Medical Neurology

Dr Sadik AL-Ghazzawi

MRCP, FRCP UK

Lecture 1

217-Oct-19

Neurology

Principles of clinical neurology

Anatomy and physiology

317-Oct-19

Nerve cells

Types of nerve cells

1-Neuron (variety of neuron)

2-Glial cells

417-Oct-19

a-Astrocyte:

it is the framework which has the following

functions :

*supporting the neuron

*biochemical control of neuron environment

*blood brain barrier by Astrocyte foot

processes.

517-Oct-19

b- Oligodendrocyte:

The function of these cells is the formation

and maintenance of the myelin sheath which

is value for transmission of action potential .

617-Oct-19

Neuron

(Nerve cell )is the basic unit of the nerve system

,characterized by:

1-limitless connection.

2-Adaptability and variability of functions.

3-Has several projection.

4-The axon transmits the impulses which are

generated in the neuron.

717-Oct-19

Anatomical organization of the nervous

system

ONE

817-Oct-19

1-Central nervous system (C.N.S.)

A-The brain :- which consist of :

* Cerebral context (CC) :-which consist of:

- Frontal lobe

-Occipital lobe

- Parietal lobe

-Temporal lobe

*Brain stem (mid brain, pones)

*Cerebellum

B- Spinal cord

917-Oct-19

2-Peripherals nervous system (P.N.S.)

❖Cranial nerves(12 pairs

❖Spinal nerves ( 31 pairs) divided into :

▪ Cervical spinal nerves (8 pairs)

▪ Thoracic S N (12 pairs)

▪ Lumbar SN (5 pairs)

▪ Sacral SN (5 pairs)

▪ Coccygeal SN ( 1 Pair)

1017-Oct-19

3-Autonomic nervous system (A.N.S.)It is divide into :

A-Parasympathetic autonomic nervous system

(crainio-sacral) ,this is because it run with cranial

nerves (3rd ,7th, 9th & 10th cranial nerves) and the

sacral spinal nerves ( 2nd ,3rd & 4th).

1117-Oct-19

B-Sympathetic autonomic nervous

system

( Thoraco-Lumbar), this is because it

runs with thoracic spinal nerves & lumbar spinal

nerves (T1-L3) and also it run with the sympathetic

trunk with its ganglia.

1217-Oct-19

Functional organization of the

nervous system

TWO

1317-Oct-19

Functional organization of the

nervous system

The nervous system is divided into the

following parts according to the function of

that part :

1417-Oct-19

1-Cerebral hemispheres:

at that level the highest nervous system

functions are carried

A-Anterior half

of the cerebral hemisphere

deals with executive functions of the

human brain

1517-Oct-19

B-Posterior half of the cerebral

hemispheres deals with the

perception of the environment .

1617-Oct-19

1717-Oct-19

The nervous system is divided physiologically

into:

1-The motor system:

which is responsible for different movement of

different parts of the body.

1817-Oct-19

Movement definition:

is a contraction or controlled relaxation of a group

of muscles and never a single muscle

1917-Oct-19

To perform a voluntary movement we need the

participation of the following:

A-The Motor Area

(Precentral area of the frontal lobe:

in this area the first spark for starting the action of

movement

,i.e. cells of motor cortex = movement.

2017-Oct-19

B-The cerebellum :

which complements the function of the motor area by

adding :

a-coordination

b- timing of contraction and relaxation of the muscle fibers

.

3- Extrapyramidal motor system,

complement the function of the motor area by giving the

movement its smooth and nice shape

2117-Oct-19

i.e.Cerebellum control the coordination of movement and

Extrapyramidal motor system control the shape and

smoothness of the movement ,while the motor area ignite

the spark of the voluntary movement .

2217-Oct-19

4- Anterior horn cells of the spinal cord and motor cranial

nuclei .-----------

5- The muscle fiber

SO,

A group of anterior horn cells = muscle

Cells of the motor cortex = movement

2317-Oct-19

Anatomy of the motor system

1-The motor system starts within the PCJ(1) of the cerebral

cortex of the frontal lobe .

2- motor signals passes within the corticospinal tract(2)

through the internal capsule(3) ,brain stem(4) were motor

fibers

coming from the motor cranial nuclei to join the CST to

decent down to

3-the spinal cord (anterior horn of the spinal cord).

2417-Oct-19

*PCJ initiates movements of different parts of the opposite

side of the body.

The representations of the movement of different parts of

the body are represented from below-upward (upside

down) in the precentral jyris cells ( the foot ,legs ,thigh

,arm ,hand ,face and tongue )are represented upside

down were the cells of the movement of the foot are

uppermost and the cell of the movement of the tongue are

the lower most.

2517-Oct-19

NOTE,

This wide representation of the body in the

precentral

jyrus leads to a limited loss of function when part of

the PCJ is affected ,example: monoplegia

2617-Oct-19

Upper motor neuron

Which include the motor system from the cerebral cortex

down to the anterior horn cell of the spinal cord passing

through the corticospinal tract which decussates below the

brain stem (lateral corticospinal tract).

2717-Oct-19

Lesion of UMN above the decussating results in :

❖Loss of some voluntary movement on the opposite side of

the body .

