Medical Neurology Dr Sadik ALGhazzawi MRCP FRCP UK

Medical Neurology Dr Sadik AL-Ghazzawi MRCP, FRCP UK Lecture 1

Neurology Principles of clinical neurology Anatomy and physiology 10/7/2020 2

Nerve cells Types of nerve cells 1 -Neuron (variety of neuron) 2 -Glial cells 10/7/2020 3

a-Astrocyte: i t is the framework which as the following functions : *supporting the neuron *biochemical control of neuron environment *blood brain barrier by Astrocyte foot processes. 10/7/2020 4

b- Oligodendrocyte: The function of these cells is the formation and maintenance of the myelin sheath which i s value for transmission of action potential. 10/7/2020 5

Neuron (Nerv e 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 10/7/2020 generated in the neuron. 6

Anatomical organization of the nervous system ONE 10/7/2020 7

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 10/7/2020 8

2 -Peripherals nervous system (P. N. S. ) v. Cranial nerves(12 pairs v. Spinal nerves ( 31 pairs) divided into : § Cervical spinal nerves (8 pairs) § Thoracic S N (12 pairs) § Lumbar SN (5 pairs) § Sacral SN 10/7/2020 § Coccygeal SN (5 pairs) ( 1 Pair) 9

3 -Autonomic nervous system (A. N. S. ) It is divide into : A-Parasympathetic autonomic nervous system (cr ainio-sacral) , this is because it run with cranial nerves (3 rd , 7 th, 9 th & 10 th cranial nerves) and the sacral spinal nerves ( 2 nd , 3 rd & 4 th). 10/7/2020 10

athetic autonomic nervous system ( Thoraco-Lumbar), this is because it runs with thoracic spinal nerves & lumbar spinal nerves (T 1 -L 3) and also it run with the sympathetic trunk with its ganglia. 10/7/2020 11

Functional organization of the nervous system TWO 10/7/2020 12

Functional organization of the nervous system The nervous system is divided into the following parts according to the function of that part : 10/7/2020 13

1 -Cerebral hemispheres: a el the highest nervous system functions are carried A-Anterior half of the cerebral hemisphere deals with executive functions of the human brain 10/7/2020 14

B-Posterior half of the cerebral hemispheres deals with the perception of the environment. 10/7/2020 15

10/7/2020 16

The nervous system is divided physiologically into: 1 -The motor system: w hich is responsible for different movement of different parts of the body. Move ment definition: is a contraction or controlled relaxation of a group of muscles and never a single muscle 10/7/2020 17

To perform a voluntary movement we need the participation of the following: A-The Motor Area (P recentral area of the frontal lobe: in this area the first spark for starting the action of movement , i. e. cells of motor cortex = movement. 10/7/2020 18

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 10/7/2020 19

i. e. Cerebellum control the coordination of movement and Extrap yramidal motor system control the shape and s moothness of the movement , while the motor area ignite the spark of the voluntary movement. 10/7/2020 20

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 10/7/2020 21

Anatomy of the motor system 1 -The motor system starts within the PCJ of the cerebral cortex of the frontal lobe. 2 - motor signals passes within the corticospinal tract t hrough the internal capsule , brain stem 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). 10/7/2020 22

*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 10/7/2020 23 uppermost and the cell of the movement of the tongue are

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 10/7/2020 24

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). 10/7/2020 25

Lesion of UMN above the decussating results in : v. Loss of some voluntary movement on the opposite side of the body. v. Preservation of the reflex activity (difference between UMN and LMN ). v. Heightened (increase the reflex activity because of the loss of the inhibitory action of the UMN on the LMN. 10/7/2020 26

Upper motor neuron lesion results in : A-Positive phenomenon (increase reflex activity ) b- Negative phenomenon (loss of voluntary movement). Signs of UMN dysfunction Ø Muscle paralysis on the opposite side of the body for the voluntary movement 10/7/2020 27

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. 10/7/2020 28

Ø Hyperreflexia. Ø Extensor planter Ø All on the opposite side. Ø Loss of abdominal reflexes Ø No muscle atrophy but long term disuse atrophy. Ø Normal electrical activity in the muscle fibers. 10/7/2020 29

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 10/7/2020 integrity. 30

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 10/7/2020 31

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). 10/7/2020 32

which are collection of ganglions in the depth of the cerebr al hemisphere to complement the function of t he motor system(PS) for optimum motor control. 10/7/2020 33

