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Optometrists embrace growing role as systemic disease consultants
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As primary eye care providers, optometrists are becoming more comfortable with their expanding role in the detection and management of systemic diseases and how they relate to the eyes. Four practitioners talked to Primary Care Optometry News about the most common tests they order in these cases and how they interact with laboratories and hospitals to get the best care for their patients.
Be sure before ordering
 Nicky R. Holdeman |
“Lab tests should confirm clinical suspicions and assist in atypical cases, but they should never replace the two most valuable diagnostic tools that we have available to us – a detailed medical history and a complete clinical examination,” Nicky R. Holdeman OD, MD, told PCON in an interview. “Listening to a patient, formulating hypotheses and verifying the plausibility of each by asking specific questions will progressively get you to the heart of the problem. The most common charting failure is poor documentation of pertinent positives and negatives.
“Unfocused testing is a financial and personal burden to the patient and can lead to wasted and misleading information for the doctor,” Dr. Holdeman continued. “For example, 5% to 10% of the population is HLA-B27 positive; consequently, if eye care providers ordered a HLA-B27 on all patients with uveitis, at least that many uveitis patients would come back positive, despite the fact that their ocular inflammation may be due to another cause. In fact, few, if any, ancillary tests will ever diagnose a disease that is not evident clinically.”
Dr. Holdeman added that clinicians should be aware that certain medications and diseases can affect lab results. For instance, patients with systemic lupus erythematosus can yield a false positive on the RPR test for syphilis.
When to order blood tests
 Bruce E. Onofrey |
Bruce E. Onofrey, OD, RPh, FAAO, FOGS, told PCON that practitioners should clearly document why they are ordering lab tests. “It’s important to document a reason for the test and an ICD-9,” he said.
Dr. Onofrey said the two most common blood tests he orders are the sedimentation rate and non-ultra C-reactive protein (CRP) to rule out possible temporal arteritis.
“A symptomatic elderly patient with significant headache or temporal tenderness or tender, palpable blood vessels, vision loss or diplopia should have these tests done,” Dr. Onofrey said. “If they have a sed rate of 47 or greater and they have a non-ultra CRP greater than 2.45 they have roughly a 98% positive chance of having temporal arteritis.”
A patient with a periocular or subconjunctival hemorrhage associated with a significant history of bleeding, which would include new bruising or repeated nose bleeds, would need a CBC, INR (prothombin time) and a liver panel to rule out a cause of abnormal bleeding, Dr. Onofrey continued.
If a person is suspected of having myasthenia gravis, Dr. Onofrey said he would order a panel of tests.
Also, Dr. Onofrey said he orders blood tests for patients who are about to have a CT scan or MRI that involve injecting dye into the body. “You have to get a creatinine study to determine if they have normal renal function or else they can’t be administered the dye,” he explained.
The sed rate is the most common test John A. McGreal, OD, orders for his patients, many of whom are elderly. He orders the test if a person older than 65 experiences a sudden loss of vision.
“Most of these patients have anterior ischemic optic neuropathy,” he said. “Sometimes that condition is coming from a systemic disease called giant cell arteritis. If you suspect the patient older than 65 with an abrupt loss of vision in one eye has an optic nerve problem, you have to order a stat sed rate, a blood test that takes 1 hour. The patient needs to be sent to the nearest hospital. In this case, you don’t want to send them to a lab, because it would take until the next day to get the results.”
 James Fanelli |
Blood tests also may help confirm diabetes, as patients are often found to have evidence of diabetic retinopathy during the course of an eye exam but may not know that they have diabetes, Dr. Holdeman said. “The best test to order is a fasting blood glucose,” he said.
Dr. Holdeman said an oral glucose tolerance test is not recommended for routine use because of the challenges of performing and interpreting the test. “However, if a high-risk patient has a normal fasting plasma glucose, a glucose challenge test may aid in the early detection of diabetes,” he said.
James Fanelli, OD, FAAO, said the most common blood test ordered through his office is for hypercholesterolemia.
“I see a lot of patients with significant arteriolar sclerotic retinopathy,” he said. If patients do not know their cholesterol level, he orders the test and forwards the results to the primary care provider.
Taking blood pressure
Dr. Holdeman said it might be useful to get a blood pressure reading in the office before deciding on what kind of blood test to order.
A patient “may be experiencing an ocular complication of an unknown, underlying systemic disease, such as a retinal vein occlusion or diabetic macular edema,” he said. “Obviously, measuring the patient’s blood pressure in the office is a straightforward test, and a blood pressure greater than 140/90 mm Hg is considered hypertensive. A fasting lipid profile can identify patients who may have elevated cholesterol levels, elevated triglycerides or low high-density lipoproteins. Each of these conditions increases the risk of cardiovascular disease.”
