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Hypertension, diabetes, cholesterol: ODs should know signs, symptoms
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As more is discovered about the relationships between ocular conditions and systemic disease, the optometrist’s role as a primary care provider becomes more important.
Systemic hypertension is currently the third leading cause of death and the number one modifiable risk factor for cardiovascular disease in the world. In light of 2003’s Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC7), which established more stringent hypertension guidelines, many optometrists are taking a more aggressive approach to checking blood pressure.
| Hypertension Guidelines: |
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“Every doctor should check blood pressure, regardless of specialty,” said Nicky R. Holdeman, OD, MD, FAAO, chief of medical services at the University of Houston College of Optometry. “Hypertension is the number one reason for physician visits. It’s a very common disease with optometric implications in everyday practice.”
Diabetes mellitus is another systemic disease that optometrists can have a hand in detecting and monitoring. Diabetes afflicts more than 16 million Americans, and diabetic retinopathy is the leading cause of blindness in those 25 to 74 years old, said Dr. Holdeman.
“The only way to help identify patients with hypertension, not to mention diabetes and hypercholesterolemia, is to actively screen for these disorders in-office,” said Alan G. Kabat, OD, FAAO, associate professor, Nova Southeastern University College of Optometry.
Hypertension: identifying risk
According to the JNC7 report, a new “pre-hypertension” level has added 45 million American adults to the 50 million diagnosed hypertensives. According to the report, cardiovascular disease risk begins at 115/75 mm Hg, doubles with each 20/10 mm Hg increment and increases in those 55 years and older.
Blood pressure of 120 to 139/80 to 89 mm Hg is the new pre-hypertension level with recommendations for health-promoting lifestyle modifications.
“One of the goals of the JNC7 guidelines is to identify a larger percentage of the population at risk for hypertension and its sequelae,” Dr. Kabat told Primary Care Optometry News in an interview. “This group of individuals must be made aware of their status, in addition to those with more severe hypertension who remain undiagnosed.”
Dr. Holdeman said the onset of essential hypertension usually occurs between 25 and 55 years of age. He said two in three adults older than 65 years have hypertension, and normotensive adults older than 55 have a 90% lifetime risk of developing elevated blood pressure. Dr. Holdeman lectured on both hypertension and diabetes at the Southwest Council of Optometry Meeting in Dallas.
Also at increased risk for hypertension are the following groups: African Americans, those with a family history of systemic hypertension or early cardiovascular disease, those with increased sodium intake, obese patients, patients with a sedentary lifestyle, those who consume excessive amounts of alcohol, smokers, those with a lower socioeconomic class, those with dyslipidemia, those with diabetes mellitus or glucose intolerance, men and postmenopausal women, and those with sleep disordered breathing and sleep apnea.
According to Andrew S. Gurwood, OD, FAAO, a Primary Care Optometry News columnist and an attending optometric physician at the Eye Institute of the Pennsylvania College of Optometry, it is very important for optometrists to be aware of their patients’ systemic health.
“Doctors need to recognize that there is a juxtaposition and an association between systemic disease and eye disease,” Dr. Gurwood told Primary Care Optometry News. “You have to be in tune with your patients’ overall physical health. This way, as you are going through your chairside exam, you are looking for these diseases from the minute you start talking to patients until the minute you are finished looking at the backs of their eyes.”
Dr. Gurwood said he believes in checking blood pressure routinely. “I put the cuff on everybody I can get the cuff on,” he said. “I have been pretty aggressive about measuring blood pressure, in case there are patients who slip through the cracks.”
According to Dr. Kabat, in-office blood pressure screenings are very important. “Blood pressure measurement is simple to perform and takes only seconds,” he said. “Ancillary personnel can easily be trained to obtain this information, either by conventional means or with an automated sphygmomanometer.”
Tests and treatment
Dr. Holdeman told the SWCO audience the American Optometric Association recommends that optometrists should be checking all patients for hypertension and be ready to counsel them on prevention and control of disease. He discussed the types of testing that may be used to screen for secondary causes of systemic hypertension or other risk factors. “Most lab tests are normal in uncomplicated essential (primary) hypertension,” he said.
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Fasting Plasma Glucose Test
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Dr. Holdeman said that the following tests are usually performed prior to initiating therapy to assess end-organ damage, screen for secondary causes of systemic hypertension and determine the presence of other risk factors: CBC, urinalysis, serum creatinine, serum K+, fasting plasma glucose, plasma lipids, electrocardiography, serum uric acid, chest X-ray and blood calcium.
He added that optional tests include creatinine clearance, 24-hour urinary protein, thyroid function tests and limited echocardiography.
In terms of treatment, Dr. Holdeman recommended that the patient be referred in a timely manner to a primary care physician for appropriate and aggressive management of both systolic and diastolic hypertension.
“The goal of therapy is to reduce the complications of high blood pressure by the least intrusive means possible. Authorities agree that patients with repeatable systolic blood pressures higher than 140 mm Hg and/or diastolic pressures greater than 90 mm Hg should be treated,” he said. “However, the risk for complications is determined not only by the level of blood pressure, but also by the presence or absence of target organ damage or other risk factors, such as diabetes mellitus or dyslipidemia. Consequently, therapy should be initiated based on individual risk stratification.”
