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
