Back pain

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Back pain (radiculopathy/ myelopathy)

Back pain is one of the most common conditions for which patients seek a neurologist’s opinion. There can be protean causes of back pain and before we discuss them here, a brief discussion about the anatomy of the spine shall serve us well.

 

Anatomy of the spine:

The human spinal column is made up of bones called the vertebra stacked one on top of the other (like a column), As the vertebral column is made up of multiple bones articulating with each other, it allows for mobility. We can bend forward (flexion of the spine), arch our back ( extension of the spine) and can also flex our spines laterally in both directions (lateral flexion of the spine). The soft cartilagenous tissue found between two vertebral bodies is called an intervertebral disc. The spinal cord is enclosed in this skeleton of vertebral bones and thus is protected from injury. From the sides of the vertebral bodies the nerve roots come out. These are the roots which later on join to form the big nerves which innervate the muscles of the arms and legs.

 

What is meant by disc herniation?

Other terms used to describe this common condition include “slipped disc” . A herniated or slipped disc refers to the condition where-in the intervertebral disc gets dislodged (herniates out of its right place or slips out of its right place). When the disc herniates out it puts pressure on the nerve roots exiting the spinal cord at that level. Inflammation of the nerve roots results. This can lead to an intense painful condition where-in the patient complains of pain radiating down in the distribution of that nerve root. We in neurology refer to this condition as Radiculopathy.

Depending upon which nerve root is compressed and at which level patients have pain. For example a disc in your neck slips out, you have pain radiating usually into your arms or even into your finger tips, while if a disc in the lower back slips out, patients usually have pain radiating down their leg ( a condition  commonly referred to as sciatica).

Causes of back pain:

As I stated earlier there can be protean causes of back pain. Here I shall list some of the common causes.

1) Slipped or herniated disk.

2) Mechanical trauma to the back resulting in soft tissue injury (injury to the para-vertebral muscles or the soft tissues eg fat).

3) Fracture/ dislocation of the vertebral bodies: sometimes the vertebral bodies may get dislocated or malaligned. One vertebral body may get displaced in relation to the vertebrae below. This condition is referred to as Spondylolisthesis. The vertebral body itself or any of its parts (arch, pedicle) may get fractured resulting in pain. Fractures of the vertebral column can either be traumatic (occuring in the setting of significant trauma) or they can be secondary fractures. Secondary fractures occur when the vertebral body is weakened by an infectious or malignant (cancerous) process.

4) Spondylosis: is one of the most common causes of back and neck pain especially in the middle aged and elderly population. In its most simplistic defination, spondylosis refers to degeneration of the vertebral column. This degeneration of the bones of the spine becomes more apparent as we age, spur formation may occur (osteophytes). These osteophyted may compress the exiting nerve root leading to pain (radicular symptoms). Further on the spinal canal may get narrowed. When this occurs the spinal cord does not have enough space, a condition referred to as spinal canal stenosis. Spinal canal stenosis classically presents with pain which radiates into the buttocks. Patient complains of pain when he walks, with relief of pain on sitting or when he bends forward (flexion). This condition is referred to as neurogenic claudication.

It is important that spinal canal stenosis be diagnosed correctly as it responds to surgical intervention with good relief of pain and discomfort.

 

“For one who has conquered the mind, the Supersoul is already reached, for he has attained tranquillity. To such a man happiness and distress, heat and cold, honor and dishonor are all the same”

Lord Krishna in the Bhagavad Gita

Neuropathy presenting features

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Neuropathy presenting features

So what are the signs and symptoms of someone with a neuropathic condition:

Sensory neuropathies present with the following signs and symptoms:

1) Numbness in the arms or legs ( a clue to neuropathy is that the signs and symptoms are usually symmetrical and start distally. For example the patient may complain of numbness in both legs or hands initially in the toes and the fingertips. As the disease progresses this numbness also moves more proximally reaching to the ankles, shin and the arms).

The patient may not complain of numbess rather may use words like ” my legs feel dead” or “my hands burn” to describe his symtoms.

2) Pins and needles sensation in the arms and legs: people with neuropathy have what doctors call paresthesias or abnormal sensations.  They may complain of feeling pins and needles , electric shocks or at times as if their skin is been touched with a feather.

