Hypertension [HTN]

Definition

Hypertension is a condition in which there is sustained elevation of anterior blood pressure i.e. systolic of over 140 and diastolic above 90mmHg.

Types of Hypertension

Two forms of high blood pressure have been described: essential (or primary) hypertension and secondary hypertension.

Essential/Primary Hypertension: This is the type of hypertension, which cause (s) is unknown except for possible risk factors associated with fluid retention and stress.  These are usually high dietary salt intake, weight gain and emotional stress. It is common in young adults. This type represents 85 – 90% diagnosed cases of hypertension.                                                                                                             

Secondary Hypertension: This type of hypertension is as a result of an underlying disease and usually subsides when the disease is treated or controlled either by medications or surgery. It is most common in people that are advanced in age.  The few causes are those related to heart disease, coarctation of aorta, endocrine disorders and pregnancy.               

  Predisposing Factors of Hypertension: 

1. Heredity - there is proof showing that kidney mal-function leading to fluid retention seems to run in families.  Fluid retention will increase blood volume. Thus, raises the pressure, as there will be increased peripheral resistance due to the increase in volume that has to flow through the same size of blood vessel lumen.                                                                                                           

2. High Sodium Intake: This causes fluid retention which eventually increase blood volume thus, raises the pressure as there will be increased peripheral resistance due to the increase in volume that has to flow through the same size of blood vessel lumen.           

3. Age: Blood pressure raises progressively with age. The is because the blood vessels lose their elasticity with ageing thereby increasing peripheral resistance, which raises the blood pressure.                                           

4. Birth Control Pill: Oral contraceptives increase the risk of developing hypertension in women, having a family history of hypertension and who also smoke.                                                                                            

5. Cigarette Smoking: It increases chances of cardiovascular diseases and hypertension in one of them.  This is because nicotine is a stimulant to smooth muscles leading to vasoconstriction causing a rise in blood pressure.    

6. Elevated Serum Lipids from the Diet: This will cause accumulation of cholesterol that settles on the walls of the blood vessels causing thickening and elasticity loss. Peripheral resistance is increased leading to hypertension. 

7. Alcohol Intake: This has a risk association with the development of hypertension. It may have to do with adrenegic stimulation leading to vaso- constriction.                                                                                     

8. Inactivity: Inactivity leads to a lot of fat storage. Since not all glucose is used, some of it is stored as fat.  This results to thickening of the blood vessels and loss of elasticity which may lead to hypertension.               

9. Socio-Economic Status: Lack of education may lead to lack of knowledge on food that is good for the body such as proteins, carbohydrates, fruits and vegetables. For example, poverty may lead to eating fats and carbohydrates always which leads to fattening and causes for lipidaemia.        

10. Stress: This stimulates secretion of adrenaline, which promotes vaso- constriction, leading to increased peripheral resistance and raised blood pressure.                                                                                                  

Clinical features

Some people with uncomplicated hypertension, however, may experience symptoms such as

• Headache; due to cerebral hypoxia, 

• Dizziness; due to cerebral hypoxia, 

• Shortness of breath; due to impaired gaseous exchange,

•  Blurred vision; due to rupture of blood vessel supplying the retina.

• Chest pain; due to anginal pain as a result myocardial ischaemia

• Palpitations; due to over work of the heart

• Nosebleed; due to rapture of blood vessel in the nose

• Tiredness; due to impaired tissue perfusion

Groups of Drugs used in Hypertension:

The groups are:

1.  Beta Adrenergic Blockers

2.  Vasodilators

3.  Calcium Antagonists

4.  Diuretics

5.  Angiotensin – Converting Enzyme Inhibitor

1. Beta Adrenergic Blockers:

A) Drug Name: Atenolol Tablet 

Dosage: 50-100mg OD or BD 

Side Effects: Bradycardia, Fatigue, Insomia, Sexual dysfunction.

Nursing Implications:

(1) Assess for manifestation of heart failure

(2) Check the pulse rate regularly

(3) Do not withdraw the drug suddenly in-patient with heart disease. 

B) Drug Name: Propranolol Tablet 

Dosage: 40mg BD 

Side Effects: Brochospasms, Bradycardia, Nightmares, Insomia, Postural hypotension.

Nursing Implications:

(1) Assess for manifestation of heart failure

(2) Check the pulse rate regularly

(3) Do not withdraw the drug suddenly in-patient with heart disease. 

2. Vasodilators:

A. Drug Name: Methyldopa Tablet/ Injection.

Dosage: 250 Orally TDS

Side Effects: Drowsiness/Sedation, General Body weakness, Impotence.

Nursing Implications:

(1) Advise not to operate machine.

(2) Men should not use it for a long time.

B. Drug Name: Hydralazine Tablet

Dosage: 20-50mg BD 

Side Effects: Headache, Flushing headache, Dizziness, Increase Heart rate and Cardiac output (if doses exceed 300mg /day)

Nursing Implications:

(1) Watch for Hypotension

(2) Give attention to fluid retention.

(3) Calcuim Antagonists 

(a) (i) Chemical Name: Nifedipine Tablet 

(ii) Dosage: 20mg Sublingual/Orally OD

(iii) Side Effects: Dizziness, Fatigue, Nausea, Headache, Oedema 

(iv) Nursing Implications:

(1) Watch for Oedema

(2) Advise on Rest

(3) Give attractive food

(Give 1% each for items i, ii, iii, & 2% for iv Max. 5%) 

(4) Diuretics:  

(a) (i) Chemical Name: Moduretic Tablet

(ii) Dosage: 5mg OD

(iii) Side Effects: Hypotension, Renal insufficiency, Dehydration

(iv) Nursing Implications:

(1) Give right dose  

(2) Monitor hydration level

(3) Daily weighing

(b) (i) Chemical Name: Frusemide/Furosemide Tablet:

  (ii) Dosage: 20-40mg BD with slow K600mg daily    

(iii) Side Effects: Dehydration, Hypokalaemia

(v) Nursing Implications:

(1) Monitor hydration

(2) Watch for signs of potassium depletion

(3) Daily weighing

(4) Monitor for ototoxic effects - ask the patient if he has experienced any hearing problem.

(Note: Mark only ONE example in this group)

  (Give 1% each for items i, ii, iii, & 2% for iv Max. 5%) 

                       (5) Angiotensin – Converting Enzyme Inhibitor:  

(i) Chemical Name: Captopril (Capoten) Tablet:

  (ii) Dosage: 18.75mg -150mg daily in 3 divided doses. Maximum   

dose of 450mg/day 

(iii) Side Effects: Hypotension, Tachycardia, Renal Proteinuria, Rash

(vi) Nursing Implications:

(1) Monitor BLOOD PRESSURE & PULSE (Supine & Standing)

(2) Administer the dose 1 hour before or 2 hours after meals. This improves

      absorption.

(3) Observe for signs of infection, mouth sores, fever, sore throat, pruritc 

      rash (usually on upper extremities or trunk) and Oedema.