoplasia?

Owners can monitor their dogs for signs of neoplasia when they show clinical signs such as ataxia, changes in behavior, seizures, muscle tremors, and loss of vision.  Take note of the onset, duration, and suspected trigger when dogs show neurological signs. Taking a video of the episode is an additional tool that the veterinarian uses to assess the problem. Dogs with suspected neoplasia require lengthy isolation and observation. Consult a veterinarian immediately if a dog shows signs of neoplasia. 

Can CBD Oil Relieve Neoplasia in Dogs?

Yes, CBD Oil can relieve neoplasia in dogs. CBD has anti-seizure and anti-convulsive features. A common sign of nervous system neoplasia is random and uncontrollable seizures or tremors. Cannabinoids help reduce the frequency, intensity, and duration of seizures in dogs of idiopathic origin. CBD for dog mobility supports dogs with neuropathic pain affecting movement. The CBD helps dogs move more freely and improve quality of life. CBD oil helps dogs with anxiety by mimicking the effects of serotonin, the feel-good hormone responsible for happiness and relaxation. 

How much CBD Oil can I give to my Dog with Seizure?

You can give your dog with seizures 0.5 mg of CBD per pound of body weight per day. Consult a CBD dosage calculator for the most accurate dosage information for the CBD potency and pound of body weight. The CBD oil dosage for dogs with seizures varies according to the dog's exact weight and specific needs. A veterinarian advises on optimal dosages of CBD oil for dogs with seizures.