What workup is indicated for a 66‑year‑old patient presenting to the emergency department with new‑onset blurry vision after starting high‑dose prednisone for an autoimmune hepatitis flare (and associated primary sclerosing cholangitis)?

Workup for New-Onset Blurry Vision in a Patient on High-Dose Prednisone

This patient requires immediate ophthalmologic evaluation with slit-lamp examination to rule out steroid-induced cataracts and glaucoma, alongside urgent assessment of hyperglycemia severity and screening for diabetic retinopathy.

Immediate Ophthalmologic Assessment

Patients receiving prednisone must undergo eye examinations for cataracts and glaucoma periodically during treatment 1. Given the acute presentation of blurry vision after starting high-dose steroids, this is not routine surveillance but an urgent evaluation:

• Slit-lamp examination is required to confirm anterior or posterior uveitis, cataracts, or other structural abnormalities 1
• Intraocular pressure measurement to detect steroid-induced glaucoma 1
• Fundoscopic examination to assess for diabetic retinopathy if hyperglycemia is confirmed (see below)
• Visual acuity testing to quantify the degree of impairment

The ophthalmologic evaluation should occur within 24 hours given the acute symptom onset and potential for vision-threatening complications 1.

Metabolic Workup for Steroid-Induced Hyperglycemia

The mention of "elevated glucose" suggests steroid-induced diabetes or worsening of pre-existing glucose intolerance. High-dose corticosteroids (≥15 mg/day prednisone) given for 2-4 weeks or longer represent the threshold where metabolic complications become clinically significant 2:

• Point-of-care glucose or stat basic metabolic panel to quantify hyperglycemia severity
• Hemoglobin A1c to distinguish new-onset steroid-induced diabetes from pre-existing uncontrolled diabetes
• Urinalysis for glucose and ketones to assess for diabetic ketoacidosis risk
• Serum osmolality if glucose is markedly elevated (>400 mg/dL) to evaluate for hyperosmolar hyperglycemic state

Blurry vision in the setting of acute hyperglycemia can result from osmotic changes in the lens causing refractive error shifts, which may be reversible with glucose control. However, if diabetes has been present longer than suspected, diabetic retinopathy must be excluded.

Hepatic and Autoimmune Disease Monitoring

While the primary concern is ophthalmologic and metabolic, the underlying PSC/AIH flare warrants concurrent assessment:

• Liver function tests (ALT, AST, alkaline phosphatase, bilirubin, INR) to assess treatment response 3
• Complete blood count to monitor for azathioprine-related cytopenias if the patient is on combination therapy 1, 3
• Serum IgG level as complete normalization of both transaminases and IgG is required for treatment success 3

Neurologic Considerations

Although less likely given the clinical context, steroid-induced complications can include:

• Brief neurologic examination to exclude posterior reversible encephalopathy syndrome (PRES) if there are associated headaches, altered mental status, or seizures
• Blood pressure measurement as steroid-induced hypertension can contribute to hypertensive retinopathy

Common Pitfalls and How to Avoid Them

• Do not attribute blurry vision solely to hyperglycemia without ophthalmologic examination—steroid-induced cataracts and glaucoma require specific treatment and can cause permanent vision loss if missed 1
• Do not delay ophthalmology referral for outpatient follow-up; acute vision changes in a patient on high-dose steroids warrant same-day or next-day evaluation 1
• Do not assume the glucose elevation is mild—steroid-induced diabetes can present with severe hyperglycemia requiring insulin therapy
• Screen for other steroid complications while the patient is in the ED: assess for signs of infection (steroids mask fever), gastrointestinal bleeding (peptic ulcer risk), and psychiatric symptoms 3

Algorithmic Approach

1. Obtain point-of-care glucose immediately → if >250 mg/dL, check for ketones and consider diabetic emergency
2. Arrange urgent ophthalmology consultation (within 24 hours) → slit-lamp exam, tonometry, fundoscopy
3. Send laboratory studies: comprehensive metabolic panel, HbA1c, CBC, liver panel, IgG
4. Initiate glucose management if hyperglycemia confirmed (insulin if severe, oral agents if mild-moderate)
5. Consider steroid dose adjustment in consultation with hepatology—the American College of Gastroenterology recommends tapering corticosteroids to ≤10 mg/day as quickly as the clinical condition allows 2, though this must be balanced against the need to control the AIH/PSC flare 1

Treatment Implications

If steroid-induced complications are confirmed, the combination regimen of prednisone and azathioprine is preferred because of its lower frequency of corticosteroid-related side effects 1, 4, 3. For patients with PSC/AIH overlap, UDCA in combination with an immunosuppressive regimen (usually prednisolone and azathioprine) is adequate medical treatment 1, allowing for lower steroid doses while maintaining disease control.