Health Literacy and Nervous System Diseases
Knowledge and understanding of the medical terminology pertaining to some of the more common nervous system disorders is an important part of health literacy. It can also aid in identifying the need for professional assessment and treatment. Prompt actions based on an acknowledged need can prevent adverse consequences and lead to better health care outcomes. Listed below are the medical terms and definitions of some of the most common nervous system diseases. To increase your learning experience you can hear the medical pronunciation of the terms in bold font in the order in which they appear. Just click the play button below.
Amyotrophic lateral sclerosis (ALS) – It is an incurable degenerative disease of the anterior horn cells of the spinal cord and brain stem. The primary problem is degeneration and death of the cells in the front portion of the spinal cord which control the movement of muscles. It commonly affects muscles of the upper and lower limbs as well as those of the chest wall. Consequently, victims experience limb weakness and breathing difficulties. Also, muscle wasting (atrophy) is a common physical sign. Brainstem involvement can cause spasticity of the upper and lower limbs, difficulty swallowing and voice disturbances. The more popular and recognized name for it is Lou Gehrig’s disease. That is because the famed baseball player, Lou Gehrig, died from it. Its cause is unknown.
Alzheimer’s disease – It is the most common form of dementia. One of its earliest signs is a decline in short-term memory. Long-term memory eventually also declines but somewhat later. A common reported problem is difficulty remembering names or recognizing faces of known individuals. Other signs of declining cognitive ability include:
- Diminished abstract reasoning
- Trouble making decisions
- Problems performing familiar tasks like preparing meals
- A tendency to get lost
- Erratic driving
- Difficulty finding words while trying to communicate
Brain autopsy following death shows two classic abnormalities of the brain tissue. They are neurofibrillary tangles and amyloid deposits. Because of its prevalence and frequent requirement for skilled long-term care it is currently the most expensive disease to manage in the United States. In recent years it surpassed heart disease and cancer in terms of its economic impact.
Bell’s palsy – Is a condition of weakness or paralysis of one side of the face resulting from inflammation of the seventh cranial nerve (facial nerve). The cause of the inflammation is usually unknown but in some instances the herpes virus is the suspect. Problems in the brain such as a stroke or tumor are sometimes mistaken as Bell’s palsy when they cause facial drooping. The difference however, is that Bell’s palsy affects the upper and lower face, whereas the seventh nerve palsy associated with brain disorders affects only the lower face.
The reason for the difference is that the nerve fibers from the brain that control the facial nerve fibers that connect directly with the muscles of the upper face originate from both sides of the brain, whereas those that control the nerve fibers of the muscles of the lower face originate only from the opposite side of the brain. Therefore, if malfunction of the facial nerve is due to disease or injury to upper motor neurons involving one hemisphere of the brain normally functioning nerve fibers from the same unaffected side still make connections with the portions of the nerve that control muscles of the upper face. Because there is not that dual supply of upper motor neuron fibers for the lower portion of the face, drooping of the mouth occurs on the opposite side of an upper motor neuron lesion.
Since Bell’s palsy is a problem with the seventh peripheral nerve itself, it causes signs and symptoms in the upper and lower portions of the face on the same side as the disease. Those symptoms include facial drooping, drooling, increased or decreased tear production, eye closure weakness and sometimes pain in or behind the ear. Because the facial nerve also governs taste in the anterior two thirds of the tongue, taste is also disturbed. The symptoms of Bell’s palsy are self-limiting in most individuals. Sometimes mild to moderate symptoms linger though.
Carpal tunnel syndrome (CTS) – Is a disorder of the median nerve that travels through the wrist to the palm of the hand and fingers. It can be associated with tingling, numbness, pain, and/or weakness in the affected hand and fingers as a result of pressure on the nerve. A fibrous band in the wrist (retinaculum) which overlies the nerve as it travels through the wrist is what causes the pressure when it thickens. Repetitive strain from activities such as long-term excessive use of a keyboard is one cause. It is also associated with rheumatoid arthritis as well as some endocrine conditions such as hypothyroidism and diabetes mellitus.
Concussion – It is a temporary alteration of one’s mental state as a result of trauma to the head. Characteristics signs are confusion and loss of memory. There may or may not be brief loss of consciousness.
Cerebrovascular Accident (CVA) – It is the medical term for a stroke.
