White Coat Hypertension

The  transient increase in blood pressure in normal individuals, when BP is recorded in a physician's
consulting room, or in a hospital.

Uses of Sphygmomanometer

Sphygmomanometer is used for the following

• To measure the BP
• To measure the difference in BP in limbs in occlusive arterial diseases
• To demonstrate postural hypotension
• To demonstrate Hill's sign in AR
• To demonstrate pulsus alternans
• To demonstrate pulsus paradoxus
• To determine IVY method of bleeding time
• To look for Hess' test
• To elicit latent tetany - Trousseau's sign

Transient Hypertension

Transient Hypertension may be seen in

•  Acute cerebrovascular accidents
• Acute myocardial infarction
• Acute glomerulonephritis
• Pregnancy
• Acute intermittent porphyria.
• Phaeochromocytoma

It is systemic hypertension seen for a transient phase of time when the patient is under stress or when he is having a disorder with a transient hypertensive phase, as may occur in the above-mentioned conditions.

Pseudohypertension

Pseudohypertension is a false increase in blood pressure recording due to stiff and noncompliant vessels (Osier's sign), occurring in old age. In these individuals, actual intra-arterial BP is lower than the BP measured by a sphygmomanometer.

Postural or Orthostatic Hypotension

BP must be recorded in lying, sitting and standing positions especially when postural hypotension is suspected. When there is a fall in systolic pressure of > 20 mm Hg after standing for 3 minutes, from the lying posture, the patient is said to have postural hypotension.
Causes of orthostatic hypotension
1.Hypovolaemia (blood or fluid loss)
2.Autonomic insufficiency

• Diabetes
• Alcoholism
• Shy drager syndrome

3. Drugs

• Diuretics
• Alfa blockers
• ACE inhibitors
• Ganglion blocking agents
• Centrally acting anti-hypertensives

4. Myocardial pump failure
5. Secondary hypertension (pheochromocytoma). 

Paradoxical Hypertension

In this form of hypertension, patients paradoxically show an increase in BP. even when on antihypertensive drugs
Examples

• Patients with DM and HTN, on beta blockers, on developing hypoglycacmia show a paradoxical risen over previously well-controlled BP. This is because the excess adrenaline released secondary to hypoglycacmia. This will acts unopposed on the alpha  receptors and thereby raises the BP.
• With high doses of clonidine, the peripheral a, receptors are stimulated, apart from its central action, thereby raising the BP.
•  In patients with bilateral renal artery stenosis, administration of ACE inhibitors, results in a paradoxical rise in BP.
• Administration of P blockers in patients with pheo- chromocytoma leads to uninhibited a receptor stimulation by epinephrine leading to paradoxical rise in BP.

Paradoxical hypertension is seen in

• Diabetics on beta blockers
• Phaeochromocytoma on beta blockers
• High doses of clonidine
• ACEI in bilateral renal artery stenosis

Normal Blood Pressure

• Systolic 100-140 mm Hg.
• Diastolic 60-90 mm Hg.

Pulse pressure is the difference between systolic and diastolic blood pressure.
Normal pulse pressure is 30-60 mm Hg.
Mean arterial pressure is the product of cardiac output and total peripheral resistance. It is the tissue perfusion pressure.
Mean arterial pressure = Diastolic blood pressure + 1 /3 of pulse pressure.
Normal mean arterial pressure is approximately 100 mm Hg.
To confirm the presence of hypertension, multiple BP recordings should be taken with a mercurial manometer on several occasions. Home monitoring and ambulatory monitoring are preferable as they eliminate anxiety.

Malignant Hypertension

A triad of the following

• Markedly elevated blood pressure of > 200/140 mm Hg
• Grade IV retinopathy (papilledema) 
• Renal dysfunction.

Limb diffefence in Bloodpressure

Blood pressures in the arms
Normally the difference is less than 10 mmHg
Right upper limb BP> left upper limb BP
Right - Left upper limb BP difference > 10 mmHg is seen in

• Obstruction of aorta, or subclavian arteries
• Supravalvular aortic stenosis

Blood pressures in lower limb
Lower limb BP > Upper limb BP
Normally difference is less than 20 mmHg.
Lower limb BP-Upper limb BP> 20 mmHg is seen in

• Aortic regurgitation

Lower limb BP < Upper limb BP observed in

• Coarctation of aorta
• Takayasu disease

Labile Hypertension

Patients who sometimes, but not always have arterial pressure within the hypertensive range, are classified as having labile hypertension.

Isolated Systolic Hypertension

This is said to be present when systolic blood pressure is > 140 mm Hg and diastolic blood pressure is < 90 mm Hg. It is commonly seen in old age (above 65 years).

Hypertensive Urgency

Hypertensive Urgency is a situation in which the BP is markedly elevated, but without any evidence of end organ damage. In this condition the control of the elevated BP can be done gradually.

