Carotid stenosis, renal artery stenosis, and mesenteric ischaemia

Question 1

What is carotid stenosis?

Answer 1

Narrowing of carotid artery - e.g. due to atherosclerosis

Question 2

Symptoms/signs of carotid stenosis

Answer 2

Symptoms of stroke or TIA
OR asymptomatic (e.g. picked up carotid bruit)

Question 3

Investigaions

Answer 3

Duplex ultrasound scan done first, if narrowing then:

CT angiogram or MR angiography

Question 4

Management of carotid stenosis

Answer 4

Determine risk
Optimise treatment + non-treatment
OR
Surgery - can be end-arterectomy or carotid stenting (determined by MDT)

Question 5

Grading of carotid artery stenosis

Answer 5

Minor = 0-49% narrowed
Moderate = 50-69% narrowed
Severe = 70-99% blocked

Question 6

Indications for surgery

Answer 6

1) Had stroke or TIA and have moderate or severe stenosis
or
2) Severe stenosis alone with no TIA/stroke

Question 7

Pathophys of plaque formation

Answer 7

Endothelial dysfunction and high circulating LDLs

• -> LDLs deposit in intima and become oxidised. This activates endothelial cells, causing them to express adhesion molecules for WBCs on surface.
• -> monocytes and T helper cells move into tunica intima
• -> monocytes become macrophages and take up oxidised LDLs and become foam cells
• -> foam cells promote migration of smooth muscle cells from media to intima and promote their proliferation (and also attract more macrophages)
• -> smooth cell proliferation increases synthesis of collagen (vessel hardening)
• -> foam cells die and release their lipid content and proinflammatory cytokines, promoting inflammation and growth of the plaque.

Question 8

Layers of blood vessels

Answer 8

Lumen
Endothelium
Intima
Media
Adventitia

Question 9

How to distinguish between mesenteric ischaemia and ischaemic colitis?

Answer 9

Mesenteric ischaemia = typically small bowel, due to embolism, sudden onset, severe, high mortality, needs urgent surgery
Ischaemic colitis = large bowel, multifactorial, transient, less severe, bloody diarrhoea, thumbprinting, conservative management

Question 10

Predisposing factors for bowel ischaemia

Answer 10

1) increasing age
2) atrial fibrillation
3) other causes of emboli - endocarditis, malignancy
4) CVD risk factors
5) Cocaine

Question 11

Features of bowel ischaemia

Answer 11

sudden onset severe abdominal pain out of keeping with physical exam findings (mesenteric ischaemia)
rectal bleeding
diarrhoea
fever
elevated WBC
lactic acidosis

Question 12

Investigation of choice for bowel ischaemia

Answer 12

CT

Question 13

Cause of acute mesenteric ischaemia

Answer 13

embolism resulting in occlusion of an artery which supplies the small bowel, for example the superior mesenteric artery.

Question 14

Management of acute mesenteric ischaemia

Answer 14

Urgent resus + early senior involvement
IV fluids, catheter, fluid balance chart, broad-spectrum abx, early ITU input
Urgent surgery is usually required - excision of necrotic/non-viable bowel or revascularisation of the bowel
poor prognosis

Question 15

Features of chronic mesenteric ischaemia

Answer 15

Colickly intermittent abdo pain

Question 16

Symptoms/signs of renal artery stenosis

Answer 16

Hypertension
CKD
Sudden or unexplained recurrent pulmonary oedema
Abdominal bruit
Other PVD

Question 17

Types of renal artery stenosis

Answer 17

Due to atherosclerosis (90%) - think if CVD risk factors, history of CVD etc.
Fibromuscular dysplasia - usually younger females

Question 18

Diagnosis of renal artery stenosis

Answer 18

Bloods - U&Es, urinalysis, aldosterone renin ratio
Duplex USS
MRA
CTA
Angiography

Question 19

Management of renal artery stenosis

Answer 19

Antihypertensive therapy and lifestyle modification
Statin
Antiplatelet
Second line = renal artery stenting
Third line = surgical reconstruction of renal arteries

Question 20

Why are ACE inhibitors used in caution in patients with (bilateral) renal artery stenosis?

