Brain Diseases: Categories, Causes and Symptoms
The nervous system – compromised of the brain, spinal cord and nerves is in effect the control centre for the body. It reaches from our head to the (nerves in) the tips of our fingers and toes. When it’s working well, the nervous system allows us to function on all levels – to walk, speak, breathe and swallow. Many of these functions are automatic and don’t require thought. But the same system also allows us to think deeply, thanks to the complicated organ at the centre of it all. The brain comprises about 86 billion nerve cells, and there are more than a trillion connections among brain and nerve cells throughout the body.
The brain gives us personality, allows us to talk and feel, gives us emotions. But when problems do occur with the nervous system, these can have a profound and even debilitating impact. In some cases neurological conditions can be fatal. Given the complexity of the brain and the rest of the nervous system, it’s not surprising that so many things can go wrong.
Causes of Brain Disease
- Inflammation: Swelling in the brain may be caused by infection, an autoimmune reaction or some unknown reason. Over time this can irritate and damage brain tissue. Multiple sclerosis and vasculitis are two examples of inflammatory brain disease. A traumatic brain injury may cause inflammation, as well as direct damage to the brain.
- Stroke: Disruption of blood flow to the brain can cause the loss of brain cells, which can affect movement, speech and thinking.
- Brain Tumors: Tumors can press on tissues and nerves and affect brain function.
- Genetics: Some brain diseases, such as Tay-Sachs disease, Huntington’s disease, muscular dystrophies and Wilson disease, are genetic. They are typically diagnosed through a clinical exam, family history and, in some cases, genetic testing.
Other causes of other neurological conditions are as variable as the diseases and disorders themselves. These may include:
- Spinal cord injury.
- Infections.
- Environmental, including toxins like lead and mercury.
- Alcohol abuse.
- Poor diet and malnutrition.
Physical/Cognitive Symptoms of Brain Disease
Of course, symptoms vary widely depending on the specific condition. But the following are some common physical and/or cognitive symptoms of a brain disease.
Physical symptoms:
- Changes in hearing, speech or vision.
- Paralysis – partial or complete.
- Seizures
- Poor balance or dizziness.
- Headaches.
- Nausea and vomiting.
- Shakes and tremors.
- Weakness in arms or legs.
- Loss of sense of smell or taste.
- Excessive fatigue.
- Problems reading or writing, when a person was able to do so previously.
- Pain that can’t be explained.
- Difficulty breathing.
- Difficulty walking.
- Problems swallowing.
- Speech changes.
Cognitive symptoms:
- Memory loss.
- Confusion.
- Difficulty concentrating.
- Personality changes.
- Mood shifts.
- Depression or anxiety.
- Poor impulse control or problems regulating emotions.
Most common categories of brain disease, along with other neurological disorders
1. Autoimmune Diseases
Multiple sclerosis, or MS, is a disease of the central nervous system in which the body’s immune system attacks myelin, the tissue that covers nerves. This interferes with neural communication between the brain and the body. Symptoms include blurred vision, weakness in the arms and legs, speech problems, tremors and sometimes paralysis. There are treatments for this autoimmune disease but no cure. Other autoimmune brain diseases include:
- Autoimmune encephalitis.
- Autoimmune-related epilepsy.
- Central nervous system vasculitis.
- Hashimoto’s encephalopathy.
2. Autism and Neural Development Diseases
Autism spectrum disorder is a developmental condition that affects an individual’s ability to communicate and interact with others. The disorder can be diagnosed at any age, but symptoms typically appear within the first two years of life. Markers of autism include social awkwardness, poor verbal and nonverbal communication, repetitive behaviours and obsessive interests and habits. Its causes are not known, though genetics and environmental factors have been suspected.
Other types of neurodevelopment disorders include hypoxic/ischemic encephalopathy (brain injury caused by oxygen deprivation to a newborn’s brain), cerebral palsy, developmental disorders and attention deficit hyperactivity disorder, or ADHD. Depending on the severity of the case, medical and behavioral therapies can help, especially if the disease is diagnosed early.
