Bacterial endophthalmitis: Difference between revisions
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===Exogenous bacterial endophthalmitis=== | ===Exogenous bacterial endophthalmitis=== | ||
====Pathogenesis==== | ====Pathogenesis==== | ||
'''Acute post-operative endophthalmitis''' is an ocular [[inflammation]] resulting from the introduction of an infectious agent, most commonly [[Coagulase-negative Staphylococcus|coagulase-negative staphylococci]], into the [[posterior segment|posterior segment of the eye]]. | '''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 Staphylococcus|coagulase-negative staphylococci]], into the [[posterior segment|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]]. | 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 immune system|innate ocular defenses]] against infection. | 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 immune system|innate ocular defenses]] against infection. | ||
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Post-operative bacterial endophthalmitis may also occur weeks to years following surgery. | 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. | 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 | ''[[Propionibacterium acnes]]'' is the most common microorganism encountered in delayed post-operative bacterial endophthalmitis. | ||
'''Post-traumatic bacterial endophthalmitis''' occurs following penetrating ocular injuries. | '''Post-traumatic bacterial endophthalmitis''' occurs following penetrating ocular injuries. | ||
Revision as of 16:42, 20 July 2016
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.
Endogenous bacterial endophthalmitis
Pathogenesis
Endogenous endophthalmitis is typically the result of hematogenous spread from a distant infective source within the body. 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:
- 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:
- Propionibacterium acnes (most common)
- Streptococcus species
Post-traumatic Bacterial Endophthalmitis
Common causes of post-traumatic bacterial endophthalmitis include:
- Streptococcus
- Bacillus cereus
- Polymicrobial
Endogenous bacterial endophthalmitis
Common causes of endogenous bacterial endophthalmitis include:
- 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]
- 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
estimated to be [number range] cases per 100,000 individuals worldwide Post-operative endophthalmitis accounts for approximately 60000 cases per 100,000 cases of exogenous endophthalmitis. In developed countries/United States, post-cataract endophthalmitis is the most common form, with approximately 0.1-0.3% of operations having this complication which has increased over the last 3 years.[1] Although this is a small percentage, large numbers of cataract operations are performed each year making the chances that physicians may encounter this infection higher. Endophthalmitis may also occur after intravitreal injections, although this risk in an analysis of over 10,000 injections is estimated at 0.029% per injection.[2]
Post-traumatic endophthalmitis occurs in 4-13% of all penetrating ocular injuries.
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 ofof all cases of endophthalmitis.[2] In Taiwan, Singapore, and other East Asian nations, liver abscess caused by Klebsiella pneumoniae is the source of 60% of cases of endogenous endophthalmitis.[3] Average annual incidence is about 5 per 10,000 hospitalized patients.
The incidence/prevalence of [disease name] is approximately [number range] per 100,000 individuals worldwide. [Cancer name] is the [number] most common cancer worldwide ● The majority of [disease name] cases are reported in [geographical region]. ● Patients of all age groups may develop [disease name]. ● [Disease name] is a common/rare disease that tends to affect [patient population 1] and [patient population 2]. ● [Gender 1] are more commonly affected with [disease name] than [gender 2]. The [gender 1] to [gender 2] ratio is approximately [number > 1] to 1. ● [Disease name] affects men and women equally. [Disease name] usually affects individuals of the [race 1] race. [Race 2] individuals are less likely to develop [disease name].
Risk Factors
Screening
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
- ↑ American Academy of Ophthalmology/eyewiki (2014) http://eyewiki.aao.org/Endophthalmitis Accessed on July 20, 2016
- ↑ 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.
- ↑ 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.