They have allodynia (a non-noxious stimuli feels noxious meaning that if I touch you with a feather you may feel as if I am boring a sharp pin into your skin) and hyperalgesia (meaning that they have an increased sensitivity to pain).

3) Patients with neuropathy may present with skin changes. This is most commonly noted on the skin overlying the shin and feet. The skin is shiny and atrophic, the overlying hair are sparse or completely lost. At times people may develop non-healing ulcers of the feet which may get infected and even gangrenous. This condition is commonly seen in diabetic patients with severe neuropathy (diabetic foot).

4) If a patient has a large fiber neuropathy, he may complain of difficulty with balance especially at night or when his eyes are closed. They feel as if they are walking on cotton wool.

5) Patients may present with ulcers or burns in their hands: this is because as they are not able to detect the sensations of heat etc they may touch something hot like a gas stove and get burnt.

 

 

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Neuropathy

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Neuropathy

In this section we shall discuss neuropathies. This is a vast topic and I shall try to make it simple. First lets start with the basics. What is neuropathy? Neuropathy refers to disease and dysfunction of the nerves.  There are different types of nerves in the human body: some nerves supply the muscles of the head, face and neck example the facial nerve supplies the muscles of the face ( it is this nerve which helps you to smile or frown).  Another  example is the auditory nerve which helps you to hear. These nerves which supply the muscles of the head and face are referred to as Cranial Nerves.

Apart from the cranial nerves there are other nerves which supply the muscles of the arms and legs and carry sensations of pain, temperature, pressure, joint sense, vibration and light touch. As these nerves supply the muscles in the periphery of the body they are referred to as peripheral nerves. Peripheral nerves are of three types:

1) Motor nerves : nerves which carry out motor functions example closing and unclosing your fist , walking etc

2) Sensory nerves: nerves which carry sensation of pain, temperature, touch, joint sense, vibration and position sense from the periphery back to the brain.

3) Mixed nerves: nerves which carry out both the above functions.

Neuropathies can thus be of different types based on which type of nerve is involved by the disease process. So you can have a motor neuropathy, a sensory neuropathy and a mixed motor-sensory neuropathy.

Another way to classify neuropathies is on the basis of the size of the nerve fibers involved. Pain, temperature and crude touch is carried by small sized nerve fibers and hence neuropathy of the small sized sensory nerves is referred to as small fiber neuropathy. Vibration, position sense and joint sense are carried by larger diameter nerve fibers and hence neuropathy of larger diameter nerve fibers is referred to as large fiber neuropathy.

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Dementias

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Dementias

In this section we shall discuss a little about dementia. Just what do we mean when we say a person has dementia?

Dementia is a disorder in which a person has cognitive impairments in multiple domains. Meaning a patient with dementia has problems with memory ( forgets things), language ( speech gets sparse and content/ vocabulary decreases), calculation (person loses the ability to calculate: subtract, multiply etc), and abstract thinking. Depending upon what part of the brain gets affected, a patient with dementia may have personality changes and problems with executive functions like planning and other goal directed actions. They may also experience what we neurologists refer to as apraxias. Apraxia is an inability to do a learned act (example you can tie your shoe laces, it is an act you learnt as a small child. Now assume you get demented, you lose the ability to tie your shoes laces even though you are not weak and have full strength in your arms and legs). Patients with dementia may exhibit various kinds of apraxias, as the disease evolves they become dependent on care-givers for nearly all activities of daily living: cannot drive, cannot tie their shoe laces, cannot feed themselves or take a shower on their own.

There are many different types of dementia. These differ from each other in the cognitive domains affected and in the way they present clinically.

Classification of dementias:

 

1) Alzheimer’s dementia

2) Fronto-temporal dementia also referred to as Pick’s disease

3) Multi-infarct dementia also called vascular dementia

4) Dementia associated with Parkinson’s disease also called Parkinson’s disease dementia

5) Diffuse Lewy Body dementia

6) Primary Progressive Aphasia

7) AIDS dementia complex or HIV encephalopathy

8) Dementias associated with infections like syphilis

9) Reversible dementias like that due to hypothyroidism, deficiency of vitamin B12, thiamine (vitamin B1), hydrocephalus (normal pressure hydrocephalus)

10) Conditions which can mimic dementia example depression (pseudodementia)

 

Let us now discuss a few of these disorders. I shall start with the most common cause of dementia in the elderly namely Alzheimer’s dementia.

