WEEK 3: Approaches to patient with CNS disorders Flashcards
Neurologic diseases are common and costly. According to the estimates of the WHO, neurologic disorders affect over 1 billion people worldwide.
This constitutes 6.3% of the global burden of disease and 12% of global deaths.
Source: Recent 20th ed Harrison’s is chapter 415
Outline different types of neurologic disorders.
- Nutritional disorders and neuropathies
- Migraine
3.Trauma
- Cerebrovascular disease
- Epilepsy
- Dementia
7.Neurologic infections
It is important to always ask.
Where is the lesion?
What is a lesion?
State the significance of the 2 questions.
- NEURO-ANATOMICAL DIAGNOSIS
- ETIOLOGICAL DIAGNOSIS
The proper approach to the patient with a neurologic illness begins with the patient’s clinical problem first in anatomic and then in pathophysiologic terms;
*Localize the disease process, i.e., to name the part or parts of the nervous system involved – Anatomical diagnosis
So, given a good history and neurologic examination, one can interpret these signs and symptoms to answer the question – where is the lesion? And eventually what is the lesion?
How to start?
State the basic knowledge needed.
Basic Neuroanatomy
Basic Neurophysiology
Etiological list
State the main components of a physical exam.
- Temporal course of the illness
Clarify Symptoms
Onset, Duration and Progression
Third Example is MS- course is progressive with relapsing remitting course
Unlike Migraines or Epilepsy wherein the patient returns to baseline function (Or normal) after each attack.
- Patients’ description of the complaint
The interpretation of the true meaning of the words used by patients to describe symptoms obviously becomes even more complex when there are differences in primary languages and cultures. - . Corroboration of history by others
Memory loss, aphasia, loss of insight, intoxication, and other factors may impair the patient’s capacity to communicate normally with the examiner or prevent openness about factors that have contributed to the illness.
Example: patient comes in with episodes of loss of consciousness, this necessitates that details be sought from observers to ascertain precisely what has happened during the event.
Example: patient comes in with memory loss, surely would need a reliable informant to give a good history regarding this complaint (the patient wouldn’t know what he has forgotten).
- Family History
Many neurologic disorders have an underlying genetic component.
Examples of disorders that may have a genetic or familiar predisposition?
Huntington’s Disease, Epilepsy, Charcot Marie tooth, Multiple Sclerosis, migraines, stroke (family history of hypertension)
What kind of inheritance pattern is demonstrated in this pedigree (shown above)?
Answer: Autosomal dominant.
The disease did not skip a generation.
Examples: Tuberous sclerosis, myotonic dystrophy, HD, Neurofibromatosis
- Medical Illnesses
Many neurologic diseases occur in the context of systemic disorders.
Stroke: Hypertension, diabetes, abnormal blood lipids
Mass lesion (abscess) in the brain: Valvular heart disease
Lymphoma or toxoplasmosis: HIV/AIDS patient
Coma patient: History of metabolic or toxic illness
It is especially important to look for the presence of systemic diseases in patients with a neurologic illness.
- Drug use and abuse and toxin exposure
- Sedatives, antidepressants, and other psychoactive medications are frequently associated with acute confusional states in the elderly.
- Aminoglycoside antibiotics may exacerbate symptoms of weakness in patients with disorders of neuromuscular transmission, such as myasthenia gravis
TB medication (INH) and ARVs may cause peripheral neuropathy.
It is essential to inquire about the history of drug use, both prescribed and illicit
Example of neurotoxins: lead, mercury, arsenic…smoke
A lot of neurologic diseases result from exposure to these toxins.
Environmental and industrial exposure to neurotoxins
There is no single, universally accepted sequence of the examination that must be followed.
Describe the sequence followed by most clinicians when doing a neurological examination.
There is no single, universally accepted sequence of the examination that must be followed, but most clinicians begin with;
- Assessment of mental status followed by
- The cranial nerves,
- motor system,
- sensory system,
- coordination, and
- Gait.
Whether the examination is basic or comprehensive, it is essential that it be performed in an orderly and systematic fashion to avoid errors and serious omissions.
It is important to do cranial nerve exam in patients with neurologic disease.
State CN II.
Describe the 5 tests for CN II.
Tested in five ways:
- Visual Acuity - tested with Snellen charts. If the patient normally wears glasses or contact lenses, then this test should be assessed both with and without their vision aids
- Colour charts - tested using Ishihara plates which identify patients who are colour blind
- Visual Fields – detect dysfunction in central and peripheral vision.
- Pupillary Reflexes - comprise direct and concentric reflexes.
- Fundoscopic exam – done on both eyes
Describe assessment of the following:
OCULOMOTOR NERVE (CN 3)
TROCHLEAR NERVE (CN 4)
ABDUCENT NERVE (CN 6)
Assess eye movements on command
Asking the patient to keep their head perfectly still directly in front of you, you should draw two large joining H’s in front of them using your finger and ask them to follow your finger with their eyes. It is important the patient does not move their head.
Ask for diplopia, look for nystagmus.
NYSTAGMUS: The eyes falling behind when doing the H test.
