LOWER MOTOR NEURON LOWER MOTOR NEURON PARAPLEGIA - PowerPoint Presentation

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LOWER MOTOR NEURON

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LOWER MOTOR NEURON PARAPLEGIA

DR RABIA RATHORE

ASSISTANT PROFESSOR

WEST MEDICAL WARD

MAYO HOSPITAL/K.E.M.U

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DEFINITION OF PARAPLEGIA

Paraplegia is a word taken from GREEK language

para

+

plessein

means

STRIKE AT SIDE.

It is defined as impairment of motor function of lower limbs with or without involvement of sensory system.

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DEFINITION

A

lower motor neuron lesion

is a lesion which affects nerve fibers traveling from the ventral horn or anterior gray column of the spinal cord to the relevant muscle(s).

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LOWER MOTOR NEURONS

Lower motor neurons are the anterior gray horn cells in the spinal cord and the motor neurons of the cranial nerve nuclei situated in the brain stem, which innervates the muscles directly.

The lower motor neurons are under the influence of upper motor neurons.

The activity of particular muscle depends upon the excitation of the alpha motor neurons in the spinal cord or cranial nerve nuclei(LOWER MOTOR NEURONS)

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DEFINITION

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PATHOGENESIS

The symptoms that arise from damage to the lower motor neurons of the brainstem and spinal cord are referred to as the

LOWER MOTOR

NEURON DISEASE

.

Damage to lower motor neuron cell bodies or their peripheral axons results in

paralysis

(loss of

movement) or

paresis

(weakness) of the affected muscles.

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In addition to paralysis or paresis , the lower motor neuron includes loss of reflexes

(AREFLEXIA

) due to interruption of the efferent (motor) limb of the sensory motor reflex arcs. Damage to lower motor neurons also entails a loss of muscle tone, since tone is in part dependent on the mono synaptic reflex arc that links the muscle spindles to the lower motor neurons.

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A somewhat later effect is atrophy of the affected muscles due to

denervation and disuse. The muscles involved may also exhibit fibrillations and

fasciculations

, which are spontaneous twitches characteristic of single

denervated

muscle fibers or motor units, respectively.

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These phenomena arise from changes in the excitability of

denervated muscle fibers in the case of fibrillation, and from abnormal activity of injured α motor neurons in the case of

fasciculations

. These spontaneous contractions can be readily recognized in an

electromyogram

, providing an especially helpful clinical tool in diagnosing lower motor neuron disorders.

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CAUSES OF LOWER MOTOR NEURON PARAPLRGIA

1.PERIPHERAL NEUROPATHY

A.Metabolic

Diabetes mellitus

Chronic renal failure

Hypothyroidism

Amyloidosis

Chronic liver disease

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B

.

Toxic

Alcohol

Drugs

Isoniazid

Phenytoin

Vincristine

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C.INFLAMMATORY

Acute Gullian

Barre

Syndrome

Chronic Inflammatory

Demyelinating

Polyneuropathy

(CIDP)

Leprosy

Connective Tissue Disorder

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D.GENETIC

Hereditary Motor And Sensory

Neuropthies

E.DEFICIENCY DISEASES

Thiamine Deficiency

Vitamin A Deficiency

F.MISCELLANEOUS

Malignancy

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2.INFECTION

Poliomyelitis

3.CAUDA EQUINA SYNDROME

4.MYOPATHIES

A.ACUTE ELECTROLYTE IMBALANCE

Hypokalemia

Hyperkalemia

Hypocalcemia

Hypercalcemia

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B.PROXIMAL MYOPATHIES

HypothyroidismHyperthyroidism

Cushing

,

s Syndrome

5.MOTOR NEURON DISEASE

6.HYSTERICAL

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CASE SCENARIO NO:1

A 22 year old Caucasian female presents to the emergency

room with a chief complaint of weakness Of both legs. One

week prior, she had a fever of 101.4*F with flu like symptoms.

After 3 days, She was doing well until this morning when she

fell while trying to get out of bed and could not stand or walk

without support. She has no headache, blurred vision,

tinnitus, vertigo, or incontinence. There is no history of toxic

ingestion or trauma. Her immunizations are up to date. While

in the ER she complains that her arms feel weak and is having

dysphagia

and shortness of breath and her eyes are drooping.

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EXAMINATION

MOTOR SYSTEM

UPPER LIMB

LOWER LIMB

BULK

NORMAL

NORMAL

TONE

DECREASED

DECREASED

POWER

3/5

2/5

REFLEX

ABSENT

ABSENT

PLANTERS

DOWN GOING

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SENSORY SYSTEM

: Intact

CEREBELLAR SYSTEM :

Intact

CRANIAL NERVES

:Bilateral 7

th

Nerve Palsy

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WHAT IS THE DIAGNOSIS ?

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WHAT IS GULLAIN BARRE SYNDROME

Guillain

-

Barre

syndrome (GBS) is an acute

demyelinating

polyneuropathy

of the peripheral nervous system characterized by progressive flaccid paralysis. It is an acquired disorder that affects people of all ages, although only rarely in children under one year of age .It has a slight male predominance of 1.5 to 1 and has an estimated annual incidence rate of 1/100,000.