 

Alzheimer’s dementia: AD is the most common primary dementia seen in the elderly age-group. The onset of AD may be very subtle and frequently the care-givers or the patient cannot tell when did the disease first start. By the time the patients come to medical attention, the dementia is usually quite prominent. A point to note here, patients with dementia usually do not seek help by themselves. They do not feel anything is wrong with them, are not bothered by the lack of memory or their forgetfulness. It is their relatives and friends who first notice something is amiss. They notice that the patient keeps forgetting simple things, may get lost in their own neighbourhood ( for example the patient may not know what street he lives on and get lost while driving), other things like going to the grocery store and forgetting why one went there in the first place and having problems with names etc may be noticed.

Suprisingly in the earlier stages of the disease patients maintain their social graces pretty well. They may interact pretty gracefully in a social setting like a party or at work and if you are inter-acting with them casually you may never realise that they are having memory problems.

Diagnosing Alzheimer’s dementia: the diagnosis of Alzheimer’s disease is mostly clinical and a neurologist would be able to make the diagnosis clinically with a reasonable level of accuracy. Your doctor may order some tests like an MRI study of the brain and some blood tests to measure the thyroid hormone levels in your body, vitamin B12 level and also to rule out diseases which can mimic Alzheimer’s disease in its presentation such as syphilis. Nowdays more advanced imaging tests are been used to diagnose Alzheimer’s disease at an earlier stage of minimal cognitive impairment (MCI), these include PET (positron emission tomography) scan, SPECT (single photon emission computed tomography) scan and fMRI (functional MRI) scans. These facilities should be available in the big neurological centers.

 

Managament of Alzheimer’s Dementia: Alzheimer’s dementia is as of now incurable. However there are medications which can slow the progression of this neurodegenerative disease and improve the cognitive abilities of the patients. These drugs belong to a class of drug called cholinesterase inhibitors.  They inhibit the cholinesterase enzyme from breaking down acetylcholine, so increasing both the level and duration of action of the neurotransmitter  acetylcholine. Commonly prescribed drugs include: donepezil (Aricept), rivastigmine (Excelon), tacrine (tetrahydro aminoacridine) and galantamine. A few years ago, a new drug called memantine (Nemanda) was introduced into the market. This has a different mechanism of action as compared to the cholinesterase inhibitors. It is a NMDA receptor antagonist. Treatment with cholinesterase inhibitors does not alter the natural history of Alzheimer’s dementia. Patients though do get a few more months and possibly a few more years of relatively preserved cognitive abilities. Caregiver burden is reduced and patients may remain independent in some activities of daily living. Certain other medications and nutritional supplements have been advocated for Alzheimer’s disease patients with no proven efficacy. These include supplements like Ginkgo biloba and supratherapeutic doses of Vitamin E.

In the more advanced stages of the disease, patient’s become mute, akinetic (do not move spontaneously), they are incontinent, cannot feed themselves and become totally dependent on caregivers. Caregiver burn out is quite common and patients may be placed in nursing homes. In this advanced stage urinary tract infections (UTI), respiratory tract infections (pneumonias) and bed sores (decubitus ulcers) are common causes of morbidity and mortality. These advanced Alzheimer’s disease patients need good nursing care.

 

Let us talk a little about other neurodegenerative dementias. Fronto-temporal dementia also called Pick’s disease resembles Alzheimer’s disease except that these patients have early and more prominent frontal lobe involvement. Thus early on in the disease course, these patients have executive dysfunction (problems with planning things, thinking about future plans and how to go about making them happen). They also have prominent personality changes (may become angry, argumentative and suspicious) and also disinhibited (say whatever comes to mind, act inappropiately in social gatherings eg may start masturbating or touch themselves inappropiately).  The cholinesterase inhibitors used to treat Alzhemier’s dementia may also be tried in patient’s with fronto-temporal dementia (Pick’s disease). The name fronto-temporal dementia comes from the fact that these patients have prominent atrophy (decrease in mass or bulk or size) of the frontal and temporal poles/lobes.

