Early recognition of diabetes complications
Early recognition of diabetes complications
January 5, 2009
Lyle Mitzner, MD
The primary goal of diabetes management is to prevent end-organ complications. Most diabetes-related visits with a health-care professional focus at least in part on blood sugar levels and hemoglobin A1c (HbA1c). As a diabetologist, I try to put things into perspective from time to time. I tell patients that a blood sugar level of 200 or 300 mg/dL or an HbA1c of 9% is not bad in and of itself; it's the long-term consequences on the microvascular system that we must work to prevent. I next explain that the damage to the body caused by diabetes occurs on a microscopic level. Long before a patient experiences deficits in visual acuity, burning or stabbing foot pain from neuropathy, or symptoms of end-stage renal disease or uremia, it is my job to detect the earliest manifestations of these conditions. This article will focus on when and how to screen for and treat retinopathy, neuropathy, and nephropathy from the perspective of a health-care professional providing primary diabetic care.
The importance of ophthalmologic care
Figure 1. Funduscopy showing damage from diabetic retinopathyTo prevent retinopathy (Figure 1), a leading cause of blindness in the Western world, the most important thing to do is educate patients about the necessity of regular dilated-eye exams. Examining the fundi under direct ophthalmoscopy in your office will reinforce to patients the importance of this aspect of their preventive diabetes eye care; however, I always stress that the small part of the fundus I can see on a non-dilated eye exam might look all right, but a dilated-eye exam and a full retinal exam by an ophthalmologist should be done on a yearly basis.
The worst thing to do would be to reassure a patient incorrectly of a normal eye exam, when real pathology exists in an area you cannot see with the tools available in your office. I have also been humbled by some of the severe retinal findings reported by an ophthalmologist after I have noted “normal” findings on my own exam. Practicing at a tertiary-care center, I see many patients who have been reassured by previous eye specialists that their “eyes are fine,” only to have our ophthalmologist find severe retinopathy requiring urgent laser photocoagulation therapy.
Last, I emphasize to patients that visual loss in diabetes can be delayed and many times avoided if retinopathy is detected at its earliest stages. Underscoring the relationship between overall glycemic control (based on the HbA1c) and developing or worsening retinopathy also encourages patients to follow up with their eye doctor.
Look for signs of neuropathy
Other parts of the physical exam aimed at preventing end-organ complications are the neurologic and foot exams. One thing patients fear when they come to grips with their diabetes diagnosis is limb amputation. Many patients remember from childhood a relative who had diabetes and was an amputee, or they have current acquaintances who have required amputations. Because amputees almost always have severe peripheral vascular disease as well, they are likely to also conjure up in patients' minds other end-organ diseases, such as MI or stroke.
Figure 2. Semmes-Weinstein monofilament test sitesI spend part of an appointment reviewing with patients the benefits of at-home foot exams. While examining their feet in the office, I reinforce to them how easy and quick the process is and how they can do the same exam at home on a regular basis. Many of our patients have trouble bending over to see the bottoms of their feet because of obesity, arthritis, or a combination of the two. For them, I recommend placing a handheld mirror on the floor or leaning it up against a wall, so that they can inspect their feet, soles, and toes. If a patient has impaired vision, I try and encourage a loved one/relative or visiting nurse (who often has had to accompany the patient to the visit and is present in the exam room) to inspect the feet on a regular basis—usually daily during dressing or bathing. Patients often ask: “What am I looking for?” The short answer is: “Anything you think is dangerous or shouldn't be there.” But scratches, bleeding, or cracks in the skin that don't appear to be healing should be shown to a health-care professional immediately. The monofilament exam test helps determine which patients are at even higher risk for ulcers and amputation; those who cannot feel the monofilament at the sites shown in Figure 2 should be told in detail that just as they can't feel the filament, they might not feel a cut, ulcer, pebble, or even a metal nail touching their foot. The foot exam also is an opportunity to refer appropriate patients to a podiatrist for help with more suitable shoes and better overall foot hygiene (e.g., nail trimming and callus management).
