Varicella keratitis
Introduction
Introduction to varicella keratitis Chickenpox is an acute infectious disease in children caused by varicella-zostervirus (VZV), which is characterized by the appearance of papules on the skin and mucous membranes, which quickly turn into herpes and scarring. Some patients with rash or rash may have different degrees of corneal damage, called varicella patitis. basic knowledge The proportion of sickness: 2.5% Susceptible people: no special people Mode of infection: non-infectious Complications: conjunctivitis
Cause
Causes of varicella keratitis
(1) Causes of the disease
Varicella-Zoster virus is a DNA virus belonging to the herpesvirus family. Chickenpox and herpes zoster are two diseases caused by the same virus. Most of the chickenpox patients are children, which are initial infections, and herpes zoster is mostly adult. The patient with low immunity is a latent infection. The basic structure of the virus is the same as that of other viruses in the herpesvirus family. The virus has only one serotype.
(two) pathogenesis
Is the result of one of the following factors or a combination:
1. Direct invasion of the cornea by the virus.
2. The host develops an inflammatory response to the intact virus or viral antigen in the cornea.
3 The body undergoes an autoimmune response to the altered tissue.
4. Secondary changes occur due to corneal sensation loss, eyelid abnormalities, and tear film changes on the corneal surface.
Prevention
Varicella keratitis prevention
Prevent chickenpox and vaccinate as soon as possible. If chickenpox has already occurred, treat it as soon as possible to avoid delaying the condition.
Complication
Complications of varicella keratitis Complications conjunctivitis
Can be associated with skin and mucous membrane varicella, other organs can also spread.
Symptom
Varicella keratitis symptoms common symptoms corneal dendritic changes eye pain keratitis edema
The keratopathy caused by chickenpox is generally mild and the prognosis is good. It is mainly characterized by diffuse corneal stroma, discoid keratitis and dendritic keratitis.
Corneal stroma
More than 4 to 5 days after the onset of varicella, manifested as diffuse mild or moderate edema of the corneal stroma, accompanied by posterior elastic membrane wrinkles and a small amount of aqueous cells, can cause temporary visual decline, the disease is transient Signs, disappeared naturally in about 1 week, leaving no corneal opacity and new blood vessel growth.
2. Corneal stroma
More than 1 to 3 months after infection with varicella, monocular onset, due to early corneal signs and mild systemic performance, it is often ignored by parents, older children can complain of eye pain, blurred vision, check visible cornea The center is disk-like turbid, the cornea is thickened in the turbid area, and the posterior elastic membrane wrinkles, the posterior corneal wall KP and aqueous humor cells are also more common, and its performance is very similar to HSV discoid keratitis, both of which are only clinically Difficult to identify, varicella platy keratitis often combined with dendritic keratitis, and often have discoid keratitis after discoid keratitis, and HSV discoid keratitis, often with dendritic keratitis, Discoid keratitis occurs after the keratitis, so the former is the immune response of the corneal stroma caused by VZV infection of the cornea.
3. False dendritic keratitis
It occurs more than 3 to 4 months after infection with varicella. Clinically, the history of varicella infection is often ignored by parents. The clinical manifestations of varicella dendritic keratitis are similar to those of monosporous keratitis (HSK).
Examine
Examination of varicella keratitis
1. Immunofluorescence technique : VZV antigen can be found by direct immunofluorescence or indirect immunofluorescence.
2. Complement binding test : The serum anti-VZV antibody titer of patients with varicella increased, and gradually decreased during the recovery period to 6-12 months, which was reduced to only detectable level. High titer VZV was detected by complement fixation test. The antibody and the anti-HSV antibody are negative, so it can be judged to be caused by VZV infection.
3. Electron microscopy : A pseudo-dendritic keratopathy blade was taken and placed under an electron microscope to find a VZV-like disease.
Diagnosis
Diagnosis and differentiation of varicella keratitis
diagnosis
History
There is a history of infection with chickenpox 1 to 8 months before onset, especially in children.
2. Corneal lesions
Transient corneal edema occurring 4 to 5 days after the onset of varicella, characteristic keratopathy of discoid keratitis caused by plaque keratitis 1 to 3 months and pseudo-dendritic keratitis occurring in the late stage.
Differential diagnosis
False dendritic keratitis often occurs 3 to 4 months after infection with varicella. Clinically, this history of varicella infection is often ignored by parents. The clinical manifestations of varicella dendritic keratitis are similar to those of monosporous keratitis (HSK). The main identification points are: varicella dendritic keratitis mostly occurs in children or infants. There is a history of varicella infection in 3 to 4 months before onset, and HSV dendritic keratitis can occur at any age and has a fever. history.
