CR - Nervous System Disorders Flashcards
Clinical presentation: an elderly woman arrives at the ED after a minor automobile accident. The airbag deployed forcing her head back and she has neck pain. She walked in unassisted. Examination reveals bilateral upper extremity weakness.
What is the diagnosis?
Central cord syndrome
- Hyperextension injury
- Centrally located fibers of the corticospinal and spinothalamic tracts are affected
- medial fibers more affected which correlate to the upper extremities
- the buckling of the ligamentum flavum into the spinal cord causes edema and neurologic loss
What is the most common spinal cord syndrome and what are its clinical features?
Central cord syndrome
Usually occurs in patients with pre-existing cervical stenosis from degenerative arthritis or cervical canal narrowing from protrusion or tumor. Weakness is greater in arms than in legs and distal muscles are affected more than proximal. Patients may have decreased pain and temperature sensation as well as spastic quadraparesis or paraparesis; generally have good bowel control. General prognosis is good but fine motor use of upper extremities may be permanently impaired
In addition to central cord syndrome, there are two other spinal cord injury syndromes.
What are these syndromes and what are their clinical features?
Brown-sequard’s syndrome
unilateral cord problem (usually from penetrating trauma) with ipsilateral paralysis and loss of position-vibratory sensation with contralateral pain and temperature loss. May also be caused by lateral cord compression secondary to disc protrusion, hematoma, bone injury, or tumor. Brown-sequard that the best prognosis for recovery of all incomplete lesions
Anterior cord syndrome
From anterior spinal artery injury or from anterior cord compression usually from hyperflexion injury. Is characterized by paralysis and pain-temperature loss distal to the lesion with sparing of the posterior columns (position-vibratory sensation). Thrombosis of the anterior spinal artery may result in anterior cord syndrome due to ischemic injury. may also be caused by external mass. Prognosis for recovery is poor.
What is the most common intracerebral bleed following head injury?
Subarachnoid hemorrhage
Trauma is the most common cause of SAH, as compared to aneurysm, AV fistula
A 24 year old female presents to the ED with sudden onset of severe headache during sexual activity. Headache has lasted for 3 days. She has a history of headaches but this is different in nature. What is likely diagnosis?
Subarachnoid hemorrhage
What is the initial diagnostic study for subarachnoid hemorrhage?
CT scan of the brain
Sensitivity of CT performed within the first 6 hours is near 100% and about 93% within the first 24 hours. 80% at 3 days and 50% in one week
What are the indications for intubation based on vital capacity and negative inspiratory force for a patient with Guillain Barre Syndrome?
Vital capacity < 15 mL/kg
Negative inspiratory force < 30cm H20
After head trauma, 20% of patients experience post-traumatic seizures, and the most common site for late post traumatic seizures is the ___ lobe
Temporal lobe
Frontal lobe is the second most common
What are the early signs of phenytoin toxicity?
- somnolence
- dizziness
- slurred speech
- diplopia / blurred vision
- coarse tremor
- nystagmus
What is the name of the post-viral acute inflammatory demyelinating polyneuropathy with ascending symmetric weakness and decreased or absent DTRs?
Guillain-Barre syndrome
Ascending paralysis may progress to the diaphragm and require intubation
LP shows high protein (>45 mg/dL) and low white blood cell count (<10 mm2) with predominantly mononuclear cells. This finding is called albuminocytologic dissociation
What is the most important potential complication of Guillain-Barre syndrome?
Respiratory failure due to paralysis of the diaphragm
Patients with signs of impending respiratory failure should be intubated without delay. Signs include patients with shortness of breath while speaking or at rest, those using accessory respiratory muscles, respiratory rate sustained at >30 breaths/min and an oxygen saturation <92%
Unilateral facial nerve paralysis that involves the muscles of the forehead and is differentiated from stroke by the absence of focal neurologic deficits is known as ___ ___
Bell’s palsy
Bells palsy affects the forehead while central CN VII deficits spare the forehead
Clinical presentation: a middle-aged man complains of muscle weakness after he climbed a flight of stairs. He also complains of double vision. On examination there is ptosis.
What is the likely diagnosis?
Myasthenia gravis
What are the most frequent initial symptoms/signs in myasthenia gravis patients?
