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The Nerve > Volume 9(1); 2023 > Article
Kim, Hur, Kim, Lee, Yun, and Lee: Ventriculitis Associated with Invasive Klebsiella Pneumoniae Syndrome: A Case Report


Invasive Klebsiella pneumoniae syndrome is defined as community-acquired liver abscess and metastatic infections in the lung, soft tissue, and central nervous system (CNS) caused by hypervirulent Klebsiella pneumoniae. Metastatic CNS infection in invasive Klebsiella pneumoniae syndrome shows rapid clinical deterioration and a high mortality rate. We present a case of ventriculitis caused by invasive Klebsiella pneumoniae syndrome successfully treated with a timely diagnosis, immediate surgical intervention, and administration of antibiotics.


Klebsiella pneumoniae is a gram-negative, anaerobic bacillus, a well-known nosocomial and community-acquired pathogen causing respiratory, urinary, and hepatobiliary infections3,6,8). Among them, hypervirulent strains have been reported to cause community-acquired liver abscesses and metastatic infections in lung, prostate, soft tissue, eye, and central nervous system (CNS) in non-immunocompromised individuals, defined as invasive Klebsiella pneumoniae syndrome (IKPS)8). The rate of metastatic infection ranges from 3.5% to 20%6) with a mortality rate of 3% to 42%8). CNS infection shows a higher mortality rate 40% to 50%7) than other metastatic infections8). It presents mostly as meningitis, encephalitis or cerebral abscess, and presenting primarily as ventriculitis or ventricular empyema is rare7). We present a case of IKPS with ventriculitis successfully treated with a timely injection of antibiotics and surgical intervention.


A 50-year-old male with no previous medical history came into the emergency room with acute mental status change with a Glasgow Coma Scale (GCS) score of 13. His mother stated he presented with hemoptysis two weeks ago, subsequently a high fever of 39℃ and right upper quadrant abdominal pain two days ago. He began to show disorientation and confusion a day ago. His pupils were isocoric and prompt with no other neurological deficits. There was no sign of neck stiffness or Brudzinski sign. Blood lab results showed an elevated white blood cell (WBC) count of 45,780/μL with 87% of neutrophil count, platelet count of 44,000/μL, elevated C-reactive protein level of 256.4 mg/L, along with elevated aspartate transaminase, alanine aminotransferase, and glucose. Urine analysis showed glucosuria, proteinuria, and hematuria. Enhanced abdomen computed tomography (CT) showed air-fluid lesion of 15 cm in left lobe of liver (Fig. 1A) and left renal abscess (Fig. 1B). Chest CT showed bilateral multiple scattered nodular and cavitary lesions suggestive of pneumonia with lung abscess (Fig. 1C). Non-contrast brain CT showed iso-dense fluid collection in depending portion of both lateral ventricles (Fig. 1D). With CT showing multiple organ abscess, brain magnetic resonance image (MRI) was done in order to differentiate intraventricular pus and hemorrhage. Diffusion-weighted image showed hyperintensity in lateral and fourth ventricles with low apparent diffusion coefficient value (Fig. 2). Mild hydrocephalus was present and enhanced MRI showed no ependymal enhancement. With high suspicion of ventricular abscess accompanied by liver, renal, and lung abscess, a percutaneous drainage tube was inserted in liver abscess and 480 cc of pus was drained. Subsequently, immediate insertion of a bilateral extraventricular drain (EVD) was done. Draining cerebrospinal fluid (CSF) showed high opening pressure with a turbid, yellowish color. CSF analysis showed WBC count of 5,150/mm3, low glucose level of 30 mg/dL, and an increased protein level of 446 mg/dL. During treatment, patient showed rapid progressive deterioration of the GCS score from 13 to 8. Patient was immediately started on meropenem and vancomycin IV. On fourth postoperative day, peripheral blood, liver and CSF culture showed growth of Klebsiella pneumoniae and antibiotic regimen was changed to ceftriaxone 2 g per 12 hr. Patient showed gradual improvement in GCS score, inflammation markers and body temperature. Both EVD were removed on eighth and tenth postoperative days and on twelfth postoperative day patient showed no fever or other systemic symptoms with a GCS score of 14. Patient was injected with ceftriaxone for four weeks and was discharged home without any neurological deficits followed by two weeks of oral cefixime.


