Bacterial endophthalmitis
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]
Overview
Bacterial endophthalmitis means bacterial infection inside the eye, involving the vitreous and/or aqueous humors. Most cases of endophthalmitis are exogenous, and organisms are introduced into the eye via trauma, surgery, or an infected cornea. Endogenous endophthalmitis occurs when the eye is seeded via the bloodstream. Patients usually have symptoms from their underlying systemic infection, but sometimes present only with eye symptom.
Historical Perspective
Classification
Based on how infectious agents generally gain access to the posterior segment posterior segment of the eye, bacterial endophthalmitis may be classified into:
- Exogenous bacterial endophthalmitis
- Acute post-operative bacterial endophthalmitis
- Delayed post-operative bacterial endophthalmitis
- Post-traumatic bacterial endophthalmitis (following a penetrating injury of the globe)
- Endogenous bacterial endophthalmitis
Pathophysiology
Exogenous bacterial endophthalmitis
Pathogenesis
Acute post-operative bacterial endophthalmitis occurs within 1 week following ocular surgery. It is an ocular inflammation resulting from the introduction of an infectious agent, most commonly coagulase-negative staphylococci, into the posterior segment of the eye. Nearly every type of ocular surgery, such as cataract, glaucoma, retinal, radial keratotomy, and intravitreal injections, may be able to disturb the eye globe integrity and contaminate the aqueous humor. Preoperative topical antimicrobial agents can decrease colony counts in the tear film, but they do not sterilize the area. The exact low rate of clinical infection following eye surgery (despite the relatively high prevalence of microorganisms in the eye) is not fully understood. It is thought that low rate of clinical infection following surgical procedure is explained by combination of low inoculum levels, low pathogenicity, and the innate ocular defenses against infection.
Post-operative bacterial endophthalmitis may also occur weeks to years following surgery. The exact pathogenesis of delayed postoperative bacterial endophthalmitis is not fully understood. It is thought that delayed pos-toperative bacterial endophthalmitis is caused by either sequestration of low-virulence organisms introduced at the time of surgery or delayed inoculation of organisms to the eye through wound abnormalities, suture tracks, or filtering blebs. Propionibacterium acnes is the most common microorganism encountered in delayed post-operative bacterial endophthalmitis.
Post-traumatic bacterial endophthalmitis occurs following penetrating ocular injuries. Following penetrating injury, the eye globe integrity disturbed. Penetrating ocular injuries are accompanied by infection at a much higher rate compere to ocular surgery. The broad prevalence range is due to factors such as:
- Presence of an intraocular foreign body
- Delay primary globe repair
- Location and extent of laceration of the globe
Post-traumatic endophthalmitis associated with a greater variety of organisms. The most common isolated organisms include Gram-positive Staphylococcus epidermidis and Streptococcus (as a part of the normal skin flora and regularly contaminate open wounds). Bacillus cereus is ranked second and some cases are polymicrobial.
Gross Pathology
On gross pathology, eyelid swelling, eyelid erythema, injected conjunctiva and sclera, hypopyon, chemosis, and mucoprulunt dischage are characteristic findings of exogenous bacterial endophthalmitis.
Microscopic histopathological analysis
On microscopic histopathological analysis, infiltration of polymorphonuclear leukocytes or chronic inflammatory cells (depending on the duration of the inflammation) and destruction of ocular structures are characteristic findings of bacterial endophthalmitis.
Endogenous bacterial endophthalmitis
Pathogenesis
Endogenous endophthalmitis is typically the result of hematogenous spread from a distant infective source, such as urinary tract infections, liver abscesses, meningitis, catheters, and illicit injection drug use. Endogenous endophthalmitis is commonly associated with immunosuppression or procedures that increase the risk for blood-borne infections, such as diabetes, HIV, malignancy, intravenous drug use, transplantation, immunosuppressive therapy, and catheterization. Under normal circumstances, the blood-ocular barrier provides a natural resistance against invading organisms. Following bacteremia, the blood-borne organisms permeate the blood-ocular barrier by:
- Direct invasion (septic emboli)
- Change in vascular endothelium (caused by inflammatory mediators released during infection)
Gross Pathology
On gross pathology, findings in endogenous endophthalmitis may be similar to those in infections of exogenous origin.
Microscopic histopathological analysis
On microscopic histopathological analysis, infiltration of polymorphonuclear leukocytes or chronic inflammatory cells (depending on the duration of the inflammation) and destruction of ocular structures are characteristic findings of bacterial endophthalmitis.
