Hypertension
Definition
High blood pressure. According to NICE, it has to be persistenly over 140/90mmHg.
Epidemiology
Ridiculously high prevalence - 11.3%. 95% is primary (i.e. no known cause).
Pathophysiology
There are two types :
- essential (aka primary or systemic) - it just happens and nobody knows the cause.
- secondary - caused by another disease.
Risks
Risk Factors
Nobody knows the exact cause of hypertension but there are some risk factors:
- Diet - high salt, calcium and coffee intake
- Genetics
- Oral contraceptive
- HRT
Associated Risks
Hypertension is massively associated with cardiovascular disease which is why it is so important. It increase the risk of:
Clinical Features
The main clinical feature of high blood pressure is high blood pressure. Go figure. Well, I'm sure you did. This is about excluding secondary hypertension.
Classification
Category | Systolic blood pressure (SBP) | Diastolic blood pressure (DBP) |
---|---|---|
Normal | ||
Optimal | <120 | <80 |
Normal | <130 | <85 |
High normal | 130-139 | 85-89 |
Hypertension | ||
Mild (grade 1) | 140-159 | 90-99 |
Moderate (grade 2) | 160-179 | 100-109 |
Severe (grade 3) | >/=180 | >/=110 |
Obviously, in most patients, looking to get the BP to normal is what you aim for. However, there are certain populations where you need to aim lower. Check this shit!
SBP | DBP | |
---|---|---|
Diabetes - no nephropathy | ||
Intervention threshold | 140 | 90 |
Target levels | 130 | 80 |
Diabetes - with nephropathy | ||
Target levels | 130 | 80 |
Proteinuria (<1g/24h protein in urine) | 125 | 75 |
Renal disease | ||
Intervention threshold | 140 | 90 |
Target | 130 | 80 |
Chronic renal disease/proteinuria (see above) | 125 | 75 |
Investigations
These are more appropriate if secondary hypertension is suspected. I'd look at the secondary hypertension page if I were you.
Management
NICE and the British Hypertension Society] (BHS) each came up with a set of guidelines regarding the management of hypertension. They came up with the algorithm on the right.
Hopefully, when to use ACE inhibitors (ramipril, lisonipril, enalapril), calcium-channel blockers (amlodipine, felodipine, nifedipine) and thiazide diuretics (usu. bendroflumethiazide) is obvious from the incredibly professionally drawn flow chart. Under the "clever other shit" moniker we have things like:
- Beta blockers - atenolol, propanolol, bisoprolol
- Angiotensin II receptor inhibitors/angiotensin receptor blocker (ARB)- losartan, irbesartan, valsartan
- alpha blockers - doxasozin
Basically, you try different drugs until you get their blood pressure to the target levels (or you give up and refer them to a specialist).
In diabetes (both types) with nephropathy an ACE inhibitor is recommeneded (with ARBs as an alternative).