❖Preservation of the reflex activity (difference between UMN

and LMN ).

❖Heightened (increase the reflex activity because of the loss

of the inhibitory action of the UMN on the LMN .

2817-Oct-19

Upper motor neuron lesion results in :

A-Positive phenomenon (increase reflex activity )

b- Negative phenomenon (loss of voluntary movement).

Signs of UMN dysfunction

➢ Muscle paralysis on the opposite side of the body for the

voluntary movement

2917-Oct-19

Hypertonia:

increase in the muscle tone ,which is of clasp knife type or

spastic type , which has pyramidal distribution i.e: involve

the flexor muscles of the upper limb and the extensor

muscles of the lower limb.

3017-Oct-19

➢ Hyperreflexia.

➢ Extensor planter

➢ All on the opposite side.

➢ Loss of abdominal reflexes

➢ No muscle atrophy but long term disuse atrophy.

➢ Normal electrical activity in the muscle fibers.

3117-Oct-19

Anatomy of lower motor neuron

Include,

1-Anterior horn cells

2- Anterior nerve roots

3- Peripheral motor nerves

4- Muscles

i.e .Motor unit=AHC +Axon +Group of muscle fibers

Note: the nutrition of the muscles depend on the LMN

integrity.

3217-Oct-19

Signs of LMN dysfunction

1-Paralysis of all movements (voluntary and involuntary),

the difference between UMN and LMN.

2- Hypotonia (flaccidity): loss of muscle tone.

3-Hporeflexia or areflexia.

4-Preservation of the abdominal reflexes

5-Flexor planter reflex

3317-Oct-19

6- Wasting of the muscles supplied by the LMN in 2-3 weeks

time, this is because the nutrition of the muscles depends

on the integrity of the LMN.

7- Fibrillation (spontaneous single fiber contraction), which

is invisible and it is electromyographic feature.

8- Fasciculation: Spontaneous contraction of a group of a

muscle fibers (visible).

3417-Oct-19

2-Basal ganglia----- (EPS)

which are collection of ganglions in the depth of the

cerebral hemisphere to complement the function of

the motor system(PS) for optimum motor control.

3517-Oct-19

3-Thalamus,

This part of the brain deals with the

appreciation and attention to the sensory

perception .

3617-Oct-19

4-Limbic system ,

deals with the emotions and memory .

5-Hypothalam the part of the brain which

deals with the internal body

functions (internal environment).

3717-Oct-19

6-Brain stem,

That part of the central nervous system which

has the following functions:

A-harboring the sensory and the motor

pathways entering and leaving the cerebral

hemisphere .

3817-Oct-19

B-Housing nuclei of the cranial nerves (3rd &4th)

which control the conjugate eye movements

( internuclear mechanism of the conjugate eye

movements) .

3917-Oct-19

C-containing the central nuclei for the cardio-

respiratory control.

D-Maintenance of the arousal of the human brain .

(RAS)

E-Complement the cerebellum for the balance

control .

4017-Oct-19

7-Spinal cord,

it has the following functions:

A-Containing the afferent and efferent fibers to the

central nervous system.

B-It contains and control the lower order motor

reflexes.

4117-Oct-19

C-Primary processing of the sensory information

coming through the sensory system, including the

pain sensation analysis.

4217-Oct-19

8-Peripheral nervous system

which compose of:

A-Afferent and efferent connection.

B-Sensory cells in the dorsal root ganglia .

C-Motor cells in the anterior horn of the spinal

cord .

4317-Oct-19

These 3 divisions of the peripheral nervous

system compose the essential parts of the (lower

motor neuron unit) .

4417-Oct-19

.

9-The autonomic nervous system,

( sympathetic

and parasympathetic )

has the following function:

A-Unconscious neural control of the body

physiology.

4517-Oct-19

B-Cardiovascular and respiratory system control.

C-Control Smooth muscles and the glands of

gastrointestinal

4617-Oct-19

Note:-

The ANS is controlled centrally by diffuse

modulatory system in the brain stem , limbic

system and frontal lobe

(the arousal(1) and

Background(2) behavioral responses to threat.

4717-Oct-19

Clinical skills in Solving Neurological Problem

ONE

4817-Oct-19

1-fundamental clinical skills of history –taking & physical

examination.

Neurological diagnosis . divided, to,

1-Functional diagnosis.

2-Etiological diagnosis

3-anatomical diagnosis,(what is the site of the lesion in

the N.S.)

4-pathological diagnosis,(what disease process has

occurred at the site).

4917-Oct-19

The history.

Rule ONE

important in determining both the anatomical &

pathological diagnosis.

Rule TOW-

many neurological patients have no abnormal

signs, or simply have physical features that

confirm clinical suspicions base on the history.

5017-Oct-19

Rule THREE

In complex problems, the history can only yield a , short

list, of potential site of the lesion(s) & final localization

must wait the formal examination.

Rule FOUR -

this is because disease at one site in the N.S may produce

symptoms mimicking a lesion at another site.

5117-Oct-19

presenting complain;

1-allow the patient sufficient uninterrupted time to

speak. age. occupation. handedness. hemisphere

dominance.

