Post-traumatic endophthalmitis
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Synonyms and keywords: Post-traumatic bacterial endophthalmitis; Post-traumatic fungal endophthalmitis

# Overview
Post-traumatic bacterial endophthalmitis occurs following penetrating ocular injuries. Post-traumatic endophthalmitis is associated with a large variety of organisms. The most commonly 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 second most common. In some cases post-traumatic endophthalmitis is polymicrobial. The risk for developing endophthalmitis after open globe injuries is estimated at about 7% of injured eyes.

# Historical Perspective
- In 1903, post-traumatic fungal endophthalmitis was first reported by Romer.
- In 1933, exogenous fungal endophthalmitis was first described by Rychener.

# Classification
Post-traumatic endophthalmitis may be classified according to the causative organisms into 2 subtypes: bacterial or fungal.

# Pathophysiology

## Pathogenesis
Post-traumatic endophthalmitis occurs following penetrating ocular injuries. 
Following penetrating injury, the eye globe integrity disturbed. The microorganisms are often implanted via direct inoculation by the penetrating object, by a retained foreign body, or by infection of the open wound. Penetrating ocular injuries are accompanied by infection at a much higher rate compared to ocular surgery.
Post-traumatic endophthalmitis is associated with a large variety of organisms. The most commonly 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 the second most common cause. In some cases post-traumatic endophthalmitis is polymicrobial.

### Gross Pathology
On gross pathology, eyelid swelling, eyelid erythema, injected conjunctiva and sclera, hypopyon, chemosis, and mucopurulunt discharge are characteristic findings of 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 post-traumatic bacterial endophthalmitis.

# Causes

## Post-traumatic bacterial endophthalmitis
Common causes of post-traumatic bacterial endophthalmitis include:
- Gram-positive bacteria
Staphylococcus species
Streptococcus  species
Bacillus cereus (most common in the setting of an IOFB or soil contamination)
Clostridium (fulminant endophthalmitis)
Propionibacterium acnes
- Staphylococcus species
- Streptococcus  species
- Bacillus cereus (most common in the setting of an IOFB or soil contamination)
- Clostridium (fulminant endophthalmitis)
- Propionibacterium acnes
- Gram-negative bacteria
Klebsiella
Pseudomonas (fulminant endophthalmitis)
- Klebsiella
- Pseudomonas (fulminant endophthalmitis)
- Polymicrobial

## Post-traumatic fungal endophthalmitis
Common causes of post-traumatic fungal endophthalmitis include:
- Candida species
- Aspergillus species
- Paecilomyces species
- Fusarium  species
- Dematacious fungi

# Differentiating Post-traumatic Endophthalmitis from Other Diseases
Post-traumatic endophthalmitis must be differentiated from:
- Post-traumatic non-infectious inflammation
- Phacoanaphylactic endophthalmitis
- Sympathetic ophthalmia with bilateral anterior uveitis

# Epidemiology and Demographics
The incidence of traumatic endophthalmitis may be decreasing due to earlier wound closure and prompt initiation of antibiotics.
Post-traumatic endophthalmitis accounts for 25,000 to 31,000 cases per 100,000 individuals with endophthalmitis. The incidence of post-traumatic endophthalmitis varies according to the following factors:
- Presence of an intraocular foreign body
- Delay primary globe repair
- Location and extent of laceration of the globe

## Prevalence and Incidence
- The incidence of post-traumatic endophthalmitis was estimated to range from 3.300 to 30,000 per 100,000 individuals with penetrating ocular trauma.
- The incidence of post-traumatic endophthalmitis was estimated to range from 1,300 to 61,000 per 100,000 individuals with intraocular foreign body.

