Neuropatho Flashcards
Guillain-Barre
Guillain-Barre syndrome————-
Guillain-Barré syndrome (GBS) is a disorder in which the body’s immune system attacks part of the peripheral nervous system. The first symptoms of this disorder include varying degrees of weakness or tingling sensations in the legs. In many instances the symmetrical weakness and abnormal sensations spread to the arms and upper body. These symptoms can increase in intensity until certain muscles cannot be used at all and, when severe, the person is almost totally paralyzed. In these cases the disorder is life threatening - potentially interfering with breathing and, at times, with blood pressure or heart rate - and is considered a medical emergency. Such an individual is often put on a ventilator to assist with breathing and is watched closely for problems such as an abnormal heart beat, infections, blood clots, and high or low blood pressure. Most individuals, however, have good recovery from even the most severe cases of Guillain-Barré syndrome, although some continue to have a certain degree of weakness.
Usually Guillain-Barré occurs a few days or weeks after the patient has had symptoms of a respiratory or gastrointestinal viral infection. Occasionally surgery will trigger the syndrome.
After the first clinical manifestations of the disease, the symptoms can progress over the course of hours, days, or weeks. Most people reach the stage of greatest weakness within the first 2 weeks after symptoms appear, and by the third week of the illness 90 percent of all patients are at their weakest.
When Guillain-Barré is preceded by a viral or bacterial infection, it is possible that the virus has changed the nature of cells in the nervous system so that the immune system treats them as foreign cells. It is also possible that the virus makes the immune system itself less discriminating about what cells it recognizes as its own, allowing some of the immune cells, such as certain kinds of lymphocytes and macrophages, to attack the myelin. Sensitized T lymphocytes cooperate with B lymphocytes to produce antibodies against components of the myelin sheath and may contribute to destruction of the myelin. In two forms of GBS, axons are attacked by antibodies against the bacteria **Campylobacter jejuni, which react with proteins of the peripheral nerves
Multiple sclerosis
Multiple sclerosis: Multiple sclerosis (MS) is a potentially disabling disease of the brain and spinal cord (central nervous system).
In MS, the immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between your brain and the rest of your body. Eventually, the disease can cause the nerves themselves to deteriorate or become permanently damaged.
Signs and symptoms of MS vary widely and depend on the amount of nerve damage and which nerves are affected. Some people with severe MS may lose the ability to walk independently or at all, while others may experience long periods of remission without any new symptoms.
There’s no cure for multiple sclerosis. However, treatments can help speed recovery from attacks, modify the course of the disease and manage symptoms.
This damage disrupts the ability of parts of the nervous system to communicate, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems.[5][8][9] Specific symptoms can include double vision, blindness in one eye, muscle weakness, trouble with sensation, or trouble with coordination.[1] MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms).[10] Between attacks, symptoms may disappear completely; however, permanent neurological problems often remain, especially as the disease advances.[10]
What is Cushing’s triad
Cushing’s triad: hypertension, bradycardia
and irregular respirations (brainstem)
Caused by increased intracranial pressure
Describe the clinical features and pathophysiology of Werdnig-
Hoffman disease
Most common (and severe) type of spinal muscle atrophy is SMA I Werdnig-Hoffmann disease
“acute infantile spinal muscle atrophy”
autosomal-recessive inheritance pattern “floppy-baby”
median age of death is 6-7 months. affects 1/10,000 lives births
Symptoms
Weakness and muscle wasting in
limbs
respiratory
bulbar muscles - sucking swallowing breathing
Uncal herniation
Results in: oculomotor paresis ipsilateral, dilated pupil), contralateral hemiparesis:
Contralateral hemiparesis occurs with compression of the ipsilateral cerebral peduncle of the midbrain - Since the corticospinal tracts decussate below the midbrain, the hemiparesis is contrateral
In addition to pupillary dilatation, a second key feature of uncal herniation is a decreasing level of consciousness (LOC) due to distortion of the ascending arousal systems as they pass through the midbrain]
A dilated pupil from in the absence of a LOC is not due to uncal herniation
Describe the major symptoms that characterize bleeding in the subdural, epidural and
subarachnoid spaces.