Dr. Holdeman said lifestyle modifications have been shown to be effective in lowering blood pressure. In addition, lifestyle modifications also enhance the efficacy of antihypertensive drugs and decrease cardiovascular risk.
If these adjustments in lifestyle do not lower pressure, Dr. Holdeman said, drug therapy will be required. The major classes of drugs frequently employed include diuretics, beta-blockers, ACE inhibitors, calcium-channel blockers and angiotensin II receptor blockers, he said.
“Many patients with systemic hypertension will require two or more antihypertensive agents to effectively control their blood pressure, especially if their untreated blood pressure is more than 20/10 mm Hg above the goal blood pressure,” Dr. Holdeman said.
Diabetes management
Because of the high risk of blindness in relation to diabetes, optometrists must carefully watch for any signs of this disease.
“A patient could end up with a severe diabetic retinopathy, which will cause life-altering circumstances,” Dr. Gurwood said. “The optometrist should ask the patient when his or her blood sugar was last taken and when his or her last glycosylated hemoglobin was taken.”
Dr. Gurwood said optometrists need to know the signs of diabetic retinopathy as described by the Diabetic Retinopathy Study (DRS) and the Early Treatment of Diabetic Retinopathy Study (ETDRS).
These signs include micro-aneurysms, intraretinal hemorrhages, venous beading, intraretinal microvascular abnormalities, intraretinal edema, neovascularization of the disk (NVD), neovascularization elsewhere (NVE), and vitreous hemorrhage.
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LDL Cholesterol (bad cholesterol)
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“They should know that the second they see any of these signs, an appropriate referral should be made back to the primary care physician,” he said. “And if there are ocular signs that will require treatment, as they would in cases of diabetic retinopathy, a prompt referral should be made to the board-certified retinologist to rule out laser treatment when necessary.”
According to Albert D. Woods, MS, OD, FAAO, associate professor at Nova Southeastern University, there is now a “pre-diabetic” category, which would include patients with a fasting glucose level over 100.
“A certain percentage of patients with a fasting blood glucose level above 100 are going to have diabetes within 10 years,” he said.
Dr. Kabat said while testing for blood glucose and high cholesterol is more involved than checking for hypertension, it is still a good idea for optometrists to do this testing.
“Good screening devices such as the BioScanner 2000 [from QuickMedical, Snoqualmie, Wash.] and CardioChek [from HealthCheck Systems] are available and are very easy to operate,” he said. “Our students are all trained to perform these procedures in hopes that they will be able to provide the highest level of care for their patients.”
Another blood glucose monitoring device available for home and in-office testing is OneTouch Ultra by Lifescan/Johnson & Johnson.
Dr. Holdeman said that diabetic screenings should occur more frequently than the standard protocol suggests for patients who meet the following criteria: are obese, have a first-degree relative with diabetes mellitus, are members of a high-risk ethnic population, have delivered a baby weighing more than 9 pounds or have been diagnosed with gestational diabetes mellitus, are hypertensive, have dyslipidemia or have had impaired glucose tolerance or impaired fasting glucose in the past.
Hypercholesterolemia
High cholesterol is another disease that optometrists should be watching for, Dr. Gurwood said.
“Hypertension and hypercholesterolemia could result in stroke and myocardial infarction, if not blindness, from embolism-forming plaques secondary to these particular diseases,” he said.
Because of these dangers, Dr. Gurwood said the optometrist should be very watchful for signs of hypercholesterolemia. “The practitioner should know what emboli look like and what cotton-wool patches are, and he or she should be able to recognize arcus sinilis, or the other signs of lipid disease,” he said
Dr. Gurwood said other signs include intraretinal superficial nerve fiber layer hemorrhages, tortuous vessels that show knicking and increased arterial light reflex.
For Your Information:
- Nicky R. Holdeman, OD, MD, FAAO, is chief of medical services at the College of Optometry, University of Houston. He can be reached at 505 J. Davis Armistead Bldg., Houston, TX 77204-2020; (713) 743-1886; fax: (713) 743-0965; e-mail: nrholdeman@uh.edu.
- Alan G. Kabat, OD, FAAO, is an associate professor at Nova Southeastern University. He can be reached at College of Optometry, 3200 S. University Drive, Fort Lauderdale, FL 33328; (954) 262-1470; fax: (954) 262-1818; e-mail: kabat@nova.edu.
- Andrew S. Gurwood, OD, FAAO, is an attending optometric physician at the Eye Institute of the Pennsylvania College of Optometry. He can be reached at the Eye Institute, Pennsylvania College of Optometry, 1201 W. Spencer St., Philadelphia, PA 19141; (215) 276-6134, ext. 6134; e-mail: agurwood@pco.edu.
- Albert D. Woods, MS, OD, FAAO, is an associate professor at Nova Southeastern University. He can be reached at 575 Crandon Blvd., Key Biscayne, FL 33149; (954) 262-1478; fax: (662) 796-9912; e-mail: albert@hpd.nova.edu.