3. Dementia
There are many types of dementia, including frontotemporal dementia, Lewy body dementia and vascular dementia, but Alzheimer’s disease is the most common and perhaps the best known. Aging, genetics and lifestyle factors all play a role in dementia, though the exact causes are unclear. Symptoms of dementia include a progressive loss of cognitive and functional ability, leading to a loss of independence.
There are currently no effective treatments, but many trials are underway that may offer hope to patients and their families in the coming years. Numerous trials are currently looking to identify the disease as early as possible, before memory problems surface, and start treatments then.
4. Infections
Common brain diseases caused by an infection include meningitis and encephalitis. Meningitis is an infection in the lining around the brain or spinal cord. Encephalitis is an infection of the brain tissue. They often occur together and can cause neck stiffness, headache, fever and confusion. They can be fatal without antiviral treatment.
5. Movement Disorders
Parkinson’s disease, ataxias, tremor, dystonia, tics and Tourette syndrome are examples of movement disorders that often progress to a complete loss of function. They can lead to tremors, slow and stiff movement, loss of balance, speech impairment and difficulty walking. Parkinson’s disease is caused by the loss of dopamine-producing brain cells.
The causes of movement disorders can range from genetics to damage to the brain, spine and peripheral nerves to stroke. Though no cure is known, drug and physical therapy treatments can help relieve some symptoms.
6. Neuromuscular Diseases
These disorders attack peripheral nerves outside the brain and the muscles they control. Amyotrophic lateral sclerosis, commonly referred to as ALS or Lou Gehrig’s disease, is the best known of these diseases. It typically progresses rapidly and is ultimately fatal. Increasingly, cognitive problems are also being recognized with ALS. And the progressive disease can cause dementia in some people. There are treatments to slow ALS or help with symptoms, but there’s no cure.
Another neuromuscular disease is peripheral neuropathy (caused by diabetes, chemotherapy or genetics), characterized by pain, numbness and weakness, usually in the hands or feet. Other neuromuscular diseases include Guillain-Barre syndrome and CIDP (chronic inflammatory demyelinating polyneuropathy), myasthenia gravis and muscular dystrophy.
For some who’ve sustained nerve damage, like from peripheral neuropathy, nerve transfer surgery may be a treatment option. This surgical technique involves harvesting a normal functioning nerve from another part of the body, and implanting it in an area where the nerve isn’t functioning.
7. Seizure Disorders
Seizures are caused by a disruption in brain activity, either because of illness, brain damage or other factors. Along with epilepsy, other seizure disorders include mesial temporal lobe epilepsy, post stroke/post concussive epilepsy and genetic and pediatric inherited epilepsy syndromes (such as Lennox-Gastaut, Dravet, West syndrome and juvenile myoclonic). They may be caused by genetic anomalies, but often the cause is unknown. Treatments like medication, surgery and even a specialized, medically-monitored diet can help many patients get seizures from epilepsy under control.
8. Stroke and Vascular Diseases
Stroke is the leading cause of permanent disability in adults. An ischemic stroke is when blood flow to the brain is impaired by a blocked blood vessel. A hemorrhagic stroke is when a blood vessel in the brain ruptures, causing bleeding into the brain. Both types of stroke kill brain tissue. Symptoms for both include sudden confusion, weakness in the arms or legs – especially on one side of the body – vision and speech impairment and sudden emotional control problems.
9. Trauma
Trauma, including concussion, can be mild or severe, and can cause anything from a mild headache to confusion, loss of consciousness, convulsions and even death. Chronic traumatic encephalopathy, or CTE, is a progressive disease that’s been found in military veterans and in athletes, such as football and hockey players, who experience repeated head trauma. It can lead to memory loss, confusion, personality and behavior changes, balance and motor impairment and violence or suicide. Surgery and medication can treat some forms of brain trauma, and physical and behavioral rehab is also sometime effective.
Trauma to the spine, such as a broken vertebrae from an automobile crash or another accident, can also be life-altering. This can lead to a significant loss of neurologic function. For example, some who sustain spinal cord injury, become partially or fully paralyzed. Some lose function and sensation in their legs (paraplegic). Others become fully paralyzed from the neck down, so that they’re unable to move and have no sensation in all four limbs (quadriplegic).