# Risk Factors
Common risk factors in the development of post-traumatic bacterial endophthalmitis include:
- Retained intraocular foreign bodies
Non-metallic intraocular foreign body (IOFB)
- Non-metallic intraocular foreign body (IOFB)
- Injury in a rural setting
- Delay in repair more than 24 hours
- Disruption of the lens
- Ocular tissue prolapse
- Large wound size

# Screening
Screening for post-traumatic endophthalmitis is not recommended after open globe injuries. There is insufficient evidence to recommend routine aqueous culture in all cases of open globe injury.

# Natural History, Complications, and Prognosis

## Natural History
Post-traumatic endophthalmitis may occur within hours after the trauma or up to several weeks after injury. Post-traumatic endophthalmitis is a medical emergency. If left untreated, It may lead to  panophthalmitis, corneal ring ulceration and infiltration, corneal opacification, corneal perforation, and permanent vision loss. 

## Complications
Common complications of post-traumatic endophthalmitis include:
- Panophthalmitis
- Decrease or loss of vision
- Chronic pain
- Cataract development
- Retinal detachment
- Vitreous hemorrhage
- Hypotony and phthisis bulbi
- Proptosis and a corneal abscess

## Prognosis
Post-traumatic bacterial endophthalmitis is associated with a particularly poor visual outcome. Only 22% to 42% patients with post-traumatic bacterial endophthalmitis obtain a final visual acuity of 20/400 or better.

# Diagnosis

## History & Symptoms

### History
- A recent history of penetrating ocular trauma

### Symptoms
Symptoms of post-traumatic bacterial endophthalmitis may include the following:
- Decreased vision
- Disproportionate pain
- Lid swelling
- Photophobia
- Tearing

## Physical Examination
Ophthalmologic examination of patients with post-traumatic endophthalmitis is usually remarkable for:
- Conjunctival injection
- Chemosis
- Purulent discharge
- Lid edema
- Periorbital erythema
- Proptosis

## Laboratory Findings
Laboratory studies consistent with the diagnosis of post-traumatic endophthalmitis include:
- Culture and gram stain of aqueous humor as well as the vitreous humor (often not sensitive)
- Polymerase chain reaction (PCR)  of aqueous humor as well as the vitreous humor (much more sensitive than culture)

## Imaging Findings

### X Ray
Plain film x ray is helpful for the detection of  intraocular foreign bodies (IOFBs). However, it may detect only about 40% of intraocular foreign bodies  (IOFBs).

### CT
Orbital CT scan is helpful for localization of metallic intra ocular foreign bodies (IOFBs) in the setting of trauma. 

### MRI
Orbital MRI scan is helpful for localization of intra ocular foreign bodies (IOFBs) that may be radiolucent on CT in the setting of trauma. However, metallic IOFB must be excluded first.

### Ultrasound
On ocular ultrasonography, endophthalmitis may be characterized by anterior vitreous haze echoes and retinochoroidal thickening.

### Other Imaging Findings
Orbital echography is helpful for assessment of vitreous opacification, presence of (IOFBs), status of the posterior hyaloid face, and retinal detachment in a patient with post-traumatic endophthalmitis.

## Other Diagnostic Studies

### Slit lamp examination
On slit lamp examination, post-traumatic endophthalmitis is characterized by:
- Mild to moderate anterior chamber reaction
- Hypopyon
- Corneal ring infiltrate
- Clumps of thick white material in the anterior chamber (fungal endophthalmitis)
- Filaments extending from the back of the cornea into the aqueous humor (fungal endophthalmitis)

# Treatment
- The patient needs urgent examination by an expert ophthalmologist and/or vitreo-retinal specialist who will determine the need for intravitreal injection of potent antibiotics or pars plana vitrectomy as needed. Enucleation may be required to remove a blind and painful eye.
- Closure of the wound is the first step in management of open globe injury
- Removal of intraocular foreign bodies (IOFB) and debridement of necrotic tissue is necessary
- Bacterial and fungal cultures from vitreous samples are required
- Vitrectomy is often indicated
- Immunization against tetanus based on history is necessary

