Bilateral Endogenous Endophthalmitis Associated with Methicillin Sensitive Staphylococcus aureus (MSSA) Related Tenosynovitis: Case Report

Abstract

Endogenous endophthalmitis is a rare, devastating intraocular infection associated with poor outcome often from late diagnosis. We present a case report of acute onset bilateral endogenous endophthalmitis caused by Methicillin Sensitive Staphylococcus Aureus causing tenosynovitis of carpometacarpal joint in a 64 year old man with Type II Diabetes Mellitus. To the best of our knowledge, this is the first case report of endogenous endophthalmitis following tenosynovitis. This case also highlights the fact that prompt diagnosis and treatment is the key for good outcome.

Keywords::

• bilateral endophthalmitis
• endogenous endophthalmitis
• MSSA
• tenosynovitis

Endogenous endophthalmitis is a rare, devastating intraocular infection associated with poor outcome often from late diagnosis. Aggressive and early treatment with appropriate antibiotics may salvage some vision. A variety of organisms have been implicated, of which bacteria and fungi are most common. Most cases are associated with an identifiable source of sepsis: gram-positive infections often have underlying endocarditis, septic arthritis, and cutaneous infections; gram-negative infections are usually associated with hepatobiliary, chest, and urinary tract infections. Fungal organisms typically are seen in patients with immunosuppression, intravenous drug abuse, bacterial sepsis, prolonged hyperalimentation, corticosteroid therapy, recent abdominal surgery, malignancy, alcoholism, diabetes mellitus, trauma, and hemodialysis.^1–3 Among East Asians, most cases of bacterial endogenous endophthalmitis are caused by gram-negative bacteria, especially Klebsiella pneumoniae (77.4%).⁴ Only 5.4% of cases are associated with Staphylococcus aureus septicemia. It commonly occurs when mucosal barriers are breached, especially among those with diabetes.⁵

Staphylococcus aureus is a major cause of bacteremia, and S. aureus bacteremia (SAB) is associated with higher morbidity and mortality, compared with bacteremia caused by other pathogens.⁶ The incidence of S. aureus bacteremia and its complications has increased sharply in recent years because of the increased frequency of invasive procedures, increased numbers of immunocompromised patients, and increased resistance of S. aureus strains to available antibiotics.⁶ In recent years, clinic relevance of SAB has become more prominent, owing to the progressive rise of methicillin-resistant strains in hospital-acquired infections and also increasing risk of infective endocarditis and seeding to other metastatic foci increasing the risk of mortality.⁶ Endogenous endophthalmitis is rare but devastating intraocular infection associated with Staphylococcus bacteremia.^5,6

We describe a patient with tenosynovitis complicated by methicillin-sensitive Staphylococcus aureus bacteremia and subsequently developing bilateral endogenous endophthalmitis. To the best of our knowledge this is the first report of endophthalmitis following tenosynovitis.

A 64-year-old Chinese man with uncontrolled type II diabetes mellitus presented with pyrexia of 38.8°C preceded by swelling and tenderness of his right thumb for 1 day. His glycemic control was poor and his HbA1C at time of admission was 9.1 g%. One day later, he complained of blurring of vision in both eyes (right > left). Vision was counting fingers in the right eye and 20/100 in the left. There was right eye hypopyon, and anterior chamber cells 2+ in the left. Dilated fundi showed vitritis in both eyes (right > left) with a Roth’s spot in the left (Figure 1). Provisional diagnosis was bilateral endogenous endophthalmitis. Bilateral vitreous tap with intravitreal vancomycin (1 mg/0.1 mL) and ceftazidime (2.25 mg/0.1 mL) was performed. Blood cultures yielded methicillin-sensitive Staphylococcus aureus (MSSA), although vitreous culture was negative in both specimens. Sensitivity report revealed MSSA to be sensitive to cloxacillin, vancomycin, cefuroxime, ceftazidime, penicillin, and ofloxacillin. The patient was commenced on intravenous cloxacillin for disseminated bacteremia with hourly levofloxacin 0.5% eyedrops to both eyes. As the patient had marginal clinical improvement following the first dose of intravitreal antibiotics, repeat intravitreal injections of vancomycin and ceftazidime were given 2 days later to maximize the therapeutic effect of antibiotics at site of infection, i.e., intravitreally in addition to parentral antibiotics. Over the next 2 weeks, his vision recovered to 20/20 in both eyes and systemically he was afebrile, and tenosynovitis was resolved as well in 3 weeks. No form of corticosteroids was administered in this patient. The patient was followed up for 2 years and his eyes remain quiescent with VA of 20/20 in both eyes and no recurrence of inflammation.

FIGURE 1  (A) Fundus photograph of the left eye showing presence of Roth’s spot. (B) Fundus photograph of the right eye showing mild to moderate vitritis.

Bilaterality has been reported in 14–25% of endogenous endophthalmitis.^1,2 Appropriate systemic antibiotics unfortunately do not prevent fellow eye involvement, presentation of which may be delayed. Infections by gram-positive organisms may be multifocal, associated with Roth’s spots and retinal vasculitis. Gram-negative infections usually cause a single choroidal abscess involving the posterior pole.^1,2 Blood, urine, and cerebrospinal fluid specimens for culture allow early and successful identification of microorganisms in at least 80% of cases, but positive cultures from ocular fluid is only seen in 36–73% of cases.^1,2,4

The value of intravitreal antibiotics in addition to intravenous antibiotics has not been established but it is accepted that the cases worsening despite medical treatment should be treated aggressively with both systemic and intravitreal antibiotics. The tight junctional complexes of the retinal pigment epithelium and retinal capillaries inhibit penetration of substances, including antibiotics into the vitreous. Hence, loading dose of locally administered antibiotic is required in severe cases to control the infection.⁷ Intravitreal injections of vancomycin (1 mg/0.1 mL) and ceftazidime (2 mg/0.1 mL) provide wide-spectrum coverage for most gram-positive and gram-negative organisms.⁴ Owing to the short half-life, repeated injections may be required.¹ Despite aggressive antimicrobial therapy, a significant percentage of eyes with endogenous endophthalmitis can end up having no light perception vision and subsequent evisceration. No perception of light has been reported in 53.1–89% of eyes in the literature.^4,8 A young age, low virulence, and gram-positive infections predicted a better outcome.^1–4

Endogenous endophthalmitis continues to occur despite the continuing development of effective antibiotics. There are no randomized trials on the use and choice of intravitreal antibiotics but they have a definite role in cases that progress despite medical therapy. Our case is unusual for its source of primary infection and bilaterality, and highlights that suspicion with prompt diagnosis and treatment can result in good outcomes. The current case showed marked improvement in final vision outcome with no areas of retinal necrosis as the patient had early diagnosis and prompt intervention with parentral antibiotics coupled with intravitreal antibiotics.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.