IKPS was first documented in 1980s in Taiwan and subsequently several cases were presented worldwide2). Its risk factors include diabetes mellitus and East-Asian descent6,7). Its etiology is yet poorly understood but is thought to be hematogenous through enterohepatic circulation8); and 75% of East-Asian are carriers of Klebsiella pneumoniae in contrast to 10%-19% in European8).
Hypervirulent strains causing IKPS are known to have specific genes, rmpA (a regulator of the mucoid phenotype) and magA (mucoviscosity-associated gene A) which are exclusive for capsule serotype K1 and K24,6). These genes are responsible for hypermucoviscosity of the capsule, making it resistant to phagocytosis3). Determination of hypermucoviscosity is based on a positive string test in which a bacterial colony on an agar plate can be stretched into viscous string of over 5mm in length with an inoculation needle4).
Ventriculitis caused by IKPS is rare and documented in few case reports. However, these case reports tend to show similar clinical course; initially presenting with nonspecific symptoms, rapid deterioration of mental status, equivocal brain CT results, diagnosis through diffusion-weighted MRI, and the need for CSF diversion1,3,7-10). This is also shown in primary pyogenic ventriculitis caused by pathogens other than Klebsiella pneumoniae. According to Gronthoud et al.2), 6 cases of primary pyogenic ventriculitis not associated with meningitis, abscess, surgical intervention or trauma were reported up to 2016. Most cases reported male patients with a median age of 63, initially presenting with nonspecific fever and headache with only one case showing meningism. Diagnosis of choice is MRI where ventricular infection shows high signal intensity in T1 and low signal intensity in T2. For early phase of infection, diffusion-weighted image tends to show higher sensitivity2,7). CT has limitations in differentiating intraventricular pus and hemorrhage, and are less sensitive in early phase of ventricular infection2). One report shows initial CT did not present an intraventricular lesion until clinical deterioration after two days, delaying diagnosis and treatment of the patient5).
Presently, there is no concrete treatment guideline for ventriculitis caused by IKPS due to its small number of cases, but pyogenic ventriculitis caused by other bacterial agents was mostly treated with intravenous antibiotics for 6 to 7 weeks2). When reviewing reported cases of ventriculitis associated with IKPS (Table 1), those who were successfully treated were administered antibiotics for 6 weeks. Either 6 weeks of intravenous antibiotics or 4 weeks of intravenous and subsequent 2 weeks of oral antibiotics was sufficient for survived cases. Intraventricular antibiotics irrigation was not conducted in any of the reported cases, which may imply that intraventricular irrigation may not be mandatory for treating ventriculitis in IKPS. However, in one case8), repetitive clogging of EVD was reported which required EVD exchange for six times. Further studies should be conducted to investigate whether intraventricular antibiotics irrigation might aid in facilitating patient’s recovery and maintaining the patency of EVD.
Most cases that showed good outcomes have undergone EVD insertion, both in ventriculitis caused by IKPS and other bacterial species2). One case of ventriculitis associated with IKPS showed a good outcome without insertion of EVD or any form of CSF drainage. However, after 6 weeks of intravenous antibiotics, patient showed mental status decline due to progressing hydrocephalus. The patient fully recovered after insertion of ventriculo-peritoneal shunt. This may indicate that insertion of EVD or CSF drainage is not a definite prerequisite for successful treatment of ventriculitis but may reduce the burden of infection in early stage of disease and risk of developing delayed hydrocephalus.
Prognostic factors of ventriculitis associated with IKPS are not well-established due to their limited studies. Yet, previous studies regarding neonatal or adult bacterial meningitis show elevated protein levels in CSF might be associated with poor outcomes10). The intensity of inflammatory response in meningitis might be reflected by high protein level10). Reviewed cases (Table 1) also show patients with poor outcomes generally having higher CSF protein level than patients with good outcomes. However, some patients with good outcomes showed higher CSF WBC and lower CSF glucose level than patients with poor outcomes. High protein levels may reflect a high infection burden but may also suggest an active inflammatory response leading to the repair and regeneration stage of inflammation. Further investigation is needed to identify prognostic factors in CSF and blood lab results or previous medical history of IKPS patients presenting with ventriculitis.


