Presumed Ocular Histoplasmosis (POHS)

Presumed Ocular Histoplasmosis (POHS)
SYMPTOMS Typically asymptomatic
Can report central vision loss and metamorphopsia with the presence of a choroidal neovascular membrane
SIGNS Typically bilateral
Triad of signs: Chorioretinal scars in the macula region and mid-periphery which are known as histo spots, Peripapillary atrophy, Maculopathy (development of a choroidal neovascular membrane)
A key finding is the absence of a vitritis and uveitis
WORK-UP Full eye exam with dilated retinal exam, OCT analysis of the macula, OCT-Angiography, Fluorescein Angiography, Indocyanine Green Angiography, Fundus photos, Infrared photos, Watzke-Allen test, Macular photostress test, Amsler grid
TREATMENT Give take home Amsler grid in order to monitor for change
Presumed ocular histoplasmosis without a choroidal neovascular membrane: Needs to be monitored. There is no ocular treatment
Presumed ocular histoplasmosis with a choroidal neovascular membrane: Refer to a retinal specialist ASAP for treatment
FOLLOW-UP Presumed ocular histoplasmosis without a choroidal neovascular membrane: Should see patient back in 6-12 months
Once choroidal neovascular membrane is treated by the retinal specialist and the retina/macula is stable, the patient should be seen back in 3-6 months
ETIOLOGY Inflammatory disease of the choroid due to inhalation of fungal spores (Histoplasma capsulatum)
DIFFERENTIAL DX Ocular toxoplasmosis, Ocular toxocariasis, Ocular sarcoidosis, Multifocal chorioretinitis, Punctate inner choroidopathy
NOTES Histoplasma capsulatum is endemic in the Ohio and Mississippi river valley
Presumed Ocular Histoplasmosis (POHS): Fundus photo demonstrating histo spots and peripapillary atrophy