Hypertension Flashcards
How common is hypertension?
Affects about 25% population in England - very common
What is the most important risk factor for premature death and CVD?
Hypertension
HTN causes 50% of all vascular deaths
Why is screening for HTN so important?
Majority of the times, HTN will be asymptomatic.
What type of HTN is the most common?
Essential (primary) HTN accounts for 85% of cases where there is no underlying cause
Likely to be a mix of genetic and environmental causes
What are causes of secondary HTN?
Secondary HTN occurs in about 10% of cases of HTN
Causes
- Renal disease, endocrine conditions
- Vasculitis, aortic dissection, aldosterone secreting tumours (conns syndrome), pregnancy
- Renal system = reduced blood flow to kidneys = renin secretion = increased BP
Which drugs are known to cause HTN?
- NSAIDs
- COCP
- Corticosteroids
- Ciclosporin
- Cold cures e.g. phenylephredrine
- SNRI antidepressants
- Anti-anxiety drugs - gabapentin
- Some recreational drugs such as cocaine and amphetamines
Signs and symptoms of HTN?
- Typically asymptomatic so screening is important
Some symptoms may be experienced in very severe HTN:
- Headaches
- Visual changes - floaters or papilloedema
- Dyspnoea - suggesting posible CHF or CAD
- Chest pain - suggesting CAD
- Sensory or motor deficit - suggesting cerebrovascular disease
We need to check for end-organ damage - retinopathy, renal disease, renal bruits, palpable kidneys, weak femoral pulses (coarctation), Cushing’s syndrome, proteinuria.
Risk factors for HTN?
- Age - normal to increase as you get older
- Sex - males typically have higher BP up to about 65 years, between 65-74 women tend to have higher BP
- Ethnicity - people of Black African and Black Caribbean origin are more likely to be diagnosed with HTN
- Genetics - family hx
- Lifestyle - smoking, excessive alcohol consumption, obesity & lack of physical exercise, high sodium intake
- Diabetes mellitus (hyperglycaemia and hyperinsulinaemia lead to oxidative stress & damage on the artery walls)
- Anxiety and emotional stress (raising BP due to increased adrenaline and cortisol levels)
Complications of HTN?
Target organ damage
- renal (kidney damage/failure due to damage to small vessels in kidneys from HTN)
- vascular (blood clots due to narrowed arteries if atherosclerosis, blurred vision from damage to eye vessels)
- cardiac (arrhythmias, chest pain, LVH, MI, HF from pulmonary oedema)
- cerebrovascular (dementia, stroke)
Aneurysm - increased pressure in the blood vessels result in damage to the arterial wall. This can cause thrombus formation and narrowing of the blood vessels. As the blood vessels weaken overtime, sections of the arterial wall can bulge out, causing an aneurysm which may rupture and cause life threatening internal bleeding.
How do we classify HTN?
Stage 1-3, masked htn, white coat effect & malignant htn
Stage 1 hypertension
- BP in clinic is ≥140/90 mm Hg
- ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring (HBPM) from 135/85 mm Hg.
Stage 2 hypertension
- BP in clinic is ≥160/100 mm Hg but less than 180/120 mm Hg and ABPM or HBPM is ≥150/95 mm Hg.
Stage 3 or severe hypertension
- Systolic BP in clinic is 180/120mm Hg or higher.
Masked hypertension
- BP in surgery/clinic is less than 140/90 mm Hg but average ABPM or HBPM readings are higher.
White coat effect
- A discrepancy of more than 20/10 mm Hg between clinic and average daytime ABPM or average HBPM blood pressure measurements at the time of diagnosis (NICE says do not treat but these people may have increased risk for HTN in future)
Accelerated (malignant) hypertension
- This is a syndrome characterised by severe hypertension (180/120 or higher) accompanied by end-organ damage (eg, encephalopathy, aortic dissection, pulmonary oedema, papilloedema, acute coronary syndrome, acute kidney injury (protein in urine)).
- We would want to examine their eyes and dipstick urine in these patients
- Accelerated hypertension needs urgent (same-day) assessment and immediate treatment to reduce the BP within minutes to hours
How do we diagnose HTN?
Clinic, ABPM, Other modalities?
If clinical BP is above or equal to 140/90mmHg → offer ambulatory blood pressure monitoring (ABPM)
ABPM: blood pressure monitoring at home every 20 mins, over 24 hours with cuff attached and BP taken twice per hour.
NICE guidelines - take BP in both arms and if difference >15mmHG, retake BP and if it persists after 2nd reading → measure subsequent BP’s in the arm with the higher reading.
OTHER MODALITIES
Unattended automated office BP - where patient is in clinic and you leave the room and they take their BP - this might remove white coat effect
Home BP measurement -patient buys their own machine and records it a 2x a day for a week or so.
Investigations for HTN?
To quantify overall risk
- Fasting blood glucose
- Cholesterol levels
To look for end organ damage
- Urinalysis - blood indicating damage of small blood vessels in the kidney
- Urine albumin: creatinine ratio - protein in urine analysis indicating chronic kidney disease
- Electrolytes, creatinine and estimated GFR - test for CKD as poor eGFR would indicated renal insufficiency
- ECHO or 12 Lead ECG - assess cardiac function and detect LVH or past MI.
Physical assessment in HTN
- Examination of optic fundi (hypertensive retinopathy & papilloedema)
- Calculation of BMI from height and weight
- Auscultation for possible carotid, abdominal, or femoral bruits
- Palpation of the thyroid gland
- Examination of the heart and lungs
- Examination of the abdomen for enlarged kidneys, masses, distended urinary bladder, or abnormal aortic pulsation
- Palpation of the lower extremities for oedema and pulses
- Neurological assessment
What is the threshold for who to treat? What does it depend on?
Treat everyone with a BP >160/100 or ABPM >150/95
For those with BP >140/90 = treating depends on their CVD risk. Treat those at high risk of CVD.
- Cholesterol levels
- Blood sugar levels
- QRISK Tool to assess 10 year risk of developing CVD
How do we manage stage 1 HTN?
- Between 140/90 - 159/99 clinic
Lifestyle interventions should be spoken about to anyone with suspected or diagnosed HTN and should be offered periodically. - Discuss starting antihypertensive treatment in addition to lifestyle factors in those <80yrs
- Discuss starting antihypertensives in those with chronic stage 1 & target organ damage, established CVD, renal disease, DM, estimate 10 year CVD risk of 10% or more