Hypertensive urgency

• Markedly elevated blood pressure without target organ damage
• Systolic BP > 220 mm Hg or diastolic BP > 120 mm Hg without symptoms

Hypertensive urgencies management

Partial reduction of blood pressure is the goal

Oral drug therapy (Clonidine, Nifedipine ,Captopril) is often enough.

Hypertensive Emergency

Hypertensive  Emergency is a marked elevation blood pressure with following

• Evidence of end organ damage
• Demanding prompt rapid control of BP

Sudden increase in systolic and/or diastolic blood pressure is associated with following clinical features
Central nervous system

• Hypertensive encephalopathy

Heart

• Acute left ventricular failure
• Acute coronary syndrome
• Dissecting aurtric aneurysm

Kidney

• Acute renal failure

Miscellaneous

• Eclampsia
• Symptomatic microangiopathic hemolytic anemia

Hypertensive emergencies management
25% reduction in blood pressure in 1 hour
Target BP of 160/100 mm Hg to be attained in 6 hours
Parenteral drug treatment (Nitroglycerine, sodium nitroprusside, labetalol, enalaprilat) is often re-
quired.

Drug withdrawal hypertension

Drug withdrawal hypertension seen with

• Clonidine
• Beta-blockers

Blood Pressure

Blood pressure is the lateral force exerted by the blood column per unit area of the vascular wall that is expressed in mm of Hg.
Korotkoff Sounds
Korotkoff sounds should be examined preferably with bell of the stethoscope. There are five phases of korotkoff sounds, i.e., the sounds produced by the flow of blood as the constricting BP cuff is gradually released.
Phase I      First appearance of clear, tapping sound. It represents the systolic blood pressure
Phase II Tapping sounds are replaced by soft murmurs
Phase III   Murmurs become louder
Phase IV Muffling of sounds
Phase V Disappearance of sounds.
Diastolic pressure closely corresponds to phase V.
However, in aortic regurgitation, the disappearance point is extremely low, sometimes 0 mm Hg and so phase IV is taken as diastolic BP in adults as well as children.
When Korotkoff sounds are not heard while recording BP, ask the patient to raise the cuffed upper limb and ask him to open and close the fist of that hand repeatedly and then record the BP.
The BP apparatus
The length of the bladder is approximately twice that of the width. The average length of the rubber bag is 25 cm.
The air bag within the cuff should extend for at least 2 /3rd of the arm length and circumference.
Various Cuff Sizes for BP Measurement
Age in Years Width of the bladder of the cuff

< 1 yr                 2.5cm
1-5 yr                 5cm
6-10 yre             10 cm
Normal adult   12.5cm
Obese adult     14cm

Blood pressure (BP) measurement

BP recording is essential to assess the patient's blood pressure, to know whether the patient is

having normal blood pressure, hypertension o hypotension.

BP apparatus 

Sphygmomanometer was discovered by Riva Rocci. 

Mercury type of manometer is the most reliable standard instrument.

Cuff dimensions

Rubber cuff has a width of 12.5 cm and length of 25 cm, Length: breadth—2:1

In obese people cuff width is 15 cm.

For measuring lower limb, BP cuff width is 18 cm, in children 7.5 cm.

Arm

Standard - 15 x 30 cm

Ideal - 12 x 24 cm

Thigh

Ideal - 18 x 36 cm

Ideal cuff length should be 80% of arm circumference and width should be 40% of arm circumference.

Method of examining blood pressure

• BP should be first recorded by palpation and then by auscultatory method
• Patient should be seated in a chair or in supine position
• Recording should be done after 5 minutes of rest.
• No smoking or coffee for 30 minutes prior to BP recording
• Rubber cuff should cover 80% of arm.
• Cuff 2-5 cm above cubital fossa, Lower border of cuff is not < 2 cm from the cubital fossa.
• BP apparatus is kept at the level of heart
• Arm horizontally supported
• Cuff at the level of the heart
•  Inflate the cuff while palpating the radial pulse to 30 mm Hg above the level at which the radial pulse is not felt.
•  Keep the stethoscope over the brachial artery and deflate at a rate of 5 mm/1 sec until the first sound of the Korotkoff heard (Phase I). This is taken as the systolic BP, continue to lower the pressure in the cuff until the sounds disappear (phase V), this indicates the diastolic BP. NIKOLAI KOROTKOFF described the korotkoff sounds in 1905.. 

Three BP measurements done. 2 minutes apart if the value difference is > 5 mm Hg then the first two measurements, then the average  is taken. BP difference between the right and Lt. arm is 10 mm Hg. Arm and leg difference  is 20 mm Hg.

