histoplasmosis retinitis

Histoplasmosis Retinopathy: A Rare but Serious Eye Condition

Histoplasmosis retinopathy, also known as presumed ocular histoplasmosis syndrome (POHS), is a rare eye condition caused by the fungus Histoplasma capsulatum. This fungus can be inhaled and then travel to the eyes, causing inflammation and scarring.

Symptoms and Characteristics

• Asymptomatic: In most cases, POHS does not produce any noticeable symptoms.
• Scarring: The condition causes atrophy (wasting) around the optic nerve and multiple scars, called histo spots, in the choroid. These scars can appear as small punched-out yellow spots at the back of the eye.
• New Blood Vessel Growth: Neovascularization, or new blood vessel growth, can occur adjacent to a histo spot, which can lead to complications such as hemorrhagic subfoveal fluid.

Causes and Risk Factors

• Histoplasmosis Infection: POHS is caused by the fungus Histoplasma capsulatum, which can be inhaled and then travel to the eyes.
• Geographic Location: The condition is most commonly found around the Mississippi and Ohio River valleys, where histoplasmosis is endemic.

Diagnosis and Treatment

• Dilated Eye Exam: A dilated eye exam is necessary to assess POHS symptoms in greater detail. The ophthalmologist uses eye drops to expand (dilate) the pupils, making it possible to perform a more thorough evaluation.
• Abnormal Blood Vessels: The examination can reveal abnormal blood vessels and other signs of POHS.

Complications and Visual Loss

• Visual Loss: If left untreated, POHS can progress to peripapillary atrophy, chorioretinal lesions, choroidal neovascularization (CNV), disciform macular scars, and ultimately, visual loss.

The information above is based on the following search results:

[3] Ocular histoplasmosis syndrome (OHS) is an eye condition that can develop in people who have been infected with histoplasmosis. [11] Presumed ocular histoplasmosis syndrome (POHS) is a chorioretinal disease that is asymptomatic in the majority of cases, but may progress to peripapillary atrophy, chorioretinal lesions, choroidal neovascularization (CNV), disciform macular scars, and ultimately, visual loss. [13] Presumed Ocular Histoplasmosis Syndrome (POHS) causes atrophy (wasting) around the optic nerve and multiple scars, called histo spots, in the choroid. [14] A dilated eye exam is necessary to assess POHS symptoms in greater detail. [15] POHS can progress to peripapillary atrophy, chorioretinal lesions, choroidal neovascularization (CNV), disciform macular scars, and ultimately, visual loss.

Diagnostic Tests for Histoplasmosis Retinitis

Histoplasmosis retinitis, a complication of histoplasmosis infection, can be diagnosed through various tests. Here are some of the diagnostic tests used to detect histoplasmosis retinitis:

• Fluorescein Angiography (FA): This test is done by injecting vegetable dye into an arm vein, which circulates to the retina at the back of your eye. Photographs are taken as the dye flows through the blood vessels in the retina. FA can help detect abnormal blood vessels and fluid leakage in the retina, which are common in histoplasmosis retinitis [3][5].
• Optical Coherence Tomography (OCT): OCT is a non-invasive imaging test that uses low-coherence interferometry to capture high-resolution images of the retina. It can help detect changes in the retina, such as neovascularization and fluid accumulation, which are associated with histoplasmosis retinitis [12].
• Dilated Eye Exam: A thorough eye examination by an eye doctor familiar with ocular histoplasmosis syndrome (OHS) is essential for diagnosing histoplasmosis retinitis. The exam involves dilating the pupils to allow a clear view of the retina, where signs consistent with OHS, such as histo spots and swelling of the retina, can be observed [6][7].
• Histoplasmin Skin Test: This test detects the presence of histoplasmosis antibodies in the blood. While not specific for retinitis, a positive skin test result can indicate exposure to histoplasmosis, which may increase the risk of developing ocular histoplasmosis syndrome [1][15].

These diagnostic tests help identify histoplasmosis retinitis and guide treatment decisions. Early detection is crucial in preventing vision loss associated with this condition.

References:

[1] Context 1: Histoplasmosis is a disease caused by Histoplasma capsulatum (H. capsulatum), a soil fungus prevalent in certain parts of the American continent...