Epidural hematoma:
From trauma to the skull: usually from middle meningeal artery.
• May also be from sinuses (~15%).
•“Lens shaped” structure on MRI
• Often has period of lucidity before severe symptoms (from a brain herniation).
Subdural Hematoma:
Horizontal (axial) MRI showing crescent-shaped subdural hematoma due to tearing of bridging veins, which often occurs during rapid accelerations. Symptoms may progress over longer periods.
-common in elderly
Subarachnoid hemorrhage: bleeding into the subarachnoid space usually secondary to head trauma.
• Usually traumatic
-[“Non-traumatic” from bleeding from an A-V malformation or ruptured aneurysm.
A burst aneurysm is responsible for 80% of non-traumatic subarachnoid hemorrhages. • Aneurysms form when the vessel wall is weakened, and can burst under conditions of increased pressure. • Most aneurysms occur in the “anterior circulation” supplied by the internal carotid artery.
The classic presentation is sudden-onset, severe headache (from blood irritating meninges) “worst headache of my life”
Subarachnoid is diagnosed by bloody CSF
Define hydrocephalus and the types of hydrocephalus and potential causes.
Hydrocephalus:
Condition of excess CSF
1- excess production (choroid plexus tumors)
2- obstructed flow anywhere in ventricles or subarachnoid space (tumors, malformations, hemorrhage)
3- decreased reabsorption via arachnoid granulations.
“Communicating hydrocephalus”: lateral ventricles communicate with subarachnoid space.
“non-communicating hydrocephalus”: flow obstructed within
the ventricular system.
Symptoms: Children and Adults: -Headache (especially in the morning)* Decreased cognitive function Neck pain Vomiting (especially in the morning)* Blurred vision (papilledema) Drowsiness Failure of upward gaze
*CSF is less reabsorbed when lying down.
What is the presentation of children with hydrocephalus? \Signs and symptoms
Treatment?
Signs:
- rapid head growth
- bulging fontanelle in infants held upright
- dilated scalp veins
Symptoms:
- downward eyes
- poor feeding
- vomiting
- irritability
- lethargy
ventriculoperitoneal shunt:
can relieve chronic hydrocephalus. Surgeons insert tubes that let the cerebrospinal fluid drain out of the brain into the abdomen, where the body reabsorbs it. These tubes, under a child’s skin, can prevent brain damage..
Chiari I
-the most common
Congenital hindbrain anatomic anomalies associated with the downward displacement of the cerebellum,
brainstem or craniocervical junction.
-produce hydrocephalus
Cerebellar tonsils
below the foramen
magnum
- Syringomyelia (Chiari is most common cause) Syringomyelia is the development of a fluid-filled cyst (syrinx) within your spinal cord. Over time, the cyst may enlarge, damaging your spinal cord and causing pain, weakness and stiffness, among other symptoms.
- Compression of brainstem
Most common symptoms are • Headache (increased intracranial pressure), • Ataxia (cerebellar dysfunction), and • Impaired movement (brainstem compression)
Chiari II (Arnold Chiari malformation)
Less common
Significant herniation through foramen magnum
cerebellar tonsils and vermis lower brainstem
• Causes aqueductal stenosis
and Hydrocephalus.
• Usually with
meningomyocele - Meningomyelocele is a type of spina bifida. Spina bifida is a birth defect in which the spinal canal and the backbone don’t close before the baby is born. This type of birth defect is also called a neural tube defect.
The spinal cord and the meninges (the tissue that covers the spinal cord) may actually protrude through the child’s back. In some cases that skin covers the spinal cord and meninges, it may also stick through the skin. - syrinx in base of spinal cord
Normal Pressure Hydrocephalus
His grave is dug
-occurs in the elderly
Classic triad of symptoms
Dementia (of varying degrees)
Urinary incontinence: May present as urgency, frequency, or a diminished awareness of the need
to urinate
Gait disturbance: Usually the first symptom; magnetic gait. :
***NOTE NO HEADACHE
May be related to impaired reabsoprtion from meningitis or subarachnoid hemorrhage
Define radiculopathy and causes
.damage to a spinal nerve
The most common pathology to spinal nerves are herniated discs.
