Fighting ocular infections
A diagnosis and treatment primer for TASS

Treat cases immediately and investigate their cause

Explanted silicone lens from
another TASS case. An oily
material was found to coat
larger areas of the anterior
and posterior lens optic
surfaces.
Source: Liliana Werner M.D.,
Ph.D.


TASS on the first post-op day.
Source: Simon Holland, M.D.



Clinical pictures taken during
the first post-op week of two
TASS cases, showing
the different aspects of an
oily material found within
the anterior chamber.
Analyses determined
the material to correspond
to ointment used post-op.
Top: TASS case number 1,
with diffuse corneal edema
and a film-like material
coating the corneal
endothelium.
Bottom: TASS case number
two, with a distinct bubble
inside the anterior chamber.
Source: Jeffrey Sher, M.D.
and Wesley Nash, M.D.,
Ontario

Physicians struggle to combat a rash of toxic anterior segment syndrome (TASS) cases that are occurring more frequently after cataract surgery.
TASS, a sterile inflammation in the anterior segment, usually clears with the use of intense topical steroids and is often confused with bacterial endophthalmitis. Severe cases can lead to cornea transplantation, an atrophic iris, or glaucoma. TASS usually occurs in clusters, vexing surgeons who try to solve the inflammatory cause only to see it recur in others.
“This can disrupt an entire surgeon's practice,” said Nick Mamalis, M.D., Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, Salt Lake City, a leading investigator of TASS.
“I still worry every time I take a patch off,” said Ronald L. Fellman, M.D., associate clinical professor of ophthalmology, Southwestern Medical Center, University of Texas, Dallas. Dr. Fellman was involved with 14 cases of TASS at a local surgery center over an 18-month period. “It's unquestionably the most miserable time I can remember.”
TASS causes can be linked to anything that is placed in the eye, including irrigating solutions, anesthetics, ophthalmic viscosurgical devices, antibiotics, or other medications, said Henry F. Edelhauser, Ph.D., Emory Eye Center, Emory University School of Medicine, Atlanta. For example, a physician may inject an antibiotic in the irrigation solution to decrease the endophthalmitis risk, he said. This off-label use has been linked to some cases of TASS, he said.
TASS cases can also occur from high endotoxin levels on instruments, detergents, sterilization problems, or poor cleaning of instruments, Dr. Edelhauser said.
“With the speed of surgery now, there's limited time to clean instruments properly,” he said. For example, an ophthalmic viscosurgical device may remain on the instrument after cleaning, leading to TASS in subsequent patients.
What follows is a guide to help surgeons identify TASS, treat it, and help investigate its cause.

Diagnosing TASS

It's easy to confuse TASS with bacterial or infectious endophthalmitis, physicians said.” Many times, the first time a doctor sees this, he thinks it's an infection and refers the patient to a retina specialist,” Dr. Mamalis said. “After the third or fourth case, the surgeon will realize it may not be an infection but something that is toxic.”
Consider these common symptoms and signs that accompany TASS to help make a differential diagnosis:
1. TASS almost always has a sudden onset, within 12 to 24 hours post-op, said Terry Kim, M.D., associate professor of ophthalmology, Duke University School of Medicine, Durham, N.C. This contrasts with the onset of endophthalmitis, which is usually three to seven days post-op.
There are some reported cases of delayed onset TASS. For example, Liliana Werner, M.D., Ph.D., John A. Moran Eye Center, University of Utah, recently reported eight TASS cases with a delayed onset that were related to penetration of ophthalmic ointments into the eye post-op. However, delayed onset is not common, she said.
2. TASS is limited to the anterior segment, Dr. Mamalis said. Endophthalmitis often has involvement of the posterior segment.
3. Cases of TASS tend to occur in clusters, Dr. Mamalis said. For example, a surgeon may see two cases in one day or 15 cases over a year. Endophthalmitis cases often occur individually.
4. TASS is always culture and Gram-stain negative, Dr. Kim said. Infectious endophthalmitis results with these tests are positive, although there are cases of sterile endophthalmitis, he said. However, the other symptoms and signs should help distinguish sterile endophthalmitis from TASS.
5. TASS cases usually present with limbus-to-limbus edema, little to no pain, blurry vision, and severe inflammation that can result in hypopyon formation, Dr. Werner said.
“If the procedure went well and you see more post-op inflammation than anticipated, you should suspect TASS,” Dr. Fellman said.
6. The patient's IOP can vary with TASS, Dr. Werner said. It may initially be low but then rise suddenly within several days following the initial insult, she said.
“As soon as the cornea clears sufficiently to allow a view of the anterior chamber angle, the patient should undergo gonioscopic evaluation to look for signs of damage,” Dr. Werner said.
7. TASS cases will improve with the use of topical and if necessary, oral steroids, Dr. Kim said.