As IKPS is also increasing in Western countries, due to its nonspecific presentation, rapid progression and high mortality rate, keen awareness of suspicion of CNS infection in multiple organ abscesses should be warranted. Although further studies are warranted, fast surgical intervention of CSF drainage combined with antibiotics is essential in improving patient’s outcomes in ventriculitis associated with IKPS.


No potential conflict of interest relevant to this article was reported.


This work has previously been presented as an oral presentation at the 108th Annual Meeting of Korean Taejon Chung-cheong Regional Neurosurgical Society held in Cheongju on 2 December 2022.

Fig. 1.
Abdominal-pelvic computed tomography (CT) shows a 15-cm irregular cystic air-fluid lesion in the left lobe of the liver (A) and a well-defined low-density lesion in the left kidney (B), suggesting a liver abscess and renal abscess. Chest CT (C) shows multiple scattered nodular and cavitary lesions in both lungs, suggesting pneumonia with a lung abscess. Brain CT (D) shows isodense fluid collection in both lateral ventricles.
Fig. 2.
The first column of brain magnetic resonance imaging (MRI) shows hyperintense lesions in the bilateral fourth ventricles and bilateral frontoparietal cortical sulcus in diffusion-weighted imaging (DWI). The second column shows low apparent diffusion coefficient values in the corresponding lesions in DWI. The third column of T1-enhanced MRI shows no meningeal or ependymal enhancement.
Table 1.
Summary of reported cases of ventriculitis associated with invasive Klebsiella pneumoniae syndrome
References Sex Age GCS Mental status change on hospital admission Causative agent String test CSF lab tests Blood lab tests Antibiotic administration period EVD Intraventricular antibiotics Liver abscess drain Outcome
WBC (/mm3) Glucose (mg/dL) Protein (mg/dL) WBC (/mm3) Platelet (/mm3)
Hyun et al.3) F 80 NA HD 6 Klebsiella pneumoniae Positive 7200 <10 359.3 13860 NA 28 days IV + 14 days PO Yes No Yes (renal abscess) Survived
Maheswaranathan et al.8) F 61 NA HD -7 Klebsiella pneumoniae Positive 5051 4 803 19900 170000 NA Yes (repetitive clogging) No Yes Died
Lee and Song7) F 84 NA HD -1 Klebsiella pneumoniae NA NA NA NA 9330 70000 10 days No No Yes Died
Rasouli and Honeybul9) F 80 10 HD 14 Klebsiella pneumoniae Positive NA NA NA NA NA NA Yes No No Survived
Sun et al.10) F 49 NA HD 1 Klebsiella pneumoniae NA 4263 10.8 882 24870 108000 NA Yes No No Died
Sun et al.10) M 62 5 HD 1 Klebsiella pneumoniae NA 17148 <1.80 1282 12390 25000 NA No No No Died
Sun et al.10) M 39 5 HD 1 Klebsiella pneumoniae NA 178640 183.8 3241 25730 NA 2 days Yes No No Died
Youn et al.11) M 60 9 HD 2 Klebsiella pneumoniae NA 18500 6 344.7 12640 NA 42 days IV + PO No (HD 42 VPS) No No Survived
This case M 50 13 HD 1 Klebsiella pneumoniae NA 5150 30 446 45780 44000 28 days IV + 14 days PO Yes No Yes Survived

F: female; M: male; GCS: Glasgow Coma Scale; NA: not available; HD: hospital day; CSF: cerebrospinal fluid; WBC: white blood cell; IV: intravenous; PO: per os; EVD: external ventricular drainage; VPS: ventriculoperitoneal shunt.


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8. Maheswaranathan M, Ngo T, Rockey DC: Identification and management of the hypervirulent invasive Klebsiella pneumoniae syndrome: A unique and distinct clinical entity. J Investig Med High Impact Case Rep 6:2324709618806552, 2018
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10. Sun R, Zhang H, Xu Y, Zhu H, Yu X, Xu J: Klebsiella pneumoniae-related invasive liver abscess syndrome complicated by purulent meningitis: a review of the literature and description of three cases. BMC Infect Dis 21:15, 2021
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11. Youn M, Lee JJ, Kim BK, Kang K, Lee WW, Yoo I. A case of invasive Klebsiella pneumoniae syndrome with ventriculitis. Encephalitis [epub ahead of print, 2022. doi: 10.47936/encephalitis.2022.00010]

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