Causes
Post-operative Bacterial Endophthalmitis
Post-operative endophthalmitis has been reported following nearly every type of ocular surgery. Common causes of post-operative bacterial endophthalmitis include:[1][2]
- Gram-positive bacteria (95%)
- coagulase-negative staphylococci (70%)
- Staphylococcus aureus (10%)
- Streptococcus (9%)
- Enterococcus and mixed bacteria (5%)
- Gram-negative bacilli (6%)
Delayed Post-operative Bacterial Endophthalmitis
Common causes of delayed post-operative bacterial endophthalmitis include:[1][2]
- Propionibacterium acnes (most common)
- Streptococcus species
Post-traumatic Bacterial Endophthalmitis
Common causes of post-traumatic bacterial endophthalmitis include:[1][2]ref name="pmid15522366">Essex RW, Yi Q, Charles PG, Allen PJ (2004). "Post-traumatic endophthalmitis". Ophthalmology. 111 (11): 2015–22. doi:10.1016/j.ophtha.2003.09.041. PMID 15522366. </ref>
- Streptococcus
- Bacillus cereus
- Polymicrobial
Endogenous bacterial endophthalmitis
Common causes of endogenous bacterial endophthalmitis include:[1][2][3]
- Gram-positive bacteria
- Staphylococcus aureus
- Bacillus cereus (primary bacterial cause in intravenous drug abusers and are most likely seeded from contaminated injection paraphernalia and drug solutions)
- Gram-negative bacteria
Differentiating Bacterial Endophthalmitis from Other Diseases
Bacterial endophthalmitis must be differentiated from:[1][2][4] Accessed on July 20, 2016 </ref>
- Fungal endophthalmitis
- Post-operative inflammation
- Intraocular foreign body
- Acute retinal necrosis
- Keratitis (interstitial)
- Uveitis
- Hyphema
- Toxic anterior segment syndrome (TASS)
- Vitreous hemorrhage
- Autoimmune disorders (Ankylosing Spondylitis, Spondyloarthropathy, acute complications of Sarcoidosis, and HLA-B27 Syndromes)
Epidemiology and Demographics
- Post-operative bacetrial endophthalmitis accounts for approximately 60000 cases per 100,000 cases of exogenous endophthalmitis.[5]
- Endogenous endophthalmitis is a rare disease that tends to affect immunocompromised patients and patients with chronic disease.
- Endogenous endophthalmitis accounts for approximately 5000 to 10000 cases per 100,000 cases with endophthalmitis.[6]
Prevalence and Incidence
- The incidence of post-traumatic endophthalmitis was estimated to be 4000 to 13000 cases per 100,000 individuals with penetrating ocular injuries.
- The incidence of endogenous endophthalmitis is estimated to be 50 cases per 100,000 hospitalized patients.[1][7]
Age
- Post-operative bacterial endophthalmitis (following cataract surgery) commonly affects patients older than 85 years.[1]
- Patients of all age groups may develop endogenous bacterial endophthalmitis.[5]
Gender
- Exogenous and endogenous bacterial endophthalmitis affects men and women equally.[1]
Race
- In East Asian populations, liver abscess caused by Klebsiella pneumoniae is the source of 60% of cases of endogenous endophthalmitis.[3]
Developed countries
- In developed countries/United States, post-cataract endophthalmitis is the most common form bacterial endophthalmitis.
- In developed countries/United States, the incidence of post-operative bacterial endophthalmitis was estimated to be 100 to 300 cases per 100,000 individuals who have ophthalmologic operations (mostly cataract).[5]
Risk Factors
Post-operative bacterial endophthalmitis
Common risk factors in the development of post-operative bacterial endophthalmitis include:[1][8]
- immunosuppressive therapy
- Implantation of an intraocular lens without a heparinized surface
- Diabetes
- Wound dehiscence or leak
- Age ≥85
- Lens implants made of polypropylene (Prolene) instead of polymethyl methacrylate
Post-traumatic bacterial endophthalmitis
Common risk factors in the development of post-traumatic bacterial endophthalmitis include:[1][7]
- Retained intraocular foreign bodies
- Delay in repair
- Disruption of the lens
Endogenous bacterial endophthalmitis
Common risk factors in the development of endogenous bacterial endophthalmitis include:[1][2][3]
Screening
Screening for bacterial endophthjalmitis is not recommended.
Natural History, Complications, and Prognosis
Natural History
Complications
Prognosis
Diagnosis
Diagnostic Criteria
History and Symptoms
Physical Examination
Laboratory Findings
Imaging Findings
X Ray
CT
MRI
Ultrasound
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Prevention
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Kernt M, Kampik A (2010). "Endophthalmitis: Pathogenesis, clinical presentation, management, and perspectives". Clin Ophthalmol. 4: 121–35. PMC 2850824. PMID 20390032.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Durand ML (2013). "Endophthalmitis". Clin Microbiol Infect. 19 (3): 227–34. doi:10.1111/1469-0691.12118. PMC 3638360. PMID 23438028.
- ↑ 3.0 3.1 3.2 Wong JS, Chan TK, Lee HM, Chee SP (2000). "Endogenous bacterial endophthalmitis: an east Asian experience and a reappraisal of a severe ocular affliction". Ophthalmology. 107 (8): 1483–91. PMID 10919895.
- ↑ American Academy of Ophthalmology/eyewiki (2014) http://eyewiki.aao.org/Endophthalmitis
- ↑ 5.0 5.1 5.2 Aaberg TM, Flynn HW, Schiffman J, Newton J (1998). "Nosocomial acute-onset postoperative endophthalmitis survey. A 10-year review of incidence and outcomes". Ophthalmology. 105 (6): 1004–10. doi:10.1016/S0161-6420(98)96000-6. PMID 9627649.
- ↑ Jackson TL, Eykyn SJ, Graham EM, Stanford MR (2003). "Endogenous bacterial endophthalmitis: a 17-year prospective series and review of 267 reported cases". Surv Ophthalmol. 48 (4): 403–23. PMID 12850229.
- ↑ 7.0 7.1 Essex RW, Yi Q, Charles PG, Allen PJ (2004). "Post-traumatic endophthalmitis". Ophthalmology. 111 (11): 2015–22. doi:10.1016/j.ophtha.2003.09.041. PMID 15522366.
- ↑ Taban M, Behrens A, Newcomb RL, Nobe MY, Saedi G, Sweet PM; et al. (2005). "Acute endophthalmitis following cataract surgery: a systematic review of the literature". Arch Ophthalmol. 123 (5): 613–20. doi:10.1001/archopht.123.5.613. PMID 15883279.