Question 1

a) Discuss the assessment and challenges of diagnosing ventriculitis in a febrile patient with a subarachnoid haemorrhage (SAH) and an external ventricular drain (EVD) in situ. (6 marks)

b) Outline the principles of management if a diagnosis of EVD-related ventriculitis is strongly suspected or confirmed. (4 marks)

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College answer

Syllabus topic/section:
2.1.3 Sepsis and Infections – L1.
2.1.8 Neurological Intensive Care – L1.
Aim:
1. To ask the candidate to demonstrate knowledge of assessment of the diagnosis of EVD related ventriculitis.
2. To test application of this knowledge to the clinical context and discuss the challenges of using the diagnostic criteria in a critically unwell patient.
3. To test knowledge of broad principles of management of EVD related ventriculitis.
Discussion:
To demonstrate competency of the subject, the answer needed to address every element requested in the stem. For part A candidate answers that addressed the assessment AND challenges as requested gained higher marks.
Examples of challenges include the difficulty of an accepted definition of ventriculitis, inflammatory changes due to brain injury with the presence of the EVD and features associated with SAH which will mask the features of infection amongst others. Candidates using the glossary of terms who structed their answer in terms of history (including risk factors for ventriculitis, e.g. patient related, and catheter related factors) examination findings and targeted investigations with rationale gained higher marks.
In Part B the expected transitional fellow level standard contained details of antibiotic choice and rationale, as well as a discussion on the management of the EVD and patient related factors. Ventriculitis is a pathology that has a specific therapy of antimicrobials and little requirement for ongoing source control, unlike, for example, pancreatitis. It is therefore necessary to go into detail about choice, rationale, timing, duration, and route in the explanation of antibiotics in this setting This is particularly important in severe ventriculitis where the intraventricular route is required for treatment resistant cases.

Marking rubric:

Part A

Assessment and challenges

6 marks

Inadequate detail

Doesn’t appreciate the challenges of diagnosis.

0-2 marks

Has knowledge of how to diagnose ventriculitis but has not demonstrated the challenges in the critically unwell patient.

2-3 marks

Good detail present.

Able to appreciate some of the challenges of making diagnosis of ventriculitis in poor detail.

3-4 marks

Contained applied clinical perspective.

Detailed and nuanced answer, Able to appreciate the challenges of making the diagnosis of ventriculitis.

5-6 marks

Part B

Principles of management

4 marks

Superficial answer, minimal details about antibiotic choice.

Minimal or no discussion about EVD.

<2 marks

Addresses antibiotics, EVD in limited detail.

1-2 marks

Improved structured answer with more detail.

Some organisation attempt of details.

2-3 marks

Detailed and nuanced answer

Included antibiotic choice, dose and rationale, management of EVD and considerations relating to change.

4 marks

Discussion

This was the first time the exam was reported upon with so much luxurious detail, with marking rubrics and blueprinting links to the Syllabus for the Second Part Examination.  The greatest challenge going forward for this sort of armchair commentary will no longer be the need to guess what was in the minds of the examiners when they wrote the paper, but how to craft an answer fit to get the maximum marks.

An additional point of interest is the removal of the "pass rate" metric, and its replacement with the Angoff score, as a better measure of question difficulty. This should be of immediate interest to everybody. The SAQs which had a pass rate of (for example) 0% in previous years (you know the ones I mean) were not the most difficult per se, they were just met with a group of trainees who were especially unprepared for this specific SAQ (it having never been seen before, and past papers being the favoured method or preparation). The question itself (eg. "list the key clinical signs of traumatic asphyxia") was not itself remarkable by the degree of knowledge or analysis it expected, but nobody knew the answer anyway. Theoretically, a group of trainees who all somehow expected a traumatic asphyxia question would have fallen into a normal distribution with the fat part somewhere around 5. The Angoff score is therefore a better metric, as it does not rely on the exam candidates level of preparation.

Anyway: a "discuss" answer will require some detail, for six marks:

1) 

Assessment of suspected ventriculitis:

  • Risk factors:

    • Patient characteristics:

      • Intraventrciular blood

      • Systemic infection

      • Duration of catheterization (11 days seems to be the cutoff for increasing risk of infection)

      • Immune compromise

    • Features of surgery:

      • Craniotomy (vs burrhole)

      • Superficial surgical site infections

      • CSF leakage

    • Catheter management

      • EVD, rather than a parenchymal pressure transducer

      • Frequent sampling

      • EVD irrigation

      • Non-tunnelled vs. tunnelled EVD

  • Symptoms

    • Headache

    • Photophobia

    • Neck pain

  • Physical signs

    • Unexplained decrease in the level of consciousness 
    • Fever 
    • Neck stiffness
    • New cranial nerve signs
    • Seizures
    • Features of meningism (eg. Kernig and Brudzinski signs)
    • Tenderness over the site of EVD insertion
  • Investigations

    • Peripheral blood
      • Increasing inflammatory markers
      • Positive blood cultures
    • CSF analysis
      • Culture, Gram stain
      • Cell count (WCC/RBC ratio of 1:106 or a rising trend)
      • Nucleic acid amplification tests for specific pathogens
      • β–D-glucan and galactomannan for fungal ventriculitis
    • Imaging
      • MRI with gadolinium could be helpful, or at least more helpful than CT

Challenges of diagnosing ventriculitis:

  • Definition of ventriculitis and diagnostic criteria are vague and not universally accepted
  • Inflammatory change in CSF promotes sterile pleocytosis
  • CSF cell count threshold is not agreed upon
  • CSF cell count fluctuates dramatically even with sequential sampling
  • Not all organisms will show up on a Gram stain
  • History and examination are difficult in the unconscious patient
  • Other causes of fever are common (eg. VAP, "central" fever)

