Hypertension Flashcards
What is the significance of ABSENCE of nocturnal dipping on amb BP monitor?
Dipping is the decrease of systolic BP by 10% when asleep.
Absent in 30% of people
Associated with increased risk of cardiovascular morbidity + mortality
And progression of CKD
52 year old with migraines.
Normotensive
Normal renal function
Carotid US identifies 55% stenosis of the cervical left internal carotid artery consistent with fibromuscular dysplasia.
Kidney US: demonstrates right renal artery stenosis 70%
What should you do?
Aspirin
- Increased risk of TIA or other thrombotic events
Counselling is recommended regarding symptoms tIA etc.
3 monthly u/e + bp check
Noninvasive imaging should be obtained every 6–12 months for evidence of progressive stenosis or loss of renal parenchyma that could indicate a need for intervention.
In the absence of symptoms attributable to FMD, angioplasty of either the carotid lesion or renal vessels is not indicated.
A role for statins in FMD has not been established.
The risk for progression is not well established, but it is reasonable to monitor as outlined above. About 6% of patients with FMD may have a renal aneurysm. About 20% of patients with FMD may have dissection, and about 20% of those are in the renal arteries. When intervention is indicated, angioplasty without stenting generally provides favorable results.
What is fibromuscular dysplasia?
FMD is a vascular disease that may cause stenosis, aneurysm, or dissection. It commonly affects the carotid and renal arteries, but it is a systemic arteriopathy and may be present in any artery. Several histopathologic types of FMD have been observed, but the most common is medial fibroplasia, which is characterized by collagen deposition in regions of elastic fibril degeneration.
Affects small + medium sized vessels.
Renal artery involvement is most common. Carotid artery involvement occurs in 21% of patients –> stroke.
FMD is a rare systemic vascular disorder that results in the non-atherosclerotic narrowing of the affected vessel. FMD is classified according to the nature of the stenotic lesions. Any of the arterial layers can be affected. FMD-related stenoses may be discrete and unifocal, multifocal, or web-like. The renal and carotid arteries are the most commonly recognized sites of involvement. Renal artery stenoses related to FMD usually occur in the mid- to distal artery, as opposed to atherosclerotic lesions that tend to occur in the proximal segment, at or near the origin
More likely to affect women and likely has a genetic component
Elevated aldosterone/ renin ratio
Primary aldosteronism
The aldosterone/ renin ratio is a screening test and does not confirm primary aldosteronism
(From another question - aldosterone- to renin ratio of 20 is considered elevated; and plasma aldosterone greater than 15 is elevated…. both are suggestive of primary hyperaldosteronism)
Primary aldosteronism is confirmed by the failure of IV saline loading to suppress the aldosterone level
OR can also do 24 hour urine aldosterone collection
Next step is adrenal CT or MRI scanning.
Because incidental adrenal nodules are identified in up to 4% of patients undergoing abdominal CT - many of these incidentalomas are non functional….
Need to lateralise the overproduction to one side - by adrenal vein sampling
To confirm it is from adrenal vein you measure a cortisol level simultaneously and you calculate an aldosterone/ cortisol ratio.
In unilateral aldosterone excess, the cortisol corrected aldosterone level is >4:1 ( when the high side is compared to the low side)
Is there a concern with too low of a diastolic in the elderly?
Observational studies involving elderly patients identified an increase in adverse events when the diastolic BP was <60 mm Hg. This increase in adverse events has also been seen in several treatment studies, including the Systolic Hypertension in the Elderly Program (SHEP) and in the Hypertension in the Very Elderly Trial (HyVET). Some have linked adverse events to an increase in the pulse pressure (the difference between the systolic and diastolic BPs), which is an independent risk factor for adverse cardiovascular outcomes.
A high pulse pressure is felt to represent an increase in aortic stiffness, which requires an increase in left ventricular work and oxygen demand. This effect may limit myocardial relaxation in diastole, which is required for normal coronary flow. Taken together, these factors may increase the vulnerability of the myocardium to ischemia.
What is the danger of blood pressure variability?
A “normal” degree of BPV has not been established, but higher levels of BPV compared with a population mean are associated with increased CV risk as well as an increased prevalence of CKD.
CCB and thiazide diuretics appear to be beneficial in reducing BP variability ALLHAT trial + SPRINT trial
Hypotension, dilated neck veins ( elevated JVP) muffled/ distant heart sounds in a patient with resistant hypetension on minoxidil
Cardiac tamponade.
Pericardial effusion attributable to minoxidil is observed in about 3% of patients receiving this drug and is occasionally complicated by tamponade.
However, if the intrapericardial pressure increases rapidly or reaches a critical point, dyspnea, chest discomfort, and other symptoms ensue because of impaired cardiac filling and diminished cardiac output. Hypotension with a narrow pulse pressure, as in this case, suggests the compromised stroke volume seen in cardiac tamponade. Management includes discontinuation of minoxidil and pericardial drainage when the effusion is large and symptomatic.
Best management for multiple drug intolerent hypertension ( Intolerance to > 3 classes of antihypertensive drugs)
- Fractional doses of conventional anti hypertensives
- Transdermal preparations such as clonidine
- Consider unconventional anti hypertensives such as 5 phosphodiesterase inhibitors
- Consider device therapy such as renal denervation
44 yo woman
Hypokalaemia + metabolic alklalosis + resistant HTN
Without any elevation of renin, aldosterone + cortiso.
Liddle syndrome
What mutation occurs in Liddle syndrome?
Autosomal dominant - HTN
Activating mutation of ENaC in the distal nephron; increased ENaC activity results in increased sodium reabsorption. n addition, the increased luminal electronegativity leads to potassium secretion from the principal cells and favors H+ excretion via the H+ATPase at the apical membrane of the α-intercalated cells.
Liddle’s syndrome is treated with blockade of ENaC by agents such as amiloride or triamterene
Treatment of a renal infarct
Heparin
The treatment of a renal infarct is usually conservative when symptoms have been present for > 24 hours
Thrombectomy or thrombolysis can be considered if the event is more recent
What % of phaechromocytomas are extraadrenal?
What % are hereditary?
25% ( Pheos that arrise outside the adrenal glands are referred to as paragangliomas)
30% are hereditary
95% are benign
Scleroderma renal crisis - what antibody do you measure?
RNA polymerase III antibody.
Topoisomerase antibodies (Scl-70) are present in 30% of patients with diffuse SS and absent in limited SS. Anti-centromere antibodies are present in about half of patients with limited SS.cleroderma renal crisis - affects 10% of patients with systemic sclerosis.
Anti-RNA polymerase III antibodies are associated with an increased risk of SRC as well as more rapid progression of cutaneous involvement.
What are the features of scleroderma renal crisis?
- Abrupt onset of hypertension + AKI
- Pulmonary oedema + hypertensive encephalopathy may occur
- Typically occurs within 5 years of diagnosis
- Presenting event in 20% of patients
ACEI therapy should be maintaing even if a patient becomes dialysis dependent as up to 55% may eventually recover renal function
Whats the risk of using nitroprusside in the setting of AKI?
Accumulation of thiocyanate