Dementia of Lewy Bodies: is another type of dementia in which patient’s typically exhibit fluctuating symptoms. Visual hallucinations is a prominent component of this type of dementia. Patient’s respond poorly if medications like Haldol (haloperidol) are used to control their behavior. Atypical antipsychotics like Seroquel (quetiapine) are better drugs to control behavioral problems in these patients like agitation and aggression.

Dementia of Parkinson’s disease: Patient’s who have Parkinson disease may also develop dementia (memory problems) later on in their disease course. I shall discuss this further under Parkinson’s disease.

Depression or pseudodementia: Patients who have major depression may also look as if they are demented. These patients have anhedonia (no interest in any pleasurable activity like watching TV, getting a cup of coffee, watching a movie with friends). They just sit still, may not eat if not asked too and look akinetic. These depressed patient’s superfically may resemble dementia patients and hence depression is also referred to as pseudodementia. Once you treat their depression, they improve and all their “memory problems” go away.

Demented patients may have superimposed depression and vice versa hence a thorough search should be made to rule out depression in a patient with dementia as it is readily treatable.

I shall discuss depression under a separate heading. There are caretaker support groups for people who have loved ones suffering from dementia. They offer advice and help in preventing caretaker burnout.

 

 

“A self realised man is one who controls his mind”

Lord Krishna in the Bhagavad Gita

Depression

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Depression is a relatively common neurological condition. It may occur on its own (as an episode of major depressive disorder or MDD) or it may occur during the course of another chronic neurological illness such as stroke. It is important that depression be recognized and treated since studies have shown that it increases the morbidity and mortality associated with these conditions.

Sometimes it is difficult to weed out which symptoms are due to depression and which due to the organic brain (neurological) condition. Patients who have fronto-temporal dementia (Pick’s disease), Parkinson’s disease, frontal lobe strokes may look depressed. They are akinetic (do not move spontaneously), have mask like emotionless faces and do not talk readily (abulia). On the first glance it may seem they have depression and not an organic neurological condition.

The point I am making is that depression may mask an underlying neurological condition like dementia or a frontal lobe tumor. The reverse is also true, people who have neurodegenerative conditions may have superimposed depression. Upon treating the depression they feel much better and may improve in caregivers rating scales.

The diagnosis of depression is essentially a clinical one. There are certain clinical features which if present for a sufficient length of time usually 2 weeks suffice to make a clinical diagnosis of major depressive disorder (MDD). These features include what is called anhedonia (loss of pleasure in day to day activities), depressed mood ( in children it may present as irritability), weight loss or weight gain, insomnia or hypersomnia (sleeping more than usual), changes in behavior and personality, feeling tired and fatigued, feeling of hopelessness and worthlessness and thoughts of death or sucide.

In a clear cut case no other investigations are warranted but like I stated earlier, at times some organic neurological conditions can present as depression. So to rule out secondary causes of depression, your doctor may order a MRI brain and tests like thyroid function tests (to check if your thyroid hormones are within the normal range–this is usually a simple blood test).

Treatment of depression: Treatment of depresion when it presents along or during the course of a neurodegenerative condition like dementia and Parkinson’s disease is essentially the same as treatment of idiopathic depression (depression which occurs without any organic cause). It involves using drugs. The most commonly prescribed drugs are those which belong to two classes:

1) Tricyclic antidepressants–drugs which belong to this class include medications like Elavil (amitriptyline) and  nortriptyline.

2) Selective Serotonin Reuptake Inhibitors (SSRIs)–drugs include Prozac (fluoxetine) and Paxil (paroxetine) among numerous others.

If a neurological condition is responsible for the depressive symptomatology. example a frontal lobe tumor then removal of that tumor or treatment of the underlying neurological condition is needed. Other treatments that may be attempted include CBT (cognitive behavioral therapy).

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Parkinson’s disease

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Parkinson’s disease is a relatively common neurodegenerative disease. It was first described by James Parkinson in his now classical essay titled ” The Shaking Palsy”. James Parkinson was an astute observer and his longitudinal description of the disease which now bears his name was on the basis of just a single patient.

