Tuesday 17th Flashcards
Following a stroke all patients should be offered
an antiplatelet drug unless the person has an indication for an anticoagulant
Immediately after an ischaemic stroke is confirmed by brain imaging
Aspirin 300 mg daily for 2 weeks should be given immediately
- Following this, clopidogrel 75 mg daily should be given long-term
- OR modified-release dipyridamole alongside low dose aspirin
Antiplatelet: Acute coronary syndrome (medically treated)
1st: Aspirin (lifelong) & ticagrelor (12 months)
2nd: If aspirin contraindicated, clopidogrel (lifelong)
Antiplatelet: Percutaneous coronary intervention
1st: Aspirin (lifelong) & prasurgrel or ticagrelor (12 months)
2nd: If aspirin contraindicated, clopidogrel (lifelong)
Antiplatelet: TIA
1st: Clopidogrel (lifelong)
2nd: Aspirin (lifelong) & dipyridamole (lifelong)
Antiplatelet: Ischaemic stroke
1st: Clopidogrel (lifelong)
2nd: Aspirin (lifelong) & dipyridamole (lifelong)
Antiplatelet: Peripheral arterial disease
1st: Clopidogrel (lifelong)
2nd: Asprin (lifelong)
Cyclizine
H1-receptor antagonist that acts by blocking histamine receptors in the CTZ
- safe to use in pregnancy
- CI: cause a drop in cardiac output and an increase in heart rate. For this reason, caution should be employed in patients with severe heart failure
metoclopramide
Dopamine antagonists
- pro-kinetics and should therefore be avoided in intestinal obstruction
- used with caution in patients with Parkinson’s disease
Motion sickness
1st: hyoscine (e.g. transdermal patch) as being the most effective treatment. Use is limited due to side-effects
2nd: non-sedating antihistamines such as cyclizine or cinnarizine are recommended in preference to sedating preparation such as promethazine
Raised superior vena cava pressure
(e.g. secondary to a bad cough) may cause petechiae in the upper body but would not cause purpura
sumatriptan
5-HT1D receptor agonist
- acute treatment of migraine
ergotamine
partial agonist of 5-HT1 receptors
pizotifen
5-HT2 receptor antagonist
- prophylaxis of migraine attacks
Methysergide
5-HT2 receptor antagonist
- rarely used due to the risk of retroperitoneal fibrosis
cyproheptadine
5-HT2 receptor antagonist
- control diarrhoea in patients with carcinoid syndrome
ondansetron
5-HT3 receptor antagonist
- antiemetic
Factors which reduce BNP levels
- aldosterone antagonists
- ACE inhibitors
- angiotensin-II receptor antagonists
- beta-blockers
- diuretics
- obesity
Increased BNP levels (>400)
- left ventricular hypertrophy
- MI
- AF
- pulmonary hypertension
- hypoxia
- pulmonary embolism
- right ventricular strain
- COPD
- liver failure
- sepsis
- diabetes
- renal impairment
- women
- older than 70
B-type natriuretic peptide (BNP)
- left ventricular myocardium in response to strain
- increase renal excretion of water and sodium
- relax vascular smooth muscle causing vasodilation
- suppresses both sympathetic tone and the renin-angiotensin-aldosterone system
Acute ischaemic stroke
thrombolysis within 4.5 hours of symptom onset
Confirmed proximal anterior circulation occlusion
thrombectomy within 6 hours
Confirmed occlusion of the proximal anterior or posterior circulation
- demonstrated by CTA or MRA and if there is the potential to salvage brain tissue
> shown by imaging such as CT perfusion or
diffusion-weighted MRI sequences showing limited
infarct core volume - Thrombectomy can be offered up to 24 hours after symptom onset
Management of acute stroke
- blood glucose, hydration, oxygen saturation and temperature should be maintained within normal limits
- blood pressure should not be lowered in the acute phase unless there are complications e.g. Hypertensive encephalopathy*
- aspirin 300mg orally or rectally should be given as soon as possible if a haemorrhagic stroke has been excluded
- with regards to atrial fibrillation, the RCP state: ‘anticoagulants should not be started until brain imaging has excluded haemorrhage, and usually not until 14 days have passed from the onset of an ischaemic stroke’
- if the cholesterol is > 3.5 mmol/l patients should be commenced on a statin. Many physicians will delay treatment until after at least 48 hours due to the risk of haemorrhagic transformation
Thrombolysis for acute ischaemic stroke
Alteplase should only be given if:
- it is administered within 4.5 hours of onset of stroke symptoms (unless as part of a clinical trial)
- haemorrhage has been definitively excluded (i.e. Imaging has been performed)
Contraindications to thrombolysis: ABSOLUTE
- Previous intracranial haemorrhage
- Seizure at onset of stroke
- Intracranial neoplasm
- Suspected subarachnoid haemorrhage
- Stroke or traumatic brain injury in preceding 3 months
- Lumbar puncture in preceding 7 days
- Gastrointestinal haemorrhage in preceding 3 weeks
- Active bleeding
- Pregnancy
- Oesophageal varices
- Uncontrolled hypertension >200/120mmHg
Contraindications to thrombolysis: RELATIVE
- Concurrent anticoagulation (INR >1.7)
- Haemorrhagic diathesis
- Active diabetic haemorrhagic retinopathy
- Suspected intracardiac thrombus
- Major surgery / trauma in the preceding 2 weeks
Carotid artery endarterectomy
- if patient has suffered stroke or TIA in the carotid territory and are not severely disabled
- should only be considered if carotid stenosis > 70% according ECST** criteria or > 50% according to NASCET*** criteria
splenic flexure
most likely area to be affected by ischaemic colitis
- splenic flexure marks the point where the majority of blood supplied changes from the superior mesenteric artery (SMA) to the inferior mesenteric artery (IMA)
Ischaemia to the lower gastrointestinal tract
- acute mesenteric ischaemia
- chronic mesenteric ischaemia
- ischaemic colitis
Common features in bowel ischaemia
- abdominal pain - in acute mesenteric ischaemia this is often of sudden onset, severe and out-of-keeping with physical exam findings
- rectal bleeding
- diarrhoea
- fever
- bloods typically show an elevated white blood cell count associated with a lactic acidosis
1st: CT
Bowel ischaemia: Common predisposing factors
- increasing age
- atrial fibrillation - particularly for mesenteric ischaemia
- other causes of emboli: endocarditis, malignancy
- cardiovascular disease risk factors: smoking, hypertension, diabetes
- cocaine: ischaemic colitis is sometimes seen in young patients following cocaine use
Acute mesenteric ischaemia
- typically embolism > occlusion > e.g. superior mesenteric artery
- Classically, history of atrial fibrillation
- Abdominal pain is typically severe, of sudden onset and out-of-keeping with physical exam findings
- Management: urgent surgery is usually required
> poor prognosis, especially if surgery delayed
Chronic mesenteric ischaemia
- Relatively rare clinical diagnosis due to it’s non-specific features and may be thought of as ‘intestinal angina’
- Colickly, intermittent abdominal pain occurs
Ischaemiac colitis
- acute but transient compromise in the blood flow to the large bowel
- may lead to inflammation, ulceration and haemorrhage
- Investigations: ‘thumbprinting’ may be seen on abdominal x-ray due to mucosal oedema/haemorrhage
- Management
> usually supportive
> surgery may be required in a minority of cases if
conservative measures fail
> Indications: generalised peritonitis, perforation or
ongoing haemorrhage
