Information based on BMJ Best Practice Guidance: https://newbp.bmj.com/topics/en-us/27/
Definitions:
Hypertensive Urgency: blood pressure ≥ 180/110 mmHg without acute target-organ damage.
Hypertensive Emergency: severely elevated blood pressure (BP) associated with new or progressive target organ dysfunction.
Although the absolute value of the BP is not as important as the presence of end-organ damage, the systolic BP is usually >180 mmHg and/or the diastolic BP is >120 mmHg.
Q: Why is this a medical emergency?
A: Can lead to irreversible end organ damage
Image from https://www.accp.com/docs/bookstore/ccsap/ccsap2018b1_sample.pdf
Causes:
There are many possible causes of hypertensive emergency.
One very common cause is essential hypertension that is either undiagnosed or inadequately treated.
Another common cause of hypertensive emergency is secondary and resistant hypertension:
- Renal: most common caused by underlying chronic disease, renal artery stenosis, acute glomerulonephritis, collagen vascular diseases, kidney transplantation.
- Neurological: head trauma, spinal cord injury, autonomic dysfunction
- Respiratory: obstructive sleep apnoea
- Vasculitis
- Endocrine: multiple causes- but rare and small print! These are also difficult to diagnose without extensive tests and investigations.
- Pregnancy: pre-eclampsia, HELLP syndrome, and eclampsia are important causes of hypertensive emergency in women. THIS IS OFTEN TREATED DIFFERENTLY
- Lifestyle factors:
- excessive dietary salt intake,
- obesity
- alcohol consumption
- smoking
- drug use
Symptoms:
Neurological:
- Blurry vision
- Dizziness
- Headache
- Seizures
- Change in mental status
- Dysphagia (swallowing difficulty)
- Numbness
- Paraesthesia
- Weakness
Cardiac:
- Chest pain
- Shortness of breath
- Sweating
- Orthopnoea (breathlessness when lying down)
- Palpitations
- Peripheral oedema
Renal:
- Decreased urine output
Examination:
An appropriately sized cuff should be used for BP readings:
- The cuff bladder should encircle at least 80% of the upper arm and the cuff length should be greater than two-thirds the distance between the shoulder and elbow.
- The arm should be supported at heart level during recordings.
- Using too large a cuff could result in an underestimation of BP; too small a cuff could lead to overestimation.
- BP readings should be taken from both arms and readings repeated after 5 minutes to confirm.
If there is a more than 20 mmHg pressure difference between arms, aortic dissection should be considered. This requires urgent transfer to a specialist hospital.
A fundoscopic examination should be performed, looking for the presence of papilloedema retinal haemorrhages, retinal exudates, or engorged retinal veins.
A bedside neurologic exam is also required and should include:
- testing of cognition
- examination of the cranial nerves
- checking gross motor strength and sensation
- checking the patient’s gait
It is important to listen to the heart sounds to check for any new murmurs or additional sounds. It is also useful to check for artery bruits and whether there is any peripheral oedema present.
Investigations
Depending on clinic facilities, it may not be possible to perform any diagnostic tests, however it is useful to check the following as a minimum if you are able to:
- FBC- to check for any abnormalities
- U&E- may show renal impairment
- Urinalysis- may show blood/protein which can signify end organ kidney damage
- ECG- may show ischaemia or left ventricular strain pattern
See: https://litfl.com/left-ventricular-hypertrophy-lvh-ecg-library/
Overall the most important thing is to check for evidence of end organ damage as this is what distinguishes hypertensive urgency from hypertensive emergency.
Treatment:
This is according to the British National Formulary and the hyperlinks should link through to the correct doses for each medication.
Hypertensive Urgency (HU):
- Blood pressure should be reduced gradually over 24–48 hours with oral antihypertensive therapy, such as labetalol hydrochloride, or the calcium-channel blockers amlodipine or felodipine.
- Use of sublingual nifedipine is not recommended.
A systematic review was carried out in the Journal of General Internal Medicine in 2018, which concluded that he optimal choice of antihypertensive agent remains unclear.
The full article can be accessed here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5880769/#!po=0.909091
Hypertensive Emergency (HE):
In UK guidelines, oral therapies are generally discouraged as first-line treatment options.
Intravenous treatment options include sodium nitroprusside [unlicensed], nicardipine hydrochloride, labetalol hydrochloride, glyceryl trinitrate, phentolamine mesilate, hydralazine hydrochloride, or esmolol hydrochloride.
The precise choice of drug depends on the past medical history and clinical status of the patient.
It is important to control the patient’s BP, however bringing it down too quickly can also cause renal, cerebral, or coronary ischaemia and should therefore be avoided.
If you do not have access to IV medication, using an oral anti-hypertensive, as per HU guidelines, is likely to do less harm than leaving a patient untreated with grossly abnormal physiology and an increased risk of irreversible end organ damage.
If you are in doubt about how best to manage a case, don’t forget you can contact us at the Virtual Doctors for patient specific advice and guidance.
