Patient Overview

A 65-year-old woman with a 12-year history of type 2 diabetes mellitus (T2DM) presented with respiratory and ocular symptoms. Her diabetes had been managed with metformin 500 mg twice daily without regular blood glucose monitoring.

On admission, glycated hemoglobin (HbA1c) was 10.8%, indicating poor glycemic control. She had diabetic peripheral neuropathy with decreased sensation in both lower extremities, without evidence of diabetic nephropathy or retinopathy.

She reported a 14-day history of productive cough with yellow purulent sputum and a 5-day history of intermittent fever, with a peak temperature of 39.6 °C. Ocular symptoms began on January 24, 2025 and progressed rapidly.

Clinical Presentation

The patient developed progressive visual loss in the left eye, declining from 0.3 to hand motion visual acuity. Severe ocular pain was present, with a visual analog scale (VAS) score of 7/10, along with eyelid swelling, conjunctival hyperemia, edema, purulent discharge, and pain exacerbated by eye movement.

Ophthalmic examination confirmed left eye endophthalmitis, with corneal edema and opacity, a 2 mm hypopyon in the anterior chamber, and significant vitreous opacity.

On admission, vital signs showed tachycardia (112 beats/min) and tachypnea (22/min), with normal body temperature (37.0 °C) and blood pressure of 127/90 mmHg.

Physical examination revealed an alert and cooperative patient without jaundice, respiratory distress, or peripheral edema. Cardiopulmonary auscultation showed a regular rhythm without murmurs. The abdomen was soft, with no tenderness, rebound, or guarding. Neurological examination was nonfocal.

Diagnostic Evaluation

Laboratory testing demonstrated a marked systemic inflammatory response, with the following findings:

• White blood cell (WBC) count: 16.22 × 10⁹/L (reference range: 3.50-9.50 × 10⁹/L)
• C-reactive protein (CRP): 151.51 mg/L (reference range: 0-10 mg/L)
• Procalcitonin (PCT): 7.73 ng/mL (reference range: 0-0.15 ng/mL)
• Erythrocyte sedimentation rate (ESR): 86 mm/h (reference range: 0-20 mm/h)

Microbiological evaluation included blood cultures, ocular swabs, and hepatic abscess drainage fluid cultured on standard media under aerobic conditions. Gram-negative bacteria were isolated from all specimens.

Klebsiella pneumoniae was identified from all sites, and repeat testing confirmed it as the sole pathogen.

Antimicrobial susceptibility testing demonstrated sensitivity to multiple agents, including amoxicillin/clavulanate, piperacillin/tazobactam, ceftazidime, imipenem, and meropenem, with no evidence of extended-spectrum beta-lactamase (ESBL) production. Importantly, no additional pathogens, including Escherichia coli, were identified in any specimen.

Phenotypic testing showed a negative string test, indicating the absence of a hypermucoviscous phenotype. Genotypic testing for virulence-associated genes was not performed.

Imaging confirmed disseminated infection. Cranial magnetic resonance imaging (MRI) using fluid-attenuated inversion recovery (FLAIR) sequences identified four intracranial abscesses involving the ventricular system, basal ganglia, and thalamus, with surrounding cerebral edema.

Pulmonary computed tomography (CT) demonstrated bilateral lung abscesses with necrosis and cavitation. Abdominal CT revealed a large hepatic abscess in the right lobe with liquefactive necrosis. Ocular MRI showed increased vitreous signal intensity with thickening and enhancement of the ocular wall, consistent with endophthalmitis.

All imaging findings were independently reviewed and showed consistent results, supporting the diagnosis of multisystem abscess formation.

Management

Empirical intravenous antimicrobial therapy was initiated on hospital day 1 (January 30, 2025) with meropenem 2 g every 8 hours and vancomycin 1 g every 12 hours. This regimen was selected to provide broad-spectrum coverage against Gram-negative organisms, including Klebsiella pneumoniae and Escherichia coli, and Gram-positive pathogens such as Staphylococcus and Streptococcus, which are commonly implicated in severe endophthalmitis. Meropenem was chosen for its ability to penetrate the blood–brain and blood–ocular barriers.

Following microbiological confirmation of Klebsiella pneumoniae as the sole pathogen and absence of ESBL production, antimicrobial therapy was de-escalated and continued as targeted treatment.

On hospital day 3, ophthalmology consultation confirmed severe infectious endophthalmitis. Intensive conservative management was initiated; however, persistent ocular pain, progressive visual deterioration, and radiological evidence of ongoing infection indicated poor response.

On hospital day 7 (February 5, 2025), ultrasound-guided percutaneous drainage of the hepatic abscess was performed using the Seldinger technique. An 8 Fr drainage catheter was inserted, and approximately 150 mL of yellow-green purulent fluid was evacuated. Culture findings were consistent with blood isolates. Continuous drainage was maintained until the fluid became clear.

On hospital day 10 (February 8, 2025), a multidisciplinary team determined that conservative therapy was insufficient. Given the poor visual prognosis, presence of hypopyon, severe vitreous opacity, and risk of ongoing systemic dissemination, enucleation of the left eye was performed. Histopathological examination demonstrated diffuse inflammatory infiltration with Klebsiella pneumoniae colonies.

The drainage catheter was removed on hospital day 14 after repeat abdominal CT showed reduction of the abscess cavity to less than 2 cm. Glycemic control was optimized using insulin therapy throughout hospitalization. Multidisciplinary coordination was maintained across specialties.

Follow-Up

Serial cranial magnetic resonance imaging (MRI) was performed at predefined intervals to monitor intracranial abscess evolution.

At week 4, fluid-attenuated inversion recovery (FLAIR) imaging demonstrated persistent perilesional edema with mild enlargement of abscesses, indicating ongoing inflammatory activity. At week 6, T2-weighted imaging confirmed well-defined abscess boundaries without reduction in size, suggesting stabilization.

From week 8 onward, imaging showed progressive regression of edema and reduction in lesion size. At week 10, further reduction in abscess volume was observed. At the same time, abdominal CT demonstrated complete resolution of the hepatic abscess, and pulmonary CT showed marked reduction in cavitary lesions.

At week 12, cranial MRI showed near-complete absorption of intracranial abscesses, with minimal residual fibrosis and no significant edema. By week 20, T2-weighted imaging confirmed complete resolution of all intracranial abscesses without recurrence.

Clinical improvement paralleled radiological findings, with defervescence and normalization of inflammatory markers, including CRP.

Based on the clinical course, the lungs were considered the most likely initial site of infection given the early respiratory presentation. However, alternative possibilities, including early bacteremia or an initially asymptomatic hepatic focus, could not be excluded. Subsequent hematogenous dissemination to the liver, eye, and central nervous system was consistent with the typical progression of disseminated Klebsiella pneumoniae infection.