Answer 20

Causes creatinine to increase dramatically since angiotensin II usually constricts the efferent arteriole and blocking it will cause the efferent arteriole to dilate and thus less filtration (lowers GFR).
Renal artery stenosis patients rely more upon that efferent constriction to maintain normal glomerular pressures for filtration.

Question 21

Stroke definition

Answer 21

Rapidly progressive clinical symptoms and signs of focal, and at times global, loss of cerebral function lasting more than 24hrs or leading to death with no apparent cause other than that of vascular origin.

Question 22

Total or partial anterior circulation infarct symptoms/signs

Answer 22

• Unilateral motor deficit
• Homonymous hemianopia
• Higher cerebral function (e.g. dysphasia, neglect)

Question 23

Posterior circulation infarct symptoms/signs

Answer 23

• Pure hemianopia
• Cerebellar signs
• Diplopia and CN palsy
• Bilateral/crossed sensory-motor signs

Question 24

Lacunar infarct symptoms/signs

Answer 24

• Pure motor (50%)
• Pure sensory (5%)
• Ataxic hemiparesis (10%)
• Sensorimotor stroke (35%)

Question 25

Causes of ischaemic stroke

Answer 25

``` Arteriolarsclerosis Atherosclerosis Carotid stenosis Carotid dissection Vasculitis AF ```

Question 26

Causes of haemorrhagic stroke

Answer 26

Primary i.e. hypertension (microaneurysm) ``` Secondary causes: Trauma AV malformation Venous thrombosis Vasculitis Coagulopathy/anticoagulation/TPA Drugs e.g. cocaine Haemorrhagic transformation of infarct ```

Question 27

Management of long-term complications of stroke in primary care

Answer 27

Specialist stroke rehabilitation team - initial follow-up Discuss any issues with a stroke specialist Incontinence - management initiated by specialist stroke team, follow up by community continence services. Can include timed toileting, prompted voiding, bladder retraining, pelvic floor exercises, drug treatments in some cases. Constipation - give advice on diet, fluid, exercise, review meds, consider toileting routines, laxatives Fatigue — assess for depression, anxiety, thyroid, infection, meds, pain, sleep apnoea + treat. Give info about daily routines, modified tasks, planned exercise schedules, sleep hygiene. Nutrition and hydration — monitor dietary intake and nutritional status, may need referral to dietician, discuss stroke specialist if unable to swallow, access to appropriate equipment and assistance Cognitive dysfunction - screen with MMSE, may need referral for neuropsych assessment Mood and wellbeing — consider depression, may need referral to psych or for psychology, motivational interviewing, problem-solving therapy, education groups, exercise, social interaction, antidepressants Mouth care - at least 3 times a day. Neuropathic pain - amitriptyline, gabapentin or pregabalin. Musculoskeletal - assess, paracetamol, topical NSAIDS, TENS Sexual dysfunction - assess for reversible causes, can use sildenafil ONLY 3 MONTHS AFTER STROKE, can refer to psychosexual specialist Spasticity and contractures — may have splinting

Question 28

TIA definition

Answer 28

Transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.

Question 29

TIA management

Answer 29

Aspirin 300 mg (unless bleeding disorder, on anticoag, on low-dose aspirin already, or aspirin contraindicated) Discuss urgently with stroke specialist if has had more than 1 or has suspected cardioembolic source or severe carotid stenosis Urgent assessment (within 24 hours) by stroke physician if within 7 days, or ASAP (within 7 days) if it happened more than week ago Advise the person not to drive Long-term - clopidogrel

Question 30

Stroke management

Answer 30

Aspirin 300mg ASAP if haemorrhagic stroke has been excluded Thrombolysis with alteplase if within 4.5 hours of onset + haemorrhage excluded Mechanical thrombectomy + thombrolysis if within 6 hours of onset Mechanical thrombectomy alone if between 6-24 hours

Question 31

Secondary prevention of stroke

Answer 31

Clopidogrel 75mg daily Carotid endartectomy in certain situations Lifestyle Atorvastatin 20-80mg daily Antihypertensives - thiazide-like diuretic, long-acting calcium channel blocker or ACE inhibitor Optimise management of other conditions e.g. diabetes Warfarin or direct thrombin or factor Xa inhibitor if AF