Like other neurodegenerative diseases, Parkinson’s disease starts in the later age groups (60’s and onwards). Sometimes it may start in the younger age groups especially if there is a family history of the disease. This is referred to as Familial Parkinson’s Disease.

Typical Parkinson’s disease has a clinical triad consisting of:

a) rigidity (patient’s are rigid–when you passively move their limbs you experience increased resistance. Rigidity is a condition in which the tone of the body is increased. Tone refers to the resistance offered to passive movement of a limb across the joint)

b) bradykinesia or akinesia: as the name suggests, this means that the patient’s are bradykinetic. They have paucity of spontaneous movements, when they walk they do not have the characteristic arm swing which describes the human walk.

c) resting tremor: Parkinson’s disease (PD) patient’s have a characteristic tremor in their hands and feet. The tremor is a resting tremor meaning that it is most prominent when they are relaxed and their arms are at complete rest (when you walk, your arms are at rest by the side of your body and the tremor can be clearly seen).

 

Other features of Parkinson’s disease (PD):

d) PD patient’s have a typical disturbance of gait and posture. They seem off balance and are prone to falls. They walk bend forward in short quick steps (as if chasing something). This characteristic gait of PD patient’s has been referred to as festinating gait. If you accidently push a PD patient to the side or backward or forward, they are unable to compensate and may fall down. Falls and the disturbance in gait and posture is an important cause of morbidity in PD patient’s. When PD patient’s turn they do not turn in one smooth motion rather thay turn with small steps.

e) PD patient’s have a mask like face. They do not have the characteristic facial expressions which so define when humans talk. They may not blink while speaking ( sort of staring look), do not smile or frown.

f) PD patient’s may notice a change in their writing. Typically the hand writing becomes smaller and smaller and more illegible. This is referred to as micrographia.

g) The voice of PD patient’s is monotonous and lacks the variations in the pitch and tone which defines human speech.

 

A point to note here is that unlike Alzheimer’s disease, PD patient’s usually have no impairment in memory at least in the early to middle stages of the disease. Later on in the disease course, they may develop cognitive impairments, this condition is referred to as Parkinson’s disease dementia (PDD) or dementia associated with Parkinson’s disease.

Brain Care Foundation

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Please visit the Brain Care Foundation of India website at www.braincarefoundation.com

We would appreciate your suggestions and comments as we strive in our endeavor to make neurological services accessible to the poorest of the poor and to care for the brain just not in disease but also in health.

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” It is declared that the senses are superior but more than the senses the mind is superior but more than the mind the intelligence is superior and more than the intelligence that which is superior is the individual consciousness”

 

Lord Krishna in the Bhagavad Gita

 

 

ALS

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Amyotrophic lateral sclerosis (ALS) is better known in the United States and Canda as Lou Gehrig disease. It comes under the umbrella of a group of progressive neurological disorders collectively known as Motor Neuron Diseases (MNDs. ALS is a devastating neurological condition and is uniformally fatal in its outcome.

As the name suggests ALS involves the motor neurons selectively. What are motor neurons you may ask? Motor neurons are neurons (nerve cells) that control voluntary muscle activity. The motor neurons that control voluntary activity like swallowing, coughing, breathing and speaking lie in the brain stem while those that control voluntary activity like walking and moving your hands lie in the spinal cord.

ALS affects motor neurons of both the brain stem as well as the spinal cord. The disease by defination affects only the motor neurons and spares all sensory neurons. Thus patients with ALS have progressive motor weakness but no sensory findings ( no numbness or sensory loss). The disease also spares other brain functions like memory, cognition, orientation, alertness, ability to calculate, eye movements and bladder/bowel function.

That is why ALS is so devastating: it leaves one quadriplegic (completely paralyzed) having difficulty with swallowing, difficulty speaking and breathing but intact of all higher mental functions. Imagine been in a situation where your mind is completely healthy trapped in a completely paralyzed body.

ALS usually affects people in their late 40’s and above. The disease has been known to occur in the younger age groups but in these rare cases it usually runs in the family an entitiy called familial ALS (FALS). The onset of the disease is very insidious and patients may present to their doctor with complaints of a wrist drop or foot drop ( inability to lift the wrist or the foot). Usually the bulbar symptoms of difficulty in swallowing and speaking come later on in the disease course. There is a constellation of signs and symptoms which physicians look for clinically when trying to secure a diagnosis of ALS. 