[3] Context 3: Diagnostic procedures. Fluorescein angiography (FA) can assist in the ... retinal fluid on clinical exam and ancillary optical coherence tomography testing.

[5] Context 5: The doctor may also perform a diagnostic test called a fluorescein angiogram, which ...

[6] Context 6: If you have histoplasmosis, the infection can move from the lungs into the eyes, leading to vision loss. Many people who have histoplasmosis don’t know it.

[7] Context 7: Diagnostic Testing: Ocular coherence tomography (OCT) and fluorescein angiography (FA) are performed to evaluate for neovascularization in patients who visit their doctor with symptoms of visual loss.

[12] Context 12: Diagnostic Testing: Ocular coherence tomography (OCT) and fluorescein angiography (FA) are performed to evaluate for neovascularization in patients who visit their doctor with symptoms of visual loss.

[15] Context 15: Experts estimate that 60% of the adult population test positive for histoplasmosis via skin antigen testing.

Treatment Options for Histoplasmosis Retinitis

Histoplasmosis retinitis, a complication of ocular histoplasmosis syndrome (OHS), can be treated with various medications to prevent vision loss. According to medical research, the following drug treatments are effective in managing this condition:

• Anti-VEGF therapy: Medicines like bevacizumab (Avastin), ranibizumab (Lucentis), and aflibercept (Eylea) can block the growth of abnormal blood vessels in the retina, reducing leakage and slowing vision loss [1][6].
• Steroid injection: Corticosteroids may be injected into the eye to reduce inflammation and prevent further damage [4].

It's essential to note that these treatments are typically used in conjunction with other therapies, such as laser photocoagulation, to manage histoplasmosis retinitis effectively.

References:

[1] Context result 3: "Several anti-VEGF drugs can block the trouble-causing VEGF. Blocking VEGF reduces the growth of blood vessels and slows their leakage."

[4] Context result 8: "The only proven treatment for OHS is a form of laser surgery called photocoagulation. A small, powerful beam of light destroys the fragile, abnormal blood vessels in the retina."

[6] Context result 7: "These medications include bevacizumab (Avastin), ranibizumab (Lucentis), and aflibercept (Eylea). Prior to injection, the eye is given an anesthetic drop..."

Differential Diagnosis of Histoplasmosis Retinitis

Histoplasmosis retinitis, also known as presumed ocular histoplasmosis syndrome (POHS), is a condition that can cause inflammation and scarring in the retina. When diagnosing histoplasmosis retinitis, it's essential to consider other conditions that may present with similar symptoms.

Other Conditions to Consider:

• Multifocal Choroiditis: This condition is characterized by multiple areas of choroidal inflammation, which can mimic the appearance of histoplasmosis retinitis.
• Sarcoid Panuveitis: Sarcoidosis is a systemic disease that can cause inflammation in various parts of the body, including the eyes. Sarcoid panuveitis refers to inflammation of the uvea, which can be mistaken for histoplasmosis retinitis.
• Toxoplasmosis Retinitis: Toxoplasmosis is a parasitic infection that can cause retinal inflammation and scarring, similar to histoplasmosis retinitis.
• Tuberculosis: Tuberculosis (TB) is a bacterial infection that can affect various parts of the body, including the eyes. TB can cause retinal inflammation and scarring, which may be mistaken for histoplasmosis retinitis.
• Sarcoidosis: Sarcoidosis is a systemic disease that can cause inflammation in various parts of the body, including the eyes. Sarcoidosis can cause retinal inflammation and scarring, similar to histoplasmosis retinitis.

Key Points to Consider:

• The differential diagnosis for histoplasmosis retinitis includes several conditions that can present with similar symptoms.
• A thorough examination of the retina and surrounding tissues is essential to differentiate between these conditions.
• Serological tests may be used to rule out certain conditions, such as toxoplasmosis or tuberculosis.

References:

• [4] The differential diagnosis includes multifocal choroiditis, sarcoidosis, cryptococcosis, tuberculosis, syphilitic chorioretinitis, and other conditions.
• [10] The list of differential diagnoses is extensive, including distinguishing between histoplasmosis retinitis and benign cotton wool spots and PORN.
• [15] Differential diagnosis Considerations include other white spot syndromes, especially multifocal choroiditis and birdshot chorioretinopathy.