Overview.
Leukemia-induced changes in the fundus of the eye, called leukemia retinopathy, leukemia patients contain a large number of immature naïve cells can cause changes in the fundus of the eye. Due to the large number of leukocytes in the blood can cause stagnation of blood flow in small vessels, and due to the obstruction of hematopoietic organs, severe anemia and thrombocytopenia can occur. In addition, excessive leukocytosis can lead to leukocyte infiltration outside the blood vessels and abnormal growth.
Causes
A variety of factors can lead to leukemia, such as genetic factors, exposure to chemicals, radiation effects, and biological factors (e.g., viral infections).
Symptoms
Most of the clinical manifestations of the disease are caused by direct invasion by tumor cells, while concomitant anemia and thrombocytopenia are also factors that cause fundus symptoms. Leukemia retinopathy can occur in acute or chronic leukemia, especially in acute more common.
1. Retinal vascular changes
Dilated and tortuous veins are the most common. The veins are tortuous and full, and the diameter of the veins can be enlarged to several times of the normal one, and the ratio of arteriovenous diameter can be 1:2 or even 1:4, especially at the intersection of arteriovenous veins. The swollen and tortuous veins are irregular in diameter and are segmental or salami shaped. Due to anemia or blood filled with white blood cells, the color of the veins becomes yellowish-red, even indistinguishable from the arteries. Veins are surrounded by white sheaths due to infiltration of leukemia cells around the vessels. Arteries may also dilate in advanced stages. The blood vessels become varicose and lighter in tone due to sluggish blood flow, and sometimes the color of the arteries and veins is very similar.
2. Retinal hemorrhage and exudation
Retinal hemorrhage accounts for the second most common fundus lesion in leukemia, especially in the acute form. Retinal hemorrhages can occur anywhere in the fundus, but are most commonly located in the posterior pole. The hemorrhage may be superficial or deep in the retina, and may be flamed, linear, punctate, patchy, or irregular in shape. If it is located in the anterior retina, it is boat-shaped and may occasionally enter the vitreous humor and obscure the fundus. Subretinal hemorrhages are rare and occasionally lead to retinal detachment. The hemorrhage may have a white spot in its center, 1/6 to 1/4 PD in size. The origin of the white spot varies, with some believing it to be a collection of cellular debris, or an aggregation of immature leukemic cells, or a capillary embolus. This white spot can sometimes sit in tumor-like proliferation and can enlarge to 1/2-1 optic disc diameter. A halo of hemorrhage often surrounds the white spot. Retinal exudates are less common and may appear as hard macular stellate exudates or cotton-wool spots, the latter of which may be due to optic nerve axonal infarcts or by localized leukemic cell accumulation.
3. Retinal and choroidal infiltration
Due to the infiltration of leukemia cells in the retina and choroid, retinal edema can be produced, and the color of the retina changes from normal orange to orange or even yellowish white. Retinal nodular infiltration occurs in patients with a high leukocyte count and immature leukocytes, and is usually fulminant, with early death. Therefore, retinal nodular infiltration combined with an increased leukocyte count in the blood is an indication of a poor prognosis. Choroidal leukocyte infiltration is often not easily visualized in the fundus. Thickening of the choroidal tissue by leukocyte infiltration or blockage of choroidal capillaries by leukemic cell infiltration interferes with the blood supply to the retinal pigment epithelium, leading to disintegration of the pigment epithelium and impairment of its barrier function. Fluorescence angiography shows early leakage of large amounts of punctate fluorescein, and in some patients with plasma retinal detachment, the dye can enter the subretinal space.
4. Optic disk edema
Leukemia lesions can invade different parts of the optic nerve. If leukemia cells infiltrate before the sieve plate, it can blur the border of the optic disk, and the edema of the optic disk can be as high as several diopters, accompanied by hemorrhage. Vision loss is usually rare, but is significantly reduced if the macula is involved. Visual acuity may also be reduced if the posterior optic nerve is involved. The cause of optic disc edema may be due to leukemic cell infiltration of optic disc tissue and blood vessels resulting in venous reflux obstruction and ischemia. It may also be caused by intracranial leukocyte infiltration or intracranial hemorrhage resulting in increased intracranial pressure. The optic disc and its surrounding retina are edematous and cloudy, and the edema may appear as radiating cloudy streaks, a phenomenon caused by anemia, which is similar to the general highly anemic fundus. Sometimes the edema of the optic disc is extremely high, and this may be considered the result of increased intracranial pressure due to intracranial green tumors.
Leukemic retinopathy is found in patients with different types and degrees of leukemia, as well as in patients with concomitant anemia and thrombocytopenia.
In addition to fundus involvement, leukemia may extensively invade other tissues of the eye, such as the orbit, eyelids, iris, cornea, and any other ocular tissue.
Tests
1. Blood test and bone marrow aspiration test
The type of leukemia and the status of the lesions can be clarified. In both acute and chronic leukemia, blood tests show a significant increase in the total number of white blood cells and a decrease in red blood cells and platelets. Bone marrow examination shows an extremely active proliferation of the leukocyte system, with an increase in the number of primitive and naive cells.
2. Pathologic examination
The ocular tissues are extensively infiltrated by leukemia cells, some of which aggregate to form nodules. The lumen of blood vessels is filled with immature leukocytes, capillaries are occluded, and leukocytes may also form white sheaths around blood vessels. Digestive pavements show extensive loss of nuclei and loss of function of capillary wall cells. The nerve fiber layer is degenerated with gliosis. There is cyst-like space formation in the outer retina, focal disintegration of the retinal pigment epithelium, and leukocyte infiltration of the optic disc. Hemorrhages were located in all layers of the retina. The choroid can be thickened to three to four times due to intravascular and extravascular leukocyte infiltration, and the vessel wall is thinned or even destroyed.
3. Imaging examination
Cranial CT or MRI examination can clarify whether there is intracranial hemorrhage.
4. Fluorescence angiography
In retinal infiltration, early massive fluorescein punctate leakage is seen.
Diagnosis
The diagnosis can be determined according to the results of laboratory tests, combined with clinical manifestations.
Treatment
Drug treatment: mainly systemic treatment, such as supportive therapy, including correction of anemia and bleeding, blood transfusion, platelet supplementation, vitamin K, 6-aminohexanoic acid and so on. Various antibiotics can be used to fight infection. There are many kinds of chemical drugs, such as cyclophosphamide, methotrexate, cytarabine, vincristine, etc. Corticosteroids can also be used. Ocular symptoms are only treated symptomatically, such as leukemia cell infiltration behind the optic nerve sieve plate, radiation therapy can be done in time to preserve vision, with a dose of 20Gy every 1 to 2 weeks.