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Hydrocephalus (Water on the Brain) in Dogs

Occurrence: very rare
Location of illness: Head/Neck

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Hydrocephalus, also known as water on the brain, is a neurological disorder in dogs characterized by an abnormal accumulation of cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). in the ventricles of the brain. This accumulation can lead to increased pressure on the brain and impair normal neurological function.

The most important facts at a glance

Hydrocephalus in dogs occurs when the balance between the production and drainageDrainage refers to the removal of fluid from body cavities, Wounds, or inflamed areas, often using a tube or other device. It is used to prevent infection and promote healing. of brain fluid is disrupted, leading to fluid accumulation and increased pressure in the brain. The causes can be congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother., often genetic, or acquired through infections, inflammatory conditions, Tumors, or injuries. Breeds such as Chihuahua and Yorkshire Terrier are particularly susceptible. Symptoms include neurological problems such as seizures, disorientation, behavioral disorders, uncoordinated gait, and in severe cases, ParalysisParalysis is the complete loss of muscle activity in one or more areas of the body, which can lead to immobility and loss of sensation. Paralysis can be caused by injuries, illnesses, or disorders of the nervous system. or comaA coma is a deep state of unconsciousness where an individual cannot be awakened and does not respond to stimuli. In dogs and cats, it can be caused by severe illnesses, poisoning, or neurological problems.. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through clinical examinations, imaging such as MRI or CT, and cerebrospinal fluid analysisCerebrospinal fluid analysis is the examination of the cerebrospinal fluid to obtain diagnostic information. It can provide information on inflammatory conditions, infections, bleeding, and other diseases of the central nervous system. to rule out concomitant infections or inflammatory conditions.

Treatment depends on the severity and cause and may include medications to reduce fluid production or control seizures. In severe cases, surgical intervention such as ventriculoperitoneal shuntA shunt is an abnormal connection between blood vessels or heart chambers that causes blood to bypass the normal circulatory system pathway. Shunts can be congenital (present at birth) or acquired. surgery may be necessary to drain excess fluid. SupportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. care can improve quality of life. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. varies depending on the severity and response to treatment. PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. in congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. cases is difficult, but responsible breeding can reduce the risk. Regular vaccinations and health care can minimize the risk of acquired cases. Research focuses on genetic factors, new treatment methods, and improving the quality of life of affected dogs.

Causes

Hydrocephalus occurs when the balance between the production and drainageDrainage refers to the removal of fluid from body cavities, Wounds, or inflamed areas, often using a tube or other device. It is used to prevent infection and promote healing. of cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). is disrupted. The fluid is produced in the choroid plexus of the ventricles and drained through a complex system of channels and openings in the brain. If this process is disrupted, fluid can accumulate, increasing pressure in the brain.

The causes of hydrocephalus in dogs can be either congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. or acquired. CongenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. causes are often genetic and may be present at birth or develop in the first few weeks of life. Breeds such as Chihuahua, Yorkshire Terrier, and Pomeranian are considered particularly susceptible.

Acquired causes can arise from infections, inflammatory conditions, Tumors, or traumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries. that block the drainageDrainage refers to the removal of fluid from body cavities, Wounds, or inflamed areas, often using a tube or other device. It is used to prevent infection and promote healing. pathway of the cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system).. Infections such as distemper or meningitis can cause inflammatory conditions that impair cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). flow. In addition, Tumors in the brain or spinal cordThe spinal cord is a long, narrow bundle of nerve tissue located in the spinal canal of the vertebral column. It is part of the central nervous system and transmits nerve impulses between the brain and body. can mechanically block drainageDrainage refers to the removal of fluid from body cavities, Wounds, or inflamed areas, often using a tube or other device. It is used to prevent infection and promote healing..

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The symptoms of hydrocephalus can vary depending on the severity and cause. In puppies with congenitalCongenital means “present from birth” and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. hydrocephalus, the symptoms are often more subtle and can be difficult to detect. The most common signs include a disproportionately large head, a domed skull, behavioral changes, and difficulty learning or training.