Nystagmus is an involuntary, rhythmic movement of the eyes that can manifest as rapid, oscillating movements in one or both eyes.
Describe tests for trigeminal nerve (CNV)
SENSORY (light touch and pain)
*Jaw area, cheek and forehead
MOTOR
To test the motor supply, ask the patient to clench their teeth together, observing and feeling the bulk of the masseter and temporalis muscles.
REFLEXES
Jaw jerk REFLEX
Corneal reflex
Describe assessment for FACIAL NERVE (CN 7)
MOTOR
supplies motor branches to the muscles of facial expression.
Crease up the forehead
Close eyes tight against resistance
Puff out the cheeks
Show teeth
Differentiate between central from peripheral facial palsy.
SENSORY
Supplies taste to the anterior 2/3 of the tongue
Discuss other parts of the neurologic exam.
- Mini-mental state exam
The bare minimum: During the interview, look for difficulties with communication and determine whether the patient has recall and insight into recent and past events.
Level of consciousness Abstract thought
Orientation Calculation ability
Speech Fund of information
Language Insight and Judgement
Memory
- Motor assessment
Assess upper extremity strength by checking for pronator drift and strength of wrist or finger extensors.
Test for lower extremity strength by having the patient walk normally and on heels and toes.
Tap the biceps, patellar, and Achilles reflexes. - Sensory exam
Ask whether the patient can feel light touch and the temperature of a cool object in each distal extremity.
The five primary sensory modalities—light touch, pain, temperature, vibration, and joint position—are tested in each limb.
Tracts that you need to understand:
*Lateral spinothalamic tract
*Anterior spinothalamic tract
*Dorsal columns/ medial meniscal system
- Testing for reflexes
-Cutaneous Reflexes: Elicited by stimulation of the skin.
Example: An example of a cutaneous reflex is the plantar reflex. When the sole of the foot is stroked, the normal response in adults is flexion of the toes. This is known as a “flexor plantar response.” In infants and young children, the normal response is extension of the toes, called a “Babinski sign.”
Function: Cutaneous reflexes help to protect the body from injury by producing rapid, automatic movements in response to sensory stimuli applied to the skin.
-Primitive Reflexes: Responses that are present in infants and are typically suppressed or replaced by more mature voluntary movements as the nervous system matures.
Examples:
*Moro reflex: Triggered by sudden loss of support or a loud noise, causing the infant to extend their arms, arch their back, and then bring their arms together as if hugging.
*Rooting reflex: When the infant’s cheek is touched, they turn their head toward the stimulus and open their mouth, seeking to suck.
*Grasping reflex: When an object is placed in the infant’s palm or sole, they automatically grasp it with their fingers or toes.
Function: Primitive reflexes are believed to be important for survival and early motor development in infants. They help in feeding, protection, and interaction with the environment.
As the nervous system matures, these reflexes are gradually replaced by more voluntary and purposeful movements.
- Testing for coordination
*Test rapid alternating movements of the hands and the finger-to-nose and heel-knee-shin maneuvers.
*Coordination refers to the orchestration and fluidity of movements
*Relies on normal function of the cerebellar and basal ganglia systems.
- Nystagmus Test Finger to Nose and Finger to Finger test
- Hypotonia Rapid alternating movements
- Scanning Speech Heel to Shin / Toe to Finger
Rebound Phenomenon
6.Gait
Observe the patient while walking normally on the heels and toes, and along a straight line.
Normal gait requires that multiple systems—including strength, sensation, and coordination—function in a highly integrated fashion.
Define the following abnormalities in coordination.
- Dysmetria:
- Dysdiadochokinesia:
Abnormalities of coordination:
Examples:
- Dysmetria:
Dysmetria is a neurological term referring to a lack of coordination in voluntary movements, typically resulting in inaccurate or overshooting movements.
It often manifests as difficulty in judging the range, force, and direction of movements.
Dysmetria can affect various body parts, such as the limbs, eyes, or speech articulators. It is commonly associated with cerebellar dysfunction, as the cerebellum plays a crucial role in coordinating movements and maintaining accuracy.
- Dysdiadochokinesia:
Dysdiadochokinesia is a specific type of dysmetria characterized by impaired ability to perform rapid alternating movements.
Individuals with dysdiadochokinesia may have difficulty executing tasks such as rapidly pronating and supinating the forearm, tapping the palm and dorsum of the hand alternately, or performing rapid toe tapping movements.
This impairment is often observed in conditions affecting the cerebellum or its connections, such as cerebellar lesions, cerebellar degeneration, or certain neurological disorders like multiple sclerosis.
Outline lab tests can be done to rule out neurologic disorders.
To narrow the list of diagnostic possibilities, and to select the laboratory tests most likely to be informative.
The laboratory assessment may include
(1) serum electrolytes; complete blood count; and renal, hepatic, endocrine, and immune studies;
(2) cerebrospinal fluid examination;
(3) focused neuroimaging studies
(4) electrophysiologic testing
Discuss the Treatment and Management of neurological disorders.
“Neurology has traditionally been thought of by many as little more than an intellectual exercise concerned with making diagnoses of untreatable diseases”