3 -Thalamus, Thi s part of the brain deals with the appreciation and attention to the sensory perception. 10/7/2020 34

deals with the emotions and memory. 5 -Hypothalam the part of the brain which he internal body functions (internal environment). 10/7/2020 35

6 -Brain stem, Th at 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. 10/7/2020 36

B-Housing nuclei of the cranial nerves (3 rd &4 th) which control the conjugate eye movements ( internuclear mechanism of the conjugate eye movements). 10/7/2020 37

C-containing the central nuclei for the cardiorespiratory control. D-Maintenance of the arousal of the human brain. (RAS) E-Complement the cerebellum for the balance control. 10/7/2020 38

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. 10/7/2020 39

C-Primary processing of the sensory information coming through the sensory system, including the pain sensation analysis. 10/7/2020 40

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. 10/7/2020 41

These 3 divisions of the peripheral nervous system compose the essential parts of the (lower motor neuron unit). 10/7/2020 42

. 9 -The autonomic nervous system, sympathetic and parasympathetic ) ( has the following function: A-Unconscious neural control of the body physiology. 10/7/2020 43

B-Cardiovascular and respiratory system control. C-Smooth muscles and the glands of gastrointestinal 10/7/2020 44

The ANS is controlled centrally by diffuse modulatory system in the brain stem , limbic system and frontal lobe (the arousal and background behavioral responses to threat. 10/7/2020 45

Clinical skills in Solving Neurological Problem ONE 10/7/2020 46

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). 10/7/2020 47

The history. Rule ONE i mportant in determining both the anatomical & pathological diagnosis. Rule TOWman y neurological patients have no abnormal signs, or simply have physical features that confirm clinical suspicions base on the history. 10/7/2020 48

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 thi s is because disease at one site in the N. S may produce symptoms mimicking a lesion at another site. 10/7/2020 49

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. 10/7/2020 50

Disc riminate 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) 10/7/2020 51

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. 10/7/2020 52

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: 10/7/2020 53

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 10/7/2020 54

Carotid bruit enlargement Anterior fontanelle baby Cardiac murmurs Prostatic irregularity Head circumference Cyanosis /respiratory insufficiency 10/7/2020 55

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 10/7/2020 56

2 -Cranial nerves(1 -12) ----------------------------------------------------3 -Upper limbs -Motor system –wasting - tone -power -Sensory system- pain -touch -temp -proprioception -stereognosis -Reflexes -Coordination 10/7/2020 57

10/7/2020 4 -Trunk -sensation -reflexes ---------------------------------------------------5 -Sphincters ---------------------------------------------------6 -Lower limbs -motor system -wasting -tone -power -sensory system -pain -touch 58 -tempt

-reflexes coordination-gait, - stance --------------------------------------------------*Alternatively the examiner may prefer to work through individual systems for the whole body, e. g. motor system, sensory system 10/7/2020 59

Symptomology in Nervous System 10/7/2020 60

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 10/7/2020 61

1 -Cerebral Hemispheres 1 -White Matter Tracts 2 -Cerebellum 3 -Basal Ganglia 4 -Brain Stem Ii-Spinal Cord 10/7/2020 62

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 10/7/2020 63

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 10/7/2020 64

-Cranial nerves iii—xii Spinal nerves & nerve roots— Cauda equina (anterior horn cell, neve root , plexus , peripheral nerves, Neuromuscular junction, skeletal muscles). 10/7/2020 65

Higher cortical functions TWO 10/7/2020 66

10/7/2020 67

Higher cortical functions 1 -Frontal lobe functions a- Executive functions b- Behavioral function c- Motor area 10/7/2020 68

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 10/7/2020 69

Frontal lobe syndromes: 1 -Personality changes: with diffuse frontal lobe damage. 2 -Behavioral disturbances 3 -Antisocial behavior 4 -Expressive dysphasia 10/7/2020 70

5 -Incontinence 6 -Anosmia 7 -Contralateral hemiparesis 8 -Return of primitive reflexes i. e. sucking reflex , grip reflex. 9 -Focal motor seizure 10/7/2020 71

Parietal lobe function: v. Integration of sensory perception. Dominant parietal lobe dysfunctions: §Language disorder §Calculations disorders 10/7/2020 72

§Apraxia : § is the inability to perform complex organized function in § the presence of a normal basic motor , sensory and § ce rebellar system (planning and ideation disorder). § It is resulted from sensory inattention and spatial perception disorder. 10/7/2020 73

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. 10/7/2020 74