In immune deficient patients or with the use of corticosteroids the ulcer may become large and in these cases it is called geographic ulcer. Disciform keratitis (Endothelial keratitis)
Endothelial keratitis manifests a central endothelitis in a disc-shaped manner. Longstanding corneal edema leads to permanent scarring and is the major cause of decreased vision associated with HSV. Localized endothelitis (localized inflammation of corneal endothelial layer) is the cause of disciform keratitis. Other forms
Metaherpetic ulcer : is not due to live virus, results from inability of the corneal surface to heal. Necrotizing keratitis
Keratouveitis : is usually granulomatous uveitis with large keratic precipitates on the corneal endothelium. Cause
HSV is a double-stranded DNA virus that has icosahedral capsid. HSV-1 infections are found more commonly in the oral area and HSV-2 in the genital area. Ocular herpes simplex is usually caused by HSV-1. Diagnosis
A specific clinical diagnosis of HSV as the cause of dendritic keratitis can usually be made by ophthalmologists and optometrists based on the presence of characteristic clinical features. Diagnostic testing is seldom needed because of its classic clinical features and is not useful in stromal keratitis as there is usually no live virus. Laboratory tests are indicated in complicated cases when the clinical diagnosis is uncertain and in all cases of suspected neonatal herpes infection:
Corneal smears or impression cytology specimens can be analyzed by culture, antigen detection, or fluorescent antibody testing. Tzanck smear, i.e.Papanicolaou staining of corneal smears, show multinucleated giant cells and intranuclear inclusion bodies, however, the test is low in sensitivity and specificity.
Spinal or neurogenic
Spinal or neurogenic claudication is not due to lack of blood supply, but rather it is caused by nerve root compression or stenosis of the spinal canal, usually from a degenerative spine, most often at the "L4-L5" or "L5-S1" level. This may result from many factors, including bulging disc, herniated disc or fragments from previously herniated discs (post-operative), scar tissue from previous surgeries, osteophytes (bone spurs that jut out from the edge of a vertebra into the foramen, the opening through which the nerve root passes). In most cases neurogenic claudication is bilateral, i.e. symmetrical. Jaw
Jaw claudication is pain in the jaw or ear while chewing. This is caused by insufficiency of the arteries supplying the jaw muscles, associated with giant cell arteritis. Diagnosis
Differential diagnosis
Vascular (or arterial) claudication typically occurs after activity or ambulation for a distance with resultant vascular insufficiency (lack of blood flow) where the muscular demands of oxygen outweighs the supply. Symptoms are lower extremity cramping. Resting from activity even in a standing position may help relieve the symptoms. Spinal or neurogenic claudication may be differentiated from arterial claudication based on activity and position. In neurogenic claudication, positional changes lead to increased stenosis (narrowing) of the spinal canal and compression of nerve roots and resultant lower extremity symptoms. Standing and extension of the spine narrows the spinal canal diameter. Sitting and flexion of the spine increases spinal canal diameter. A person with neurogenic claudication will have worsening of leg cramping with standing erect or standing and walking.