Severe, Atypical Toxoplasmosis

History of Present Illness (HPI)

A 64-year-old man presents complaining of decreased vision in his right eye (OD). He is positive for human immunodeficiency virus (HIV) and has a history of cytomegalovirus (CMV) retinitis, left eye (OS), complicated by recurrent retinal detachment and ultimately phthisis bulbi OS.

Questions to Ask

• How long has this been going on for?

• Is there any pain?

• Have you had recent illnesses or hospitalizations?

• Are you taking your HIV medications? What is your current CD4 count?

• When was the last time you saw an infectious diseases doctor?

He responds that his vision has been declining for a few weeks. There is no pain. He has HIV medications at home but hates taking pills and takes them “when I feel like it.” He has not seen his infectious diseases doctor in about a year.

Assessment

• Focal retinitis OD with adjacent retinal vasculitis

• Phthisis bulbi OS secondary to CMV retinitis complicated by retinal detachment

Differential Diagnosis

• CMV retinitis

• Atypical toxoplasmosis

• Other herpetic retinitis (herpes simplex virus [HSV], varicella zoster virus [VZV])

• Syphilis

Working Diagnosis

• CMV retinitis OD

• Although the patient’s exact immune status is unknown, he has HIV and admits noncompliance with highly active antiretroviral therapy (HAART). One can safely assume that he is immunocompromised. He is monocular and has already lost the left eye to CMV retinitis. He now presents with decreased vision and active retinitis without vitritis or anterior chamber (AC) reaction in the right eye. Although the lack of hemorrhages in the right eye and the unusual morphology of the retinitis lesion are atypical for CMV, he is at high risk of CMV in this eye.