Dementia – Is a general term referring to the loss of or decline in mental abilities to the point that it interferes with normal activities of daily living. It is an acquired condition not present at birth. In contrast to delirium with which has some of the same manifestations it develops gradually over time. It is most commonly the result of degeneration of the cerebral cortex. Alzheimer’s disease is the most common form. Other common causes include prior stroke(s), atherosclerosis of brain blood vessels, acquired immune deficiency syndrome, Parkinson’s disease, multiple sclerosis, hypothyroidism, hypercalcemia, certain vitamin deficiencies, and brain tumors. There are also a few other rare conditions that can cause it.
Epilepsy (Seizure disorder) – Is a disorder of recurrent bouts of abnormal bursts of electrical activity in the brain accompanied by a change in mental status, muscle movement control, vision, voice, and/or awareness. There are many types and causes. Some of the more common causes are head injury from trauma, stroke, brain tumor and infection. Oftentimes though, the cause cannot be determined. EEG might establish or confirm the diagnosis, but the test might be normal in between seizures. Therefore repeat testing might increase the accuracy of diagnosis.
Guillain-Barré syndrome – Is a form of neuropathy in which several peripheral nerves throughout the body are involved. It occurs usually 3-4 weeks following recovery from an acute viral illness. In contrast to other forms of neuropathy which develop gradually and persist as chronic diseases, Guillain-Barré is an acute illness which usually subsides with complete resolution of symptoms within one year of its onset in 90% of the individuals affected. It commonly begins with weakness and numbness in the fingers and toes with eventual weakness and/or paralysis involving both upper and lower limbs. Additionally there is oftentimes a loss of reflexes and diminished sensation in the limbs. Its cause is unknown.
Herniated disc – Is a condition in which one of the discs (spongy jelly-filled structures) between adjacent bones of the spine (vertebrae) ruptures and releases the jelly inside. The release of the material results in the application of pressure to adjacent spinal nerve roots. The resulting symptoms depend on the site of the herniation and the nerve roots affected. Some of the common symptoms are neck pain ± radiation into the upper limbs, back pain ± radiation into the lower limbs, limb weakness, limb numbness, loss of bladder control and loss of bowel control. It is a common cause of sciatica.
Hydrocephalus – It is the increase in the size of the ventricles of the brain due to the accumulation of excessive CSF. The excessive buildup is the result of blockage of outflow of the fluid from the cavities. The condition can be present at birth or may result from hemorrhage, infection or tumor within the brain. Symptoms include headaches, blurred vision, lack of coordination, abnormalities of urination, nausea, vomiting, weakness, visual disturbances and intellectual deficits.
Meningitis – It is inflammation of the meninges. The most common cause is a bacterial or viral infection, but fungi can also be a cause. There are some other rarer causes. A lumbar puncture or spinal tap confirms the diagnosis.
Migraine headache – Is a severe headache usually on one side of the head lasting several hours or days. The pain most commonly is throbbing and may be associated with nausea or vomiting. An aura may precede the pain. Flashing lights in the visual fields, blind spots, or tingling in the arms and/or legs are common aura. Physical activity tends to make the headache worse and there may be associated sensitivity and intolerance to light and noise.
Chronic migraine is a headache syndrome in which the sufferer experiences headaches at least 15 days out of a month for three consecutive months. The headaches last for at least four hours if untreated. Some of the headaches are typical migraine headaches with aura, but they need not all be. Some may be associated with symptoms more characteristic of tension headaches, sinus headaches, or a combination of both.
Ménière’s disease – It is a disease in which there is increased pressure associated with the flow of fluid which is normally present within the bony canals of the inner ear (labyrinth). Its classic symptoms are hearing loss, tinnitus, vertigo and a feeling of fullness or pressure in the ear. It usually begins in one ear but may extend to involve both ears over a period of several years. It differs from Ménière’s syndrome in that its cause is unknown. The syndrome on the other hand, can result from conditions which interfere with the production or absorption of fluid within the labyrinth. Some of those conditions are trauma, certain medications, infection and autoimmune disease.
Multiple sclerosis – Is a neurological disease in which the main pathophysiology is damage to the myelin covering of the nerve fibers in the brain and spinal cord. The actual cause of the disease is unknown. Experts believe it is an autoimmune disease in which the body inappropriately attacks its own tissues as though they are foreign substances. Common symptoms include muscle weakness, stiff or spastic movements, blurred vision, double vision, poor control of urination, constipation, paresthesia, numbness, other abnormal sensations, imbalance, lightheadedness, vertigo, cognitive impairment and emotional problems. Typical findings on an MRI scan of the brain establish and confirm the diagnosis. It is an incurable disease but in recent years many new medications to treat it have emerged and are available at this time.