Though this is technical let me try to explain it to you. If we as physicians find weakness in an arm or leg and the muscles are visibly atrophic (shrunken) but the reflexes (these are the reflexes which we elict by tapping your tendons with our hammers) are brisk, we think about possible ALS. If we find these signs in 3 different limbs it makes the diagnosis more secure. We also look for fasiculations. Fasiculations are visible involuntary muscle twitches under the skin arising from spontaneous discharge of motor neurons. In ALS one may see widespread fasciculations involving different muscle groups as well as fasciculations in the tongue (remember the tongue is also a muscle).

A word of caution here. A lot of us have visible fasciculations, we all have experienced the feeling when one of our muscle such as the eye-lid or thigh suddenly starts twitching. These are called benign fasciculations and do not protend ALS. Only when fasciculations are accompanied by visible muscle wasting and weakness that one should be worried. Benign fasciculations usually occur when one is tired or after heavy exercise and dehydration.

Other symptoms which commonly occur in patients with ALS include cramping especially of bigger muscle groups like that of the back.

 

If a diagnosis of ALS is been considered, it is imperative that other diseases which can mimic ALS in their presentation be ruled out. Some of these are readily treatable as against ALS for which currently we have no effective treatments. So how is the diagnosis of ALS secured?

When ALS is advanced, the diagnosis is readily apparent on a routine clinical neurological examination. The patient has visible atrophy (wasting) of the muscles of the limbs. Wide-spread fasiculations (muscle twitches) are visible to the naked eye. We as neurologists search for these in the tongue and the big muscle groups on the back. To secure the diagnosis in the earlier stages of the disease when the clinical features are not so florid, your doctor may order a few tests. The most important among these is the EMG (electromyogram). The EMG is a test which is not as bad as it looks. It basically involves putting a recording needle electrode in different muscles of the limbs, back and even the tongue to look for signs of denervation (damage to the motor nerves). There are criteria on EMG that help secure the diagnosis of ALS.

 

Management Issues in an ALS patient: ALS as a disease is incurable as of now. That said there is a lot which can be done to help a patient with ALS. Only one medication by the name of riluzole is approved for the treatment of ALS. That too prolongs the life expectancy by only a few months. Patients with ALS need a multitude of services and their care is best handled by a multi-speciality team consisting of neurologists, respiratory therapists, gastroenterologist, physical and occupational therapists and speech therapists. As the disease progresses and takes its toll, patients are prone to pneumonia and other respiratory tract infections. As their swallowing and speech functions become progressively impaired, nutrition (feeding) may have to be accomplished via either a feeding tube or a tube in the stomach (we call this a PEG tube).  Physical and occupational therapy helps to preserve motor functions. These patients are greatly helped by assist devices like motorized wheel chairs, a simple straw to aid them in drinking water and other liquids etc.

Tremendous research is going on to find a cure for ALS. Your doctor might also prescribe some vitamins and supplements like coenzyme Q 10. Whether these help is doubtful but they most likely do not cause any harm. You should discuss and other experimental therapies with your physician.

Some diseases which may resemble ALS superficially in their presentation:

1) Benign Cramping Fasiculation Syndrome: I explained this above. A lot of people have visible fasiculations (their muscles quiver) and they may also have complaints of cramps. There is no associated muscle weakness or atrophy. Reassurance is all that is needed.

2) Multi-focal motor neuropathy with conduction blocks: an uncommon neurological condition characterized by involvement of multiple motor nerves (thus resulting in weakness). Conduction blocks are present in nerve conduction study. It resembles ALS in that it presents with weakness and does not cause sensory symptoms.

3) High cervico-medullary junction involvement–if there is a high cervical disk herniation, it at times can present just like ALS.

4) X-linked spinal and bulbar muscle atrophy also referred to as Kennedy’s disease: neuromuscular disease due to mutations in the androgen receptor. Presents with cramps and progressive weakness due to degeneration of motor neurons in the brainstem and spinal cord.

