What is Hydrocephalus in Dogs?
Hydrocephalus in dogs refers to the abnormal accumulation and expansion of cerebrospinal fluid (CSF) within the brain’s cavities. CSF serves to cushion and support the brain and spinal cord, providing essential nutrients. However, in cases of hydrocephalus, there is either an increase in CSF production, a decrease in its absorption, or a blockage in its circulation within the brain, leading to fluid buildup and subsequent pressure on the brain tissue.
This increased pressure can result in significant brain damage, as the skull restricts its expansion. Potential complications include brain herniation and even fatality. While the exact mechanisms underlying hydrocephalus remain complex and not fully understood, veterinarians and researchers generally classify it into two main types: congenital and acquired. Congenital hydrocephalus is present from birth, whereas acquired hydrocephalus develops over time, with initially normal brain function but later abnormal fluid accumulation.
Symptoms
Symptoms of hydrocephalus in dogs can vary widely depending on the underlying cause and the specific area of the brain affected. Some dogs may show no symptoms at all.
Symptoms can manifest suddenly or progress gradually and may include:
- Difficulty with training and decreased responsiveness to stimuli
- Visual impairments, often resulting in blindness
- Abnormal eye movements, such as eyes fixed downward and away
- Seizures
- Pressing of the head against objects
- Enlarged, dome-shaped head, particularly evident in cases of congenital hydrocephalus with open fontanelles (soft spots on the skull)
- Impaired brain function
- Unusual behaviors, including inappropriate vocalization, excessive excitability, drowsiness, and circling
- Irregularities in gait
- Increased pressure within the skull, potentially leading to stupor or coma.
Causes
Congenital hydrocephalus stands as one of the predominant forms of this condition in dogs. “Congenital” indicates that the condition is present from birth, although it doesn’t necessarily imply a genetic origin. Various brain malformations can lead to the obstruction of cerebrospinal fluid (CSF) flow. Common causes of congenital hydrocephalus encompass:
- Genetic abnormalities
- Prenatal infections, often attributed to the parainfluenza virus
- Exposure to substances harmful to fetal development
- Brain hemorrhage resulting from a challenging birth
- Deficiency in prenatal vitamins
In some cases, the precise cause of congenital hydrocephalus remains elusive to veterinarians. Nonetheless, they frequently diagnose congenital hydrocephalus alongside other malformations such as:
- Skull and vertebrae abnormalities at the base of the skull, which restrict adequate brain function space
- Underdevelopment of the cerebellum, accompanied by cyst formation and subsequent fluid accumulation
- Abnormalities within the spinal cord, including certain cysts and a variation of spina bifida
- Specific cysts within the nervous system
Acquired hydrocephalus occurs when an initially normal brain encounters an obstruction, leading to CSF accumulation and dilation. Causes of acquired hydrocephalus encompass:
- Tumors
- Infections
- Traumatic injuries
- Brain hemorrhages
- Inflammatory brain diseases
Diagnosis
Diagnosing hydrocephalus in dogs typically begins with a veterinarian’s physical examination, which may prompt suspicion based on observable signs. The vet will carefully assess the dog’s appearance and behavior, including its response to stimuli. Dogs presenting with characteristic features such as an enlarged dome-shaped head, open fontanelle (soft spot on the skull), and eyes positioned downward and outward are often evaluated for hydrocephalus.
Diagnostic procedures may include:
X-Rays: X-rays can be employed to examine the dog’s skull for indications such as open plates and other suggestive signs of hydrocephalus.
Ultrasound: If the dog has an open fontanelle, ultrasound imaging may be utilized to visualize any dilated chambers within the brain.
CT and/or MRI Scans: These advanced imaging techniques offer a more detailed assessment of the internal brain structure and function, allowing for a definitive diagnosis of hydrocephalus.
In certain cases, additional diagnostic tests such as electroencephalography (EEG) to measure brain electrical activity and cerebrospinal fluid analysis to evaluate spinal fluid composition may also be performed by the veterinarian.
Treatment
Treating hydrocephalus in dogs focuses on addressing the underlying cause, aiming to halt the progression of the disease. However, not all forms of hydrocephalus can be completely resolved. The treatment approach takes into account factors such as the dog’s age, the severity of the condition, and the intensity of symptoms.
Initial treatment often involves medication to reduce the production of cerebrospinal fluid, particularly in cases of mild to moderate hydrocephalus. Commonly prescribed medications for this purpose include:
- Steroids such as prednisolone and dexamethasone
- Diuretics like furosemide
- Proton-pump inhibitors such as omeprazole
In more severe instances or when medication fails to produce desired results, neurosurgery may be recommended as an option. This typically entails the insertion of a shunt to divert excess fluid from the brain to another part of the body, often the abdominal cavity. Surgical intervention boasts a success rate ranging from 50% to 90% in animals with hydrocephalus.
In cases where a dog experiences seizures, immediate measures may include administering valium. Subsequently, the veterinarian may prescribe additional treatments such as antibiotics, surgery, or steroids once the dog’s condition stabilizes.
Living and Management
The long-term management of hydrocephalus in dogs using medications like steroids and diuretics may increase the risk of developing conditions such as Cushing’s disease and electrolyte imbalances. Consistent follow-up appointments with the veterinarian are crucial to closely monitor the dog’s health.
Dogs undergoing surgery to implant a shunt may necessitate additional procedures to address any blockages that may occur in the shunt over time.
While dogs with mild cases of hydrocephalus can often lead relatively normal lives with minimal medical intervention, severe cases carry a less favorable prognosis. As the disease progresses, it can lead to complications such as brain herniation, seizures, and even death. Generally, around 50% of affected animals respond well to treatment, whether through medical management or surgical intervention.
Hydrocephalus in Dogs FAQs
What is the survival rate of hydrocephalus in dogs?
The outlook for dogs with hydrocephalus varies, ranging from optimistic to pessimistic, contingent on factors such as age, location, and symptom severity. Around 50% of dogs respond positively to treatment.
Is hydrocephalus in dogs genetic?
Certain forms of hydrocephalus in dogs have a genetic basis.
Can a puppy grow out of hydrocephalus?
While not all puppies display clinical signs of hydrocephalus, once symptoms emerge, it is improbable for them to naturally diminish or disappear without intervention.
Can hydrocephalus be cured?
Hydrocephalus cannot be eradicated, but it can be effectively managed through a combination of surgical procedures and medication.