What is the best approach to manage a patient with type 2 diabetes mellitus, essential hypertension, and mixed hyperlipidemia presenting with blackouts, dizziness, and vision disturbances?

Urgent Ophthalmologic Evaluation and Comprehensive Workup Required

This patient requires urgent referral to ophthalmology within 1 month for dilated fundoscopic examination to evaluate for diabetic retinopathy, given his visual symptoms of "seeing stars" in one eye, which may indicate proliferative diabetic retinopathy or other vision-threatening complications. 1

Immediate Ophthalmologic Assessment

• Urgent ophthalmology referral is mandatory for any patient with diabetes presenting with visual disturbances, as this may represent center-involving diabetic macular edema, proliferative diabetic retinopathy, or vitreous hemorrhage 1
• The visual symptom of "seeing stars" (photopsia) combined with his 2-month duration warrants evaluation within less than 1 month per international guidelines for suspected severe nonproliferative or proliferative diabetic retinopathy 1
• Annual dilated comprehensive eye examinations should have been performed starting at diagnosis for all type 2 diabetes patients, and this patient's visual symptoms indicate he may have missed critical screening 2

Essential Laboratory Testing

Order the following labs immediately:

• Hemoglobin A1c to assess glycemic control over the past 3 months, with target <7% 2, 3
• Comprehensive metabolic panel including serum creatinine and eGFR to evaluate renal function (critical before adjusting metformin dose and to assess for diabetic nephropathy) 3
• Fasting lipid panel to verify LDL is at goal <100 mg/dL given his cardiovascular risk 2
• Complete blood count to evaluate for anemia (which can cause dizziness) and rule out hematologic abnormalities 4
• Serum glucose to assess for hypoglycemia or severe hyperglycemia as potential causes of his symptoms 1
• Thyroid stimulating hormone (TSH) as thyroid dysfunction can cause dizziness and is more common in diabetics 5, 6
• Vitamin B12 level given his metformin use, as deficiency can cause neuropathy and dizziness 1

Cardiovascular and Neurologic Evaluation

The combination of blackouts and dizziness requires systematic evaluation:

• Orthostatic vital signs (blood pressure and heart rate supine and after 1-3 minutes standing) to evaluate for orthostatic hypotension, which is common with his antihypertensive regimen and may indicate autonomic neuropathy 1, 7
• 12-lead electrocardiogram to evaluate for arrhythmias (atrial fibrillation, bradycardia, heart block) that could cause syncope 8, 7
• Detailed history using timing and triggers approach: Determine if episodes are spontaneous vs. triggered, duration, associated symptoms, and whether true loss of consciousness occurs vs. near-syncope 7
• Cardiovascular examination focusing on heart rhythm, murmurs, and carotid bruits given his multiple cardiovascular risk factors 7

Critical Medication Review

His current antihypertensive regimen may be excessive:

• He is on triple antihypertensive therapy (amlodipine 10 mg, hydrochlorothiazide 25 mg, lisinopril 40 mg), which increases risk of orthostatic hypotension and syncope 4, 9
• Amlodipine can cause dizziness (3.4% incidence at 10 mg dose) and peripheral edema (10.8% at 10 mg), and these side effects are more common in patients on multiple antihypertensives 4
• Check blood pressure control: Target is <130/80 mmHg per current guidelines, but overtreatment causing hypotension may explain his symptoms 2, 9

Evaluate for hypoglycemia risk:

• He is on triple diabetes therapy (glipizide ER 10 mg, Basaglar 15 units daily, pioglitazone 30 mg, metformin 750 mg BID), placing him at significant hypoglycemia risk 1, 3
• Glipizide (sulfonylurea) is a major hypoglycemia risk, especially in combination with basal insulin 1
• Review his home glucose log to identify patterns of hypoglycemia that could cause blackouts and dizziness 3

Diabetic Neuropathy Assessment

Screen for autonomic and peripheral neuropathy:

• 10-gram monofilament testing of both feet to assess for diabetic peripheral neuropathy 1
• Assess for symptoms of autonomic neuropathy: gastroparesis, erectile dysfunction, bladder dysfunction, and cardiovascular autonomic neuropathy (resting tachycardia, exercise intolerance) 1
• Autonomic neuropathy can cause orthostatic hypotension and dizziness independent of medication effects 1

Vestibular Examination

If cardiovascular and metabolic causes are excluded:

• Dix-Hallpike maneuver to evaluate for benign paroxysmal positional vertigo if dizziness is triggered by head movements 7
• HINTS examination (Head Impulse, Nystagmus, Test of Skew) if acute vestibular syndrome is suspected, though this is less likely given the 2-month duration 7
• However, the visual symptoms ("seeing stars") make ophthalmologic pathology more likely than primary vestibular disease 5, 6

Blood Pressure Optimization Strategy

Given his symptoms and medication burden:

• Target blood pressure should be <130/80 mmHg, but avoid overtreatment causing symptomatic hypotension 2
• Consider reducing or discontinuing hydrochlorothiazide if blood pressure is at goal and orthostatic hypotension is present 9
• Lowering blood pressure decreases diabetic retinopathy progression, but strict goals (systolic <120 mmHg) provide no additional benefit and increase adverse effects 1

Glycemic Control Assessment

His complex diabetes regimen requires optimization:

• Perform A1C testing quarterly since his therapy includes insulin and he may not be meeting glycemic goals 3
• If A1C is ≥9%, he may benefit from insulin intensification rather than multiple oral agents 1
• Metformin should be continued as long as eGFR ≥30 mL/min/1.73 m² and is the preferred agent 3
• Consider discontinuing or reducing glipizide if hypoglycemia is documented, as sulfonylureas have high hypoglycemia risk with minimal cardiovascular benefit 1

Common Pitfalls to Avoid

• Do not attribute visual symptoms to "floaters" or benign causes without dilated fundoscopic examination—this patient has multiple risk factors for proliferative diabetic retinopathy 1
• Do not order brain MRI as first-line testing for dizziness without completing cardiovascular and metabolic evaluation first, as these are more common causes in diabetic patients 5, 7
• Do not assume blackouts are seizures without considering cardiac syncope, hypoglycemia, and orthostatic hypotension first—the history is the most important diagnostic tool 8
• Do not continue aggressive blood pressure lowering if orthostatic hypotension is present, as this increases fall risk and does not provide additional retinopathy benefit below 130/80 mmHg 1, 2