Lesson 13

Nervous System Diseases

We are going to discuss common neurological conditions under this section. History taking has crucial role in suggesting diagnosis because course (evolution) of disease helps us in diagnosis of disease and pathology behind it such as some of the diseases have gradual progression of disease over years e. g. Alzheimer`s disease, Parkinson`s disease etc.

Headache

Headache is a common presenting complaint in day to day practice. To find out cause of headache detailed history is important for example overall pattern (intermittent or continuous), speed of onset, location of pain, effect of posture, coughing etc. and any associated symptoms. This information helps us in clinical diagnosis of headache. If the headache occurs secondary to the underlying cause it is called as secondary headache. e.g. space occupying lesion, meningitis etc. we are going to concentrate on primary headache syndrome as it is common.

Tension Type Headache (TTH) – This is most common type of headache and is experienced at some time by majority of people. Though exact cause is not known, anxiety or emotional strain is common precipitant.

The pain of TTH is mostly constant and generalized. The pain may continue for weeks or months without interruption. Associated symptoms like vomiting, photophobia is absent. It usually increases as day goes on and less noticeable when patient is occupied.

Migraine is common condition in clinical practice which commonly affects females more than males. It usually starts at young age and presentation after 40 years is very less. Family history is common in migraine. Though the cause of Migraine is incompletely understood, current understanding about cause is that Migraine are sensitive to light, noise and other external factors because of abnormal brain stem modulation means diencephalic and brain stem nuclei that can modulate sensory information from cranial vasculature of brain and produces various symptoms of migraine.

If patient presents with paroxysmal headache, with nausea or vomiting and an “aura” of focal neurological events, then it is termed as classical migraine or Migraine with aura. Aura consists of either fully reversible visual or sensory symptoms such as flickering lights, needle like sensation etc. Migraine without aura is termed as common migraine. Usually Migraine headache is episodic and last for at least 4 hrs. (without analgesics). The character of pain is pulsating type with unilateral location. Most of the time it is associated with nausea or vomiting and photophobia. History, physical and neurological examination does not suggest any organic disorder.

Aura consists of either fully reversible visual or sensory symptoms such as flickering lights, needle like sensation etc. Migraine is commonly triggered by following factors such as hunger, physical exertion, stress, noise, menstrual cycle in females etc.

The diagnosis of Migraine is totally clinical based on above mentioned symptoms. CT or MRI is completely normal.

By homoeopathic treatment intensity and frequency of headache reduces to considerable extent.

Cluster Headache – It is less common in practice with predominance for males in 3rd decade.

The characteristic presentation is periodic, severe, unilateral peri-orbital pain accompanied by lacrimation. It typically remains for 30 to 90 minutes. The headache occurs repeatedly for number of weeks. Then subside for months before another cluster occurs.

Trigeminal Neuralgia – It is thought to be caused by compression of Trigeminal nerve. It is characterized by lancinating pain usually in patients over the age of 50 yrs. The pain is severe and of short duration but repetitive and precipitated by blowing on the face or by eating. There is a tendency to remit and relapse over many years.

Post-Coital and Exercise induced Headache – It usually affects man in 3rd or 4th decade. It starts a sudden severe headache at the climax of intercourse. It does not persist for more than 10-15 minutes. This type of headache needs to be investigated by CT and CSF examination to from subarachnoid hemorrhage.

Giant cell arteritis or temporal arteritis also causes localized headache in temporal or occipital region associated with scalp tenderness. The average age of onset is 70 with elevated E.S.R. It is not very common in practice.

Infectious Diseases of Nervous System

Incidence of infection of Nervous system is not common. However, the initial presentation is similar to any viral fever. Therefore, we should be cautious while treating this day to day cases and we should rule out the possibility of infections of nervous system. Altered consciousness with neurological symptoms like severe headache, neck rigidity, seizure etc. arouses suspicion.

Meningitis and Encephalitis are relatively common in practice.

Meningitis – Inflammation of meninges (pia, arachnoid and dura) is termed as Meningitis. It predominantly involves subarachnoid space.

The child with infection of ear and sinus and a person with skull fracture are prone to develop meningitis.

When bacteria enter into subarachnoid space, immune response of body against invading pathogen causes inflammation of meningitis leading to different manifestations and complications. Usually patient presents with high grade fever and headache with altered level of consciousness. On examination we find nuchal rigidity. In few patients projectile vomiting and seizures are concomitant features.

The diagnosis is made by collecting CSF fluid by lumbar puncture. CSF shows increased concentrations of poly-morphonuclear cells, protein with reduce glucose content. CT or MRI is necessary to rule out other neurological conditions like space occupying lesion (SOL).

Viral Meningitis – It can occur as one of the complications of viral infections like mumps, measles and herpes zoster etc.

Usually it is benign and self-limiting. It is less serious illness than bacterial meningitis. Clinically it presents with severe headache, but focal neurological signs are rare. It is mainly differentiated from bacterial meningitis with normal glucose and protein level in CSF examination.

