Master of Neurosurgery preparatory course: Diagnosis and treatment of CSF shunt infection

1. CSF Shunt Infection:CSF Shunt Infection:
Diagnosis and TreatmentDiagnosis and Treatment
10

2. Incidence
• The term “CSF shunt infection” was defined when1
– the CSF or the shunt tip was contaminated with bacteria
– the patient shows clinical signs of acute bacterial meningitis and
– symptoms of shunt malfunction or obstruction
• Incidence of shunt infection ranges from 1 to 40 % and
average 8.5–15 %.2
– 11.7 % per patient3
– 7.2 % per procedure3
• The rate of infection does not appear to differ greatly
between ventriculoatrial, ventriculopleural and
ventriculoperitoneal shunts.4
1
Ritz R et al. (2007); 2
Di Rocco C, et al. (2006); 3
Simon TD et al (2009);
4
Crnich CJ et al. (2003)

3. Incidence
• Ventricular shunt infection is a common complication of
CSF shunting that causes high morbidity and mortality.
• Infection is a common etiology of shunt failure and
represents the second cause of shunt dysfunction after
mechanical malfunction.1
• CSF shunt infection is an important contributor to the
cost of care.2
– long hospital stays
– costly interventions
1
Di Rocco C, et al. (2006); 2
Arthur AS et al. (2002);

4. Risk Factors
• Significant risk factors for infection include1
– Young age
– Intraventricular hemorrhage
– Respiratory complex chronic conditions
– Subsequent revisions
– Hospital volume
– Surgeon case volume
• Mode of infection2
– Intraoperative contamination - skin flora
– Other sources of shunt infection
• Proximal seeding from meningitis
• Distal seeding from peritonitis and wound infections
1
Simon TD et al (2009); 2
Sivaganesan A et al. (2012)

5. Risk Factors
• Risk factors for shunt contamination comprise1
– Recent (<90 days) shunt surgery
• 70 % within 1 month2
• 85 % within 9 months2
• mainly due to contamination during the surgery2
– originate from the skin incision proper related to insufficient asepsis,
defective surgical material, and long-lasting operations
– Fever with leukocytosis (>15,000)
– Abdominal pain
– CSF leak
– Erythema or swelling along the shunt tract
1
Rogers EA et al (2012); 2
Di Rocco C, et al. (2006)

6. Risk Factors
• Risk factors for shunt infection in adults include1
– Previous CSF leaks
– Revisions for dysfunction
– Operation performed late in the day
– Longer surgical time
• Late infections are less common2
– 10–15 % of overall infectious complications
– 1 year after the shunt implantation
– attributed to
• contamination of the distal catheter by the visceral content
• infiltration of germs through superficial skin wounds
1
Korinek AM et al (2011); 2
Di Rocco C, et al. (2006)

7. Etiology
• Early CSF shunt infection1
– Skin bacteria (coagulase-negative staphylococci)
• S. epidermidis (50–90 % of the cases)
• S. aureus (15–40 %)
– Other causative agents
• gram-negative rods (15 %) (Escherichia coli, Pseudomonas , and
Enterobacter)
• Anaerobic: Propionibacterium acnes, Corynebacterium diphtheriae
• Late CSF shunt infection
– Propionibacterium. acnes, Enterococcus faecalis ,
Streptococcus faecalis, arise from
• