Overview.
Conjunctival tuberculosis is an inflammation of the conjunctiva caused by infection with Mycobacterium tuberculosis, which is relatively rare in clinical practice. It is divided into two types: primary and secondary. Primary infection means that the patient has never suffered from tuberculosis, and the tubercle bacillus enters into the conjunctival sac directly through the patient’s secretion, dust or foreign objects, and causes conjunctival tuberculosis infection, which occurs in the inferior sulcus of the epiglottis and is often accompanied by caseous necrosis of the preauricular and submandibular lymph nodes. Secondary infection refers to the patient’s other parts of the body already have tuberculosis foci, the patient through the hands or utensils will bring the tuberculosis bacilli to the conjunctiva, or from the neighboring tissues directly spread, but also through the blood dissemination to the conjunctiva, and lead to conjunctival infection. Secondary infections usually do not affect the local lymph nodes.
Etiology
Primary infection means that the patient has never suffered from tuberculosis, and the tubercle bacillus enters into the conjunctival sac directly through the patient’s secretion, dust or foreign objects, and causes conjunctival tuberculosis infection; secondary infection means that the patient has tuberculosis foci in other parts of the body, and the patient brings the tuberculosis bacillus to the conjunctiva through his hands or appliances, or spreads it directly by the neighboring tissues, or spreads it to the conjunctiva via bloodstream, which leads to the conjunctival infection.
Symptoms
The affected eye may have eyelid swelling and purulent discharge, often without pain. The lesions can be of the following types:
1. Ulcerated type
Mostly occurs in the lid conjunctiva, but also sometimes occurs in the bulbar conjunctiva, manifested as a single or several scattered corn-shaped ulcers, the surface of the ulcers is proliferating granulation tissue, which can be gradually extended in all directions, and in severe cases, it can involve the cornea, sclera, and even invade the whole eyelid. Mycobacterium tuberculosis can be found in the scrape at the bottom of the ulcer.
2. Nodular type
Small grayish-yellow nodules appear under the conjunctiva, which are granular and elevated, with unbroken surface, surrounded by follicles or granulation tissues, and eventually develop into cauliflower shape, with necrotic areas in the center.
3. Papillary hyperplasia
Mostly occurs in the dome of the conjunctiva, can also be seen in the lid conjunctiva, the lesion for the proliferation of granulation tissue, occurring in the dome of the gelatinous hyperplasia elevated, similar to the cockleshanks-like cumbersome organisms, the surface of the superficial ulceration.
4. Polyp type
Mostly occurring in the lid conjunctiva, shaped like a fibrous tumor with a tip.
5. Tuberculosis ball type
It may be metastatic tuberculosis, there is a single, hard, yellow or yellow-red, soybean-sized painless nodule under the bulbar conjunctiva, the surface epithelium is intact, no ulcers are formed, and the base of the nodule is often adhered to the sclera, which can not be moved.
6. Conjunctival tuberculosis rash
The histopathology is the same as that of cornual tuberculosis, with a rash-like nodule of about 1mm on the bulbar conjunctiva, surrounded by no congestion.
Examination
1. Conjunctival scraping combined with special staining of Mycobacterium tuberculosis can determine the pathogenic bacteria.
2. Pathologic examination can reveal 3 typical tuberculous pathological changes in the tissue.
3. Imaging can reveal foci of tuberculosis infection in other parts of the body.
Diagnosis
Diagnosis can be confirmed on the basis of typical conjunctival lesions, history, conjunctival scraping or biopsy, special staining of Mycobacterium tuberculosis and pathologic examination.
Treatment
First of all, strict sterilization and isolation measures should be taken for patients. If the disease develops in one eye, a transparent eye patch should be worn to avoid infecting the healthy eye.
1. Systemic anti-tuberculosis treatment
Isoniazid, ethambutol, pyrazinamide can be given.
2. Local treatment
50~100mg streptomycin can be used for subconjunctival injection, and local drops of 1% streptomycin, 0.1% rifampicin and 0.3% ofloxacin can be used.
Prevention
It should start from controlling the source of infection, cutting off the way of transmission, strengthening immunity and reducing susceptibility, and timely vaccination with BCG vaccine.