Essay: Pathologies of the Nervous System

Pathologies of the Nervous System
Epilepsy
Epilepsy affects the brain and causes repeated seizures or absences, this occurs due to a sudden surge of electrical activity in the brain causing the brain’s messages to get mixed up.   It is not always a life long illness.
Causes
The brain is part of the central nervous system and contains neurones and electrical impulses so that massages can continually be transmitted around the body.  A sudden surge of electrical impulses or damage to the brain can cause an epileptic seizure causing confusion within the brain, consequently, brain messages are jumbled up causing the person to suffer from erratic behaviour.
There are numerous causes of epilepsy but due to the intricacy of the condition and research studies still ongoing for some suffers they may never know the reason for them developing the illness.
The two main types of epilepsy:
• Idiopathic (or primary) epilepsy – for many people there is no known reason for them to develop the condition, other than there may be a family history of the condition.
• Symptomatic (or secondary) epilepsy – This type has a known cause which may include:
o Severe head injury
o Infections that affect the brain such as meningitis
o The brain not developing probably
o A stroke
o A scar
o A tumour
o Complications during birth  (NHS Choices.net)
Some of the above may cause epilepsy in childhood, symptomatic epilepsy is more prevalent in the older generation, more so in the over 60’s.
Signs and Symptoms
As this condition affects the brain, depending on where in the brain the surge of electrical energy started and how far and quickly it has spread will decide the type of seizure the person will experience, although most people do have a consistent pattern of symptoms.
Seizures can happen when the person is awake or during sleep.
There are a number of different types of seizures dependant on the part and how much of the brain has been affected:
• Partial seizure – only a small area of the brain is affected
• Generalised seizure – a large/most of the brain is affected (* NHS Choices.net)
The two types of ‘partial seizures’ are:
Simple partial seizure – during the seizure you are fully conscious throughout, symptoms include
• A strange sensation that’s difficult to explain
• A raising feeling in the tummy, similar to feeling to a fairground ride
• A ‘deja-vu’ feeling
• An unusual smell or taste
• Tingling/pins and needles in arms and legs
• Intense feeling of fear or joy
• Stiffness/twitching in a part of the body, arm or hand (* NHS Choices.net)
Complex partial seizures – during the seizure you are unaware and can’t remember what has happened, also unable to respond to anyone else.
The symptoms involve strange and random bodily movements and behaviour:
• Smacking of lips
• Rubbing of hands
• Making random noises
• Moving arms around
• Picking of clothes
• Fiddling with objects
• Adopting an unusual posture
• Chewing or swallowing (* NHS Choices.net)
Generalised Seizures
There are six main types:
Absences – this seizure usually affects children, and can last up to 15 seconds, they will have recollection of the seizure.  The symptoms include being unaware of their environment and staring vacantly into space.  Some may demonstrate erratic behaviour of fluttering their eyes and smacking their lips.
Myoclonic seizure – the symptoms are very similar to receiving an electric shock; jerking or twitching of limbs or upper body.  It usually lasts for only a slight second and the person is normally conscious the whole time.  Often occurs in the first few hours of awakening and in combination of other generalised seizures.
Clonic seizures – similar twitching to myoclonic, jerking, but will last longer, usually 2 minutes, may lose consciousness.
Atonic seizures – with this type of seizure the muscles unexpectedly relax, which may cause the person to fall to the ground.
Tonic seizure – the muscles unexpectedly tense, which may cause the person to lose balance and fall down.
Tonic-clonic seizure – There are two parts to this seizure/convulsion and normally lasts a few minutes.  The body becomes tense and then erratic and the arms and legs begin to twitch.  The person loses consciousness which may cause them to lose control of bodily functions, they may urinate themselves.   This is the type of seizure associated with epileptic fits.
Myasthenia Gravis
A rare long-term autoimmune condition that can develop at any age, it causes antibodies which normally attack infections and bacteria to be misguided and instead attacks healthy tissue and movement muscles, making the person feel weak and tired.  It affects the muscles that we control such as muscles used for eating and swallowing, speaking and facial expressions.  It isn’t commonly life threatening.
Cause
In normal circumstances messages are sent down the nerves to stimulate the nerve endings to release a chemical called acetylcholine.  Acetylcholine stimulates the receptors on the muscles to contract.
When a person suffers from myasthenia gravis their immune system blocks or damages the acetylcholine receptors on the muscles, which stops the muscles contracting.  This causes the muscles to weaken and tire easily.
It is not fully known why for some people the immune system produces antibodies that attacks the muscle receptors.  Some believe the thymus gland maybe linked to the production of antibodies.
Signs & Symptoms
The symptoms may come on suddenly and the first signs are droopy eye lids, problems with swallowing and sometimes double vision.  Also feeling tired and weak in the neck, arms and legs.