-Osteophytes can also cause radiculopathy
-spinal stenosis - hypertrophy of ligamentum flavum
-Foramen stenosis-hypertrophy of facet
Typical Symptoms related to radiculopathy
1. Burning, tingling pain that radiates from the back along
dermatome
a. “lancinating” or stabbing pain
b. Location, location, location 2. Numbness (anesthesia, analgesia)
a. possible, but there is overlap in dermatomes.
b. analgesia, tested with a pinprick may be more sensitive 3. Worsening of symptoms with coughing, sneezing, straining.
Flexing the head in the case of cervical radiculopathy.
4. Muscle weakness
***5. T1 radiculopathy can cause a Horner’s syndrome, because it
interrupts the sympathetic pathway to the eye.
a. constricted pupil (miosis)
b. anhidrosis (decreased sweating) of the skin of the face
c. ptosis (drooping) of the eyelid
Describe the features of spinal shock.
Spinal Cord injury causes immediate flaccid paralysis: Spinal Shock
This is because descending influences are interrupted immediately. After that there is a loss of motor and autonomic function from the lesion down.
Following a spinal cord injury, there is a loss of all motor and autonomic function below the lesion.
flaccid paralysis bowel and bladder paralysis loss of vasomotor tone (hypotension)
The period of time is usually 1-6 weeks. The mechanism is thought to be a loss of descending facilitation that keeps the spinal cord circuits in a continual state of activation/readiness.
Horner’s syndrome
T1 radiculopathy can cause a Horner’s syndrome, because it
interrupts the sympathetic pathway to the eye.
a. constricted pupil (miosis)
b. anhidrosis (decreased sweating) of the skin of the face
c. ptosis (drooping) of the eyelid
Chiari 1 vs Chiari 2
Chiari 1:
Findings typically asymptomatic in children
abnormally shaped cerebellar tonsils are downwardly displaced through the foramen magnum
Associated condition: syringomyelia
Chiari 2: Findings typically symptomatic cerebellar vermis and tonsil are downwardly displaced through the foramen magnum Associated condition spinal meningomyelocele
Fetal alcohol spectrum disorder
Fetal alcohol spectrum disorder (FASD) shows that there is a link between maternal alcohol ingestion and a range of birth defects, including intellectual disability and growth deficiencies/structural abnormalities of the brain, such as microcephaly (small head size) and holoprosencephaly (failure of forebrain to form separate cerebral hemispheres with associated midline facial defects), face (small midface and eyes, low nasal bridge and short nose, smooth philtrum and thin upper lip), and heart (including ASD, VSD).
Fetal alcohol syndrome (FAS) is on the severe end of FASD. There is no known safe amount or time period to drink alcohol during pregnancy because although abnormalities may sometimes not be evident with minimal alcohol consumption, it may cause behavioral issues.
Dandy-Walker syndrome
In individuals with the rare Dandy-Walker syndrome, there is congenital malformation of the cerebellum, which may result from cystic enlargement of the 4th ventricle and leads to developmental delays, defective muscle tone, poor coordination and balance (ataxia), and sometimes hydrocephalus.
Spinal Muscle Atrophy (SMA I-IV)
Describe the clinical features and pathophysiology of Werdnig-
Hoffman disease
A group of diseases caused by degeneration of the anterior horns.
These are progressive and begin in infancy.
Due to abnormalities in chromosome 5
Motor neurons are affected in the spinal cord and cranial nerve motor nuclei
_________________________________
Most common (and severe) type of spinal muscle atrophy is SMA I Werdnig-Hoffmann disease
“acute infantile spinal muscle atrophy”
__________ _________
autosomal-recessive inheritance pattern “floppy-baby” median age of death is 6-7 months. affects 1/10,000 lives births
Symptoms:
Weakness and muscle wasting in
-limbs
-respiratory
-bulbar muscles:
sucking, swallowing, breathing
Pathological changes that occur with sustained lower motor neuron disease: e.g., polio, peripheral neuropathies.
