Endogenous Nocardial Endophthalmitis in an Immunosuppressed Patient: A Serious Warning of an Underlying Life Threatening and Blinding Disorder.

PURPOSE: To report a case of bilateral endogenous nocardial endophthalmitis with central nervous system involvement in an immunocompromised individual with an extremely poor outcome. CASE REPORT: A 35-year-old man with a history of long-term, prescribed oral steroid use for membranoproliferative glomerulonephritis presented with profound bilateral vision loss. Patient's diagnosis of bilateral endogenous nocardial endophthalmitis was delayed. Nocardia was finally isolated from a brain biopsy after a repeat magnetic resonance imaging revealed a brain abscess. With anti-nocardia therapy, patient improved systemically, but the visual outcome was poor, with no light perception in both eyes.
CONCLUSION: Ocular nocardiosis is a serious vision and life threatening disorder, particularly in patients on immunosuppressive therapy. A high index of suspicion is required for successful treatment.

INTRODUCTION

Ocular nocardiosis is uncommon, difficult to diagnose disorder, and encountered primarily in immunocompromised patients. It is typically caused by Nocardia asteroides.[1] This is an aerobic, gram positive, partially acid fast organism belonging to order Actinomycetales. Initially this bacterium was classified as a fungus; however its cell wall structure and intracellular organelles resemble those of bacteria, and it is now classified as a bacterium. Historically, nocardial infections in humans are very rare and often self-limiting. However, their frequency and severity are increasing, particularly as immunosuppressive and chemotherapeutic agents are used more frequently for systemic diseases. We present a case of an immunocompromised patient presenting with bilateral endogenous nocardial endophthalmitis along with central nervous system involvement that resulted in an extremely poor outcome.

CASE REPORT

A 35-year-old-male patient presented with sudden loss of vision associated with periorbital swelling in both eyes (OU). He had systemic complaints of fever and pedal edema. The patient was already undergoing treatment for membranoproliferative glomerulnephritis, and for the previous seven months was taking oral prednisone (pg. mg/day) and Angiotensin converting enzyme inhibitor. Ocular examination revealed visual acuity of light perception (LP) with inaccurate ray projection in OU.

Slit lamp biomicroscopic examination revealed 2+ cells in anterior chamber and pigments over the anterior lens surface in OU. Fundus examination revealed hazy media along with retinal detachment in the inferotemporal area in OU. Sub-retinal exudates, intraretinal hemorrhages along with dilated veins and narrowed arteries were visible. Intraocular pressure (IOP) was 16 mmHg in OU. The patient had blood pressure of 160/100 mmHg and bradycardia. Hence, the initial diagnosis was hypertension related exudative retinal detachment, although both atypical central serous chorioretinopathy and Vogt-Koyanagi Harada syndrome were also considered in differential diagnosis. After receiving a nephrologist's opinion, the patient was stabilized with an injection of hydrocortisone 200 mg OD, frusemide 40 mg OD, cefixime 200 mg BD along with amlodipine 5 mg OD as a hypertensive drug.

After two days, the patient developed generalized hypotony, a staggering gait, truncal ataxia, and buccal and proximal weakness with decreased plantar reflexes. After neurology consultation, a pontomedullary lesion or cytomegalovirus meningitis was considered as an initial cause. A cerebrospinal fluid tap was performed to rule out meningitis; the results were normal. Magnetic resonance imaging (MRI) of the brain [Figure 1a and b] showed multiple cystic-enhancing lesions over both cerebral hemispheres, suggestive of tuberculomas or neurocysticercosis.

Figure 1

Magnetic resonance images brain and orbit. (a) Sagittal and (b) axial scans showing multiple sub-centimeter discrete ring enhancing lesions scattered in bilateral cerebral hemispheres; (c), T2W axial image after six weeks of initial MRI showing enlarged cerebral lesion with accompanying significant edema and mass effect; (d), with post contrast irregular enhancement; (e), axial orbit sections show the deformed globes with associated inflammatory changes in retro-orbital fat as patchy T2 hyper intensity; (f), T1W image shows the evidence of hemorrhage within the left globe.

The patient was started on anti-tubercular treatment (ATT) along with oral steroids. Four days after starting ATT, the patient had a generalized tonic-clonic seizure. A contrast MRI showed disseminated parenchymal lesions. At the beginning of anti-epileptic treatment, patient showed signs of improvement over the next two weeks; however after this period the patient started worsening. The patient had restricted abduction, sluggishly reacting pupils, 3+ cells in the anterior chamber OU with IOP of 66 and 52 mmHg in the right and left eyes, respectively. Fundus examination revealed increased exudates, increased height of retinal detachment and vitreous cells OU. A diagnosis of disseminated toxoplasma or malignancy was considered. Analysis of an aqueous tap via polymerase chain reaction (PCR) was negative for malignant cells, tuberculosis, cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and toxoplasma.