Adenoviruses and upper respiratory infections
Dr. McGreal said he uses the Adeno Detector by Rapid Pathogen Screening (Sarasota, Fla.) in the office to diagnose ocular adenoviruses. “It’s a simple test,” he said. “You give patients a drop of topical anesthesia, obtain a small sample of tears and put it into a test cassette and it tells you if they have adenovirus or not in 10 minutes,” he said. “Adenovirus causes conjunctivitis, but also often causes upper respiratory infections. It can cause an eye problem or it can be an ear, nose and throat problem.
“The importance of knowing if patients actually do or don’t have adenovirus helps guide you in providing advice on whether or not they should return to work,” he continued, “especially if they are a school teacher, day care worker or health care worker. They are infectious for the first 8 days. It also helps guide you in proper use of pharmaceuticals.”
Ordering imaging studies
Dr. Onofrey said he orders CT scans to evaluate a patient’s periocular sinuses for inflammation as well as Graves’ disease patients’ muscle cones. He said he would order an MRI in optic neuritis patients to rule out demyelinating disease.
For uveitis, Dr. Onofrey said he would also order a chest X-ray to rule out tuberculosis or sarcoid. “We do a lower back X-ray on patients who may have ankylosing spondylitis,” he added.
“About 60% of uveitis is limited to the eyes; in the other 40% of patients, an underlying systemic disease, often autoimmune origin, can be identified,” Dr. Holdeman said. “Clinicians who use patient demographics, signs and symptoms associated with certain types of uveitis as a guide for determining which tests to order should have better success than those performing an unfocused ‘million-dollar’ workup.”
Dr. Holdeman – who said the most common systemic conditions in the eye care practitioner’s office needing an imaging study are thyroid eye disease and optic neuritis associated with multiple sclerosis – said he would leave it to the doctors who will manage the disease to order the images.
“I personally prefer to have the patient’s general physician or even a neuro-ophthalmologist order the tests,” he said. “Knowing which test (e.g., MRI, CT, MRA, MRV, etc.) will reveal the most information, localizing where to image, the size of the cuts, proper contrast agents and use of orbital fat suppression can be critical in obtaining the proper data.”
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Ordering cultures
Dr. Onofrey said he does not culture often to rule out systemic disorders. However, a person who has an orbital cellulitis would require a blood culture, he said.
For culturing, some practitioners prefer culturettes.
“The Amies transport medium (without charcoal) may be a useful alternative to direct inoculation onto blood agar,” Dr. Holdeman said. “My personal preference when culturing for external diseases such as bacterial keratitis is to use small calcium alginate swabs and directly plate onto blood, chocolate and Sabouraud’s media. I typically moisten the swabs with thioglycolate broth prior to swabbing the tissues.”
Setting up for tests, establishing bond with labs
Believe it or not, the experts say becoming a systemic disease consultant is as easy as making a phone call.
Labs are in the business of making money, and they are glad to take in more patients, these sources say. These labs also will supply practitioners with necessary materials, such as X-ray order forms or culture plates, most times at no charge.
“You can set up an account with a lab rather easily,” Dr. Fanelli said, adding that giving the lab the proper information is key. “They need to have a diagnosis, because that’s how the lab gets paid. It’s straightforward in setting up an account.”
Dr. Fanelli noted that providing the lab with a “rule-out” diagnosis is generally not acceptable. “However, if you are concerned about a particular condition, you can use that condition as a differential diagnosis and order accordingly.”
For more information
- Nicky R. Holdeman OD, MD, 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. Dr. Holdeman has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Bruce E. Onofrey, OD, RPh, FAAO, FOGS, is director of primary eye care services, Lovelace Medical Center, Albuquerque, N.M., and a member of the Primary Care Optometry News Editorial Board. He can be reached at Lovelace at Journal Center, 5150 Journal Center Blvd., NE, Albuquerque, NM 87109; (505) 275-4226; e-mail Eyedoc3@aol.com. Dr. Onofrey has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- John A. McGreal, OD, can be reached at Missouri Eye Associates, 11710 Old Ballas Rd., St. Louis, MO 63141; (314) 569-2020; fax: (314) 569-1596; e-mail: jamod1@aol.com. Dr. McGreal is a member of the Rapid Pathogen Screening Advisory Board.
- James Fanelli, OD, FAAO, can be reached at 5311 S. College Road, Wilmington, NC 28412; (919) 452-7225; fax: (910) 452-7229; e-mail: faneleye@aol.com. Dr. Fanelli has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.