Viral Encephalitis – When whole brain parenchyma is involved after viral infection like herpes simplex, it is termed as Viral Encephalitis. Neurological signs like aphasia, hemiplegia and seizures are more common than meningitis after fever.

CT scan or MRI shows lesion in temporal lobe in herpes simplex infection and E.E.G. is abnormal. Lumbar puncture rules out Meningitis.

Tuberculous Meningitis is a common form of chronic Meningitis in India. It occurs most commonly after an episode of primary infection or as a part of miliary tuberculosis. The diagnosis is difficult because patient presents with common complaint like headache, low grade fever etc. When chronic headache persists for long time without much relief, we should suspect TB Meningitis. CSF examination and culture will guide us to the diagnosis. CT scan may show intracranial tuberculoma.

Cerebrovascular Disease (CVA)

Cerebrovascular Disease is one of the most common causes of death encountered in practice. Stroke or cerebrovascular accident is the term used to describe episode of focal brain dysfunction because of localized ischemia or hemorrhage.

If symptoms of stroke resolve within 24 hours, it is called as Transient ischemic attack (TIA).

There are 2 major types of strokes

  1. Ischemic stroke – It is caused by lack of blood flow, accounting for 87% of cases.
  2. Hemorrhage stroke – It is caused by rupture of blood vessel, accounting for 13% of strokes.

Ischemic Stroke – In this condition the patient may fall on the floor because of sudden onset of neurological disease. Patient experiences unilateral motor weakness. Change in gait, vision as well as speech may get affected. The clinical presentation varies with the area supplied by the affected vessel and size of lesion. E.g. patient with supratentorial (Frontal, parietal, temporal or occipital) lesion can present with cortical signs like aphasia, difficulty in higher cognitive functions (like calculation) like confusion etc. whereas infratentorial (brain stem or cerebellum) lesion can present with dysarthria, double vision, nystagmus, ataxia, nausea and vertigo.

Intracranial Hemorrhage (ICH) or Hemorrhagic strokes are roughly classified according to location of bleeding site. The sub types are a) subarachnoid b) epidural c) subdural and intraparenchymal. ICH almost always occurs while the patient is awake and sometimes when stressed. The focal neurological deficit typically worsens steadily over 30-90 minutes associated with signs of increased intracranial pressure like headache and vomiting.

Thorough clinical examination of patient is necessary to find out cause and complication of stroke. It is very important to distinguish ischemic stroke from hemorrhagic stroke from treatment point of view, because they are completely different in both cases.

Cranial CT scan has very crucial role in diagnosis of hemorrhagic stroke.

Parkinson’s Disease

It is commonest neurodegenerative disease like Alzheimer disease. The degeneration and accumulation of misfolded protein occurs in the portion of substantia nigra. It leads to degeneration of dopaminergic neurons, which releases dopamine in caudate nucleus and putamen. Dopamine and GABA are inhibitory transmitters. They act as a stabilizer or help controlling the movements. Degeneration of dopaminergic neurons allows continuous output of excitatory signals to corticospinal motor control system leading to rigidity and tremors.

The incidences of PD are common after the age of 50. In the beginning patient notices changes in handwriting and other nonspecific symptoms like tiredness, aching limbs etc. Afterwards unilateral rest tremors are common presenting feature. It involves upper extremities, first distally, then spreads to lower limbs, tongue etc. It is of pill rolling character.

Bradykinesia (slowness of movements) develops gradually with following motor difficulties.

  1. Slow to start walking
  2. Reduced arm swings
  3. Rapid, small steps, tendency to run (festination gait)
  4. Impaired balance on turning

As disease advances, bilateral involvement occurs with indistinct and soft speech, expressionless face. Dementia also occurs in few cases. Muscle strength and reflexes are normal with planter flexor response and exaggerated blink reflex. The diagnosis is mainly clinical as there is no specific diagnostic test for Parkinson’s disease. CT and MRI are necessary to rule out other causes of movement disorder.

Dementia

Dementia is defined as acquired deterioration in cognitive abilities that impairs the successful performance of activities of daily living.

Cognitive means mental activity associated with thinking, learning and memory or any process whereby one can acquire knowledge. Memory is the most common cognitive ability that is lost with dementia. Other mental faculties allocated are language, visuospatial ability like dressing, eating etc., calculation, judgment and problem solving.

Dementia occur commonly because of following causes

  1. Alzheimer’s disease – It is most common cause of dementia in elderly people. There is degeneration of cerebral cortex and hippocampus. AD occurs in patients over years and usually presents with insidious onset of memory loss (short term is affected more than long term) followed by slowly progressive dementia over several years. Delusions are common in late stage of disease.

The diagnosis is clinical. Lab investigations are necessary to rule out other causes of dementia. CT or MRI showing diffuse or posteriorly predominant cortical and hippocampus atrophy are highly suggestive of AD.

2. Vascular Dementia – It occurs because of cerebrovascular disease. It occurs commonly in individuals who have had several strokes in the history commonly called as multi infarct dementia. It is more common in Asia.

