Friday, May 1, 2015

Hypertensive Emergencies


Presentation


This may be asymptomatic or may present with any of the many symptoms and signs of end-organ damage:
  • Headache
  • Fits
  • Nausea and vomiting
  • Visual disturbance
  • Chest pain
  • Neurological deficit
  • Bleeding due to disseminated intravascular coagulopathy
  • Microangiopathic haemolytic anaemia

(Thomas H. 2011)

Figure 1 - Hypertensive emergencies in children and adolescents
Source - www.netterimages.com

Causes


  • Unilateral renovascular hypertension (Ex: renal artery stenosis)
  • Renin-secreting neoplasms
  • Trauma to the kidneys
  • Renal vasculitis (Ex: scleroderma, polyarteritis andsystemic lupus erythematosus)
  • Phaeochromocytoma
  • Cocaine abuse
  • Drugs such as monoamine-oxidase inhibitors, combined oral contraceptives or the withdrawal of alcohol, alpha stimulants such as clonidine, or beta-blockers.
  • Sodium-volume overload and low renin levels (Ex: acute glomerulonephritis, primary aldosteronism)
  • Pre-eclampsia/ eclampsia
  • Hyperthyroidism
  • Hypothyroidism

 (Thomas H. 2011)



Investigations


  • Full history - including:

  1. -       Past medical history
  2. -       Full systems review
  3. -       Drug history including over-the-counter, herbal remedies and recreational drugs

  • Full examination - including:

  1. -       Blood pressure measurements
  2. -       Fundoscopy
  3. -     Cardiovascular examination (look for signs of cardiac failure or pulmonary edema, carotid or renal bruits, left ventricular heave, cardiac murmurs, third or fourth heart sounds)

-       Neurological examination
  • Blood tests:

  1. -       FBC ± clotting screen
  2. -       U&Es, creatinine
  3. -       Liver and TFTs
  4. -       Blood sugar measurement
  5. -       ± Cardiac enzymes and fasting blood lipids

  • ± Ambulatory blood pressure monitoring
  • Urine dip testing for protein and blood
  • CXR (cardiac size, cardiac failure, etc.)
  • ECG (left ventricular hypertrophy or left atrial enlargement)
  • Subsequent investigations may include:

  1. -       CT/MRI scan of the head or kidneys
  2. -       Plasma renin activity
  3. -       Plasma aldosterone level
  4. -       24-hour urine for vanillylmandelic acid (VMA) and catecholamine levels.
  5. -       Auto-antibody levels (Ex: antinuclear factor)

 (Thomas H. 2011)



Stepwise Management


  • Initially, try to reduce the mean arterial pressure by approximately 25% over the first 24-48 hours.
  • An arterial line is helpful for continuous blood pressure monitoring.
  • There may be severe sodium and volume depletion; volume expansion with isotonic sodium chloride solution may be required.
  • Drugs
-       Intravenous route is usually used. Nitroprusside is the most commonly used IV drug.
-       Phentolamine is the drug of choice for a phaeochromocytoma crisis.

 (Thomas H. 2011)



REFERENCES



Thomas H. 2011. Patient.co.uk. [ONLINE] Available at: http://www.patient.co.uk/doctor/hypertensive-emergencies [Accessed 27th April 15].

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