Hypertension

Definition

(Show Disclaimer) Note: I copy the "definition" of something straight from the book. I find it's best to have an all-encompassing definition in order to better orient myself when I am studying.

Show Definition

Hypertension (HTN) is considered to be a systolic blood pressure (SBP) of 130 mmHg or more, a diastolic blood pressure (DBP) of 80 mmHg or more, or describes a condition in which a person is taking antihypertensive medications.
Resistant HTN is defined as follows:
1. BP that is not at target despite a three-drug regimen, with one of the agents being a diuretic appropriate for the client’s glomerular filtration rate (GFR).
2. BP that is controlled while taking four or more medications is also considered resistant HTN.
Standing and supine blood pressure (BPs) should be measured before the initiation of combination antihypertensive therapy. Orthostatic (postural) hypotension is diagnosed when, within two to five minutes of quiet standing, one or more of the following is present:
1. At least a 20 mmHg fall in systolic pressure.
2. At least a 10 mmHg fall in diastolic pressure.
3. Symptoms of cerebral hypoperfusion, such as dizziness.
The average nocturnal BP is approximately 15% lower than daytime values. Failure of the BP to fall by at least 10% during sleep is called “nondipping” and is a stronger predictor of adverse cardiovascular outcomes than daytime BP.
Isolated systolic HTN (ISH) is when the SBP is ≥130 with DBP normal or below normal (< 80 mmHg). ISH usually affects the elderly, increasing their risk of stroke or myocardial infarction (MI).
Isolated diastolic hypertension (IDH) is defined as a diastolic pressure ≥80 mmHg with a systolic pressure < 130 mmHg. IDH is more common in younger men who are overweight/obese and in individuals younger than 40 years.
Malignant HTN is marked HTN with (i.e. end-organ damage) retinal haemorrhages, exudates, or papilloedema. Malignant HTN is usually associated with DBP > 120 mmHg.

Table: Whelton 2017 High Blood Pressure Clinical Practice Guideline

Blood Pressure Classification	SBP (mmHg)	DBP (mmHg)
Normal	< 120	AND < 80
Elevated BP	120 - 129	≥ 80
Stage 1 HTN	130 - 139	80 - 89
Stage 2 HTN	≥ 140	OR ≥ 90

Source: Whelton P. K., et al. (2017). High Blood Pressure Clinical Practice Guideline. A guideline for the prevention, detection, evaluation, and management of high blood pressure in adults. Hypertension, DOI: 2017; HYP.0000000000000065.

Incidence/Prevalence

Likely not important for the NAC OSCE Exam:

(If you're a keener click here)

Affects almost 1 billion people worldwide.
Approx. ⅕ Canadians have HTN.
Some estimate 12% of clients have resistant HTN.
Those at higher risk include:
- Indigenous.
- South Asian.
- Black.
- Low Socioeconomic status.

Pathogenesis

Majority (90%) have no identifiable cause, and thus are considered primary or essential HTN.

The remaining 10% of cases have secondary cases:

Renal Causes:
1. Glomerulonephritis.
2. Pyelonephritis.
3. Polycystic Kidney Disease.

Endocrine Causes:
1. Primary hyperaldosteronism.
2. Pheochromocytoma.
3. Hyperthyroidism.
4. Cushing's Syndrome.

Vascular Causes:
1. Coarctation of the aorta.
2. Renal artery stenosis.

Chemical/medication induced:
1. Oral contraceptives.
2. Nonsteroidal anti-inflammatory drugs (NSAIDs).
3. Decongestants.
4. Antidepressants.
5. Sympathomimetics.
6. Corticosteroids.
7. Lithium.
8. Ergotamine alkaloids.
9. Cyclosporine.
10. Monoamine oxidase inhibitors (MAOIs), in combination with certain drugs or foods.
11. Appetite suppressants, in combination with certain drugs or foods.
12. Cocaine.
13. Amphetamines.

Obstructive Sleep Apnea (OSA).

