Syphilitic keratitis

Parenchymatous keratitis in congenital syphilis is considered a late manifestation of the general disease. Syphilitic keratitis usually develops between the ages of 6 and 20, but there are known cases of typical parenchymatous keratitis in early childhood and adulthood. For a long period of time, deep stromal keratitis was considered a manifestation of tuberculosis, and only with the advent of serological diagnostic methods was it established that the cause of the disease was congenital syphilis. Almost all patients with parenchymatous keratitis (80-100%) have a positive Wasserman reaction. At present, the full triad of symptoms of congenital syphilis (parenchymatous keratitis, changes in the anterior teeth, and deafness) is rarely detected, but in addition to eye disease, some other manifestations of the underlying disease are always detected: changes in the bones of the skull, nose, flabbiness and wrinkling of the skin of the face, gummatous osteomyelitis, inflammation of the knee joints.

Pathogenesis of syphilitic keratitis

As for the pathogenesis of this disease, it is also quite complex. It is known that the main link in the pathogenesis of syphilitic inflammation is vasculitis, and there are no vessels in the cornea. At present, it has been precisely established that parenchymatous keratitis in the fetus and newborn is caused by spirochetes that penetrated the cornea during the period of intrauterine development, when there were vessels in it. Another pathogenesis in late congenital stromal keratitis, developing in the absence of vessels: this is an anaphylactic reaction of the cornea.

At the end of the intrauterine development period, when the vessels are reduced, the corneal tissue becomes sensitized to the decay products of spirochetes. As a result, in the first two decades of life, when congenital syphilis is activated, when the concentration of decay products of spirochetes in the blood is increased, any provoking factor (trauma, colds) leads to the development of an anaphylactic reaction in the cornea. There is also other evidence indicating that syphilitic keratitis is caused by a special form of filterable spirochetes.

Symptoms of syphilitic keratitis

The inflammatory process begins with the appearance of barely noticeable point foci in the peripheral part of the cornea, more often in the upper sector. Subjective symptoms and pericorneal vascular injection are weakly expressed. The number of infiltrates gradually increases, they can occupy the entire cornea. During external examination, the cornea seems diffusely turbid, like frosted glass. Biomicroscopy shows that the infiltrates are deep, have an uneven shape (dots, spots, stripes); located in different layers, they overlap each other, as a result of which the impression of diffuse turbidity is created. The superficial layers, as a rule, are not damaged, epithelial defects do not form. The optical section of the cornea can be thickened almost 2 times.

There are 3 stages of the inflammatory process. The initial infiltration period lasts 3-4 weeks. It is followed by the stage of neovascularization and spread of the pathological process over the cornea. Deep vessels approach the first infiltrates, facilitating the resorption of opacities, and new foci of inflammation appear next to them, to which deep vessel brushes also approach after 3-4 weeks. Thus, the process slowly spreads from the periphery to the center. Near the limbus, opacities are resorbed, but the number of vessels going to new foci in the center increases. By the end of this period, the entire cornea is penetrated by a dense network of deep vessels. In this case, superficial neovascularization may also occur.

In stage II of the disease, symptoms of iridocyclitis usually appear, pericorneal injection of vessels increases, the pattern of the iris becomes blurred, the pupil contracts, and precipitates appear that are difficult to see behind the shadow of corneal infiltrates.

The progression of the disease continues for 2-3 months, then comes stage III - the regression period, which lasts 1-2 years. During this period, starting from the periphery, the cornea becomes transparent, becomes empty and some of the vessels disappear, but visual acuity does not recover for a long time, since the central section is cleared last.

After parenchymatous keratitis, traces of deserted and separate semi-deserted vessels, foci of atrophy in the iris and choroid remain in the corneal stroma for life. In most patients, visual acuity is restored to 0.4-1.0, they can read and work.

If parenchymatous keratitis is detected in a child, a consultation with a venereologist is necessary not only for the child, but also for members of his family.

Parenchymatous keratitis in acquired syphilis. The disease develops extremely rarely, is unilateral with mild symptoms. Corneal vascularization and iritis are usually absent. The recovery process may subside without leaving a trace. Differential diagnostics are performed with diffuse tuberculous keratitis.

Gummatous keratitis is a focal form of inflammation, rarely observed in acquired syphilis. Gumma is always located in the deep layers. The process is complicated by iridocyclitis. When the lesion disintegrates, a corneal ulcer may form. This form of keratitis must be differentiated from deep focal tuberculous keratitis.

Treatment of syphilitic keratitis

Treatment is carried out jointly by a venereologist and an ophthalmologist, since the main disease and cause of keratitis is syphilis. Specific treatment does not prevent the development of parenchymatous keratitis in the second eye, but significantly reduces the frequency of relapses. Patients are prescribed penicillin, bicillin, novarsenol, miarsenol, biyoquinol, osarsol, iodine preparations according to existing schemes, desensitizing and vitamin preparations.

Local treatment of syphilitic keratitis is aimed at resolving corneal infiltrates, preventing iridocyclitis and occasional corneal erosions. To prevent the development of iridocyclitis, mydriatic instillations are prescribed once a day or every other day under the control of pupil dilation. If iritis occurs, the number of instillations is increased to 4-6 times a day (1% atropine sulfate solution). If adhesions have formed and the pupil does not dilate, electrophoresis with atropine, drops and turundas with adrenaline (1:1000) are used. Corticosteroids (dexazone, dexamethasone) in the form of subconjunctival injections and instillations give a good therapeutic effect. Due to the fact that treatment is carried out over a long period of time (1-2 years), it is necessary to alternate drugs within one group of drugs and periodically cancel them. The introduction of mydriatics should also be stopped for several days. If the pupil does not contract on its own, miotics are used. As soon as the pupil has narrowed, it is dilated again. This procedure is called iris gymnastics. It prevents the immobilized wide pupil from adhering to the lens.

During the period of regression of syphilitic keratitis, drops and ointments are prescribed to improve trophism and prevent the formation of corneal erosions.