Advances in the management of central nervous system infections in the ICU

Inflammatory Markers in Serum and Cerebrospinal Fluid for Early Detection of External Ventricular Drain-associated Ventriculitis in Patients With Subarachnoid Hemorrhage

BACKGROUND

External ventricular drain (EVD)-associated ventriculitis is a serious complication. Early diagnosis can be difficult particularly in critically ill patients with aneurysmal subarachnoid hemorrhage (aSAH). We examined the diagnostic potential of standard serum and cerebrospinal fluid (CSF) biomarkers to differentiate between EVD-associated infections and aseptic courses in patients with aSAH.

MATERIALS AND METHODS

We retrospectively evaluated the levels of inflammatory markers in serum (white blood cell count, percentage of neutrophils [sN%], and procalcitonin) and CSF (total leukocyte count [CSFTLC], CSFglucose, CSF/serumglucose ratio, CSF total protein [CSFTP]) of 63 consecutive patients with aSAH. Receiver operating characteristic curves and the area-under-the-curve (AUC) were calculated to detect the diagnostic potential, optimized threshold, sensitivity (SE), specificity (SP), + likelihood ratio (LR), and -LR of each biomarker.

RESULTS

Of all patients, 17 (27%) developed an EVD-associated ventriculitis within a mean of 7.8±2.3 days after implantation. sN% had a very good diagnostic potential (AUC=0.900, SE=70.0%, SP=100%), followed by the CSFTLC with good diagnostic potential (AUC=0.841, SE=75.0%, SP=88.5%), and the CSFTP with moderate diagnostic potential (AUC=0.772, SE=73.3%, SP=76.0%). sN% higher than 70% and a CSFTLC higher than 635/µL were highly associated with the diagnosis of ventriculitis (+LR=∞ and 6.5), sN%<70% or a CSFTLC<635 made a diagnosis of ventriculitis unlikely (-LR=0.3 and 0.28).

CONCLUSIONS

Routine determination of N% and CSFTLC are useful to distinguish ventriculitis from aseptic courses in the acute phase after aSAH and regardless of the bacteriological test result.

Poor Central Nervous System Penetration of Tigecycline in a Patient with Sepsis and Ventriculitis Caused by Multidrug-Resistant Klebsiella Pneumoniae

Objective:

To report the use of tigecycline in a case of ventriculitis and concurrent bacteremia.

Case Summary:

A 57-year-old African American male with a ruptured brain aneurysm was admitted to the intensive care unit after surgical intervention and external ventricular drainage placement. His hospital course was complicated by myocardial infarction, ventilator-associated pneumonia, ventriculitis, and sepsis, with multidrug-resistant (MDR) Klebsiella pneumoniae isolated from multiple sites, including blood and cerebral spinal fluid (CSF). The patient was treated with high doses of intravenous tigecycline and gentamicin along with intrathecal gentamicin. This combination eradicated infections outside the central nervous system (CNS) within 48 hours, but it took approximately 8 days for the CSF culture to become negative. Timed serum and CSF fluid samples were collected to determine CSF penetration of tigecycline on day 12 of therapy. CSF concentrations obtained 30 minutes after the dose and at the end of the dosing interval remained below the detectable limit of 0.05 μg/mL.

Discussion:

Although CSF tigecycline concentrations may not represent actual CNS tissue concentrations at the site of infection, the low CSF concentrations observed in our case may be responsible for the slow CSF clearance of infection. It was not clear whether gentamicin therapy alone, administered both intravenously and intrathecally, would have achieved the same outcome and cleared the infection from the CNS in this patient.

Conclusions:

Until additional clinical data are available, tigecycline should not be used for the management of MDR infections associated with the CNS.

Hyperdense large artery sign in meningitis: A marker of ominous thrombogenic potential of pneumococcus?

Hyperdensity in the middle cerebral artery (MCA) or posterior cerebral artery (PCA) on non-contrast head CT, suggests the presence of a thrombus inside these vessels, often referred to as the “MCA sign” or “PCA sign” respectively. These two signs are classically associated with strokes secondary to cardiovascular etiologies and are only infrequently reported with other types of stroke. Whereas stroke is a recognized complication of pneumococcal meningitis hyperdense large vessel sign (in this case a combination of MCA and PCA) has not been previously reported. We report a case of rapidly progressive pneumococcal meningitis that presented as acute stroke involving large vessels in the vicinity of the circle of Willis in a patient with a history of non-Hodgkin lymphoma (NHL) in remission for 6 years. This patient had received a week of high dose steroids before admission. Head CT scan on admission showed the presence of hyperdense MCA and PCA signs. The patient rapidly deteriorated and a follow-up head CT revealed diffuse brain edema and increased density in the basal cisterns without evidence of sub arachnoid hemorrhage. Tc99m exametazime brain flow scan showed no intracerebral blood flow both supra and infratentorially. Steptococcus pneumoniae, NHL cells and high-dose steroid use can upregulate tissue factor synthesis and may have led to a hypercoagulable state via activation of the extrinsic pathway in the large intracerbral arteries.

Infectious intracranial complications in the neuro-ICU patient population

PURPOSE OF REVIEW

To provide an overview of infectious intracranial complications secondary to invasive procedures or trauma in the neuro-ICU patient population. Nosocomial infections of the central nervous system are a serious complication contributing to morbidity, prolonged length of stay in the ICU and/or hospital, and mortality of neurocritical care patients.