Myasthenia gravis –It is a disease of the neuromuscular synapse or the junction between the nerves and the muscles of voluntary control. The problem is the body’s production of antibodies which block the normal response of muscles to the neurotransmitter, acetylcholine by damaging the receptors within the muscle. Because of the resulting defective communication between the nerves and the muscles, sufferers experience muscle weakness which worsens as the muscles are used. In addition to skeletal muscles, muscles of eyelids and those that govern eye-movement are also affected. Consequently many sufferers have droopy eyes and experience double vision. Its cause is unknown.
Neuritis (Peripheral neuritis) – Is inflammation of one or more peripheral nerves. It is a form of peripheral neuropathy in which inflammation is the main pathology. Systems can be the same as those of neuropathy. Pain tends to be more frequent though, depending on the cause and duration of the disorder.
Neurodegeneration – Is the progressive loss of function or structure of neurons, including their death. Nerve cell bodies affected might be in the brain or spinal cord depending on the disease it is a part of. It is an umbrella term that includes many neurodegenerative diseases. Alzheimer’s, Parkinson’s, multiple sclerosis and Lou Gehrig’s disease are some examples, to name a few. – Neurodegenerative –adj.
Neuropathy (Peripheral neuropathy) – It is a general term for a disorder of function and structure of one or more peripheral nerves. The pathology can be inflammation, degeneration or combination of both. Motor, sensory or a combination of both types of nerves can be involved, although it is most common for only sensory nerves to be involved. Diabetes mellitus is a common cause. Other causes include:
- alcohol abuse
- heavy metals, other toxins
- kidney failure
- liver failure
- vitamin B12 deficiency
- excessive amounts of vitamin B6
- trauma or other injury
- certain drugs
Common peripheral neuropathy symptoms are:
- tingling sensation in the limbs
- pins and needles or burning pain in the limbs (particularly the hands and feet)
- decreased sensation in the limbs
- weakness or paralysis of the limbs
Mononeuropathy is involvement of a single nerve. Polyneuropathy is the simultaneous involvement of several nerves. Peripheral neuropathy is a more specific term which distinguishes a disorder of motor and sensory nerves from autonomic neuropathy, a disorder of nerves of the autonomic nervous system. Those nerves control involuntary functions of the body such as blood pressure, heart rate, urination, digestion and saliva production. An EMG with nerve conduction velocity study confirms the diagnosis.
Parkinson’s disease – It is a neurodegenerative disease of the brain in which there is gradual deterioration of cells and their ability to produce the neurotransmitter, dopamine. Those cells are in the substantia nigra of the midbrain. Since dopamine is involved in sending signals from the brain which regulate movement, the disease is a movement disorder. The classic signs needed for diagnosing the condition are a tremor, slow body movements (bradykinesia), stiffness (rigidity), and problems with balance (postural instability). The tremor is usually in one upper limb initially but may eventually involve both as the disease progresses. The tremor is present at rest as opposed to during movement of the limb. A shuffling gait, stooped posture and reduced arm swing are common features. These motor features of the disease improve when treated with dopamine and medications which stimulate cell receptors to be more reactive to dopamine (dopamine agonists). Loss of smell, constipation, drooling, slow speech (bradyphrenia), falls, acting out of dreams, anxiety, depression, cognitive decline and even dementia are some of the many other associated symptoms which can be present at various stages of the disease. The cause of Parkinson’s disease is unknown, but side effects of certain medications can be some of the symptoms of the disease.
Radiculopathy – It is a disease or other problem affecting a spinal nerve root. When the problem is one of mechanical compression from a herniated disc, a bone spur, or thickening of the ligaments around the spine it is oftentimes termed a pinched nerve. Typical symptoms are pain, numbness, tingling and sometimes weakness and the limb supplied by the nerve which the root gives rise to.
Restless leg syndrome – Is a disorder consisting of the irresistible urge to move one’s body in an attempt to halt odd or uncomfortable situations. It most commonly involves the legs but it might also affect the arms and other parts of the body. The cause of it is unknown.
Seizure disorder – It is a term synonymous with epilepsy.
