A 57-year-old man presents to the ED complaining of acute onset of right eye pain and vision loss over three hours and shortness of breath for one week. He has a history of aortic valve replacement, congestive heart failure, and remote cataract surgery. He denies headache, trauma, focal weakness, paresthesias, recent eye surgery, or significant weight loss. He is febrile (38.7°C), tachycardic (116 bpm), and hypoxic (84% saturation on room air).
Vision in his right eye is light perception only. The right pupil is 7 mm and not reactive. You are unable to see the retina because of corneal haze. Of note, he has a holosystolic and diastolic murmur, rales, anasarca, and an unremarkable neurological examination.
What is the differential diagnosis?
Endophthalmitis, inflammation of the ocular cavities and their adjacent structures, usually in the context of infections, is a vision-threatening emergency that requires prompt diagnosis and action. There are only a few etiologies of endophthalmitis, including postoperative complication, trauma, and endogenous infection.
Postoperative infection is the most common cause of endophthalmitis in the United States, and is thought to occur after normal bacterial flora from the conjunctiva, eyelashes, or eyelid skin is inoculated into the aqueous humor during routine ocular surgery. Immunocompetent patients are thought to be able to handle this. Postoperative endophthalmitis presents as sudden onset of increased eye pain and decreased vision, and is classified as acute days after surgery (75% of cases present within one week of surgery) or subacute weeks to months after surgery.
Endophthalmitis occurs in four percent to 13 percent of penetrating traumatic globe injuries. (Curr Opin Ophthalmol 1998;9:59.) The risk of infection is increased if the lens is disrupted (Ophthalmology 1995;102 :1696), primary repair is delayed more than 24 hours, or a foreign body is retained. (Ophthalmology 1993;100 :1468.)
Endogenous endophthalmitis is rare and may be the most difficult to diagnose. It often presents as a painful, red eye with decreased vision in those who are acutely ill, immunocompromised, or intravenous drug users. In one small case series, 40 percent of endogenous endophthalmitis cases were caused by endocarditis. (Ophthalmology 1994;101:832.)
Numerous infectious organisms cause endophthalmitis. Endogenous infection can be the result of Bacillus cereus (IV drug users), streptococci, Staphylococcus aureus, Haemophilus influenza, Neisseria meningitidis, and fungal species. Postoperative organisms are most commonly Staphylococcus epidermidis and S.aureus and streptococcus. Traumatic infections often depend on the underlying mechanism of injury (retained foreign body, soil, etc.), but in addition to staph and strep species, can be Bacillus species, gram-negative species, fungi, or mixed flora. Interestingly, parasites and viruses do not cause endophthalmitis, but infect the retina or uvea.
Patients likely will have decreased vision in the affected eye, injected conjunctiva, cells and flare in the anterior chamber or hypopyon, vitreous cells, and haze. Patients may variably have eyelid edema, chemosis, corneal edema, corneal abscess, associated orbital cellulitis with proptosis and ocular motility restriction, a blunted or absent red reflex, retinal inflammation, hemorrhages, or abscesses. In 80 percent of cases, retinal vessels cannot be visualized because of vitreous haze. (Arch Ophthalmol 1995; 113:1479.) It is important to document visual acuity and perform a slit lamp examination. In patients with delayed traumatic endophthalmitis, a retained foreign body must be ruled out as the source. Orbital CT with 1 mm cuts or ocular ultrasound (B-scan) are recommended to rule out a retained foreign body. In the case of nontraumatic endophthalmitis, a B-scan also may be helpful to identify intraocular inflammation (increase echogenicity).
Once the diagnosis of endophthalmitis is suspected, ophthalmology should be consulted immediately. Patients with suspected endogenous endophthalmitis should be “pan-cultured,” and preparations for hospital admission should be made. Lumbar puncture should be considered in those whom meningitis is suspected. Intravenous or oral antibiotics should be initiated to cover suspected sources of hematogenous seeding. Some ophthalmologists also recommend topical ocular antibiotics, in addition to standardized intravitreal antibiotics.
This patient was diagnosed with Streptococcus agalactiae subacute endocarditis with hematogenously transmitted endophthalmitis and acute congestive heart failure. He had a complicated hospital course that included the development of septic emboli to the wrist. Despite intravitreal, intravenous, and topical antibiotics, the patient's endophthalmitis worsened, and an evisceration was performed because of the concern for infectious globe rupture.