# Hypertension
## Definitions
### Hypertension

Hypertension, as defined by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC 7), is defined as the systolic blood pressure (SBP) > 140 mmHg and/or diastolic blood pressure (DBP) > 90 mmHg. In order to diagnose a patient with hypertension, the blood pressure must be above these levels for the average of at least two separate readings in a seated patient on at least two separate office visits.
JNC 7 defines two stages of hypertension:
* Stage I: SBP 140-159 mmHg and/or DBP 90-99 mmHg
* Stage II: SBP >= 160 mmHg and/or DBP >= 100 mmHg

### Hypertensive Urgency

Hypertensive urgency is defined as severe hypertension without acute evidence of target organ damage/dysfunction (CNS, cardiovascular, renal).

### Hypertensive Emergency

Hypertensive emergency is defined as severe hypertension with evidence of acute target organ damage/dysfunction. Treatment always requires IV medication and reduction of blood pressure within one hour.
* Note: a patient does not necessarily have to carry a previous diagnosis of hypertension to present with hypertensive emergency!

## Etiology

In most cases, the exact cause of hypertension is never found, and the hypertension is said to be "essential". There are, however, several reversible and correctible causes that should be searched out and eliminated if at all possible.
These include:
* Drug use
** OTC sinus preparations
** PCP
** Amphetamines
** Cocaine
** Oral contraceptives
* Drug withdrawals
** Beta blockers
** Alpha2 agonists
* Renal Artery Stenosis
* Pheochromocytoma
* Aortic coarctation
* Cushing Syndrome/Disease
* Pre-eclampsia/Eclampsia
* Hyperaldosteronism

## Diagnosis
### History

Historical account should focus on the presence or absence of organ damage/dysfunction (see below), any previous history of hypertension, current medications, and ruling in/out the above etiologic factors.
Specifically ask about:
* Back pain - Aortic dissection
* Chest pain - Myocardial infarction or ischemia
* Dyspnea - Pulmonary edema, CHF
* Neurologic symptoms - headache, visual disturbances, altered level of consciousness, seizures
** Symptoms of Encephalopathy

### Examination

Vital signs: Should be monitored every 5–10 minutes if hypertensive emergency is considered.
General: Level of consciousness, fluency of speech
HEENT: Funduscopic exam should be performed looking for papilledema, new exudates, and flame hemorrhages.
Cardiovascular: Look for signs of long standing hypertension and acute cardiovascular dysfunction
* Heaves
* Displacement of the PMI
* Carotid bruits
* Elevated JVP
* Peripheral edema
Pulmonary: Evaluate for signs of CHF
* Crackles
* Wheezes
* Accessory muscle use/retractions
Abdomen: Assess for bruits or pulsatile masses
Neurologic: Look for signs of hypertensive encephalopathy
* Altered level of consciousness
* Acute confusional states/delirium
* Visual field deficits
* Focal deficits, either centrally or peripherally

### Imaging/Lab Studies

BMP, CBC, UA, Tox studies (if indicated)
EKG should be performed if chest pain or dyspnea is present
Chest radiographs may be indicated if there is chest pain or dyspnea
Head CT is indicated if there are focal neurological findings

## Treatment
### Hypertensive Urgency

Treatment of hypertensive urgency involves reducing the blood pressure to normal or near-normal levels within 24 to 48 hours. These patients, who do not have any objective evidence of end-organ damage, may be discharged on oral anti-hypertensives with close follow-up at their primary physician's office within the next 2–3 days.

### Hypertensive Emergency

Hypertensive emergency requires rapid BP lowering and admission to a step-down unit or the ICU. General principles include reducing the mean arterial pressure (MAP) by 20% in 1–2 hours with IV anti-hypertensives, including nitroprusside, nitroglycerin or IV beta-blockers. Afterwards, the blood pressure should be brought to 160/100 over the next 6–8 hours.

## References

* The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (PDF link)
* Murphy, C. "Hypertensive Emergencies." Emerg Clin North Am. 1995 Nov;13(4):973-1007. PMID 7588198