RECENT FINDINGS

Any type of neurosurgical interventions, specifically ventriculostomy/external ventricular drainage, constitutes a major risk factor for infectious intracranial complications. Other predisposing factors are comorbidities with immunocompromised state and the presence of a distant focus of infection. The emergence of multiresistant pathogens adds to the complexity of the management of infectious intracranial complications. In recent years, several antimicrobial agents suitable for the treatment of nosocomial central nervous system infections have been extensively studied with respect to pharmacodynamics and pharmacokinetics in serum and - of special importance in the neurocritical care setting - cerebrospinal fluid.

SUMMARY

Despite recent advances in prevention and treatment, the management of nosocomial intracranial infections still poses a challenge to the neuro-ICU specialist and must consider timely diagnosis and prompt initiation of appropriate antibiotic therapy. This review focuses on the definition, epidemiology, clinical features, and therapeutical approach to this distinct complication of neurocritical care.

Handheld point-of-care cerebrospinal fluid lactate testing predicts bacterial meningitis in Uganda

We validated a handheld point-of-care lactate (POCL) monitor's ability to measure lactate in cerebrospinal fluid (CSF) and diagnose bacterial meningitis in Uganda. There was a strong linear correspondence between POCL and standard laboratory lactate test results (R(2) = 0.86; P < 0.001). For 145 patients with clinical meningitis, the area under the receiver operating characteristic curve for the prediction of bacterial meningitis by CSF POCL was 0.92 (95% confidence interval = 0.85-0.99, P < 0.001). A CSF POCL concentration of 7.7 mmol/L provided 88% sensitivity and 90% specificity for the diagnosis of bacterial meningitis. CSF POCL testing had excellent use in the diagnosis of bacterial meningitis, and it may be useful where CSF analyses are delayed or laboratory infrastructure is limited.

Central nervous system infections as a cause of an altered mental status? What is the pathogen growing in your central nervous system?

There are several central nervous system (CNS) infections (meningitis, encephalitis, and brain abscess), any of which may present with an altered level of consciousness. Because CNS infections can have a devastating outcome, it is important to recognize the presence of a CNS infection and begin treatment as soon as possible because early appropriate therapy may, in some cases, limit morbidity and mortality.

Nosocomial ventriculitis and meningitis in neurocritical care patients

BACKGROUND

External ventricular drainage (EVD) is frequently necessary in neurological and neurosurgical intensive care patients. A major complication of this procedure is an EVD-related venticulitis or meningitis. The purpose of this review is (1) to address the magnitude of the problem in the neurocritical care patient population, (2) to discuss the difficulties in providing an appropriate and timely diagnosis of this disease entity and (3) to propose an algorithm for both rapid diagnosis and appropriate therapy.

METHODS

A MEDLINE literature search was carried out for studies from January 1990 through March 2008 reporting on ventriculostomy, EVD-related central nervous system infections, in particular ventriculitis and meningitis.

RESULTS

EVD-related ventriculitis is a serious nosocomial complication in the neurocritical care setting where EVD catheters are frequently used for the management of elevated ICP secondary to acute hydrocephalus primarily caused by subarachnoid and intraventricular hemorrhage or traumatic brain injury. Infection rate is high with reported incidences in the range of 5 % up to more than 20 %. Predisposing factors for infection are non-adherence to rigid insertion and maintenance protocols, leakage of cerebrospinal fluid (CSF), catheter irrigation and the frequency of EVD manipulation. Diagnosis is frequently impaired either by the presence of systemic inflammation due to the primary disease or because the hemorrhagic CSF itself may cause an inflammatory reaction. Furthermore, the most common pathogens involved in EVD-related infections, i. e., staphylococci, initially provoke only a mild inflammatory response in the CSF and therefore patients rarely present with clear-cut clinical signs indicating severe central nervous system infection, in particular, ventriculitis.

CONCLUSION

Nosocomial EVD-related ventriculitis is a significant cause of morbidity and mortality in critically ill neurological patients. Rapid diagnosis and prompt initiation of appropriate antimicrobial therapy is needed. A stepwise algorithm for the management of EVD-related ventriculitis is proposed.

Management of nosocomial external ventricular drain-related ventriculomeningitis

INTRODUCTION

Neurocritical care patients requiring external ventricular drainage are at risk for the development of a device-related infection. Infection rate of external ventriculostomy catheters is high with reported incidences ranging from 5% up to more than 20%. Nosocomial ventriculitis or ventriculomeningitis are potential life-threatening conditions which may contribute to a permanent adverse outcome of the patient. Reducing morbidity and mortality is strongly dependent on prompt diagnosis and on the initiation of appropriate antiinfective therapy.

SCIENTIFIC BACKGROUND

Management of nosocomial ventriculitis is challenging and needs to consider the most likely pathogens involved, local resistance patterns, the nature of the underlying disease, patient factors such as age, comorbidity, and immune status. Further, decisions on catheter exchange and the type and duration of systemic or local antimicrobial therapy have to be made. Because so many factors have to be taken into account, it is evident that the diagnostic and therapeutic approach to nosocomial ventriculitis is difficult to standardize. Staphylococci are the pathogens most frequently identified in nosocomial ventriculitis. Therefore, initial treatment with an antistaphylococcal agent with adequate cerebrospinal fluid penetration may be considered as first-line therapy for this infection.

CONCLUSION

In the review of a contemporary case we will discuss important issues in the management of device-related ventriculitis.

Acute bacterial meningitis

Despite advances in medical care including antibiotics and vaccines, meningitis still has a high morbidity and mortality rate, especially in certain high-risk patients. Early diagnosis with the administration of appropriate antibiotics remains the key element of management. This article highlights methods of diagnosis, differential diagnoses, treatment options, and complications of treating bacterial meningitis.