Hypertension: THE SILENT KILLER

Cardiovascular disorders are now one of the most common lifestyle disorders of our age.  The term cardiovascular disorders cover a vast array of afflictions such as atherosclerosis, ischemia, angina, hypertension.   Hypertension referred to as persistently elevated blood pressure. Normal blood pressure is in the range of 120-130 for systole and 80-90 diastole. However, it falls upon the observer to identify what is normal blood pressure for that specific patient.

Hypertension is a silent killer, there are no defined symptoms. Diagnosis can only be made at routine check ups.

Since blood pressure can be numerically measure it can be classified accordingly.

Blood pressure has risk factors that are modifiable and non-modifiable (these are applicable to almost all CVD and lifestyle disorders).

Modifiable risk factors are smoking, alcoholism, obesity, hyperlipidaemia, diet/dietary salt, lack of physical activity, mental and physical stressors.

Non-modifiable risk factors include age, sex, ethnicity and family history.

Primary hypertension/ essential hypertension: Again, like most disorders when hypertension develops unrelated to any identifiable underlying cause it may be called essential hypertension. This is the most common form. It may be due to any of the risk factors, it may be due to SNP genetic mutations. It may be due to a variety of environmental or genetic factors.

Secondary hypertension:  When we can clearly connect the cause of diabetes to an underlying medical condition such that if that medical condition is addressed the hypertension is controlled it may be referred to as secondary hypertension. This may be commonly seen in case of many hormonal disorders. Addison’s disease, thyroid disorders, renal disorders, pheochromocytoma, use of illegal drugs can cause secondary hypertension.

Hypertensive crisis: In the classification of hypertension after stage 2 there is another class mention as hypertensive crisis. It is when the blood pressure is severely elevated above 180/100. This is a medical emergency where in due to the high pressure the smaller blood vessels may lose their capacity to withstand and force exerted by the blood on them and rupture. This can cause what is known as end organ damage. Organs such as brain, kidneys and eyes may be damaged irreversibly.

If evidence is found in the patient that end organ damage has occurred, it may now be called hypertensive emergency. In both cases aggressive management of blood pressure is carried out to lower the BP to stage 2 levels and then further reduced slowly.

Preeclampsia is a situation where there is elevated blood pressure in a pregnant patient and thus developmental risk to the foetus and eclampsia is a complication of the latter where there are seizures in the patient due to the high blood pressure.

Pathophysiology:

The pathophysiology of hypertension is tied to the heart, RAAS, and the kidneys.

Imagine there is a situation that causes reduced blood supply to the kidneys, (renal hypoperfusion), the highly sensitive juxtaglomerular cells will cause the activation of the rennin-angiotensin-aldosterone system.

The first step would be the activation of and release of rennin. Rennin will convert angiotensinogen to angiotensin I.

Angiotensin converting enzyme (ACE) will convert angiotensin I to angiotensin II.

Angiotensin II will have actions at multiple location all of which will increase blood pressure.

It will cause release of aldosterone (thus retention of sodium and water), increased vasoconstriction, increased cardiac output and heart rate. Eventually in long run it will cause cardiac remodelling which sets the grounds for heart failure/ cardiac myopathy.

Drugs:

ACE inhibitors:

Common side effect is dry cough. Since they inhibit the breakdown of bradykinin that causes cough.

  • Benazepril
  • Captopril
  • Enalapril
  • Ramipril

Angiotensin II receptor antagonist:

  • Telmisarten
  • losarten
  • valsarten

Rennin antagonist:

  • Aliskirin

Beta blockers (Beta 1 selective preferred)

  • Esmolol
  • atenolol
  • acebutolol
  • Carvidilol

Calcium channel blockers

  • verapamil and diltiazem

Centrally acting alpha blockers: Alpha methyl Dopa

Diuretics: Furosemide, torsemide (Loop diuretic) , Spironolactone (Aldosterone antagonist)=Potassium sparing diuretic.. Hydrochlorothiazide

References:

  1. Essential Hypertension – Pathogenesis and Pathophysiology

https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure/types-of-blood-pressure-medications

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