It can be difficult to restore function in such cases. But research suggests nerve transfer is one technique that may help some patients who’ve been fully paralyzed regain function in their arms and hands. Assistive devices, like power wheelchairs, help others navigate mobility challenges.
10. Tumors
Both benign and malignant tumors can put pressure on brain tissue or destroy tissue, causing problems in the body associated with the area of the brain affected. Tumors can start within the brain or metastasize there from other organs. The most common brain tumors are:
- Metastatic, cancer having spread from another site.
- Glioblastomas, which originates from the brain.
- Astrocytomas, which originate in star-shaped cells called astrocytes.
- Meningiomas. Forming outside the brain in the meninges, the membranes that cover the brain and spine spinal cord, these tumors are still commonly lumped in with other brain tumors.
Symptoms depend on the size and location of the tumor, but can include pain, headaches, seizures, nausea and vomiting, vision or hearing problems, behavioral and cognitive problems or motor and balance issues. Tumors can actually develop either in the spinal column – so within the bones … or within the spinal cord or spinal nerves, or in the spaces in between. Far and away the most common type of spinal tumors are those that develop in spinal column secondary to other cancers. So, for example, if a person has breast, prostate or lung cancer, those tumors spread from their original site to the spinal column.
Treatments for brain or spinal tumors may involve surgery, radiation, chemotherapy or a combination of them. Newer and still-experimental treatments, including gene therapy and immunological therapy, show promise for future tumor treatment strategies.
11. Scoliosis
Most often, the cause of scoliosis, or abnormal curvature of the spine, is unknown – called idiopathic scoliosis. In other cases, it may be degenerative and occur as a person ages. In the latter case, over time, the spine may become more curved, until a person is left slumping over a walker or cane. Less commonly, spinal tumors can also cause scoliosis. When scoliosis is associated with another neurological or muscular disease like cerebral palsy, spinal trauma or spina bifida, it’s referred to as neuromuscularscoliosis.
In most cases, scoliosis is mild and doesn’t require any medical intervention or oftentimes is just monitoring with X-rays. In rare cases, though, idiopathic scoliosis can be significant, and as the adolescent develops or matures skeletally they can get rapid progression of the curvature. Those are the scenarios where surgery is considered to halt that progression. This can help to keep scoliosis from getting worse and correct the curvature.
12. Spina Bifida
This birth defect – specifically what’s called a neural tube defect – occurs on a continuum: It can be more or less severe. The most severe form is known as myelomeningocele. As long as a pregnant woman is receiving appropriate, regular obstetric care, spina bifida is usually first detected on a prenatal ultrasound – typically around midway through the pregnancy. If a mom has had inadequate prenatal care or if it was just missed on the previous ultrasounds, on occasion it’s diagnosed at birth when the child (has) an obvious defect on their back.
Depending upon severity, spina bifida can lead to a range of complications. This may include developmental delays, as well as an associated defect called chiari malformation type 2 in the brain and accumulation of fluid in the brain, or hydrocephalus. The resulting neurologic dysfunction linked with spina bifida can cause symptoms ranging from headaches to trouble swallowing and breathing. When spina bifida is diagnosed during pregnancy, women are introduced ahead of time to specialists who would care for the child and counseled on all options.
13. Bell’s Palsy
This condition causes temporary paralysis or weakness of one side of the face. It’s a loss of function of the seventh cranial nerve. There’s a right and left seventh cranial nerve, and it supplies only the muscles on that side of the face. This nerve extends just below the earlobe and across the jaw, and it fans out over the side of the face. As it branches out it reaches all the different muscles that raise the eyebrows that crinkle the forehead, that allow you to smile, that give us our visual expression.
What causes the trauma to the nerve and subsequent loss of function isn’t clear. But experts think that viral infections may play a role. Most who develop the condition make a full recovery, whether they undergo treatment or not. But medications to decrease inflammation may be prescribed. And other approaches, such as physical therapy to massage or exercise the face, may be recommended to speed recovery.