Herpes Zoster Opthalmicus
by Alex W
1. Transmission
1.1. Droplets
1.2. Aerosols
1.3. Direct contact with fluid of active lesion/vesicle
1.4. Indirectly through contact with contaminated items
2. Signs and symptoms
2.1. Fatigue
2.2. Headache
2.3. Sensitivity to light and touch
2.4. Pain, numbness or tingling
2.5. Red, vesicular rash that starts centrifugally on the thorax and spreads to the extremities
2.6. Itchiness
3. Complications
3.1. Conjunctivitis
3.2. Keratitis
3.3. Ptosis
3.4. Corneal ulceration
3.5. Iridocyclitis
3.6. Glaucoma
3.7. Decreased visual acuity or blindness
4. Pathogenesis
4.1. Early chickenpox infection led to latent infection in dorsal nerve ganglia
4.2. Reactivation of VZV occurs when a patient is immunocompromised
4.3. Multiplication and spread of VZV in sensory and trigeminal ganglion
4.4. Virus travels anterogradely and infects skin on the dermatome innervated by the ophthalmic root of the trigeminal nerve
5. Prevention
5.1. Passive immunization with VZV immunoglobulins
5.2. Vaccine: live attenuated
5.3. Infection control procedures
6. Varicella Zoster Virus
6.1. Herpesviridae
6.2. Alpha-herpesvirinae
7. Epidemiology
7.1. 75% cases secondary attack with chickenpox
7.2. Increased incidence after the age of 60 years
7.3. Greater in immunocompromised patients
8. Diagnosis
8.1. Clinical history
8.2. Viral culture
8.2.1. Swab of vesicle, tissue or body fluid used
8.2.2. Slow process with low sensitivity
8.3. Viral PCR
8.3.1. Vesicular fluid, scrapings or active lesions
8.3.2. High specificity and sensitivity
8.3.3. Expensive, requires trained personnel and is a lengthy procedure
8.4. Tzanck test
8.4.1. Scraping from floor of vesicle is placed on a slide and stained with Wright/Giemsa stain
8.4.2. Inexpensive, fast and widely available
8.4.3. Cannot differentiate between VZV and HSV
8.5. Direct fluorescent antibodies
8.5.1. Cellular scraping from base of fresh lesion placed on slide with fluorescent antibody stain
8.5.2. Can differentiate between VZV and HSV