Toxic syndrome of the anterior segmen

Toxic syndrome of the anterior segment. Sterile postoperative inflammatory reaction, caused by non-infectious substances that enter the anterior segment in the first 12-48 hours, in uncomplicated cataract surgeries .


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  • 1 Symptoms
  • 2 signs
  • 3 Diagnostic protocol
  • 4 Differential diagnosis
    • 1 Surgical
    • 2 Non-surgical
  • 5 Treatment protocol
    • 1 Medical treatment
  • 6 Follow-up
  • 7 Sources


  • Blurry vision.
  • Eye pain
  • Red eye .


  • Moderate ciliary injection.
  • Diffuse corneal edema .
  • Inflammatory reaction in the anterior chamber, with or without a membrane in the pupillary area and fibrin deposits.
  • Hypopyon .
  • Irregular, dilated, reactive but slow pupil, in case there is no membrane.
  • Hypothalamia , in case of pupillary membrane seclusion, plus ocular hypertension .

Diagnostic protocol

  • History: history of uncomplicated cataract surgery, 12-48 hrs in evolution.
  • Better corrected visual acuity.
  • Slit lamp biomicroscopy: look for described signs.
  • Applanation tonometry : normal or increased, if corneal edema.
  • Ocular ultrasound: rule out signs of significant inflammatory reaction of the vitreous cavity, or other associated alterations in the posterior segment.
  • Differential diagnosis. The most important and emergent is with postoperative acute bacterial endophthalmitis .

Differential diagnosis

It is still a challenge for the ophthalmologist. Under normal conditions, the aqueous blood barrier prevents the passage of macromolecules and plasma cells such as polymorphonuclear cells and macrophages, but we must bear in mind that even the least traumatic surgery causes an inflammatory reaction due to the temporary permeabilization of the aqueous blood barrier (Sham and Spalton, 1994 ), and allows the passage of plasma proteins and inflammatory cells in the anterior chamber. Differential diagnosis has been made with surgical and non-surgical entities.


  • Fibrinoid reaction postvitrectomy pars plana.
  • Cortical remains / dislocated nucleus.
  • Chemical response.
  • Complicated surgery (manipulation).
  • Microscopic hypertension .
  • Phacoanaphylaxis .
  • Toxic anterior segment syndrome (TASS).


  • Pars severe planitis.
  • Ancient hemovitreous .
  • Retinochoroiditis by Toxoplasma and Toxocara .
  • Necrotic retinoblastoma .

Differential diagnosis with toxic syndrome of the anterior segment acquires a special connotation today due to its increasingly frequent appearance. For many authors, if it is presumably a toxic syndrome of the anterior segment, topical corticosteroid therapy is used for 24 h, if there is no response, the impression ceases to be a toxic syndrome of the anterior segment and the presumptive diagnosis of endophthalmitis is established.

Toxic syndrome of the anterior segment is the clinical picture that includes various forms of uveitis that do not have an infectious origin and that can occur after any surgery of the anterior segment, although it is mostly associated with cataract surgery.

Treatment protocol

Medical treatment

  • Oral and topical steroidal anti-inflammatory drugs:
  • Eye drops : prednisolone , dexamethasone 1 drop every 3-4 h.
  • Subconjunctival or transparpebral route of immediate action: dexamethasone or betamethasone (1 ml).
  • Oral route: prednisone (5-20 mg) 1 mg / kg / day.
  • Mydriatics: homatropin (2%) 1 drop every 8 h; atropine (0.5-1%) 1 drop every 8 h.
  • Hypertonic solutions: NaCl hyperton (5% and 10%) 1 drop every 4 h during the day; ophthalmic ointment before bed.
  • If ocular hypertension: Timolol (0.5%) 1 drop every 12 h; dorzolamide (2%) 1 drop every 8-12 h; acetazolamide (250 mg) 1 tablet every 8 hours orally.


  • According to the severity of the condition and the patient’s reliability. Evaluate admission in severe cases and insecurity in compliance with treatment.
  • Consider clinical discharge when there is complete resolution of the clinical picture.
  • Consider postoperative endophthalmitis if:

No obvious response to medication.

Impaired visual acuity.

Worsening of the initial inflammatory picture.


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