Ocular (eyelids and extraocular) weakness: diplopia, ptosis
Clinical presentation: an 85 year old male on warfarin for a fib presents with confusion after a fall. There are no outward signs of trauma other than a small abrasion to the forehead. He has no focal neurologic deficits.
What diagnostic test is indicated?
CT of the brain without contrast
Have a very low threshold for obtaining CT of brain in elderly patients on anticoagulation or alcoholics presenting with head trauma. This patient is at risk for subarachnoid hemorrhage, epidural hematoma, or subdural hematoma
What is the most common cause of focal encephalitis in AIDS patients
CNS toxoplasmosis
The clinical picture: fever, headache, focal neuroloogical deficits, altered mental status or seizures. CT of the brain with contrast shows ring enhancing lesions (the signet ring sign)
What pathologies are most commonly associated with post-traumatic epilepsy?
Penetrating brain injury, depressed skull fracture, alcohol-related injuries, intracranial hemorrhage, intracranial infection, surgical procedures (hemorrhage evacuation, ventriculostomy, etc)
What must be considered in a patient presenting with acute onset vertigo with associated neurologic complaints?
Posterior circulation stroke
A patient with subtle meningeal signs hast he following CSF findings:
Protein - elevated
Glucose - low
Cell count - 80% lymphocytes
Which type of meningitis is this?
Subacute meningitis
CSF findings of increased protein, decreased glucose, and a lymphocytic predominance of WBCs suggest chronic or subacute meningitis from tuberculosis, syphillis, or fungal infection. In additional to TB and fungal cultures, acid-fast smear, cryptococcal antigen and WDRL test should also be ordered
What bedside test can be used to support a diagnosis of myasthenia gravis?
Ice pack test
placing an ice pack over the closed eye lids for 2 minutes will decrease ptosis temporarily by >2mm if myasthenia gravis is present, indicating a positive test.
Can only be used if patient is exhibiting ptosis. Consider this an extension of your neurological exam.
What is the most common presenting neurologic manifestation of diphtheria?
Paralysis of the palatal muscles
What is the primary consideration for the etiology of meningitis in an AIDS patient?
Cryptococcus neoformans
If you suspect a patient has cryptococcal meningitis, which studies should be ordered on the cerebrospinal fluid examination?
Cryptococcal antigen and an India ink preperation
Where does the spinal cord originate and terminate
The spinal cord begins at the medulla oblongata (approximately at the atlanto-occipital junction) and ends at L1-L2 in adults and upper border of L3 in a child
What is the main cause of lumbar radiculopathy in patients > 65 years old?
Spinal stenosis
Spinal stenosis is an unusual narrowing of the spinal canal that impinges on the caudal equine and nerve roots. This results in pain in one or both extremities brought on by walking, relieved by rest, and exacerbated by back extension
An absent deep tendon reflex at the ankle suggests a lesion of what nerve root
S1
What is the physical exam finding of nerve root involvement in patients with lumbar disk compression at L3, L4
Pain in posterolateral thigh and anterior tibial area; weakened quadriceps; diminished / absent patellar reflex
What motor finding on exam is seen in patients with a lumbar disk compression at the L5 level
Decreased / absent dorsiflexion of great toe
A patient is unable to make an “OK” sign on their right hand by bringing together the tips of their thumbs and index finger. What nerve has been injured?
Anterior interosseous nerve (branch of the median nerve)
What cervical spine injury occurs as the result of axial loading?
Jefferson fracture of C1 ring blowout fracture
A patient with HIV has a focal intracranial mass. What is the most likely cause? What are some common neurological signs and symptoms of this condition?
Toxoplasma gondii
Common signs and symptoms include headache, fever, altered mental status, and seizures
What psychiatric disorder is most common confused with stroke?
Conversion disorder
Clinical presentation: A young woman presents with papilledema and recurring headaches. CT reveals slit-like ventricles. You perform an LP. What would you expect the opening pressure to be? What are some risk factors for developing this diagnosis?
High opening pressure
Idiopathic intracranial hypertension. This is seen primarily in young, obese women of childbearing age. Risk factors include oral contraceptive use, anabolic tetracyclines and vitamin A use. CSF pressures are >20 cm H2O if not obese and >25 cm H2O if obese
How does mannitol work in the treatment of cerebral edema?
