It seems like a large percentage of our patients have some semblance of hypertension. For most ophthalmologists, the majority of what used to keep us up late at night in medical school - treating hypertensive urgency, adjusting long-term meds, counseling patients about sodium intake, debating whether or not to work someone up for pheochromocytoma, etc. - no longer has any direct relevance. I don't mean this in any negative sense, of course, but the point is, management of hypertension is no longer our field of expertise. However, there are still some key things to remember about hypertension. After all, we're still medical doctors.
The OKAP content outline lists 7 specific categories of knowledge that are important to know about hypertension:
- Definition and prevalence
- Evaluation and diagnosis
- Laboratory tests
- Goals of treatment
- Nonpharmacologic therapy
- Pharmacologic therapy (antihypertensives)
- Management of special population groups
As briefly as I can, I will try to touch on the highlights of each of those topics and what I think might be testable. Honestly, I had a hard time coming up with good test questions for some of these sections, so if you want to skim this section, I think that would be fair.
Definition and Prevalence
- Normal blood pressure is defined as a systolic blood pressure < 120 mmHg AND a diastolic blood pressure < 80 mmHg. Hypertension and its various categories are defined by EITHER a high systolic OR a high diastolic pressure. The categories and definitions are listed below (adapted from BCSC Section 1: Update on General Medicine). I doubt that the OKAP would test over something as banal as the classification of hypertension, so this is just for reference:
Stage 1 hypertension
Stage 2 hypertension
Systolic Blood Pressure
≥ 160 mmHg
Diastolic Blood Pressure
≥ 100 mmHg
- Most people experience a 10-20% decrease in blood pressure at night ("dipping pattern"). This nocturnal hypotension is theorized to be the mechanism for nonarteritic anterior ischemic optic neuropathy (NAION).
- People who do not experience this "dipping pattern" are at higher risk for cardiovascular events.
- Family history, black race, and increasing age are associated with increased prevalence of hypertension.
- 90% of patients with hypertension have primary (essential) hypertension, where there is no known cause, and the remaining 10% have a known cause.
Evaluation and Diagnosis
- The evaluation of hypertension consists of the following assessments:
- Lifestyle and biological risk factors for cardiovascular disease
- Consideration of secondary causes of hypertension
- Determination of presence or absence of end-organ damage
- There are several key components to the physical exam that may be testable:
- Blood pressure should be measured in both arms (asymmetry may suggest a secondary pathology)
- Waist circumference is the most important anthropometric factor associated with hypertensive risk.
- Of course, there are many other metrics and organs measured, but those are the ones that stuck out to me as very useful to know.
- These tests are recommended prior to starting treatment. They include:
- Electrocardiogram (EKG)
- Complete blood count
- Serum chemistry
- Lipid profile
- Other tests for rarer causes of hypertension are not recommended unless standard management is not working.
Goals of Treatment
- The primary goal of treating hypertension is to reduce cardiovascular morbidity and mortality.
- Systolic blood pressure is a more important risk factor than diastolic blood pressure.
- For people with no other comorbidities, reducing blood pressure to below 140/90 is sufficient.
- For people with diabetes or renal disease, the goal should be to reduce blood pressure to below 130/80.
- Weight reduction to a BMI between 18.5-24.9 may reduce systolic blood pressure by 5-20 mmHg for every 10 kg of weight loss.
- The Dietary Approaches to Stop Hypertension (DASH) plan, which includes eating primarily fruits, vegetables, and low-fat dairy with reduced fat intake, may reduce systolic blood pressure by 8-14 mmHg.
- Reducing dietary sodium intake to no more than 100 mEq/L (2.4 g sodium or 6 g sodium chloride) may reduce systolic blood pressure by 2-8 mmHg.
- Regular aerobic physical activity most days of the week (> 30 minutes per day) may reduce systolic blood pressure by 4-9 mmHg.
- Moderate ethanol consumption (2 drinks in men and 1 drink in women and lighter-weight men) may reduce systolic blood pressure by 2-4 mmHg.
Pharmacologic Therapy (Antihypertensives)
- There are many classes of antihypertensive drugs. While I could spend thousands of words going into detail about the different meds, their mechanism of action, and their adverse effects, I don't know that it would be very helpful for the test.
- Typically a thiazide (like hydrochlorothiazide) is the first-line treatment for hypertension without any other comorbidities, followed by an ACE inhibitor (like lisinopril).
- In cases of hypertensive emergencies, sodium nitroprusside is the drug of choice. In pregnancy with hypertensive emergency (such as in preeclampsia or eclampsia), labetalol is the drug of choice (although diazoxide and hydralazine are also options).
Management of Special Population Groups
- ACE inhibitors and ARBs should be avoided in pregnancy.
- Beta blockers should be avoided in acute drug withdrawal (phentolamine is a good initial medication).
- Beta blockers are good for patients with previous cardiac/cardiovascular disease.
Sample Questions (answers at the bottom of the page)
- Which of the following is NOT a risk factor for hypertension?
C. Waist circumference
- Which of these statements about hypertension are TRUE?
A. The primary goal of hypertension treatment is to lower systolic blood pressure below 140 mmHg.
B. People who do not experience nocturnal hypotension are at higher risk for developing cardiovascular disease.
C. Smoking does not contribute to cardiovascular morbidity and mortality.
D. Blood pressure should be measured in both arms and legs.
- Which of the following is NOT an appropriate method for lowering systolic blood pressure?
A. Improving BMI to below 25
B. Decreasing sodium intake to below 4 g per day
C. Aerobic exercise greater than 30 minutes per day
D. DASH diet
- Which of the following is NOT an appropriate medication for use in pregnancy?
Sample Question Answers
- D. Age, race, family history, and waist circumference have all been shown to increase the risk or prevalence of hypertension. Height is not a reported risk factor for hypertension.
- B. The "dipping effect" is normal nocturnal hypotension of 10-20%. It is the proposed mechanism for NAION. People who do not have this dipping effect have an increased risk for cardiovascular events. The primary goal of hypertension treatment is to decrease cardiovascular complications. Smoking increases cardiovascular morbidity and mortality. Typically blood pressure is measured in both arms, and in specific situations, both legs.
- B. Sodium intake should be decreased to less than 2.5 g per day. Moderate alcohol intake can also decrease systolic blood pressure.
- A. ACE inhibitors and angiotensin receptor blockers are contraindicated in pregnancy.
References and Additional Reading
- Basic and Clinical Science Course, Section 1: Update on General Medicine. American Academy of Ophthalmology, 2017-2018.
Do you have any suggestions on what else might be important to know about hypertension? Do you have any tips for helping to remember all of this information? Do you have any requests for specific topics to cover? Leave a comment or contact us!