The most important aspect of the foot exam is to do it; I cannot emphasize this enough. I am often stunned when a new patient with a history of diabetes emerges from the changing area wearing only an examination gown and socks on their feet. When questioned, these patients invariably report that their feet were not included in regular examinations by previous clinicians and that they do not perform home foot exams on a routine basis. This immediately tells me that the patient has not been taught about the importance of regular foot examination—performed by either the provider or the patient. The reason I do a foot exam is to reinforce its importance to the patient. An early-stage abrasion or foot ulcer is certainly easier to treat than a deeper one, and it's less likely to result in surgery and/or amputation. One of the more rewarding experiences I've had came when a longtime patient questioned why I had not examined his feet. He was right in demanding a foot exam, and this told me that I had been effective at communicating the importance of the foot and neurologic exams at previous visits.
Keeping an eye on kidneys
Another major concern on the minds of patients who have any personal or familial experience with diabetes is kidney disease and dialysis (Figure 3). All patients who have had diabetes (type 1 or 2) for at least five years should have urine microalbumin testing on a yearly basis.The rationale for this is that the earliest damage from diabetic nephropathy can be detected by increased spillage of albumin in the urine. The routine urine dipstick used by many clinicians is an insensitive test for this, detecting urine protein only when the excretion rate is >300 mg/day—about 10-15 times the normal rate in someone with a pair of healthy kidneys. A spot or random urine protein measurement of >30 µg albumin/mg urine creatinine on a persistent basis almost always indicates early diabetic kidney disease. I use this test and the rationale for its use as a paradigm for most end-organ diseases associated with diabetes. I explain to patients that the usual urine test or measure of overall kidney function with a serum creatinine will pick up kidney disease only at a more advanced stage. We have known for many years the benefits of ACE inhibitors and angiotensin receptor blockers on slowing the progression of diabetic nephropathy in patients with microalbuminuria (i.e., urine microalbumin/creatinine ratios of >30 µg/mg). Therefore, detecting damage to the nephron at an early stage, like early detection of neuropathy and eye disease, enables us to target individual patients who may benefit from specific interventions, which may be behavioral, medical, or both.
Monitor for macrovascular disease
While there is no formal recommendation for screening for macrovascular disease, this condition likely accounts for the greatest health-care costs, morbidity, and mortality related to diabetes and warrants special mention. Questioning patients about cardiovascular disease symptoms and looking for signs on examination should be part of the regular follow-up visit. Weak pulses on the foot exam should alert the clinician to the possibility of ischemic heart disease. More important, adherence to accepted guidelines for LDL lowering and BP management should be emphasized to all patients with diabetes.
When I encounter a patient who smokes and is coming to me for better blood sugar control or an elevated HbA1c, I try and put things in perspective. I caution the patient that smoking increases the risk of or worsens all the end-organ diseases we as endocrinologists/diabetologists work so hard to prevent. While we certainly need to minimize risks for eye, nerve, and kidney disease in our smoking and nonsmoking patients alike, this approach sometimes makes patients realize the serious damage that smoking does to multiple organs. I am almost never the first health-care provider to tell them this, but hearing it again from a new clinician sometimes opens patients to trying new behavioral and medical therapies for smoking cessation. The willingness to try new treatments, to see a new endocrinologist with either a new diagnosis of diabetes, or to seek care for this chronic condition in a new setting are all positive signs of a patient's resolve to avoid end-organ damage.
Back to basics
Let's not forget about blood sugar control and HbA1c. We have known for years now, since the Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS), that better blood sugar control will slow the progression of diabetes complications and even prevent them entirely in some patients. So while we educate our patients on better detection and treatment of diabetes complications, we still need to do what most of us do best and that is to make sure that blood sugar control is as close to accepted American Diabetes Association and or American Association of Clinical Endocrinologists guidelines as possible.