LECTURE 2

LECTURE 2


1) Given a clinical presentation of a patient with a neurological complaint localize the pathology to the cortex, Sub cortex white/gray matter, brainstem, spinal cord, anterior horn cell, peripheral nerves, myoneural junction, or muscle.

AND SEE 2-9
2) Cortex
a) Stroke: Given a clinical presentation, recognize two types of strokes.
(1) Ischemic Stroke:
(a) caused by a lack of blood supply to part of the brain. T
(b) caused by atherosclerosis.
(c) Caused by blood clot can form on the plaque and block blood flow to the brain.
(i) This is a thrombotic stroke.
(2) Hemorrhagic Stroke:
(a) artery in the brain ruptures.
(b) Blood puts pressure on the surrounding brain tissue, causing edema.
(c) Brain cells beyond the rupture site become ischemic.
(i) Hypertension: The most common cause of a hemorrhagic stroke is high blood pressure.
1. The constant force of high blood pressure weakens blood vessel walls; this is typically in the basal ganglia or cerebellum.
(ii) Aneurysm leak: Another cause of a hemorrhagic stroke is leakage from an aneurysm
(iii) AV malformation: An uncommon cause of hemorrhage is rupture of an arteriovenous malformation. This group of congenitally malformed blood vessels can rupture.


Patients present with speech disturbances….aphasias.
Imaging: MRI
b) Aphasia: Given a clinical presentation, recognize expressive, receptive, conduction, transcortical motor, transcortical sensory, or anomic aphasia.

3) Subcortical White/Gray Matter disorders causing movement disorders: Given a clinical presentation, recognize chorea,
athetosis, tremor, dystonia, or tics.

v CHOREA: Rapid, irregular, relatively small amplitude, random-appearing rather continuous, non-stereotyped jerks or distal limbs.

Ø Non-repetitive or rhythmic brief muscle contractions
§ Huntington's disease
§ Sydenham's chorea
§ Tardive dyskinesia
Ø Hyperkinetic disorder

v ATHETOSIS: Wormlike, writhing, twisting movements of the limbs. They are slow
v TREMOR: Rhythmic, oscillatory movements, of the limbs, head, laryngeal muscles
Ø Essential
Ø Intention
Ø Hyperkinetic disorder

v DYSTONIA: Involuntary, sustained, patterned, and often repetitive muscle contractions of opposing muscles resulting in twisting, spasmodic or other abnormal postures
Ø Primary idiopathic
Ø Secondary
Ø Acute-drug induced

v TICS: Semi-involuntary, (often compulsive), repetitive, stereotyped movements
Ø . Motor tics: facial grimace, eye squint, head flip, etc.
§ Simple motor tic
§ Chronic motor tic
Ø Vocal tics: grunt, sniff, cough, snort, etc.
Ø Tourette syndrome


4) Brainstem: recognize crossed findings in brainstem lesions
CASE 5
right sided weakness and double vision.
left part of his mouth seemed drooped.

CAUSE OF CROSSED FINDINGS
Left lateral rectus palsy secondary to Cranial Nerve 6th nerve palsy.

Left pontine stroke presenting as a ventral pontine or “Millard-Gubler” syndrome

5) Spinal Cord: given a clinical presentation, recognize dorsal column disease, anterior spinal cord disease, and Brown-
Sequard syndrome, anterior horn cell disease, tabes dorsalis, and subacute combined degeneration.

· dorsal column disease: vibratory sense, proprioception, and deep pain (will be impaired?)
· anterior spinal cord disease: Loss of pain and temperature (+/- loss of corticospinals) with preservation of vibration and position sense specifically localizes to
· Brown-Sequard syndrome 9hemi-cord ): vibration and position sense are lost ipsilateral to the lesion, and pain and temperature sensation are lost contralateral to the lesion.
· anterior horn cell disease: SEE OBJ 6
· tabes dorsalis: is a manifestation of tertiary syphilis, where just the dorsal columns are affected.
· subacute combined degeneration: is the lesion of severe B12 deficiency, where both the dorsal columns and the corticospinal tracts (motor control descending from the cortex to the muscles) are impaired.

6) Anterior Horn Cell Diseases – recognize conditions primarily affecting this area.