Management of ventriculitis

  • Source control:
    • Remove the EVD if at all possible to survive without ICP monitoring and CSF drainage
    • Replace the EVD with a sterile parenchymal monitor, if is still necessary to monitor the ICP but where CSF drainage is not essential
    • If you absolutely need CSF drainage, perhaps remove the EVD and reinsert a new one after at least 48 hours of effective antibiotic therapy
    • If you absolutely cannot remove the EVD, at least open it continuously, to let the infected CSF drain out. 
  • Systemic antibiotics
    • Empiric treatment is with vancomycin and an anti-pseudomonal beta-lactam (such as cefepime, ceftazidime, or meropenem) - these are the IDSA-recommended agents
    • Doses of these agents have to be adjusted to permit penetration into the CSF
  • Intrathecal antibiotics for patients with treatment failure

References

Chavali, Siddharth, et al. "Fever in the neurointensive care unit.Journal of Neuroanaesthesiology and Critical Care 6.03 (2019): 275-283.

Laws, Craig, and Jack Jallo. "Fever and infection in the neurosurgical intensive care unit." JHN Journal 5.2 (2010): 5.

Goyal, Keshav, Neha Garg, and Parmod Bithal. "Central fever: a challenging clinical entity in neurocritical care." Journal of Neurocritical Care 13.1 (2020): 19-31.0

Ball, Perry A. "Fever in the Neurocritically Ill Patient." Acute Care Neurosurgery by Case Management: Pearls and Pitfalls. Cham: Springer International Publishing, 2022. 293-302.

Rabinstein, Alejandro A., and Kirsten Sandhu. "Non‐infectious fever in the neurological intensive care unit: incidence, causes and predictors." Journal of neurology, neurosurgery, and psychiatry 78.11 (2007): 1278.0

Commichau, Christopher, Nikolaos Scarmeas, and Stephan A. Mayer. "Risk factors for fever in the neurologic intensive care unit." Neurology 60.5 (2003): 837-841.

Wang, Zhuo, et al. "Clinical factors and incidence of prolonged fever in neurosurgical patients." Journal of Clinical Nursing 26.3-4 (2017): 411-417.

Migliorino, Ernesto, et al. "Neurogenic fever after subarachnoid hemorrhage in animal models: a systematic review." International journal of molecular sciences 24.14 (2023): 11514.

Lenski, Markus, et al. "Significance of cerebrospinal fluid inflammatory markers for diagnosing external ventricular drain–associated ventriculitis in patients with severe traumatic brain injury." Neurosurgical Focus 47.5 (2019): E150

Ramanan, Mahesh, Andrew Shorr, and Jeffrey Lipman. "Ventriculitis: infection or inflammation." Antibiotics 10.10 (2021): 1246.

Bådholm, Marcus, et al. "Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study." Critical Care 25.1 (2021): 1-14.

Willer‐Hansen, Rasmus Stanley, et al. "Diagnostic criteria of CNS infection in patients with external ventricular drainage after traumatic brain injury: a pilot study." Acta Anaesthesiologica Scandinavica 66.4 (2022): 507-515.

Mayhall et al.  "Ventriculostomy-related infections." New England Journal of Medicine 310.9 (1984): 553-559.

Brooks, Michael, et al. "Cerebrospinal fluid white cell count to red cell count ratio as a predictor of ventriculitis in patients with external ventricular drains." ANZ Journal of Surgery 92.12 (2022): 3278-3282.

Mehndiratta, Manmohan, et al. "Appraisal of Kernig's and Brudzinski's sign in meningitis." Annals of Indian Academy of Neurology 15.4 (2012): 287.

Savin, Ivan, et al. "Healthcare-associated ventriculitis and meningitis in a neuro-ICU: incidence and risk factors selected by machine learning approach.Journal of critical care 45 (2018): 95-104.

Kim, Joon-Hyung, et al. "Factors contributing to ventriculostomy infection." World neurosurgery 77.1 (2012): 135-140.

Dorresteijn, Kirsten RIS, et al. "Factors and measures predicting external CSF drain-associated ventriculitis: a review and meta-analysis." Neurology 93.22 (2019): 964-972.

Beer, R., et al. "Nosocomial ventriculitis and meningitis in neurocritical care patients." Journal of neurology 255 (2008): 1617-1624.

Tunkel, Allan R., et al. "2017 Infectious Diseases Society of America’s clinical practice guidelines for healthcare-associated ventriculitis and meningitis." Clinical Infectious Diseases 64.6 (2017): e34-e65.

Wen, Dennis Y., et al. "The Intraventricular Use of Antibiotic." Neurosurgery Clinics of North America 3.2 (1992): 343-354.

Llave, Nathaniel, et al. "Efficacy and Safety of Intraventricular Antibiotic Administration: A Review of the Literature." Infectious Diseases in Clinical Practice 29.6 (2021): e340-e346.

Naidech, Andrew M., et al. "Fever burden and functional recovery after subarachnoid hemorrhage." Neurosurgery 63.2 (2008): 212-218.

Mendieta Zerón, Hugo, and JULIO CESAR ARRIAGA GARCIA RENDON. "Remission of central fever with morphine post traumatic brain injury." (2014).

Korepu, Priyanka, Kamath Sriganesh, and Byrappa Vinay. "Hyperpyrexia following hemispherotomy and role of unconventional therapy.Journal of Neuroanaesthesiology and Critical Care 1.03 (2014): 210-211.

Lavinio, Andrea, et al. "Targeted temperature management in patients with intracerebral haemorrhage, subarachnoid haemorrhage, or acute ischaemic stroke: updated consensus guideline recommendations by the Neuroprotective Therapy Consensus Review (NTCR) group." British Journal of Anaesthesia (2023).