Spina bifida – Is a birth defect in which there is incomplete formation of bone involving the portion of the vertebral column which encloses the spinal cord, resulting in the spinal cord at the point of the defect not having its normal bony enclosure. Most individuals with spina bifida have only a mild defect and do not experience any problems. Oftentimes they are not even aware of the defect until x-rays reveal it. Others may have an abnormality in the appearance of the skin such as a dimple, a birthmark, or a hairy patch overlying the defect, but still not have any symptoms. More severe forms of the defect though, can result in a meningocele or myelomeningocele. With a meningocele cerebrospinal fluid leaks out of the spinal cord and pushes against the skin of the back resulting in a bulge. With a myelomeningocele, which is rare, but the most severe form of spina bifida, part of the spinal nerves themselves bulge through the defect in the spinal canal and are oftentimes damaged, which causes problems with walking and bladder control. The cause of spina bifida is unknown.
Stroke – Is the acute irreversible damage to brain cells and tissue in a localized area of the brain. It can result from a blood clot in an artery blocking the flow of blood to the brain or the rupture of a blood vessel and bleeding into brain tissue. A stroke resulting from the blockage of blood flow by a clot is an ischemic stroke. A more specific medical term for the irreversible damage to brain tissue resulting from blockage of blood flow in an artery is an acute cerebral infarct. The medical term for the event is acute cerebral infarction. A stroke due to the rupture of a blood vessel is a hemorrhagic stroke.
Ischemic strokes can occur because of clot formation within an artery of the brain, an artery outside of the brain, or a site in the left side of the heart. Events that occur from clot formation within a brain artery are thrombotic strokes. Those that occur as a result of clot formation outside of the brain are embolic strokes. Embolic events occur when a portion of a remote blood clot breaks off from its original site and becomes lodged in a brain artery. That event is termed cerebral embolism. The clot itself is termed a cerebral embolus.
A thrombotic stroke is the most common type. It occurs when clot forms within an artery of the brain already narrowed due to atherosclerosis. Atrial fibrillation is a common heart condition that can result in a cerebral embolism. The most common causes of a hemorrhagic stroke are severely elevated blood pressure or an aneurysm of a brain artery (cerebral artery).
The signs and symptoms of a stroke vary depending on the portion of the brain affected. Some of the more common ones are facial and/or limb weakness, facial and/or limb paralysis, dysphasia, loss of consciousness, visual problems, swallowing difficulties, headache, numbness, other abnormalities of sensation, vertigo and problems with equilibrium or balance.
Subarachnoid hemorrhage – It is bleeding into the subarachnoid space of the brain. Its causes include head trauma, an aneurysm, an abnormal connection between an artery and a vein (arteriovenous malformation) and the taking of too much blood thinner medication. In some cases though, the cause is not determined. The main symptom is a severe sudden headache. Nausea, vomiting and a stiff neck oftentimes accompany the headache. A CAT scan of the head is the diagnostic test of choice. Neurosurgery is often required to remove the blood and stop the bleeding.
Subdural hematoma – It is a collection of blood in the subdural space of the brain. Although the bleeding is under the skull and outside of the brain it can cause brain damage from the pressure it exerts. If the increased pressure within the skull reaches a high enough level it can result in coma and death. Head trauma is the usual cause. The trauma results in the tearing of vessels at the surface of the brain which leads to bleeding within the subdural space. The injury can be the result of a direct blow to the head such as during an assault, fall, or motor vehicle accident. But can also be the consequence of sudden deceleration from a high velocity of speed, causing the brain to strike the inside of the skull. A subdural hematoma can be a rare complication of a spinal tap. Treatment of a subdural hematoma can range from conservative observation to neurosurgery to remove the blood collection, depending on its severity.
Transient ischemic attack (TIA) – It is often referred to as a mini stroke because much like a stroke, it is caused by a blood clot in an artery of the brain. It can cause the same symptoms of a stroke, but they are much briefer and by definition subside within 24 hours. Individuals who experience a TIA(s) are more likely to experience a stroke in the future.
Trigeminal neuralgia – It is inflammation of the trigeminal nerve or fifth cranial nerve. It causes severe sharp pain in one side of the face. It can involve either or all 3 branches of the nerve. Therefore the pain can be in the upper, mid, or lower facial regions. Light touch and chewing tend to make the pain worse. Because the severity the pain oftentimes causes involuntary wincing it is also termed tic douloureux. There may be only one attack with recurrent pain every few hours to seconds, or attacks may recur after months or years of absence. Its cause is usually unknown.