Endogenous endophthalmitis secondary to pyogenic liver abscess

1. Introduction 

Endophthalmitis is a severe inflammation of the intraocular cavities. The condition can be caused by the introduction of contaminating microorganisms following trauma, surgery or via hematogenous spread from distant sites. Thus, the broad classification of endophthalmitis: endogenous and exogenous.

Individuals at higher risk of developing endogenous endophthalmitis have comorbidities that predispose them to infection. These include diabetes mellitus, chronic renal failure and valvular heart disease, among others. A variety of etiologic agents have been identified that include fungi, gram negative and gram positive organisms. In diabetes mellitus, Klebsiella pneumonia is the most likely causative agent [4]. A high clinical suspicion allows immediate diagnosis and treatment. Early antibiotic therapy remains the cornerstone of treatment.

We report the first case of endogenous endophthalmitis associated with Klebsiella pyogenic liver abscess from an Arab ethnic population in the Middle East.

2. Case history 

This a case of a 55year old Palestinian male who sought to consult the emergency room with a chief complaint of abdominal pain localized in the right upper quadrant, associated with vomiting. The patient was afebrile, with no associated signs and symptoms noted. The patient is a diagnosed case of Type 2 diabetes, maintained on and poorly controlled with insulin for 11years.

On the fourth hospital day, the patient complained of sudden onset of left eye pain, accompanied by swelling and ecchymosis (Fig. 2). Visual acuity was noted to be decreased to having no light perception. On slit lamp examination, severe conjunctival congestion, cloudy cornea and shallow anterior chamber (Fig. 3) were reported. Multiple vitreous opacities were also noted via B-scan (Fig. 4). Right eye examination, including general physical examinations, were unremarkable.

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Fig. 1. US, abdomen showing liver abscess.

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Fig. 2. Lt. eye swelling and ecchymosis.

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Fig. 3. Slit lamp showing Lt. eye conjuctival congestion and cloudy cornea.

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Fig. 4. B-scan Lt. eye showing opacity of aqueous humor.

The patient was then diagnosed with liver abscess via HBT ultrasound, supported by abdominal CT scan (Fig. 1). Culture of vitreous humor showed growth with K. pneumonia which was sensitive to vancomycin, aminoglycosides and cephalosporins. The patient was initially given an intravitreal injection of vancomycin 1mg/0.1ml and ceftazidime 2mg/0.1ml. Aspiration of the liver abscess was later undertaken after assessing for his liver status.

Baseline complete blood count revealed leukocytosis of 34,100 with a differential of neutrophil predominance (89%). Liver function tested positive for hepatitis and elevated liver enzymes. Microscopic examination of urine showed a WBC count of 5000/mm3 and an RBC count of 200RBC/mm3 probably secondary to left renal stones as supported by ultrasound of kidneys.

BUN and electrolytes, as well as Alpha feto-protein, were within normal ranges. Urine and blood culture and sensitivity were negative for any growth. Other serological tests were negative.

Patient was managed with the pars plana vitrectomy of the left eye and intravitreal injection of vancomycin 1gmq 12h and ceftazidime 1gmq 12h. The patient was discharged with improved general condition but with no light perception on his left eye.

3. Discussion 

Endophthalmitis is an infection of the interior of the eye that frequently results in visual loss despite appropriate therapeutic intervention. It is an ocular inflammation, resulting from the introduction of an infectious agent into the posterior segment of the eye. Entry of the offending microorganism occurs via three different routes: (1) seeding of the microorganism during intraocular surgery (postoperative), (2) following a penetrating injury of the globe (posttraumatic), or (3) from hematogenous route from distant anatomic area (endogenous) [5]. In endogenous endophthalmitis, a remote primary site of infection may seed the posterior segment of the eye via hematogenous spread, causing endogenous endophthalmitis. Endophthalmitis generally results in visual loss even after aggressive pharmacologic or surgical intervention, often within a few days of inoculation.

The eye is protected against invading organisms through the blood-ocular barrier. Derangements in this barrier permits permeation of blood borne organisms. Intraocular tissues are then destroyed, probably by direct invasion of the organism and/or from inflammatory mediators of the immune response.

The precise evolution of endogenous endophthalmitis is only beginning to emerge. It has historically been linked with toxin production during infection. However, much is to be researched as to the exact mechanisms of retinal toxicity and the triggers for induction of the intraocular immune response.

A relatively rare kind of disease, it accounts for 2–8% of all endophthalmitis cases [6], [7], [8]. In two systematic reviews of endophthalmitis, it was noted that two thirds of cases had a predisposing factor or concurrent illness, including diabetes mellitus, valvular heart disease, among others. Diabetes mellitus is one of the most common concurrent medical conditions and is present in up to 40% of the cases [9]. It has been identified that diabetes mellitus is the major associated clinical condition with K. pneumonia liver abscess. Cases of endogenous endophthalmitis pyogenic liver abscess is more commonly reported in the Far East. K. pneumonia primary liver abscess, particularly those associated with metastatic infection, are more commonly reported in Taiwan and are community acquired.

Endophthalmitis has a variable presentation, depending on the type. However, when presented with a combination of red eye, decreased vision, pain, history of ocular surgery, trauma, immunocompromised state, it is a diagnosis to consider. Occasionally, endophthalmitis may present itself painlessly.

A complete eye examination is mandatory, and should include visual acuity testing, external examination, funduscopic examination and slit lamp biomicroscopy. If seriously considered, prompt referral to ophthalmology is indicated.

Generally, the most important laboratory study for endophthalmitis is Gram stain and the culture of aqueous and vitreous humor. For endogenous endophthalmitis, blood work ups are done to evaluate signs and sources of infections. Imaging studies are done to look for sources, as well as differential diagnoses. Cultures from other body fluids may also prove helpful to identify sources of the disease.

The anatomy and physiology of ocular tissues poses a challenge to the successful treatment of endophthalmitis. The vitreous and the anterior chamber are avascular structures and isolated from the systemic circulation by the blood ocular fluid barrier. This acts as a barrier to immune mediators, as well as for the delivery of pharmacologic agents administered systemically. A further obstacle is that the retinal photoreceptors and other retinal cells are highly sensitive to high doses of antimicrobial agents administered locally [10], [11], [12].

Intravitreal administration of antibiotics is a key component in the management of exogenous bacterial endophthalmitis. The commonly utilized antibiotics include vancomycin 1mg, amikacin 0.4mg and ceftazidime 2.2mg [13].