Anterior Horn Cell diseases tend to be progressive and commonly at onset have upper and lower motor features. Fasciculations is a prominent clinical finding in these patients.
1. Poliomyelitis present with a spinal form as well as a brainstem form. The spinal form (most common) can occur with muscle pain and within 24 hrs the weakness reaches maximal intensity in the muscles involved. It involves the anterior horn cell area.
2. Amyotrophic Lateral Sclerosis (Lou Gehrig’s Disease) presents with progressive weakness, muscle twitching, and atrophy of the muscles.

CLIN PRESENT

A 3-day-old term infant has required Cesarean section at delivery because labor failed to progress. The infant has shown little spontaneous movement since birth, and has required intubation for respiratory failure. On examination, the infant has a "frog-leg" appearance, and absent deep tendon reflexes. Response to pin-prick is vigorous in all limbs. Prominent tongue fasciculation are noted, but otherwise the cranial nerves are normal.
Where is the lesion? Anterior Horn Cell (muscle biopsy showed changes consistent with neuropathic process. The condition is felt to be Spinal Muscular Atrophy).

7) Peripheral Nerve: Given a clinical presentation of a patient with sensory deficits, recognize peripheral neuropathy,
radiculopathy (spinal root lesion), mononeuropathy, diabetic neuropathy, combined system degeneration (B12 deficiency),
and carpal tunnel syndrome.
v Peripheral neuropathies are characterized by a "proximal-distal gradient", which means that the distal extremities are affected more than proximal extremities. This is called stocking-glove sensory loss.
v Peripheral sensory nerve disorders: Tingling, burning, and "pins and needles" complaints
Ø Diffuse distribution of these abnormal sensations (dysesthesias) suggests a systemic (i.e. diabetic) polyneuropathy. Local examples include
§ Compression of the median nerve causes dysesthesias of the thumb-half of palm. This is commonly caused by compression of the nerve in the bony tunnel of the wrist, called Carpal Tunnel Syndrome.
§ Compression of the radial nerve causes dysesthesias of the thumb-half of dorsum of hand and ulnar nerve compression causes dysesthesias on remaining half of palm and dorsum.
v Root lesions produce pain and sensory loss in a dermatomal distribution.
v Mononeuropathies have focal complaints and findings;
Ø polyneuropathies affect both sides of the body about equally.
Ø Carpal Tunnel Syndrome: injury to the median nerve as it passes through the carpel tunnel in the wrist. It can be caused by overuse of the wrist or other reasons why the nerve may thicken (hypothyroidism, amyloidosis, pregnancy).
Ø TInels and Phalen’s tests will be positive.
§ Tinel’s test is positive when shooting pain in the distribution of the median nerve is produced when the carpal tunnel is tapped.
· Phalen’s test is positive when the same pain is produced when the patient presses the dorsum of each hand against each other (therefore hyperflexing the wrist).
CLIN PRESENT:
A 25-year-old carpenter develops pain in his right forearm at night, and at work he notices that he cannot grip his hammer as strongly as before. On exam of the right upper extremity he has weakness of the right abductor pollicis brevis, and the finger flexors of the first and second digits. Loss of sensation in noted over the first two fingers of the right hand. His exam is otherwise normal. Where is the lesion? 􀃆Peripheral Nerve (consistent with Carpal Tunnel Syndrome-mononeuropathy).

A 42-year-old woman arises from bed one morning and notes a tingling sensation in both legs that progresses over the day. By evening, she is unable to get out of bed. On examination she has absent reflexes in her legs, with trace reflexes in her arms. Both toes are down-going and her sensation is normal. She can barely move her legs but arm strength is normal. By the next morning she has lost all reflexes and is having trouble moving her arms. Where is the lesion? 􀃆Peripheral Nerve (consistent with Guillain-Barre Syndrome – Polyradiculopathy)


8) Neuromuscular Junction: Given a clinical presentation, recognize myasthenia gravis.
Fatigability of the muscle is a hallmark of neuromuscular junction disease. Myasthenia gravis is the most common example of this type of lesion. Patients will report weakness getting worse with repetition, better with rest. The Electromyogram is diagnostic
CLIN PRESENT:
A 10-year-old boy with diabetes complains that over the past month he is very tired at the end of the day. He also has begun seeing double. On examination, he has bilateral ptosis, right greater than left, and he cannot adduct the left eye, nor elevate the right eye. He has mild symmetric proximal weakness, and he cannot close his eyes tightly.

