Thrombotic Thrombocytopenic Purpura (TTP): This condition is characterized by thrombocytopenia, microangiopathic hemolytic anemia, renal failure, neurological symptoms, and fever. The presence of retinal hemorrhage and hemolytic anemia in a previously healthy individual makes TTP a strong consideration due to its classic pentad of symptoms, which can include visual disturbances.

Hemolytic Uremic Syndrome (HUS): Similar to TTP, HUS presents with microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. While it more commonly follows a diarrheal illness, atypical HUS can occur without a clear precipitant and could explain the patient's symptoms.
Systemic Lupus Erythematosus (SLE): SLE can cause a wide range of symptoms, including hemolytic anemia and retinal hemorrhages due to vasculitis or antiphospholipid syndrome. It is a consideration in a young woman presenting with these symptoms.
Antiphospholipid Syndrome: This condition can cause arterial or venous thrombosis, including retinal vein occlusion leading to hemorrhage, and can also be associated with hemolytic anemia.

Malignant Hypertension: Severe, uncontrolled hypertension can lead to retinal hemorrhages and, in rare cases, can be associated with microangiopathic hemolytic anemia. It's crucial to check blood pressure in this patient.
Disseminated Intravascular Coagulation (DIC): While less likely, DIC can cause both thrombotic and hemorrhagic complications, including retinal hemorrhage, and is associated with consumption of platelets and coagulation factors, potentially leading to a picture that includes hemolytic anemia.
Sickle Cell Disease: Although less common in a previously healthy adult without known sickle cell disease, a crisis could potentially present with these symptoms, especially if there's an undiagnosed hemoglobinopathy.

Atypical Hemolytic Uremic Syndrome (aHUS): A rare condition characterized by the formation of blood clots in small blood vessels throughout the body, which can lead to hemolytic anemia, thrombocytopenia, and kidney failure. It's less common than TTP or HUS but should be considered in the differential.
Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells (hemolytic anemia), bone marrow failure, and the potential for blood clot formation. Retinal vein thrombosis could be a presenting feature.
Cancer-Associated Hemolytic Anemia: Certain cancers can cause hemolytic anemia through various mechanisms, including autoimmune hemolytic anemia or microangiopathic hemolytic anemia due to metastatic disease affecting small blood vessels.