Treatment plan for patients and the practice

When a surgeon still is not certain if a patient has TASS or endophthalmitis—and this will occasionally happen—they should treat it as the latter, Dr. Mamalis said.
“I'd err on the side of caution because [I] don't want to miss an infection,” he said.
The first line of treatment for TASS should be topical prednisolone acetate 1% (Falcon Pharmaceuticals, Fort Worth, Texas) every hour to two hours, Dr. Mamalis said. Check that the patient's condition is improving within the first day of treatment and watch the eye closely the first couple of days to make sure the condition is not getting worse, he said.
An anterior chamber washout is not recommended because maximum damage to the anterior chamber has usually occurred by presentation, Dr. Werner said.
If the patient is not improving, surgeons can consider adding oral steroids, Dr. Kim said.
Just how soon the patient's condition will improve depends on the severity of the insult, Dr. Mamalis said.
“For a mild or moderate reaction, most clear over a couple of days to a couple of weeks,” he said. Patients at Dr. Fellman's practice recovered 20/20 vision in about two months.
“If there's a severe reaction initially, you can still have a poor outcome.” TASS could lead to severe glaucoma or the need for a corneal transplant, said Dr. Mamalis.
Although treatment for the patient is fairly straightforward, the investigation of how TASS occurred will require more legwork, said Dr. Fellman.
First, if TASS is suspected, contact Drs. Mamalis or Edelhauser (contact information at the end of the story). The task force they are managing to investigate TASS will further advise how to manage the inflammation and will collect information about the case.
Next, surgeons should inform staff members about the case(s), said Dr. Kim. It's an easy part of the treatment process to forget, especially during an initial encounter with TASS.
“The surgeon has a key role in identifying TASS and notifying appropriate staff because a suspected case(s) of TASS should prompt a thorough analysis and investigation to identify the underlying cause(s). In perplexing cases such as these, communication is crucial,” he said.
The physician should involve various staff members to track down the cause of TASS, but appoint one staff person who will compile the information and organize it, Dr. Fellman said.
“If you have a big outbreak, you need a dedicated individual. It's not the sort of thing you can just spend a little time on,” he said.
Those who can help drill down what caused TASS include surgical nurses, technicians, the hospital's infection control department, and surgeons from other institutions. Surgeons from outside the practice or hospital may think of causes that the staff members have not considered, said Simon Holland, M.D., clinical professor, University of British Columbia, Vancouver. Dr. Simon experienced 17 cases of TASS that were ultimately linked to short-cycle steam sterilization of instruments.
“Look at every aspect of the surgical process and document everything,” Dr. Holland said. Consider medications, fluids, ointments, instruments, cleaning practices, and even staff changes that may have led to the problem, he said. For example, the cleaning staff may have changed and that has led to a breakdown in the instrument-cleaning protocol.
Surgeons that experience TASS may need to make more than one change at a time to discover what is causing TASS, Dr. Holland said. The disadvantage is that this makes it harder to pinpoint the one cause of TASS. However, it is better to fix the problem quickly by making changes immediately rather than one by one, he said. This is especially important if a cluster of TASS cases has occurred.
“A shotgun approach is what you have to do,” Dr. Fellman said.
Prevention is also important, physicians said. Surgeons may want to use disposable instruments more frequently to avoid cross contamination, Dr. Holland said. Also, surgeons can place a suture in the eye at the end of the surgery to eliminate a leaky wound as a culprit, Dr. Fellman said. h

Editors' note: Dr. Kim receives research grant support from Alcon (Fort Worth, Texas) and Allergan (Irvine, Calif.), and is a consultant for Becton-Dickinson (Waltham, Mass.) and Hyperbranch Medical Technology (RTP, N.C.). Dr. Mamalis performs contract studies for Advance Medical Optics (Santa Ana, Calif.). Alcon, Allergan, and Bausch & Lomb (Rochester, N.Y.). Dr. Edelhauser is a consultant for Alcon (Fort Worth, Texas). Drs., Fellman, Holland, and Werner have no financial interests related to their comments.

Contact Information
Edelhauser: 404-778-5853, ophthfe@emory.edu
Fellman: 214-360-0000, rfellman@aol.com
Holland: 604-875-5850, simon_holland@telus.net
Kim: 919-681-3568, terry.kim@duke.edu
Mamalis: 801-581-6586, nick.mamalis@hsc.utah.edu
Werner: 801-581-8136, liliana.werner@hsc.utah.edu