9) Muscle: Given a clinical presentation, recognize myopathy.

Weakness tends to be proximal - patients have trouble rising from sitting, climbing stairs, reaching over their head). Pseudohypertrophy may be present, but atrophy is more common. Muscles may feel rubbery or doughy
Proximal symmetric weakness suggests a neuromuscular junction disorder or a myopathy.


10) Given the clinical presentation of a patient with altered awareness:

a) Determine whether the most likely cause of coma is metabolic-toxic or structural.
· structural lesions have focal features on the neurological examination
o has asymmetric findings.
· Examples of toxic-metabolic causes of coma include CNS-depressive drug overdosage, hyper- or hyponatremia, hypercalcemia, hepatic or renal encephalopathy, and hypoglycemia.

1. State of consciousness: Patients with metabolic problems often are less obtunded and may have waxing and waning of their arousal. Patients with acute structural lesions tend to stay at the same level of arousal or progressively deteriorate.
2. Respirations: Deep, rapid respirations are most commonly due to metabolic abnormalities.
3. Funduscopic examination: Papilledema usually indicates structural lesions. Papilledema does not occur in metabolic diseases except hypoparathyroidism, lead intoxication, and malignant hypertension.
4. Pupils: The pupils are usually symmetrical in coma from toxic-metabolic causes and asymmetric in structural causes.
Hypothermia may lead to fixed pupils, as does severe barbiturate intoxication. Neuromuscular blocking drugs produce midposition or small pupils.
5. Eye movements: Roving spontaneous eye movements with full excursion most often suggest metabolic-toxic disorders. Reflex eye movements are normally intact in toxic-metabolic coma, except rarely in phenobarbital or phenytoin intoxication or deep metabolic coma from other causes. Asymmetry in eye movement is a feature of structural lesions.

CLIN PRESENT
A 5-year-old boy is found unresponsive on the sidewalk. On exam there is no sign of trauma, but his pupils are equal, midposition and reactive. Both toes are upgoing and his DTRs are symmetric. Fundi are normal. He moves all limbs a little when stimulated. Which type of coma? 􀃆Metabolic Coma.

b) Suggest the appropriate laboratory and radiographic evaluation.

1. Lumbar Puncture (LP): is indicated for the diagnosis of meningitis, subarachnoid hemorrhage, inflammatory diseases etc.
a. Red blood cells may be present in the collected CSF; this implies either a traumatic tap (common and an artifact of the collection process) or sub-arachnoid hemorrhage (very serious indicator of pathology).
b. marked decrease in the number of red blood cells from the first to the last tube collected (four are usually collected) usually indicates a traumatic tap.


2. CT: DXà alcohol-related syndromes
3. check serum B12 and thyroxine levels in any patient with dementia** B12 deficiency and hypothyroidism
4. electroencephalography (EEG) : To DX seizures à3 Hz spike and wave complexes

ALSO SEE OBJ 14.
c) Differentiate delirium from dementia and suggest the appropriate evaluation of dementia
d) Recognize alcohol-related dementia, normal pressure hydrocephalus (NPH), intracranial mass lesions (e.g., tumors and subdural hematoma), vitamin B12 deficiency, hypothyroidism, and neurosyphilis
· alcohol-related syndromes:
· normal pressure hydrocephalus (NPH): NPH is suggested in a patient with two or more characteristics of a classic triad: 1) Dementia, 2) Incontinence, and 3) Ataxia.
· intracranial mass lesions (e.g., tumors and subdural hematoma)
· B12 deficiency and hypothyroidism : may be suggested by their clinical syndromes, but it is wise to check serum B12 and thyroxine levels in any patient with dementia.
· neurosyphilis: presence of tabes dorsalis, Argyll-Robertson’s pupil, or cells and a positive VDRL in the CSF from a lumbar puncture.

