hypertension

risk factors for hypertension

older age
obesity
genetics:
- 2x risk if parent has HT, higher incidence in those of African descent
- rare familial causes:
  - hypertension and
  - brachydactyly (HTNB) syndrome (Bilginturan syndrome) due to a faulty, over-active form of phosphodiesterase 3A (PDE3A) ¹⁾
chronic exposure to air pollution particulate matter ²⁾³⁾
high sodium diet
high alcohol intake
sedentary lifestyle
diabetes
personality traits
depression
? role of T_EM cells activated by CD70 on Antigen Presenting Cells:⁴⁾
- these memory cells can be long lived, lasting decades, and reside in the bone marrow and can potentially sensitize the host to repeated mild hypertensive stimuli and may play a critical role in salt-sensitive and angiotensin II–induced hypertension
- these cells are major sources of IL-17A and IFN-γ, which are thought to be prime mediators of hypertension
- recurrent hypertensive stimuli which appear to activate CD70 and T_EM cells include:
  - emotional stress
  - catecholamine surges in sleep apnea
  - repeated bouts of excess sodium intake

medications such as:
- combined oral contraceptive pill (OCP)
- non-steroidal anti-inflammatory drugs (NSAIDs)
- antidepressants
- corticosteroids
- sympathomimetics such as pseudoephedrine, amphetamines, cocaine
renal disease
renovascular disease
primary hyperaldosteronism ⇒ hypokalaemia, metabolic alkalosis
obstructive sleep apnoea
Cushing's syndrome
phaeochromocytoma
coarctation aorta
possibly, but unproven:
- cervical spondylosis / cervical disc prolapse (often also causes vertigo, headaches which are not due to vertebrobasilar insufficiency from cervical disease, but perhaps due to stimulation of sympathetic nerve fibres around the proximal vertebral artery or perhaps due to pain)
  - see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4602471/
- chronic pain syndromes

if no end organ damage evident, Dx is usually best made on at least 3 BP checks over a period of weeks and taking into consideration white coat false positive BP values
caffeine intake in the 0.5-4hrs prior to measurement may increase systolic BP 3-15mmHg, and diastolic BP 4-13mmHg and this needs to be taken into account, and the hypertensive effect seems greatest in males with stage 1 hypertension ⁵⁾ ⁶⁾
BP should be similar in both arms and if more than 15mmHg, one should suspect subclavian stenosis and peripheral vascular disease (PVD or PAD), or in the context of chest pain, the life threatening emergency of aortic dissection
in the adult:
- Stage 1 hypertension = systolic 140 to 159 mmHg or diastolic 90 to 99 mmHg
- Stage 2 hypertension = systolic ≥160 mmHg or diastolic ≥100 mmHg

prepubertal onset
age < 30 with no overt risk factors
presentation in Stage 2
severe HT (> 180/120 mmHg) at age > 55yrs or with small kidney (<9cm or > 1.5cm smaller than other kidney)
acute rise in BP or malignant HT
renal impairment with sustained rise of > 50% in serum CRN after starting ACE inhibitors
resistant hypertension
flash acute pulmonary oedema (APO) ⇒ ?renovascular
paroxysmal high BP ⇒ phaeochromocytoma
hypokalaemia ⇒ ? aldosteronism
abdominal bruit ⇒ ? renovascular
Cushingoid
sleep apnoea risk
brachio-femoral delay ⇒ ? coarctation
renal impairment or abnormal urinalysis

life style modications
- sodium restriction to 100mEq/d may reduce BP by up to 5mmHg and reduce age-related increases
- weight loss gives 0.5-2mmHg reduction per kg lost
- cut down on caffeine intake
- avoid sympathomimetic agents such as pseudoephedrine
- DASH diet gives additive benefits to modest sodium restriction
- limit alcohol intake to 2 glasses a day (1 glass/day for women) and have at least 2 alcohol free days per week
- increase aerobic exercise may reduce BP by ~4mmHg
- ensure at least 6hrs sleep each night as long term sleep deprivation increases risk of hypertension
- cease smoking to avoid the compounding effects on atherosclerosis
initial pharmacologic Rx:
- if diabetic or proteinuria then ACE inhibitors
- if ischaemic heart disease or other compelling reason, then beta adrenergic blockers
- if black, then diuretic or long acting calcium blocker
- if BP > 20/10mmHg above goal then consider ACE inhibitors + long acting calcium blocker

patient category	BP target (mmHg)
most adult patients under 60yrs	< 140/90
most adult patients 60yrs and over	< 150/90

patient category	BP target (mmHg)
adults with proteinuria > 1g/day	< 125/75⁷⁾
adults < 65yrs or diabetic or renal impairment or proteinuria 0.25-1g/day	< 130/85 or 130/80 if diabetic⁸⁾
adults 60yrs and older without above factors	< 140/90

this group of patients are those who:
- are not pregnant (see pre-eclampsia and eclampsia),
- not on dialysis,
- do not have overt evidence of end-organ complications:
  - hypertensive encephalopathy
  - acute renal impairment
  - aortic dissection
  - angina
  - acute pulmonary oedema (APO)
they thus do NOT need Ix in ED
- ECG, CXR, blood tests are NOT needed in the ED - they can be arranged as OP by LMO
they also do NOT need urgent Rx in ED
- see ACEP guidelines
- rest is generally as good as acute Rx, however, oral antihypertensive such as amlodipine 5mg may be considered

if there is encephalopathy, see posterior reversible encephalopathy syndrome (PRES) as iv labetalol may be the preferred Rx
otherwise, consider:
- sodium nitroprusside 0.3 microgram/kg/minute IV for 10 minutes, then increasing or decreasing by 0.3 microgram/kg/minute every 5 to 10 minutes (up to a maximum of 10 micrograms/kg/minute), or,
- hydralazine 5 to 10 mg slowly IV, repeating at 20 minute intervals if necessary, or,
- GTN infusion