An Ahmed glaucoma valve was implanted in the left eye subsequent to failure of IOP control with maximum medical therapy. Postoperatively, the left eye was stony hard with severe conjunctival chemosis and a shallow anterior chamber [Figure 2].

Figure 2

Clinical photographs of the patient after Ahmed glaucoma valve implantation showing severe conjunctival chemosis and mechanical complete ptosis of both eyes.

Due to suspicion of metastatic endophthalmitis, five weeks after initial presentation, a vitreous biopsy was performed through pars plana vitrectomy. Intravitreal vancomycin (1 mg/0.1 ml), ceftazidime (2.5 mg/0.1 ml), and voriconazole (1 mg/0.1 ml) were instilled at the end of the procedure and the patient was started on fortified cefazolin 5% and tobramycin 1.4% every hour and Natamycin 5% (every six hours) for presumptive fungal endophthalmitis. All tissue sample smears and cultures that were tested for bacterial and fungal organisms were negative.

Subsequently, the patient had no LP along with severe conjunctival chemosis, exposure keratopathy, and conjunctival abscesses. Cerebrospinal fluid was negative for CMV and Cryptococcus sp. Blood tests were negative for HIV and TORCH (Toxoplasma gondii, other viruses [HIV, measles, and so on), rubella [German measles]), CMV, and herpes simplex. Blood culture showed no evidence of bacterial and fungal organism growth. A bone marrow biopsy was performed to rule out blood cell malignancy but results were normal.

Due to the progressive worsening of patients' systemic status and severe cachexia, a repeat MRI of the brain was done, and revealed a large right parieto-occipital mass lesion [Figure 1c and d]. The orbital region showed bilateral globe deformities, intraocular hemorrhages, and extraocular soft-tissue inflammation [Figure 1e and f].

A multiloculated intracerebral abscess was drained, and a brain biopsy was performed, revealing the presence of the Nocardia organism along with granulomatous reactions [Figure 3a–d]. The patient was administered intravenous imipenem for two weeks, amikacin for four weeks, and later, oral cotrimoxazole and trimethoprim. However, the patient had no LP in both eyes despite anti-nocardial treatment, probably because of delayed diagnosis and severity of involvement. Although the patient improved systemically over next two weeks, he subsequently developed phthisis of both eyes.

Figure 3

(a) Scanner view of necrotic area (H and E ×40) and high power view (b) (H and E ×100) of the same area showing granulomatous response with giant cells; (c), high power view of the same area showing granulomatous response with multinucleate giant cells (H and E ×400); (d), Gram stain of the same area showing gram positive filamentous hyphae of Nocardia (Gram ×400). H and E, hematoxylin and eosin staining.

DISCUSSION

Ocular nocardiosis usually presents with insidious, painless vision loss caused by chorioretinal infiltrates or a mass lesion with overlying hemorrhage in the macular region with mild inflammatory reaction.[2] Nocardial infections in the eye manifests as keratitis, scleritis, and endophthalmitis. Keratitis and scleritis are mostly associated with exposure to soil and plant matter.[1] In various case reports and case series, endogenous nocardial endophthalmitis is described in association with immunosuppression therapy[3] used for cardiac transplants,[4] renal transplants,[5] systemic lupus erythematosus,[6] chronic lymphocytic leukemia,[7] Behcet's disease,[8] and glomerulonephritis.[3]

The current case was unique in the level of difficulty and consequent delay of final diagnosis. There was a six-week delay in reaching the final diagnosis and definitive treatment. The patient recovered well, but unfortunately lost his sight.

Endogenous Nocardia asteroides endophthalmitis is associated with dismal outcomes, with many cases leading to blindness despite prolonged and aggressive treatment. Currently, amikacin is the drug of choice for treating nocardiosis.[910] Nocardia sp. also shows susceptibility to some of the second and third generation cephalosporins. Therapy duration is poorly standardized, but should be prolonged because relapse is common. In immunosuppressed patients, the treatment should be administered for at least one year.[11] In this case, although the brain abscess responded to the treatment, the ocular lesion continued to demonstrate disease progression.

Endogenous nocardial endophthalmitis is a rare disease that can cause severe patient morbidity and mortality. Successful treatment requires a high index of suspicion, particularly in an immunocompromised patient.

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Conflicts of interest

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