Stroke Flashcards
Thrombolysis, which drug and time window
Alteplase. Start within 4,5 hours from symptom onset. Best efficacy within 3 hours.
Alteplase - Dose and route
0,9 mg/kg (max 90mg) - 10% of total dose by bolus followed by remaining of total dose as infusion over 1 hour
Alteplase - MoA
Recombinant forms of human tissue plasminogen activator(t-PA) enzyme, converts plasminogen to plasmin and cause fibrinolysis
Alteplase - Adverse effects
Hemorrhage
Arrhythmias (Bradycardia, Tachycardia)
Alteplase - Contraindications
- Unknown time of onset of symptoms or onset of symptoms after 4,5 hours
- CT that shows intracranial bleeding
- Previous intracranial bleeding
- Known AV- malformation, aneurysm, or intracranial neoplasm
- Blood glucose < 2,8 mmol/L or >22 mmol/L
- Surgery or trauma within last 21 days
- Aortic dissection
- Risk of bleeding, anticoagulation therapy. Can give if INR<1,8
- Systolic blood pressure > 185 mmHg, Diastolic blood pressure > 110 mmHg
Prehospital treatment
- Observe vital function
- Give oxygen 7-10 L/min with mask or 2-3 L/min with nasal catheterization if saturation is <95%
- Slightly raised upper body (15-20 degrees), or position the pt sideways if unconscious
- Give IV fluids (max 1000 mL) if dehydrated, Lower BP if it exceeds 220/120
- Paracetamol 1 g PO if temp >37,5 °C. Don’t give PO if suspicion of swallowing problems.
Medical Treatment of Stroke
Prevent complications of bedridden pts: infections (pneumonia, UTI, skin), DVT with pulmonary embolism.
Heparin (subc), pneumatic compression stockings
BP: lower if it exceeds 220/120 (Esmolol- 500mcg/kg over 1 min IV), malignant HTN, myocardial ischemia, or if BP >185/110 and thrombolytic therapy is anticipated
Fever: antipyretic and surface cooling.
Serum glucose: keep <10,0 mmol/L (180 mg/dL), and above at least 3,3 mmol/L /60 mg/dL) Insulin infusion if necessary.
IV isotonic fluids: maintain intravascular V
Water restriction and IV mannitol: cerebral edema –> brain herniation. Raise the serum osmolarity, but avoid hypovolemia –> hypotension and worsening of infarction. May also perform hemicraniectomy.
Mannitol: 150 mg/ml 0,50-1g per kg
Cerebellar infarction: mimic labyrinthitis because of prominent vertigo and vomiting. Head or neck pain –> cerebellar stroke due to vertebral artery dissection. Small amounts of cerebellar edema can increase the ICP by obstructing CSF flow –> hydrocephalus or compress brainstem –> coma and respiratory arrest; surgical
Antithrombotic treatment
Platelet inhibition: all pts not receiving thrombolytic treatment should get Aspirin 250-300 mg initially in water-soluble form asap –> 75 mg daily
Anticoagulation: pts with acute stroke and atrial fibrillation –> aspirin + anticoagulation (heparin/LMWH) can be started after 4-7 days; more efficient as long-term prophylaxis.
Deep venous thrombosis prophylaxis: Dalteparin 5000 U or enoxaparin 40 mg subcutaneously is recommended
Enoxaparin - Dose and route
40mg x 1 subcutaneoulsy
Enoxaparin - MoA
Inactivate factor X
Enoxaparin - Adverse effects
Bleeding caused by excessive anticoagulation
Heparin induced thrombocytopenia(HIT)
Enoxaparin - Contraindications
Recent bleeding
Recent trauma or surgery
Bacterial endocarditis
Peptic ulcers
Secondary prophylaxis
Antiplatelet agents:
Aspirin (75mg x 1)/Dipyridamole (200mg x 2) and Clopidogrel (75mg x 1)
Anticoagulation agents:
Warfarin for patients with prosthetic heart valve and INR should be less than 2,5. Newer anticoagulation drugs such as Dabigatran, rivaroxaban and apixaban.
Lipidreducing agents:
Statins is recommended for every patient with ischemic stroke if LDL > 2,0 mmol/l.
- Surgery: Carotid endarterectomy (Carotid stenosis), Encovascular stening (carotid disease)
Dipyridamole - MoA
Inhibiting platelet adhesion to the vessel wall.
Dipyridamole - Adverse effects
Headache
Dizziness
Nausea
Thrombocytopenia
Dipyridamole - Contraindications
Caution in patients with hypotension, coronary artery disease.
Clopidogrel - MoA
Adenosine diphosphate inhibitor
Clopidogrel - Adverse effects
Bleeding
Neutropenia
Clopidogrel - Contraindications
Previous intracranial bleeding
Thrombocytopenia
Neutropenia
Lever damage
Warfarin - Dose and route
7,5 mg orally
Warfarin - MoA
Vitamin K antagonist
Warfarin - Adverse effects
Bleeding (mild nose bleed to life threatening hemorrhage)
Fetal warfarin syndrome (bone deformities and bleeding.
Warfarin - Contraindications
Pregnancy (Crosses the placenta and can cause fetal hemorrhage + fetal warfarin syndrome)
Warfarin - Interactions
Interacts with drugs that induce or inhibit cyt P450.
Most serious interactions are with drugs that increase the anticoagulant effect and place the patients at risk of hemorrhage, ex: Salicylates (by reducing prothrombin), cephalosporins
Decrease anticoagulant effect by inducing CYP enzymes that metabolize warfarin: rifampin, barbiturates
Cholestyramine inhibit absorption of warfarin from gut.
Amiodarone, cimetidine, erythromycin, fluconazole, gemifibrozil, isoniazid, metronidazole, sulfinpyrazone inhibit metabolism of warfarin –> increase the risk of bleeding.