 

It is imperative that the above conditions be looked for and ruled out before a diagnosis of ALS is arrived at, as some (multi-motor motor neuropathy with conduction blocks) do respond to therapies like intravenous immunoglobulin.

 

Multiple Sclerosis

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Here I shall try to give you a broad overview of Multiple Sclerosis (MS). Multiple sclerosis is a demyelinating disease of the central nervous system (CNS). In the CNS, the axons  are covered by myelin. The axon is the long slender projection of the nerve cell (neuron) that conduct’s nerve impulses away from the body of the cell. The axons in the CNS are coated / covered with myelin, an electrically insulating layer made of phopholipids (a kind of fat). Schwann cells supply the myelin for peripheral neurons ( neurons outside the brain), whereas oligodendrocytes ( a type of cell found in the brain) supply myelin for axons of the CNS.

MS is characterized by demyelination of these axons, that is some process starts to destroy the myelin leading  to loss of myelin. As the disease progresses even axons get destroyed.

Just what sets off this process is still not clear. Various infectious agents and environmental factors have been postulated but none conclusively linked to MS causation.  As a disease MS is more common in Caucasians and more common as you head further from the equator both in the Northern and Southern hemisphere. Thus the incidence of disease is more in Ireland than say in Sub-Saharan Africa. Why you may ask and the answer is no one knows. Maybe it is an environment factor.

Fifteen years of age is the cut off. So if you were born in a country which has a low incidence of MS such as in Asia or Africa and then emigrate to a country with a higher incidence of MS such as Ireland or Canada after the age of 15, you shall carry that low risk of the country of birth with you but if you emigrated say around 6 years then your risks of developing MS go up to the risk of a native in Ireland or Canada.

MS is more common in women as compared to men but when it does occur in men it is usually more severe.

Clinical presenting features of MS-MS has been rightly called the great mimicker in neurology. It can present with a myriad of clinical signs and symptoms which are referrable to both the brain as well as the spinal cord. MS typically presents in the following ways:

1) Isolated attack of optic neuritis: the usual history is a young to middle aged woman who presents with sudden and rapid onset of loss of vision in one eye at times associated with pain on moving the eyes. This occurs due to demyelination of the optic nerve (the nerve which is involved in vision). If the attack remains confined to the optic nerve, this is referred to as a Clinically Isolated Syndrome (CIS). Not all patients with a CIS go on to develop MS, as there are other causes of optic neuritis besides MS.

2) Numbness or weakness in one part of the body.

3) Visual complaints like double vision (diplopia), eyes not moving well (weakness of a muscle of the eye).

4) problems with balance and coordination.

5) ataxia and tremors (patients have a prominent tremor in their hands or in their trunk, as well as are off balance while standing or walking). This is due to involvement of the cerebellum and cerebellar pathways by the MS demyelinating process.

6) problems with bladder control leading to urinary incontinence.

7) Weakness in the legs (paraplegia or paraparesis)–if MS involves the spinal cord, it may cause weakness of both the legs. This condition is referred to transverse myelitis or transverse myelopathy.

So what are the presenting features of MS? MS can present in various fashions, at times the presenting features are vague and this may lead to a delay in diagnosis. The commom presenting features of MS are as follows:

1) MS may present acutely as an attack of optic neuritis. Opitic neuritis is inflammation of the optic nerve and hence the patient seeks medical attention for acute loss of vision and pain in the eye. If this occurs in a young women or man, MS should be borne in mind though there are numerous other causes of loss of vision. Patient may also complain of a desaturation of the color red ie the color red does not appear as bright and ” red” as it used to.

All attacks of optic neuritis do not necessarily lead to MS. Hence this limited presentation at onset is referred to by doctors as a ” clinically isolated syndrome“.

To be certain that your presentation is indeed isolated, your doctor shall have to take a thorough history to make sure you have never had any other attacks suggestive of MS in the past. MRI of the brain and spine as well examination of the cerebro spinal fluid is carried out to rule out any other silent lesions of MS. If no other lesions/ plaques of MS are found in the brain or spinal cord on MRI and the spinal fluid comes back normal then and only then one has a clinically isolated syndrome.

