Neurological Emergencies Flashcards
What are some neurologic emergencies?
Mentation changes, seizures, traumatic brain injury, tetanus and Botulism and Toxins
What are the types of mentation changes and what part of the brain do they effect?
Obtunded (Decreased response to stimuli and consciousness) - forebrain or brainstem
Stuporous (Dulled) - Brainstem
Comatose (prolonged loss consciousness) - Brainstem
What is the ARAS (Ascending Reticular Activating System) Responsible for?
Wake and dreaming states (effects consciousness)
What are some causes of mentation cahnge?
Toxins, Metabolic, Cardiovascular, neurologic, hydrocephalus, inflammation (abscess, MUE, neoplasia, Trauma, Vascular
What is your clinical approach to mentation change?
Hx: rule out trauma, toxin or metabolic, signalment (hypoglycemia puppy), previous diagnosis
Ex: systemic hypothermia, pulse, pale, neuro
Min Database: CBC, Biochem (hypernatremia)
How do you confirm diagnosis of a stroke?
MRI or CT, CSF analysis
What are the 2 types of stroke?
Ischaemic or Haemorrhagic
What are some underlying causes of stroke?
Cushings (too much cortisol), Hypothyroidism, Hyperthyroidism, PLN, Liver Disease, Idiopathic, Hypertension, Neoplasia, Heart Disease
Toxin, vWD, Haemophilia, Neoplasia, Thrombocytopenia, Liver Disease, HYpertension
What is your triage treatment for Mentation Change?
Correct patient temp, correct metabolic derangements, treat toxin if indicated, Hypo/hypertension treatment, look for signs increased intracranial pressure
Hypothermic warm up
What do you do if you think the animal has gotten into a toxin that is causeing the neurological signs?
Decontaminate, treat if possible (call pet poison helpline), treat symptoms (muscle relaxer, anti-seizure), non-specific - IV fluids, Intravenous lipids, Ion trapping, Hemodialysis
What is the equation for Cerebral Perfusion Pressure?
CPP = MAP-ICP
(Want around 50mmHG)
What is normal ICP? Why so low?
ICP is normally 0-15mmHg
Low because there is not a lot of room between the skull and thehinflammation
What are some things that increase intercranial pressure?
Edema, Inflammation, CSF, Tumor and trauma
How can you decrease CPP?
Increase MAP or decrease CPP needed to perfuse brain
If ICP 200-300mmHg what occurs?
Reflex bradycardia
What is the Cushing’s Reflex?
When you have decreased cerebral blood flow (b/c increased ICP), raised Co2, meduallary vasomotor center, symatheric stimulation, increase MAP that increase CPP and ICP and Carotid baroreceptor that increased vagal stimulation and leads to reflex bradycardia
What are some signs of increased ICP?
Pupil Changes (myotic or mydriatic non-responsive) , Tetraparesis, ataxia, proprioception defects, cranial nerve defects, decerebrate posture
How do we decrease ICP?
Decrease edema (manitol, hypertonic saline, steroids, diuretics), Craniectomy, remove space occupying lesion (tumor, granuloma, depressed skull fracture)
How does the brain try to decrease ICP?
Push out skull
What are some primary neurologic diseases?
Encephalitis, Brain tumor, vascular accident, head trauma
If it is primary neurologic what do you do?
Stabilize or decrease ICP to buy time and send to neurologist
When is surgery the only option?
BP over 300
What is status epilepticus?
Failure of seizures to terminate, meaning last longer than 5 min, or more than 2 without return to normal conciousness
TRUE EMERGENCY
What the cascade that leads to brain damage?
Glutamate release, NMDA receptor - calcium influx, 2nd messencer, ca release and mitocondrial damage or Cosium influx, cytotoxic edema, cell death
What are the systemic effects of brain damage?
Hypertension, tachycardia, arrhythmia, hyperglycemia, respiratory compromise (inadequate ventilation, noncardiogennic edema, aspiration pneumonia, hyperthermia, acidosis, myoglobinuria
What leads to death with Status Epilepticus?
Brain herniation, ventricular arrhythmia, respiratory compromise, renal failure
What is Emergency triage for status epilepticus?
Check temp (active cooling), Oxygen supplementation, Anti-seizure therapy
What are some antiseizure therapies that can be used?
Diazepam (rectal or IV)
Midazolam (Nose or IV)
3 failed benzo go to Propofol (intubate)
Phemobarbitol and levetiracetam needed long term
What are the 2 types of seizures?
Epilepsy and Reactive
Reactive seizures are caused by what?
Metabolic and toxins (treatable)
What are some differntials for structural epilepsy?
Cognitive dysfunction, hydrocephalus, prencephaly, neuronal ceroid lipofuscinosis, brain tumor, meningioencphalitis, traumatic brain injury, cerebral vascular accident
What is traumatic brain injury?
Increased intracranial pressure that damages the cells
-Space occupying lesion
-Ischemia (K, Ca, EAA, Free Radical, mitochonria failure) - cytotoxic edema, necrosis and increase ICP)
-Injury - damage parenchyma and vasculature - contusion - increase tissue osmolar loat ICP
When a traumatic brain injury occurs what are you look for? How do you triage it?
Seizures? (benzo/ASD)
-No seizures then evaluate ABS and then neuro eval (Airway (oxygen), Breathing (ventilation) and Cardio (perfusion)
TPR and metabolic evaluaiton
-Check spine, thorax, abdomen
-May need fluids and oxygen
-No imporvement then manitol and elevate head
-No improvement - surgical decompensation, hypersalivation and hypothermia
What does the glagow comma scale tell you?
severity of coma (Normal is high 15-18)
-Use to monitor trends (evaluate every 4-24 hours
What is the causative agent of tetanus?
Clostridium tetani (ubiquitous)
How long does it take to see signs of Tetanus and what are they?
5-10 days post infection, generalized more common in dogs, stiffness, rigid, sardastic grim
How do you treat tetanus?
Antimicrobials (metronidazole) and antitoxin
What are the signs of botulism?
Flaccid paralysis (LMN)
within 12 hours of exposure
Diaphragm resistant to toxin
What’s the treatment for botulism?
supportive care
Where is the causative agent of botulism?
Clostridium botulinum
What is the pathophysiology of these clostridiums?
Botulism - bind at neuromuscular junction - peripheral nerves affected
Tetanus - bind at brain stem (Renshaw cells)
What are some clinical signs of a metabolic encephalopathies?
Seizure, behavioral change, aggression, anxiety, dementia, mania, mentation change, cortical blindness
What are some etiologies of metabolic encephalopathies?
Hypoglycemia, hyponatremia, hypocalcemia, hepatic encephalopathy, thiamine deficiency