History

1-probe the history in specific areas.

2-timing of symptoms.

onset, progression, duration, recovery, frequency.

5217-Oct-19

Discriminate questions ;is

To differentiate between tow pathology which

could produce similar clinical picture .e.g. ,

Glove & stocking sensory loss in peripheral

neuropathy & C. spinal cord disease.

(neck pain , injury, sphincter dysfunction)

5317-Oct-19

Examination .

Initial impression,

Gait, facial expression, hand shake, speech,

cognitive function.

(Screen) examination,

1-level of consciousness.

2-cognitive function.

3-speech.

4-cranial nerves.

5-neck & trunk

6-limbs-motor & sensory examination.

7-gait.

5417-Oct-19

1-Neurological disease may produce systemic

signs and systemic disease may affect the

nervous system

2-a complete general examination must

therefore accompany that of the

central nervous system.

3-in particular , note the following:

5517-Oct-19

Temperature Evidence of weight loss

Septic source, teeth ,ears

Blood pressure Breast lumps

Skin marks, e.g. reshes

Neck stiffness lymph adenopathy

café-au-lait spots

Pulse irregularity hepatic & splenic

angiomata

5617-Oct-19

Carotid bruit enlargement

Anterior fontanelle baby

Cardiac murmurs Prostatic irregularity

Head circumference

Cyanosis /respiratory

insufficiency

5717-Oct-19

CNS examination is described systematically

from the head downward

and include:

1-Conscious level and higher cerebral function

2-Cognitive skills –Memory –Reasoning -

Emotional states

5817-Oct-19

2-Cranial nerves(1-12)

--------------------------------------------------------------------

-------------------------------------

3-Upper limbs

-Motor system –wasting

- tone

-power

-Sensory system- pain

-touch

-temp

-proprioception

-stereognosis

-Reflexes

-Coordination -

5917-Oct-19

4-Trunk

-sensation

-reflexes

----------------------------------------------------------------------

---------------------------------

5-Sphincters

----------------------------------------------------------------------

---------------------------------

6-Lower limbs

-motor system

- -wasting

-tone

-power

-sensory system

- -pain

-touch

-tempt

-proprioception

6017-Oct-19

-reflexes

coordination-gait,- stance

----------------------------------------------------------------------

--------------------------------

*Alternatively the examiner may prefer to work

through individual systems for the whole

body,e.g.motor system, sensory system

6117-Oct-19

Symptomology in Nervous System

6217-Oct-19

Central Nervous System

(Upper Motor Neuron)

1-Brain

2-Spinal Cord

UMN Lesion

1-Cognitive disorders

2-Spastisity

3-Hyperreflexia

4-Sensory alteration

5-Pathological reflexes

6317-Oct-19

1-Cerebral Hemispheres

1-White Matter Tracts

2-Cerebellum

3-Basal Ganglia

4-Brain Stem

Ii-Spinal Cord

6417-Oct-19

A-Cortical (gray matter) lesions

Defect in Higher cortical functions

1-Dementia.

2-Aphasia.

3-Seizures.

B-Subcortical (white matter) lesions

1-Hemiparesis

2-Hemisensory defects.

C-mixed cerebral lesions

6517-Oct-19

Peripheral Nervous System(PNS)

Lower motor neurons

A-Weakness

B-Flaccidity.

C-Sensory alterations.

D-loss of deep tendon reflexes.

E-absence of pathological reflexes

6617-Oct-19

-Cranial nerves iii—xii

Spinal nerves & nerve roots—

Cauda equina

Lmn

(anterior horn cell, neve root , plexus

,peripheral nerves,

Neuromuscular junction,skeletal muscles).

6717-Oct-19

Higher cortical functions

TWO

6817-Oct-19

6917-Oct-19

Higher cortical functions

1-Frontal lobe functions

a- Executive functions

b- Behavioral function

c- Motor area

7017-Oct-19

The functional area of the frontal lobe are :

1-Primary motor cortex (pre central jyrus)

2-Brocas area (speech center)

3-Frontal eye field center (Broadman 8)

4-Higher order motor control

5-Micturation center

7117-Oct-19

Frontal lobe syndromes:

1-Personality changes: with diffuse frontal lobe

damage.

2-Behavioral disturbances

3-Antisocial behavior

4-Expressive dysphasia

7217-Oct-19

5-Incontinence

6-Anosmia

7-Contralateral hemiparesis

8-Return of primitive reflexes i.e. sucking reflex ,grip

reflex.

9-Focal motor seizure

7317-Oct-19

Parietal lobe function:

❖Integration of sensory perception.

Dominant parietal lobe dysfunctions:

▪Language disorder

▪Calculations disorders

7417-Oct-19

▪Apraxia :

▪

is the inability to perform complex organized function in

▪

the presence of a normal basic motor ,sensory and

▪

cerebellar system (planning and ideation disorder) .

▪

It is resulted from sensory inattention and spatial

perception disorder .

7517-Oct-19

Temporal lobe

It contains the following:

1- Primary auditory cortex

2- Primary vestibular cortex

3- Memory function

Occipital lobe

It contains the visual and image processing.