Predisposing Factors

Family history of HTN.
Obesity.
Alcohol consumption.
Stress.
Sedentary lifestyle.
African American ancestry.

Male gender.
Age > 30 years.
Excessive salt intake.
Medications.
Drug use.

Common findings

Majority of HTN is asymptomatic.

Other signs and symptoms

Headaches.
Advanced disease: Organ specific complaints with end-organ damage.
Retinopathy.

Potential Complications

Cerebral vascular accident (CVA).
Not included in the book: intracerebral hemorrhage.
MI.
Heart failure (HF).
Peripheral arterial disease (PAD).
Renal failure.

History

Family history of HTN/cardiac/renal disease.
PMH HTN/cardiac/renal diseases.
Home/Clinic BP readings.
Risk factors:
1. Smoking.
2. Alcohol intake.
3. High fat intake.
4. Obesity
5. Diabetes
Social factors:
1. Lifestyle.
2. Exercise regimen.
3. Work environment. (Note: I wonder how does it relate?)
4. Stress level.
Does the patient have sx related to causes you don't want to miss?
1. Palpitations, headache, diaphoresis (pheochromocytoma).
2. Anxiety, weight gains, or loss (thyroid abnormality).
3. Muscle weakness, polyuria (primary hyperaldosteronism).
Rx hx: including OTC and herbal products.
Are you nervous? (i.e. "white coat HTN").
Recreational/illicit drug use.

Physical Examination

Will post later.

Note however:Diagnosis is made after the average of ≥ 2 readings in ≥ 2 visits at (From my understanding, though it is not in the book) at least 2 weeks apart.

Also note:(for later) Systolic blood pressure readings in the left and right arms should be roughly equivalent. A discrepancy of more than 15 mmHg may indicate subclavian stenosis and, hence, peripheral arterial disease.

Diagnostic Tests

Things you will probably order at initial visit:

Hemoglobin/Hematocrit.
Chemistry profile.

Monitor K⁺ if using ACE/ARBs or spironolactone.

Liver function tests (LFTs; lactate dehydrogenase [LDH], uric acid).
Lipid profile (total and HDL cholesterol and TGLs)
Urinalysis for proteinuria
eGFR
ECG

If Hx/PE/Laboratory tests indicate the need, patient may get:
1. Intravenous pyelography (IVP).
2. Renal arteriogram.
3. Plasma renin.
4. Catecholamines.
5. Chest radiography.
6. Aortogram.
7. Ultrasonography.
8. Sleep study.

Differential Diagnoses

Primary/Secondary HTN.
Drug-induced HTN.
"White coat" syndrome.

Plan

General Interventions:
- Weight loss
- Reduce alcohol intake
- Smoking cessation
- Exercise: 150 minutes/week, at least 10 min. per session
- Max 2 g (2000 mg) sodium intake/day
- Manage stress
Client teaching:
- Stress asymptomatic nature of disease
- Self-monitoring
- Review risk factors and institute prevention
- Diet counselling
  - Limit saturated fats (mostly animal fats)
  - Diet must be balanaced by lifestyle modifications.
Pharmacy: HTN Canada (2018) recommends commencing antihypertensive therapy when SBP > 160 mmHg or DBP > 100 mmHg, especially if no comorbid conditions or presence of risk factors (Double check this). Some evidence start treating at a threshold of 130/80 or 140/90 depending on comorbid conditions and risk factors. Especially diabetes
- Initial monotherapy: Thiazides/Β-blockers, ACE/ARB, CCB
- Do not combine ACE/ARB. Caution when combining βB and CCB
- Low-dose ASA is considered for those > 50 years
US - JNC8 Management Guidelines for HTN

Follow-Up

2 - 4 wks if drug therapy is initiated, if stable, every 3 - 6 months.
Often a patient requires a BMP within 2 weeks to check for hypokalemia and creatinine levels when initiating an ACE/ARB and/or changing the dose of the drug.