By elevating blood plasma osmolality, mannitol enhances the flow of water from tissues into interstitial fluids and plasma. Water in the intracellular space is moved out to the extracellular space, which decreases cerebral edema, cerebrospinal fluid volume, and intracranial pressure.
What reflex should be checked in patients with suspected spinal shock?
The bulbocavernosus reflex
This is a normal cord-mediated reflex elicited by placing a gloved finger in the rectum and squeezing the glans penis or clitoris (or gently tugging the Foley catheter). Contraction of the anal sphincter is the normal response; absence indicated the presence of spinal shock: a concussive injury to the spinal cord that results in total neurologic dysfunction distal to the site of injury
Fundoscopy shows pale retina and a cherry red macula in a patient with acute painless vision loss.
What is the most likely diagnosis?
Central retinal artery occlusion
Epidural abscess are most common in which two spinal regions?
Thoracic and lumbar
Most common bacterial cause is staph aureus (63%), followed by gram-negative bacteria (16%)
What defines a simple febrile seizure?
A febrile patient 6 months to 5 years of age with a generalized seizure that lasts less than 15 minutes and does not recur in a 24 hour period. patient returns to normal neurologic baseline after a brief postictal state. Patient does not have an intracranial infection, metabolic disturbance or history of afebrile seizures
What maneuver can be utilized to diagnose benign paroxysmal positional vertigo
Epley maneuver can be used to treat BPPV and it begins after the last step of the Dix-Hallpike which diagnoses the disorder
A young patient develops a fixed posturing of his head and tilting of his neck. He recently received a dose of Haldol. What is the most likely diagnosis?
Dystonic reaction
Treated with anticholinergic medication such as diphenhydramine or benztropine (M1 receptor antagonists). Second line treatment with IV benzodiazepines may new considered if anticholinergic meds fail
A patient arrives in the emergency department after a night of drinking and reports weakness of his wrist and numbness over the dorsum of his hand. He reports having fallen asleep on his arm over a table’s edge.
Which nerve compression caused the above symptoms?
Radial Nerve Compression
Also known as “Saturday night palsy”
The patient usually also has median nerve weakness; however if you splint the patient in slight wrist extension, the patient will regain grip strength
What is the definition of status epileptics?
A patient who has been seizing for greater than 5 minutes or recurrent seizure activity without return to baseline mental status.
Previous definition: seizure that lasted 30 minutes
A patient presents with seizure like activity, altered mental status with visual disturbances and a headache. He is found to be profoundly hypertensive. MRI shows cerebral edema in the posterior circulation.
What is the diagnosis?
Posterior reversible encephalopathy syndrome
Other clinical features include vomiting.
Risk factors such as sepsis, autoimmune disease, cancer, chemotherapy, hypertension, post organ transplantation, immunosuppression or eclampsia.
It is commonly, but not always, associated with acute hypertension.
Lambert-Eaton Syndrome is caused by auto-antibodies against?
Voltage-gated calcium channels at the neuromuscular junction associated with acetylcholine release
A patient presents with ophthalmoplegia, nystagmus, ataxia, and is acutely altered.
What deficiency does this patient have?
Thiamine deficiency
This is wernicke’s encephalopathy. In addition to alcohol, other causes are severe malnutrition, hyperemsis gravidarum, prolonged parenteral nutrition, malignancies, immunodeficiency syndromes, liver disease, hyperthyroidism, and severe anorexia nervosa.
___ is an autosomal dominant channelopathy that causes acquired hypokalemia and often presents with weakness or paralysis
Hypokalemic periodic paralysis
It is common in young asian males. It is brought on by strenuous exercise, high carb or high sodium meals, emotional stress. It may last several hours to several days. Exam may show decreased or absent reflexes
Clinical presentation: a 45 year old female is brought in by her family member with acute loss of short-term memory. The patient appears to be unaware that she cannot recall events. She is alert and oriented with no other focal neurologic symptoms. There is no drug use or trauma / injury. Her head CT imaging is negative for acute abnormalities. What is the most likely diagnosis?
Transient global amnesia