Lower Limb Blood Pressure

Check for calf blood pressure and auscultate over the posterior tibial vessels with the bell.Lowerlimb BP is recorded if coarctation of aortoarteritis and A.R. (Hill's sign) is present

On standing systolic and diastolic BP rises. Fall of systolic 10 mm Hg while standing for 3 minutes is indicative of postural hypotension,

Before labeling a person as hypertensive, 2 or more BP recording at each visit for 3 or occasions at an interval of 2 -3 weeks is a must

Normal          -    130-139/85-89 mm Hg, 

Hypertension > 140/90 mm Hg

Isolated systolic hypertension – SBP mm Hg DBP < 90 mm Hg

Accelerated hypertension-recent increase in BP the previous BP value with evidence of vascular changes in the optic fundi without papilledema

Malignant hypertension-is a triad of high BP of 130-140, papilledema and renal dysfunction

Korotkoff's sounds

Phase 1 : Tapping sound

Phase 2 : Soft murmurs

Phase 3 : Loud murmurs

Phase 4 : Muffled sounds

Phase 5 : Disappearence of sounds

Phase 4 taken as the diastolic pressure in aortic regurgitation and pregnancy.

Auscultatory gap

At times the Korotkoff's sounds disappear between auscultations, it is called the 'auscultatory gap' or the 'silent gap'.This will underestimates sytolic and overestimates diastolic  pressures

Mean blood pressure

Diastolic blood pressure + l/3rd of pulse pressure

Bp measurement in Atrial fibrillation

Average of three readings in the same limb is taken

Blood Pressure in the basal condition

In order to determine BP in basal condition

• The patient should rest in a quiet room for 15 minutes.
• He should not have consumed coffee or tea for the preceding one hour or smoked for the preceding 15 minutes. 
• He should not be on adrenergic stimulants and there should be no bladder distension.
• It is desirable to record the BP in both the arms as the differences in systolic pressure exceeding 10 mm Hg between the two arms when measured simultaneously or in rapid sequence suggest obstructive lesions of aorta, innominate or subclavian arteries.
• In vertebrobasilar insufficiency, a difference in pressure between the arms may signify that a subclavian steal is responsible for cerebrovascular symptoms.
• Normally systolic pressure in the legs is up to 20 mm Hg higher than in the arms, but diastolic BP is the same. When systolic pressure in the popliteal artery exceeds that in brachial artery by > 20 mm Hg (Hill's sign), AR is usually present. Measuring lower limb BP is useful in detecting coarctation of aorta or obstructive disease of the aorta or its immediate branches.
• When the diastolic pressure is below 90 mm Hg, a systolic pressure below 140 mm Hg indicates normal blood pressure.
• Blood pressure between 140-149 mm Hg indicates borderline isolated systolic hypertension
• Blood pressure more than 140 mm Hg or higher indicates isolated systolic hypertension.
• When there is an elevation of systolic pressure of > 30 mm Hg and a diastolic pressure of > 20 mm Hg from the basal original level, it indicates presence of hypertension.

Accelerated Hypertension

Accelerated Hypertension is characterised by significant recent increase in blood pressure over previous hypertensive levels, and this is associated with evidence of vascular damage on fundoscopic examination, but without papilledema.

Hypertensive States

These are situations in which there is a marked increase in both systolic and diastolic BP, occurring in normal individuals, as during sexual intercourse or on diving into cold water.

What is Malignant hypertension ?

Malignant hypertension and accelerated hypertension are both hypertensive emergencies, both of them have similar outcomes and therapies. Malignant hypertension may or may not be associated with clinical signs and symptoms present in hypertensive urgency. A patient is said to have malignant hypertension when he or she has retinal papilledema as well as flame-shaped hemorrhages and exudates. 

More modern definition for malignant hypertension,states that this is a hypertensive emergencies, in the absence of retinopathy, be based on the criteria of acute elevated blood pressure accompanied by damage to a minimum of three different target organs.

Other clinical features of malignant hypertension may include the following 

• Encephalopathy 
• Confusion 
• Left ventricular failure 
• Intravascular coagulation 
• Impaired renal function, with hematuria 
• Weight loss.

About 1% of patients with essential hypertension may develop malignant hypertension, but the reason why some patients develop malignant hypertension is unknown.

What is the pathologic hallmark of malignant hypertension?

The pathologic hallmark of malignant hypertension is fibrinoid necrosis of the arteriole, eventhough it occurs systemically, but specifically seen in the kidneys. These patients develop fatal complications if untreated, and more than 90% will not survive beyond 1-2 years.. 

Red blood cells are damaged when they flow through thse vessels that are obstructed by fibrin deposition, resulting in microangiopathic hemolytic anemia

What are the causes of malignant hypertension?

• Any form of secondary hypertension; 
• Complications of pregnancy
• Renal artery stenosis
• Pheochromocytoma
• Aortic coarctation 
• Hyperaldosteronism is also a secondary cause of hypertension
• Both hyperthyroidism and hypothyroidism can cause hypertension.
• Use of cocaine
• Monoamine oxidase inhibitors (MAOIs)
• Oral contraceptives
• Withdrawal of alcohol, beta-blockers, or alpha-stimulants. 

Other conditions that should be excluded are 

• Stroke
• Intracranial mass
• Head injury 
• Epilepsy 
• Postictal state 
• Connective-tissue disease (especially lupus with cerebral vasculitis)
• Drug overdose or withdrawal, cocaine or amphetamine ingestion
• A anxiety
• Thrombotic thrombocytopenic purpura.