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CLASSIFICATION

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Miller-Fisher syndrome

The clinical variant of GBS is the Miller-Fisher syndrome with its triad of:

External

ophthalmoplegia

Ataxia

Areflexia

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PATHOGENESIS

Current research suggests that

ANTI

GANGIOSIDE ANTIBODIES

play an important role in the pathogenesis of GBS.

Gangliosides

are

glycolipids

containing

sialic

acid residues and are the surface components of many cells, including nerve cells. Many patients with GBS have antibodies to various

gangliosides

such as GM1, GD1a, GD1b, and GQ1b.

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INVESTIGATIONS

BLOOD COMPLETE EXAMINATION & ESR

BLOOD CULTURE

LUMBAR PUNCTURE

Elevated protein level

Normal cell counts

Glucose level normal

Culture negative

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4. ELECTRODIAGNOSTIC STUDIES:

Nerve conduction:

studies reveal slowing in both motor and sensory nerves.

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Electromyography

(EMG)

May show acute

denervation

of muscle .

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CASE SCENARIO NO:2

A 15 years male presented in emergency with sudden weakness of lower limbs when he woke up in the morning .He had similar episode 3 months back. He had a carbohydrate diet as a dinner just before going to sleep .There is no history of trauma, incontinence ,backache or fever. Examination revealed flaccid paralysis of both lower limbs rest of the CNS examination was normal.

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What is the likely diagnosis?

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HYPOKALEMIC PERIODIC PARALYSIS

HYPERKALEMIC PERIODIC PARALYSISNORMOKALEMIC PERIODIC PARALYSIS

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HYPOKALEMIC PERIODIC PARALYSIS:

Periodic paralysis may have a familial (dominant inheritance)basis. The syndromes to be described are

channelopathies

that manifest as abnormal, often potassium-

sensitive,muscle

-membrane excitability and lead clinically to episodes

of flaccid weakness or paralysis, sometimes in association with abnormalities of the plasma potassium level.

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PATHOGENESIS

Hypokalemic

periodic paralysis has been

related to mutations in the

CACNL1A3, SCN4A, or KCNE3(11q13-q14) gene.

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CLINICAL FEATURES

It is characterized by attacks that tend

to occur on awakening, after exercise, or after a heavy meal and may last for several

days.It

may be associated with thyroid disorders.

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INVESTIGATIONS

Serum potassium level

Thyroid function test.

Electro diagnostic studies :

Nerve Conduction Studies

There is reduced motor amplitude during the attack and normal in between the attacks.

Electromyography

(EMG)

Often demonstrate

myotonic

discharges during the attack.

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MUSCLE BIOPSY

:

It shows vacuoles that are

smaller,less

numerous and more peripherally placed.

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CASE SCENARIO NO:3

A 60 Years school teacher had complaints of pain in both thighs radiating to the perineum while walking for few months .This pain is relieved by resting or bending forward. Now presented with weakness of both lower limbs ,

perianal

numbness with bowel and bladder incontinence. Examination revealed wasting of quadriceps, weakness of foot inverters, absent ankle and knee jerk with down going planters and saddle anesthesia.

WHAT IS THE LIKELY DIAGNOSIS?

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CAUDA EQUINA SYNDROME

The spinal cord tapers and ends at the level between the first and second lumbar vertebrae in an average adult. The most distal bulbous part of the spinal cord is called the

conus

medullaris

, and its tapering end continues as the

filum

terminale

. Distal to this end of the spinal cord is a collection of nerve roots, which are horsetail-like in appearance and hence called the

cauda

equina

(Latin for horse's tail)

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INVESTIGATIONS

Plain Radiographs

Lumbo

sacral spine

Myelography

Computed tomography

MRI

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Electromyography:

(EMG)may show evidence of acute

denervation

, especially in

cauda

equina

lesions and multilevel lumbar spinal

stenosis

. EMG studies also could help in predicting prognosis and monitoring recovery. Performing needle EMG of the bilateral external anal sphincter muscles is recommended.

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CASE SCENARIO NO.4

A 65 years female known diabetic for the last 25 years with poor control of diabetes had complaints of numbness of both hands and feet for many months now for the last few days is unable to walk . On examination there is flaccid

paraparesis

with glove and stocking pattern of sensory impairment.

WHAT IS THE DIAGNOSIS?

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PROGESSIVE MUSCULAR ATROPHY

Ii is a variety of motor neuron disease in which only lower motor neurons of spinal cord are affected.

There is gradual progressive weakness. Usually all the four limbs are involved.

Muscle wasting is marked.

Fasiculations

are the most prominent feature.

There is no sensory loss.

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ACUTE INTERMITTENT PORPYRIA

The sequence of events in attacks of acute intermittent

porphyria

(AIP) usually is as follows:

Abdominal pain

Psychiatric symptoms

Peripheral neuropathies, mainly motor neuropathies.

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LEAD POISONING

Central nervous system and neuromuscular symptoms usually result from intense exposure, over longer periods . Signs of chronic exposure include

loss of short term memory or concentration,

nausea & abdominal pain

loss of coordination

numbness, tingling in the extremities

lower motor neuron

paraparesis

problems with sleep

headaches

stupor

slurred speech

Anemia

A blue line along the gum with bluish black edging to the teeth, known as

BURTON LINE

is another indication of chronic lead poisoning.

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HYSTERICAL

Weakness is variable.

Social history is suggestive of underlying psychiatric problem.

There is anesthesia in a distribution which is not possible due to organic lesion.

Reflexes are normal.

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