11) Seizures: be able to characterize the seizure as tonic-clonic, absence, complex partial and simple partial
1) Tonic Clonic Seizures
a) The person may make a loud noise and fall to the floor
b) The body stiffens and the arms and legs begin to jerk rhythmically
c) Breathing may be shallow and irregular; skin may look blue
d) Bowel/bladder control may be lost
e) Excessive drooling may occur, and the tongue may be bitten

2) Absence Seizures
a) Loss of consciousness may last several minutes or even longer
b) Consciousness is regained slowly
c) Loss of consciousness is brief, 5-15 seconds
d) May look like daydreaming and be ignored
e) Associated with minor repetitive motions such as eye blinking or lip movements
f) Often there are 50-100 seizures a day
g) Immediate recovery of awareness
h) Occurs almost always in children and is often out grown

3) Simple Partial Seizures
a) Consciousness is not impaired.
b) The seizure may arise form any area of cortex with clinical manifestation depending on the site.
c) sensory seizures (flashing lights - occipital cortex, unusual odors - olfactory cortex), motor seizures (twitching of a limb or part of the face - motor cortex), or autonomic seizures (tachycardia - limbic system)

4) Complex Partial Seizure
a) most common type of focal seizures in both children and adults.
b) seizure may start with strange sensations (auras) such as fear, nausea, tingling.
c) Consciousness is impaired and the person may look dazed.
d) Repetitive movements are common, such as plucking at clothes, walking aimlessly or smacking of lips.
e) The vast majority last 1-5 minutes and are followed by drowsiness.

12) Headache: Given a clinical presentation, recognize:
1) Tension Headaches:
a) The headache is usually bilateral, frontal, occipital, or diffuse.
b) It tends to have gradual onset and may persist for days or even weeks.
c) The patient may describe a sensation of having a tight band around the head.
d) There may be mild nausea, but other associated symptoms are uncommon.
e) Many patients can identify stress as a precipitating factor.
f) The neurologic examination is normal, and many of these patients just want reassurance that their headaches are not a sign of a serious illness.

2) Musculoskeletal Headaches:
a) The pain usually begins in the neck, either unilateral or bilateral, and radiates forward to the occipital or frontal regions.
b) The headaches tend to last for days or weeks, and may be exacerbated by particular movements of the neck.
c) The neurologic examination is normal except for tenderness and spasm of the cervical spine and muscles.

