Dr. Kiran Shah: a Case of Non-Resolving Diabetic Macular Edema
CASE OVERVIEW
Diabetic retinopathy and diabetic macular edema are common microvascular problems in diabetic individuals that can cause an abrupt and devastating loss of vision, leading to blindness. Thiazolidinediones are insulin sensitizers with PPAR- γ (Peroxisome Proliferator-Activated Receptor) activity that has been linked to increased fluid retention. OCT is a new research method for in vivo imaging of the human retina that provides cross sectional information about retinal topography and tissue structure with a longitudinal resolution of less than 10 microns. It is utilized clinically for quantification and classification of macular edema. Because of its superior reproducibility and agreement with other central macula measurements, central foveal thickness is the most essential metric in macular thickness assessment. It’s also more closely linked to visual acuity, with the fovea having the most densely clustered cones.
Dr. Kiran Shah has came across such case, when a 57 year old male, non-addict was referred to him for evaluation and further management of non-resolving macular edema. The patient was a k/c/o Type 2 DM since 2 year with no history of hypertension and 19.25kg/m2 BMI. He had c/o blurred vision in both eyes since a month and had been evaluated by a retina consultant and diagnosed with macular edema.
DIAGNOSIS
His examination revealed P- 72/min regular, BP – 130/80mmHG right arm supine position. There was no edema in feet. Blood Investigations at the Hospital revealed a FBS -102mg/dL, PLBS- 139mg/dL, and HbA1c -6.2%. The renal parameters were S. Creatinine- 0.7mg/dL, eGFR: > 90mL/min/1.73m2 with normal UACR. His lipid profile showed T. Cholesterol – 132mg/dL, LDL- 79mg/dL, TG- 57mg/dL, and HDL-42 mg/dL.
It was unclear if this is a case of refractory diabetic macular edema because even after the treatment, the previously diagnosed macular edema did not resolved.
TREATMENT
Patient was previously prescribed by endocrinologist with Amaryl 2 mg twice a day and one more medicine for weight gain, which turned out to be T. Pioglitazone 15mg three times a day (45mg/day for a period of 1 year) for the management of diabetes mellitus.
The OCT revealed loss of foveal contour , with cystoid spaces and sub-retinal fluid in both the eyes. (Figure 1)
The treatment history that is Pioglitazone has been missed by both endocrinologist and treating retina specialist. Due to the known consequences of Pioglitazone, the final diagnosis of Pioglitazone induced Diabetic Macular edema was confirmed. Pioglitazone was stopped.
Results
A follow-up OCT done after 3 months revealed resolution of edema in both eyes. (Figure 2)
Figure 2.
Pioglitazone therapy is related to a significant increase in macular thickness although at times this increase may be subclinical in terms of visual acuity. Pioglitazone is usually taken once a day at a dose of 15 mg under vigilance. Avoid greater doses and have I have little experience with smaller ones such as 7.5 mg. In clinical practice, diabetic macular edema has been linked to patients who develop pioglitazone-induced pedal edema. The index patient, on the other hand, developed macular edema in both eyes but no pedal edema.
Pioglitazone should only be used in triple medication combinations in persons who actually need all three drugs, rather than being administered as a single tablet to start therapy, commonly prescribed in India, and should never be up-titrated to BD or TDS. ( Pioglitazone 30mg or 45mg respectively). Because of the increased risk of fluid retention, discourage using pioglitazone with insulin. Ongoing DR has an effect of retinal thickness, in patients with established DR irrespective of the stage, avoid or prefer not to prescribe pioglitazone. OCT is a good way to see the retina up close and is sensitive enough to detect subclinical changes in macular thickness that aren’t reflected in visual acuity.