The severity of symptoms varies from one person to another.  The condition isn’t over painful but people will suffer from aching muscles, especially after physical exercise, but they will improve after a rest.  The symptoms can be aggravated by:
• Stress
• Illness (such as an infection)
• Hot weather
• Menstruation (monthly period)
• Having an operation   *  (Bupa.net)
The main areas affected are:
Eyes, eyelids and face – symptoms may include blurred or double vision, usually as the person tires or at the end of the day.  One or both eyelids may droop.  For some sufferers the eye muscles are the only muscles affected by the condition.  If the facial muscles are affected the persons facial expressions maybe affected such as lower facial weakness which affects their ability to smile.
Swallowing and breathing – the muscles around the mouth or tongue may be affected and this may lead to problems chewing and talking.  Also tongue and palate muscle weakness can present problems with swallowing leading to coughing and choking symptoms.  This can also cause ongoing chest infections.
A few sufferers may have breathing difficulties especially when lying down flat or during and after exercise.
Speech – it can make speech slurred.
Limbs and movement – It can present problems with movement and stature and affects muscles of the arms, legs and neck such as walking, head droop and lifting objects.  Due to muscle weakness it can be difficult and tiring to perform repetitive tasks, climbing stairs/walking, washing/brushing hair and elevating from a sitting position.
The symptoms may stay the same but can worsen especially if untreated.
Peripheral Neuropathy
This is a condition due to nerves being damaged or destroyed which prevents the nerves functioning as normal.  The normal function is to detect stimuli such as temperature or pain and send the message back to the brain (central nervous system) for a response and messages to be conveyed from the central nervous system to the muscles or glands.  The nerves can be damaged or destroyed by injury, other health conditions and some medications.  For some people there is no known cause.
Causes
Neuropathy can be caused by diabetes which is known as diabetic polyneuropathy and it is believed 60% of people with diabetes are at risk of peripheral neuropathy, as diabetes can damage nerves due to high blood sugar levels which damage the blood vessels that supply the nerves.
If a person has diabetes they are at greater risk of developing peripheral neuropathy, diabetes type 1 or 2 can cause it.
There are many causes and factors of peripheral neuropathy:
• Family history of the condition, this is one of the most common forms
• Kidney disorders
• Heavy drinking over a prolonged period
• Chronic liver disease
• Deficiency of B12 or other vitamins
• Damage to nerves due to injury or surgery
• Some cancers
• Hypothyroidism (under-active thyroid so production the thyroid hormone is produced)
• Diseases that cause chronic inflammation
• Exposure to toxic chemicals and heavy metals (lead, mercury and poisons)
• Infections where bacteria directly attacks the nerve tissue
• Autoimmune disorders such as rheumatoid arthritis and lupus
• Medications
o Drugs to treat seizures
o Medications to treat bacterial infections
o Certain blood pressure medications
o Cancer treatments (* NHS choice.net & Healthline.net)
Signs & Symptoms
The condition can affect one or all three of the nerve systems, the most common combination is sensory and motor neuropathy known as sensorimotor polyneuropathy.  The three types of peripheral nerves are:
• Sensory nerves (carry messages from the skin to the brain)
• Motor nerves (carry messages from the brain to the muscles and glands)
• Autonomic nerves (carry messages to the involuntary systems)
The condition can advance quickly or slowly depending on the origin of the peripheral neuropathy.
The main symptoms for the more common strains are:
Sensory neuropathy
• Prickling and tingling/pins and needles sensation in the affected body part.
• Numbness and a reduced ability to feel pain or changes in temperature, particularly in your feet.
• A burning or sharp pain, usually in the feet and legs.
• Feeling pain from something that should not be painful at all, such as a very light touch.
• Loss of balance or co-ordination (*NHS Choices.net)
Motor Neuropathy
• Twitching and muscle cramps.
• Muscle weakness or paralysis affecting one or more muscles.
• Thinning (wasting) of muscles.
• Foot drop (difficulty lifting up the front part of your foot and toes, particularly noticeable when walking).
(*NHS Choices.net)
Autonomic Neuropathy
The symptoms will be terminated on which bodily system have been affected:
• Constipation or diarrhoea particularly at night.
• Feeling sick, bloating and belching.
• Low blood pressure which can make you feel faint or dizzy when standing up.
• Rapid heartburn.
• Excessive sweating or lack of sweat.
• Problems with sexual function (particularly for men).
• Difficulty fully emptying your bladder of urine.
• Bowel incontinence.
• Problems swallowing. (*NHS Choices.net)
Mononeuropathy
Again the symptoms will be terminated by the nerves affected:
• Altered sensation or weakness in the fingers.
• Double vision or other problems with focusing your eyes, sometimes with eye pain.
• Weakness of one side of the face (Bell’s palsy).
• Foot of shin pain, weakness or altered sensation. (*NHS Choices.net)
The most common type of mononeuropathy is carpal tunnel syndrome, the nerve passing through a tunnel within the wrist becomes compressed.  (*NHS Choice.net)