Acute postoperative endophthalmitis

Acute endophthalmitis is classified as an extremely serious complication occurring in 1 out of 1000 cases.

[1], [2], [3], [4]

Causes of the postoperative endophthalmitis

The causative agents are most often coagulase-negative staphylococci (for example, Staph. Epidemidis), Gram-positive (for example, Staph. Aureus) and Gram-negative (for example, Pseudomonas sp., Proteus sp.) Microorganisms.

The source of infection is difficult to identify. The most frequent culprit is considered to be its own bacterial flora of the eyelids, conjunctiva and lacrimal canaliculus. Other potential sources of infection include infected solutions, instruments, the environment, including operating personnel.

[5], [6], [7], [8], [9], [10], [11], [12]

Symptoms of the postoperative endophthalmitis

The severity of endophthalmitis depends on the virulence of the pathogen.

1. Extremely severe is characterized by pain, a significant decrease in vision, edema of the eyelids, chemosis, injection of the conjunctiva, gioevilleleiem, corneal infiltrates and a large hypopion.
2. Of moderate severity is characterized by the precipitation of fibrinous exudate into the anterior chamber, smaller hypopion, vitreitis, absence of reflex from the fundus and impossibility of ophthalmoscopy even in indirect light.
3. The mild form may be accompanied only by minor pain, by the absence or slight hypopion and by the preservation of some reflex from the fundus with the possibility of partial ophthalmoscopy by an indirect ophthalmoscope.

The determination of the time interval from surgery to the development of symptoms of endophthalmitis may be useful for speculating about the causative agent of the process. For example, Staph. Aureus and Gram-positive bacteria are usually present 2-4 days after surgery with pronounced endophthalmitis. Staph. Epidermidis and coagulase-negative cocci usually appear on the 5th-7th day of surgery with less severe symptoms.

Diagnostics of the postoperative endophthalmitis

1. Detection of the pathogen in aqueous humor or the vitreous is a confirmation of the diagnosis. However, a negative reaction does not exclude the presence of infection. The fence of the material in the operating room is as follows:
   • a sample of 0.1 ml watery moisture is taken by aspiration with a needle on a tuberculin syringe from the already existing second incision;
   • a specimen of the vitreous body is best taken with a mini-visector through the pars plana at 3.5 mm from the limb. If there is no mini-vitrector, an alternative is a partial sclerotomy at 3.5 mm from the limb with aspirating the vitreous from the middle sections of the vitreal cavity using a needle on the tuberculin syringe. The vitreous in a volume of 0.1-0.3 ml is added to blood agar, liquid thioglucolate and Sabourand agar. If there are no ready-made media, a good alternative is to place the sample in special ready-made dies for blood samples. A few drops are also placed on the glass with a dye according to Gram or Giemsa.
2. Vitrectomy is indicated only in the case of an acute infectious process and reduced vision to light. At higher rates of visual acuity (from arm movements and higher), vitrectomy is not necessary.
3. Antibiotics of choice are amikacin and ceftazidine, sensitive to the majority of Gram-positive and Gram-negative bacteria, as well as vancomycin, sensitive to coagulase-negative and coagulase-positive cocci. Amikacin shows synergism with vancomycin, but it is potentially more retinoxic than ceftazidine and does not show synergy with vancomycin.
   • Intravitreal administration of antibiotics begins immediately after determining the type of pathogen and reducing the density of the eyeball. Amicacin (0.4 mg in 0.1 ml) or ceftazidine (2.0 mg in 0.1 ml) and vancomycin (1 mg in OD ml) are slowly introduced into the middle region of the vitreal cavity with a needle. The bevel of the needle should be directed anteriorly to minimize contact of the drug with the macula. After the first injection, disconnect the syringe and leave the needle in the cavity to make a second injection through it. If the probability of precipitate formation is high, you need to use two different needles with different antibiotics. After the removal of the needle, a parabulbar injection of the antibiotic is made;
   • parabulbar injections of vancomycin 25 mg and ceftazidine 100 mg or gentamicin 20 mg and cefuroxime 125 mg can achieve therapeutic concentrations. They are prescribed daily for 5-7 days, depending on the condition;
   • local therapy is used with limited, except in cases accompanied by infectious keratitis;
   • systemic therapy is in doubt. Endophthalmitis Vitrectomy Study Group has been shown that the general use of ceftazidine and amikacin is ineffective. These antibiotics, being water-soluble, have weak activity against gram-positive bacteria and small permeability for the organ of vision. Perhaps other antibiotics, such as fat-soluble quinolones (eg, ciprofloxacin, ofloxacin) and imipenem, which have better permeability and broad antimicrobial spectrum, are more effective. The answer to this question remains to be obtained in the course of future research.
4. Steroid therapy is prescribed after taking antibiotics to reduce inflammation. Steroids are less dangerous only if the bacteria are sensitive to the antibiotic.
   • parabulbarno betamethasone 4 mg or dexamethasone 4 mg (1 ml) daily for 5-7 days depending on the condition;
   • Inside prednisolone 20 mg 4 times a day for 10-14 days in severe cases;
   • Dexamethasone topically 0.1%, at first every 30 min, then less often.
5. Further therapy and its size are determined depending on the isolated bacterial culture and clinical picture.
   • Signs of improvement - weakening of the cellular reaction and a decrease in hypopion and fibrinous exudate in the anterior chamber. In this situation, treatment does not change regardless of the results of the analysis.
   • When isolating a resistant bacterial culture and worsening the clinical picture, antibiotic therapy should be changed.
6. The results of treatment are low, despite vigorous and correct therapy (in 55% of cases the visual acuity achieved is 6/60 or lower).

In some cases, decreased vision may be due to retinotoxicity of antibiotics, in particular aminoglycosides. The PHAG is determined by hypofluorescence caused by ischemia.

[13], [14], [15], [16], [17]

Differential diagnosis

1. Remnants of the lens masses in the anterior chamber or vitreous can provoke acute anterior uveitis.
2. A toxic reaction is possible on irrigation fluid or foreign materials used during the operation. Less pronounced fibrinous film develops on the anterior surface of the intraocular lens. In this case, large doses of steroids (topically or parabulbar) in combination with cycloplatics are effective, but the formation of synechia with an intraocular lens is possible.
3. A complicated or prolonged operation leads to corneal edema and uveitis, which is detected directly in the postoperative period.

[18], [19], [20], [21], [22]

Prevention

Optimal prevention is still not defined. However, the following measures can be useful.

1. Preoperative treatment of already existing infections, such as staphylococcal blepharitis, conjunctivitis, dacryocystitis, and in persons with prostheses - sanation of the contralateral cavity.
2. Povidone-iodine instillation before surgery:
   • a commercially available 10% betadine solution used for the treatment of the skin is diluted with physiological saline until a 5% concentration is obtained;
   • two drops of the diluted solution are punctured into the conjunctival sac a few minutes before the operation, and careful manipulations contribute to the distribution of the solution over the surface of the eye. This solution can be used to treat the eyelids before applying the eyelid;
   • Before the beginning of the operation, the eyeball is irrigated with physiological saline.
3. Careful installation of the eyelid. Implying the isolation of eyelashes and the edges of the eyelids.
4. Prophylactic administration of antibiotics
   • postoperative administration of antibiotic in the subtenon space is widely used, but evidence of the effectiveness of the method is not enough;
   • intraoperative irrigation of the anterior chamber with the addition of antibiotics (vancomycin) to the infusion solution can be an effective measure, but at the same time promote the emergence of resistant strains of bacteria.

[23], [24], [25], [26], [27], [28], [29]