Describe apraxia and how to test for it.
Results from lesions to Premotor cortex or Posterior Parietal cortex
Would be contralateral apraxia, difficulty in using body part to perform complex voluntary actions.
Tested by asking patients to do tasks such as grasping a pencil, even though there is no obvious, weakness, paralysis, or altered tone. Affects complex movements such as buttoning.
Compare the upper motor neuron and lower motor neuron syndromes.
Weakness Atrophy Fasciculations Reflexes Tone
Weakness: Yes in both (only similarity)
Atrophy: Only in LMN, mild from disuse in UMN.
Fasciculations: Only in LMN
Reflexes: Increased in UMN, decreased in LMN
Tone: Increased in UMN, decreased in LMN
Define hyperreflexia, clonus, hypertonia, spasticity clinically and physiologically.
Spasticity: (vestibulospinal and reticulospinal > reflex excitability)
1. UMN damage disturbs the balanced modulation of spinal cord interneurons and motor neurons by descending pathways (+ and -).
• Removing any of these inputs changes the balance of excitability of motor neurons and reflexes
2. Loss of inputs to motorneurons produces neuroplastic changes in motor neurons: denervation supersensitivity and sprouting from local interneurons.
3. Reduced muscle extensibility due to muscle contracture >increased muscle spindle activation.
Clonus: Occurs with severe hyper-reflexia: oscillation when the muscle is rapidly stretched and then held at a constant length.
Hypertonia:
Velocity-dependent: less resistance to slow movement compared to fast
Clasp-knife response: initial resistance followed by inhibition of the muscle (possibly due to golgi-tendon response)
Differentiate between the symptoms of Bell’s palsy and a corticobulbar tract
lesion.
Corticobulbar tract lesion:
Exceptions to compensation:
1- lower nucleus of VII. These go to the lower face.
2- mostly contralateral to CN XII (motor neurons to the tongue.)
Lesions to one corticobulbar tract produce the following deficit:
1- Paralysis to contralateral lower face. 2- Some paralysis to the opposite tongue, and difficulty swallowing (dysphagia).
Bell’s palsy:
-Right Cranial nerve VII lesion (Bell’s palsy) causes lower motor neuron paralysis of ½ the face.
Both upper and lower face affected on right or left
-corticobulbar is only contralateral lower face
Recognize decorticate and decerebrate rigidity.
Decorticate - lesion ABOVE midbrain
- upper limb: flexed - elbow, finger
- lower limb: extended: knee
Decerebrate - lesion BELOW midbrain All limbs extend
Discuss some of the common causes of upper motor neuron syndromes.
Trauma: Head injury or spinal cord injury
Stroke: In cortex, internal capsule, ventral pons, spinal cord (sudden onset)
Multiple Sclerosis: Autoimmune/inflammatory disease that affects myelin pathways in the central nervous system. Symptoms separated in time and space.
Amyotrophic Lateral Sclerosis: Degenerative disease of upper and lower motor neurons. Also called Motor neuron disease, Charcot’s disease or Lou Gehrig’s disease. Characterized by fasciculations, weakness, and spasticity. Rapid progression, resulting in death in 2-3 years.
What are the *unique signs of upper motor neuron lesions?
- hyperreflexia - thought to be because the muscle becomes super sensitive without period stimulation from UMN so you get a really strong sensory response at the level
- Clonus - rhythmic contractions of antagonist muscles- lets say you flex at the ankle joint, pt with UMN injury will be sent into involuntary movements of up and down.
- Hypertonia - when a doctor moves the leg around, there is more resistance, instead of relaxed like LMN
- Extensor Plantar response aka Babinski sign : if you take a hard object, scrape up along bottom foot, normal plantar response is flexor.
Cerebral Palsy - a review
A variety of non-progressive neurological disorders that appear in infancy or early childhood and permanently affect body movement and muscle coordination.
Causes: Ischemia at birth Hypoperfusion Trauma Hemorrhage
Cerebal Palsy Presentation:
1: Some degree of motor impairment
2: An insult to the developing brain
3: Intellectual disability in ~50%