3) Migraine Headaches:
a) occur more often in women than men,
b) Migraines may begin at any age, although the peak incidence is in the second and third decades.
c) About 2/3 of the patients have unilateral pain, with 1/3 being bilateral.
d) headache may be frontal, temporal, occipital or diffuse.
e) onset is usually over minutes or hours, with the duration 4 hours up to 3 days.
f) The most common associated symptoms include
i) nausea,
ii) vomiting
iii) visual disturbances, such as flashing lights or fortification scotoma.
g) The patient may also have a variety of transient neurologic complaints such as hemiparesis or decreased sensation on one side of the body in association with the headache.
h) In common migraine (Migraine without aura), the patient has headache and associated symptoms, but without focal neurologic complaints or findings.
i) In classic migraine (Migraine with aura), there are focal neurologic complaints or abnormalities on examination
i) such as ophthalmoplegia: associated with the headache.
ii) "prodrome" of a strange feeling or flashing lights, which heralds the onset of the headache by 15 to 45 minutes.
j) A minority of patients can identify a dietary factor such as chocolate, coffee, or alcohol, which precipitates the headaches.
k) Some patients will have a family history of similar headaches. Patients often complain of photophobia and phonophobia, so that they prefer to lie down in dark quite room when they get a headache.
l) Most patients will report that sleep will resolve the headache.
4) Cluster Headaches:
a) These are severe retroorbital headaches that occur almost exclusively in men.
b) The onset is usually in the 3rd or 4th decade, and the headaches occur several times a day or several times a week for several weeks or several months, followed by a remission which lasts for several months or several years.
c) Recurrent
d) unilateral,
e) Asociated with autonomic symptoms
i) rhinorrhea,
ii) excessive lacrimation
iii) conjunctival injection.
f) The headaches last for 15 minutes to 2 hours.
g) During the headaches the patient may be agitated, pace, or even bang his head against the wall.
h) This pain is so severe that many patients have considered suicide during the headache.
5) Subarachnoid Hemorrhage:
a) This headache has an instantaneous onset, often with associated loss of consciousness, and severe nausea and vomiting.
b) The patient comes to the emergency room and is either unconscious, or if awake, is completely disabled by a pain which is so severe that the patient cannot move.
c) There may be neck stiffness, generalized hyperreflexia, and upgoing toes.
d) An emergency CT scan of the head without contrast will show blood in the subarachnoid space.
e) emergency arteriogram to look for an aneurysm.
f) lumbar puncture may be done to look for red blood cells in the CSF if clinical suspicion is low.
6) Meningitis:
a) The headache usually begins over several hours or several days and is usually diffuse.
b) there may be associated fever or meningismus,
c) . Patients may have focal neurologic findings,
i) delirium
ii) lethargy,
d) CT or MRI scan of the head should be done if it is immediately available. In patients with a high level of suspicion for meningitis, do not wait several hours for an imaging procedure before proceeding with a lumbar puncture and instituting IV antibiotics.
7) Pseudotumor Cerebri (Idiopathic Intracranial Hypertension):
a) 95% of these patients are females, with the usual onset of headaches in the 3rd or 4th decade.
b) Patients are almost always markedly obese.
c) headaches tend to be dull, diffuse, with minimal associated symptoms
i) other than nausea and occasional episodes of visual disturbance (known as Transient Visual Obscurations).
d) headaches are gradual in onset and may last for weeks, months, or even years.
e) The neurologic examination is normal except for papilledema, with occasional visual field cut, particularly the nasal visual field.
f) Diagnostic studies include imaging of the head to exclude the presence of a structural lesion, and a lumbar puncture to document an increased (greater than 200 mm/H20) CSF pressure with otherwise normal spinal fluid.
8) Temporal Arteritis:
a) Patients have temporal, usually unilateral, headaches, which last for weeks or months. T
b) These are more often women than men and are usually over 60 years of age.
c) There may be a prodrome with weight loss, malaise, or a low-grade fever, all persisting for several weeks prior to the onset of headache.
d) Symptoms associated with the headache may include tenderness of the temporal artery, transient blurring of vision, jaw claudication (virtually pathognomonic), or muscle pain (in polymyalgia rheumatica).
e) The neurologic examination is usually normal except for possible scalp or temporal artery tenderness. Diagnostic studies to confirm the diagnosis include elevated sedimentation rate. A diagnosis of temporal arteritis is confirmed by a biopsy of the temporal artery, which is a relatively simple procedure.
9) Brain Tumor
a) occur at any age, and patients complain of gradual onset of focal or diffuse headache.
b) Increased intracranial pressure may result in nausea and vomiting, and patients may have a full range of neurologic complaints or abnormalities on examination.
c) Systemic symptoms such as weight loss or loss of appetite, or a history of previously diagnosed cancer, combined with focal neurologic complaints or findings, give a high probability for an intracranial tumor.
d) Diagnosis is made by cranial MR scanning, followed by brain biopsy.

13) Ataxia: Given a clinical presentation, recognize cerebellar, vestibular, or sensory ataxia.
Cerebellar ataxia is produced by lesions of the cerebellum itself or its afferent or efferent connections in the cerebellar peduncles, pons, or red nucleus.

Vestibular ataxia is produced by lesions anywhere along the peripheral eighth nerve pathway from labyrinth to brainstem and in the vestibular nuclei.

Sensory ataxia results from abnormalities anywhere along the afferent pathway from peripheral nerve, dorsal root, dorsal spinal tracts, or the sensory projection from the thalamus to the parietal lobe cortex. Most commonly the dorsal spinal tracts are the location but severe sensory neuropathy can also cause ataxia.

14) Given a clinical presentation, recognize when the following procedures are indicated and how to interpret their results:
a) Electroencephalogram: Seizure
b) Lumbar Puncture : Infection, low suspicion for subarachnoid hemorrhage.
c) Head CT : Tumor, hemorrhage
d) Head MRI : Tumor
e) Temporal artery biopsy : Temporal Arteritis.