3. Alcoholism and Drugs also produces dementia.

4. Parkinson’s disease is also one of the causes of dementia. Other cardinal features like tremors, hypokinesia and other symptoms predominate.

The management of dementia depends upon the causative factor.

Epilepsy

Epilepsy is a condition in which person gets recurrent seizures (i.e. convulsions) due to chronic, underlying process.

Pathophysiology –

In healthy human being excitation and inhibition of neuron is balanced. It is likely that seizure results from excessive excitation or decreased inhibition by neurotransmitter.

Classification –

Seizures are termed as partial or focal where paroxysmal neuronal activity is limited to one part of the cortex. The symptoms depend on which part of cortex is affected.

If a person is conscious during the attack, it is termed as simple partial seizure. Patient gets alteration in memory or perception or experience complex hallucination of sound, smell, vision etc. without unconsciousness.

If above changes occur with subsequent alteration in consciousness it is called as complex partial seizures. In this type, patients sometimes stop what they are doing, and stare blankly, often blinks repetitively etc.

When neuronal activity involves both hemispheres simultaneously and synchronously it is termed as generalized seizure. In this type tonic clonic seizures are relatively common in practice. In few cases it starts with aura. The patient then becomes rigid and goes unconscious, falling down heavily if standing. During this phase respiration is arrested and central cyanosis may occur. After some time, the rigidity is relaxed producing clonic jerks. Some patient do not have clonic phase and rigidity is replaced by flaccid stroke of deep coma with post ictal confusion (patient remain in confused and disoriented state for half an hour or more). During an attack, urinary incontinence and tongue biting may occur. It is mainly differentiated from syncope and psychogenic epileptic attacks.

Absence seizure – It is characterized by sudden, brief lapses of consciousness without loss of postural control. It usually lasts for few seconds with higher frequency (20-30 times a day) and there is no postictal confusion. Absent seizure is usually accompanied by rapid blinking of eye movements, chewing movements etc. It always starts in childhood.

Partial motor seizure affects motor activity of contralateral face, arm or leg. It is characterized by rhythmical jerking of affected part.

Partial sensory seizures – Seizures arise in sensory cortex and cause unpleasant tingling or electric sensations in the contralateral face or limbs.

Common causes of partial seizures –

  1. Cerebrovascular diseases
  2. Tumors
  3. Trauma
  4. Infections like cerebral abscess, Tuberculosis, Encephalitis etc.

Common causes of secondary generalized seizures –

  1. Infections like meningitis, post infectious encephalopathy
  2. Metabolic diseases like hypocalcaemia, Hypoglycemia, hyponatremia, renal failure and renal failure etc.
  3. Cerebral anoxia
  4. Drugs like isoniazid, metronidazole etc.
  5. Toxins like heavy metals (lead, tin) etc.
  6. Alcohol (especially withdrawal)

Triggering factors for seizure –

  1. Sleep deprivation
  2. Physical and mental exhaustions
  3. Flickering lights, including TV and computer screen
  4. Intercurrent infection and metabolic disturbances.

Investigations – EEG may help to establish a diagnosis as well as type of epilepsy.

CT and MRI are advisable particularly in patient over the age of 20 to rule out any focal lesion. Few blood investigations like calcium, blood sugar sodium level etc are necessary to find out metabolic causes.

Management – It is important to explain the nature and cause of seizures to patient and relatives. It is advisable to explain first aid management to relatives.

First aid for seizure –

  1. Move person away from danger (fire, water etc.)
  2. After convulsion cease, turn patient into semi prone (recovery) position.
  3. Ensure airway is clear, but do not insert anything in mouth because tongue biting occurs at seizure onset and cannot be prevented by observer.
  4. Do not leave person alone until fully recovered from drowsiness and confusion.

Myasthenia Gravis

 It is an autoimmune disease of neuromuscular junction. The disease is caused by presence of autoantibodies to acetylcholine receptors in post synaptic membrane.

It usually presents between ages of 15 to 50 years with affinity for females. It is characterized by progressive fatigable weakness, particularly of ocular, neck, facial and bulbar muscles. Clinically patient presents with ptosis, difficulty in chewing, swallowing and speaking etc. The symptoms commonly increase towards end of the day or following exercise. The prognosis is variable, sometimes remission occur spontaneously.

We find anti acetylcholine receptor antibody (AChRA) or anti-musk antibodies in lab investigation. EMG is also useful in some cases.

Demyelinating diseases

In these diseases destruction of myelin sheath of nerve fibre occurs.

Guillain – Barre Syndrome is a demyelinating disease. Patient usually presents with rapidly progressing muscle weakness from lower limbs to upper limbs with history of prior respiratory tract infection or diarrhea 1 to 4 week back. One should refer this type of case to hospital because respiratory failure occurs as one of the complications.

The diagnosis should be done on clinical history and examination.

Multiple Sclerosis – Patches of sclerosis occur in the brain and spinal cord following inflammation. The patient usually presents with optic neuritis and relapsing and remits sensory symptom like tingling, numbness etc. There is no specific test for MS. MRI is useful modality to find out anatomical location of lesion.