Neurological Emergencies Flashcards
Viral meningitis
Commonly affects children and you adults
Symptoms less severe than bacterial meningitis and last for 7-10 days
Self limiting and slower onset
Management is symptomatic relief and may include antivirals depending on pathogen
Bacterial meningitis
Acute inflammation of the meningies- mainly the Pia and arachnoid matter
Neurological and infectious emergency
Most common causative organism: N.meningitidis and streptococcus pneumoniae
Can trigger a systemic inflammatory response; increased capillary permeability contributes to fluid shifts resulting in hypovolaemia
Blood vessels are damaged, blood leaks from capillaries as seen in the petechial rash of meningococcal meningitis
Thrombolysis
For pts with potentially disabling ischaemic stroke due to large vessel occlusion with in 4.5 hours who meet specific criteria after the time patient was last seen well with Intravenous tenectaplase or altaplase
Subarachnoid haemorrhage
Is the presence of extravasated blood within the subarachnoid space.
Most common cause is head trauma.
Non traumatic or spontaneous SAH results from rupture of a cerebral aneurysm in approx 85% of cases.
Blood leaks into the subarachnoid space from a cerebral vessel inducing acute global ischaemia
Signs and symptoms of spontaneous SAH
Sudden severe headache is the hallmark presentation in up to 95% of cases
Typically described as being occipital and the worst headache experienced
Nausea and vomiting are common
Pts can also experience a brief LOC and neck stiffness
33% of pts will experience a warning week or days prior -niggling headache
Encephalitis clinical features
Headache, fever, and altered conscious state are hallmarks as well as seizures, behavioural changes and speech and movement disorders.
Management of encephalitis
Acyclovir +- AB’s while waiting specific results, supportive care.
ICP management, respiratory, circulation and seizure management
Guillian-Barre syndrome key diagnostic findings
Recent onset - days or at most 4 weeks of symmetrical weakness, usually starting in the legs
Abnormal sensation such as pain, numbness and tingling in the feet
Absent or diminished deep tendon reflexes
Sometimes pts will have had a recent viral infection
Meninges
Three connective tissue membranes that cover and protect the brain and spinal cord
Made up of: dura mater (outer most layer and has two layers),
arachnoid mater: web like
Pia mater (lines the surface of the brain and spinal cord follows every fold)
Functions of the meninges
Cover and protect the CNS
Protect blood vessels and enclose venous sinuses
Contain CSF
Form partitions in the skull
Subdural haematoma
Bleeding in the space between the dura mater and arachnoid mater
Sluggish pupil response
Increased ICP
Fixed dilated pupils
Compression on the occipital nerve through foramen magnum
Cerebral perfusion pressure (CCP)
The pressure required to adequately perfuse the brain. CCP is determined by the mean arterial pressure (MAP) and intracranial pressure (ICP). CCP = MAP - ICP
Normal CCP
60-100mmHg
A change in either the ICP or the MAP can result in an inadequate CCP - resulting in inadequate cerebral perfusion.
Monro-Kellie hypothesis
Blood, CSF brain tissue exist in a dynamic equilibrium.
If the volume of any of the 3 increases the volume of the others must decrease to maintain normal pressures
Compensatory mechanisms to preserve the integrity of the brain
Displacing or shifting CSF, increasing absorption of CSF or decreasing cerebral blood flow. Without these changes ICP will increase
Early signs and symptoms of Increased ICP
Changes in mental status, such as disorientation, restlessness and mental confusion
Purposeless movements
Pupillary changes
Constant headache that increases in intensity and is aggravated by movement
Nausea and vomiting
Seizures
Late signs and symptoms of raised ICP
Deterioration in level of consciousness until the pt become comatose
The cushings response
Decrease in respiratory and pulse rates
Increased BP and temp
Altered respiratory patterns
Severe TBI <8 gcs
Prolonged LOC at time of injury
Increasingly severe headache with or with out vomiting
Decreased conscious state - responding only to pain or unresponsive
Abnormal/change in behaviour
Bleeding/csf leak from nose or ears
Unequal pupils
Laterlising motor weakness
Signs of increased ICP
The Cushings response
Changes in pupillary size or reactiveness
Seizures
Out of hospital arrest
Penetrating head injuries
Management of severe TBI
Adequate ventilation and oxygenation- PO2 80mmHg and PCO2 35-40 mmHg
Elevate head 30 degrees
Midline head position
Correct hypovolaemia
Sedation and analgesia to prevent movement, coughing and pain that can increase ICP
Normoglycaemia
Seizure management
Management of seizures
A- protect and prevent aspiration (lateral position, suction)
B- supplemental O2
C- usually maintained
D- duration of seizure and type
E- injury prevention (pillows, blankets)
Identify and treat complications and precipitating factors
The Penumbra (ischaemic CVA)
Is the area surrounding the ischaemic area - some of this may be salvageable depending on time to Reperfusion and the severity and duration of occlusion