In more severe cases, neurological symptoms such as convulsions, Blindness, ataxia (coordination disorders), and circulatory disorders can occur. The dogs may also exhibit unusual behavior, such as walking in circles or bumping into walls.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of hydrocephalus usually begins with a thorough clinical examination and a detailed medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits.. The veterinarian will look for typical symptoms and examine the dog’s head for signs of abnormal shape or size.

Imaging procedures are crucial for diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients.. UltrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examinations can be performed in some cases in young puppies whose skull bones have not yet fully ossified. However, more advanced imaging procedures such as magnetic resonance imaging (MRI)Magnetic resonance imaging is an imaging technique that uses strong magnetic fields and radio waves to create detailed images of the inside of the body. It is used in veterinary medicine to diagnose diseases of the brain, spine, and other organs. or computed tomography (CT)Computed tomography (CT) is an imaging technique that uses X-rays and computer technology to create cross-sectional images of the body. It enables a detailed view of bones, organs, and other structures and is used for the diagnosis of injuries, diseases, and for planning medical interventions. provide a more detailed view of the ventricles and brain.

In addition, cerebrospinal fluid analysisCerebrospinal fluid analysis is the examination of the cerebrospinal fluid to obtain diagnostic information. It can provide information on inflammatory conditions, infections, bleeding, and other diseases of the central nervous system. can be performed to detect possible infections or inflammatory conditions that may be contributing to hydrocephalus.

Therapy

Treatment for hydrocephalus depends on the cause and severity of the condition. In mild cases, medications that reduce the production of cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). or control convulsions may be sufficient. Commonly used medications include diureticsDiuretics are medications that increase urine production in the kidneys to rid the body of excess salt and water. They are often used to treat high blood pressure, heart failure, and certain types of edema. such as acetazolamide and furosemide.

In more severe cases, surgery may be required. A common procedure is ventriculoperitoneal shuntA shunt is an abnormal connection between blood vessels or heart chambers that causes blood to bypass the normal circulatory system pathway. Shunts can be congenital (present at birth) or acquired. surgery, in which a tube is placed in the ventricleA ventricle is one of the two lower chambers of the heart that pump blood into the arteries. The right ventricle pumps blood to the lungs, while the left ventricle pumps blood throughout the body. to drain excess cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). into the abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. cavity, where it can be absorbed. However, this requires careful monitoring and can be associated with complications.

In addition to medical and surgical treatment, supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. care may be necessary to improve the dog’s quality of life. This may include adjusting the environment, physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. measures, and a special diet.

Prognosis and follow-up care

The prognosis for dogs with hydrocephalus varies greatly and depends on the cause, severity of the condition, and responsiveness to treatment. With mild cases and early intervention, many dogs can achieve a good quality of life and live a relatively normal life.

Dogs with severe neurological symptoms or those who do not respond well to treatment have a poorer prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop.. In such cases, the quality of life can be severely impaired, and it may be necessary to make humane decisions.

Prevention

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. hydrocephalus is difficult because genetic factors play a major role. However, breeders should be careful not to breed dogs with a known predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. to hydrocephalus in order to reduce the risk in future generations.

For acquired cases, preventing infections that can lead to hydrocephalus is crucial. This can be achieved through regular vaccinations, parasiteA parasite is an organism that lives on or in another living being (the host) and feeds at its expense. Parasites can cause a variety of diseases in animals and humans. control, and good general health care.

An awareness of the symptoms and an early veterinary examination if neurological problems are suspected can also help minimize the effects of the disease and improve treatment outcomes.

Outlook on current research

Research into hydrocephalus in dogs is a dynamic and constantly evolving field. Scientists are working to better understand the genetic and environmental factors that can lead to this condition. It is believed that certain breeds are genetically predisposed to developing hydrocephalus, and ongoing studies aim to identify the specific genetic markers that increase the risk. Advances in genetic sequencing and the availability of more comprehensive genetic databases are enabling researchers to isolate these markers and better understand them.

Another important area of research focuses on the development of new and improved treatment methods. While surgical procedures such as the placement of a ventriculo-peritoneal shuntA shunt is an abnormal connection between blood vessels or heart chambers that causes blood to bypass the normal circulatory system pathway. Shunts can be congenital (present at birth) or acquired. are currently the most common treatment method, there are significant research efforts to develop non-invasive techniques. These include the use of medications that can regulate cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). flow and the exploration of new materials and technologies for shuntA shunt is an abnormal connection between blood vessels or heart chambers that causes blood to bypass the normal circulatory system pathway. Shunts can be congenital (present at birth) or acquired. implantation that cause fewer complications and side effects.