## Medical Therapy
- Systemic broad spectrum antibiotics are recommended
- Systemic antifungal agents are recommended in patients with suspected fungal endophthalmitis

## Antimicrobial Regimens
- Infectious endophthalmitis
- 1. Empiric antimicrobial therapy
- Preferred regimen: Vancomycin 1 mg per 0.1 mL normal saline intravitreal injection, single dose AND Ceftazidime 2.25 mg per 0.1 mL normal saline intravitreal injection, single dose AND Amphotericin B 5-10 microgram in 0.1 mL in normal saline intravitreal injection, single dose
- Note (1): Removal of foreign bodies and debridement of necrotic tissue is necessary
- Note (2): In addition to antimicrobial therapy, vitrectomy is necessary
- Note (3): Systemic broad spectrum antibiotics are recommended in post-traumatic endophthalmitis
- 2. Pathogen-directed antimicrobial therapy
- 2.1 Bacillus spp.
- Preferred regimen: Vancomycin 1 mg per 0.1 mL normal saline intravitreal injection, single dose AND Vancomycin 1 g IV bid for 2 weeks AND Clindamycin 600-1200 mg IV bid to qid for 2 weeks
- Note: In addition to antimicrobial therapy, vitrectomy is usually necessary
- 2.2 Non-Bacillus gram-positive bacteria
- Preferred regimen: Vancomycin 1 mg per 0.1 mL normal saline intravitreal injection, single dose AND Vancomycin 1 g IV bid for 2 weeks
- Note: In addition to antimicrobial therapy, vitrectomy is usually necessary
- 2.3 Gram-negative bacteria
- Preferred regimen: Ceftazidime 2.25 mg per 0.1 mL normal saline intravitreal injection, single dose AND Ceftazidime 1 g IV bid for 2 weeks
- Note: In addition to antimicrobial therapy, vitrectomy is usually necessary
- 2.4 Candida spp.
- Preferred regimen: (Fluconazole 400-800 mg IV/PO qd for 6-12 weeks OR Voriconazole 400 mg IV/PO bid for 2 doses followed by 200-300 mg IV/PO bid for 6-12 weeks OR Amphotericin B 0.7-1.0 mg/kg IV qd for 6-12 weeks) AND Amphotericin B 5-10 microgram in 0.1 mL in normal saline intravitreal injection, single dose
- Note (1): In addition to antimicrobial therapy, vitrectomy is usually necessary
- 2.5 Aspergillus spp.
- Preferred regimen: Amphotericin B 5-10 microgram in 0.1 mL normal saline intravitreal injection, single dose AND Dexamethasone 400 microgram intravitreal injection, single dose
- Note (1): In addition to antimicrobial therapy, vitrectomy is usually necessary
- Note (2): Repeat antimicrobial regimen in 2 days post-vitrectomy

## Surgery

### Vitrectomy
Vitrectomy surgically debrides the vitreous humor, similarly to draining an abscess. It is the fastest way of clearing infection in eyes with fulminant endophthalmitis.
- Vitrectomy is recommended for all patients who develop exogenous bacterial endophthalmitis.
- Vitrectomy is recommended in severe cases of endogenous bacterial endophthalmitis.
The benefits of vitrectomy include:
- Better vitreous sample
- Rapid and complete sterilization of the vitreous
- Removal of toxic bacterial products
- Enhancement of systemic antimicrobial penetration in to the eye

## Prevention

### Primary prevention
Effective measures for the primary prevention of post-traumatic endophthalmitis include:
- Primary globe repair within 24 h
- Removal of foreign bodies and debridement of necrotic tissue
- Intracameral or intravitreal antibiotic injection after penetrating eye injury
- Systemic antimicrobial prophylaxis is recommended
- Systemic antifungal prophylaxis is recommended with the suspicion of fungal infection.

### Secondary prevention
There are no secondary preventive measures available for post-traumatic endophthalmitis.