Patients who have a clinically isolated syndrome do not warrant treatment with MS specific drugs like interferons. Your doctor might give you a short course of IV and oral steroids to hasten the recovery of eye function. Most patients who have optic neuritis regain their visual acuity.

2) Numbness or weakness in an arm or leg; patients with MS may present initially with complaints of numbness or weakness in an arm or leg. This usually occurs due to involvement of motor and sensory pathways in the brain or spinal cord by MS lesions.

3) Weakness in legs: if the MS lesions involve the spinal cord, patients may present with more symmetrical involvment like numbness or weaknes in both legs (paraparesis). This condition in which MS lesions are seen in the spinal cord is referred to acute transverse myelitis.

4) Problems with balance and incoordination; MS lesions frequently involve those parts of the brain which control balance and coordination (cerebellum). Thus MS patients frequently have problems with balance and are ataxic ( drunken like gait). They have a prominent tremor in their hands and feet especially when they try to reach out to touch something. These problems with gait and balance are one of the major causes of disability and morbidity in patients with MS.

5) urinary incontinence and sexual dysfunction: MS patients may experience erectile dysfunction and urinary incontinence is very common in female MS patients.

6) Double vision: MS patients may complain of seeing double (diplopia), this occurs due to involvement of tracts in the brain which control eye movements ( an example of such a tract which is frequently involved in MS is medial longitudinal fasiculus or MLF)

Thus as you can imagine MS can present with a myriad of symptoms and the diagnoisis may not be made at the first presentation. It is usually a constellation of signs and symptoms which do not localize to any one particular area in the brain or spinal cord which makes doctors think of MS as the differential diagnosis.

Thus as I stated earlier MS is a disease which is characterized by plaques (MS lesions) which are disseminated in space ( different areas in brain and spinal cord) and time (clinical attacks occur at different times in a person’s lifetime).

 

Diagnosis: how is the diagnosis of MS finally confirmed? Let us discuss that now. As I stated earlier if you present with certain clinical signs and symptoms your doctor may entertain the diagnosis of multiple sclerosis.

Now once the diagnosis is entertained how do you go about confirming the diagnosis. This is usually done with the aid of an MRI of the brain and spinal cord which may show the characteristic plaques of demyelination. Your doctor may also want you to get a spinal tap (lumbar puncture). Lumbar puncture or LP is a test where in a needle is inserted into your lower back to get some of the cerebro-spinal fluid (CSF). About 10-15 ml of CSF is usually removed and sent to the laboratory for various tests. We look for some markers of MS in the CSF. If they are present, they strengthen the case for MS. At times, tests like MRI brain and spinal cord as well as lumbar puncture are unrevealing or non-diagnostic, in that case your doctor may order other tests like visual evoked potential (VEP) and somatosensory evoked potential (SSEP).

Certain diseases like for example Lyme disease, sarcoidosis can mimick MS in their presentation both clinically as well as on the MRI. Hence in appropiate circumstances more tests may be ordered to rule out these conditions.

 

Treatment of Multiple Sclerosis: There are now many treatments available for MS. Here I shall list a few of them without going into too much detail.

Treatment of an acute attack of MS: patients may present to the hospital with an acute attack of MS. This may involve an acute episode of optic neuritis presenting with pain and visual loss in the affected eye or they may present with increased weakness or lethargy. Acute attacks of MS respond well to corticosteroids. Usually steroids are given intravenously at high doses for about 3-5 days. Steriods help in aborting the attack and hasten recovery but they do not change the natural history of the disease (meaning that the MS disease process still continues its relentless progression).

To change the natural history of the disease, drugs that modulate the immune system are used. The most commonly used drugs are :

1) Interferons–usually interferon beta 1 b or interferon beta 1 a. Interferon beta 1 b comes by the brand name of Betaseron while interferon beta 1 a comes by two brand names: Avonex and Rebiff. When compared to each other, the interferons have some difference with respect to potency, easy and frequency of administration. You doctor shall help decide which interferon is best for you. All the interferons have some common side-effects namely injection site reactions, depression, hypothyroidism etc.

2) Glatiramer acetate also called Copolymer 1 -marketed under the brand name Copaxone.

3) Mitoxantrone

4) Natalizumab marketed under the brand name Tysabri