Advances in diagnostic imagingDiagnostic imaging includes medical procedures that create images of the inside of the body to diagnose, monitor, or treat diseases and injuries. Examples include X-ray, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI)., particularly in the use of MRI and CT, have improved diagnostic capabilities for hydrocephalus. Researchers are investigating how these technologies can be used to detect the disease earlier and improve treatment outcomes. The development of portable and less invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. imaging techniques could revolutionize the monitoring and treatment of hydrocephalus in the future.

Finally, there are also efforts to improve the quality of life for dogs with hydrocephalus. Research is investigating how physical therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. approaches and targeted rehabilitation programs can help affected dogs improve their motor skills and live as normal a life as possible. The exploration of diet plans and nutritional supplements that promote neurological health is also an emerging field of research.

Overall, research into hydrocephalus in dogs is promising, and the continuous efforts of scientists could lead to significant improvements in the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients., treatment, and quality of life of affected animals in the near future.

Frequently asked questions (FAQs)

What is Hydrocephalus in Dogs? Hydrocephalus, often referred to as “water on the brain”, is a condition in which excess cerebrospinal fluidCerebrospinal fluid is a clear, colorless liquid that surrounds and protects the brain and spinal cord. It acts as a shock absorber and is involved in regulating the chemical environment of the CNS (central nervous system). accumulates in a dog’s brain. This accumulation can lead to increased pressure on the brain, which can cause neurological symptoms and behavioral changes.
What symptoms can occur in a dog with hydrocephalus? The most common symptoms include an enlarged skull, behavioral changes, balance disorders, seizures, and in some cases, Blindness. Symptoms may vary depending on the severity and progressionProgression refers to the advancement or worsening of a disease over time. It describes an increase in the severity or extent of the disease symptoms. of the disease.
Which breeds are most commonly affected by hydrocephalus? Certain breeds such as Chihuahuas, Pomeranians, Yorkshire Terriers, and other small breeds are more commonly affected. This is often due to genetic predispositions and the anatomyAnatomy is the scientific study of the structure of living things. It deals with the construction and organization of organisms, including their systems, organs, and tissues. of these breeds.
How is hydrocephalus diagnosed in dogs? Diagnosis is usually made through a combination of clinical examination, neurological tests, and imaging procedures such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow., MRI, or CT scans. These methods help visualize the accumulation of fluid in the brain.
What treatment options are available for dogs with hydrocephalus? Treatment may include medications to reduce fluid production or surgical procedures such as implantation of a shuntA shunt is an abnormal connection between blood vessels or heart chambers that causes blood to bypass the normal circulatory system pathway. Shunts can be congenital (present at birth) or acquired. that drains the excess fluid. The choice of treatment depends on the severity of the condition and the dog’s general health.
Can hydrocephalus be cured in dogs? Hydrocephalus is usually not completely curable, but the symptoms can often be successfully managed with appropriate treatments to improve the dog’s quality of life.
Is hydrocephalus a life-threatening condition in dogs? Without treatment, hydrocephalus can cause serious neurological impairments and, in some cases, Death. However, with early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and appropriate treatment, many dogs can live a relatively normal life.
How common is hydrocephalus in dogs? Hydrocephalus is relatively rare, but occurs more frequently in certain breeds. The exact prevalence is difficult to determine, as many cases may go undiagnosed or milder forms of the disease may go undetected.
Can environmental factors contribute to the development of hydrocephalus? While genetic factors play a significant role, environmental factors such as infections, injuries, or toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. exposures can also contribute to the development of hydrocephalus. These factors can interfere with the natural flow of fluid in the brain and lead to fluid accumulation.
What can dog owners do to minimize the risk of hydrocephalus? While genetic factors cannot be directly controlled, dog owners can help minimize the risk by avoiding head injuries, ensuring a healthy environment, and having regular veterinary checkups. When choosing a puppy, breeders with a good reputation who pay attention to genetic health should be chosen.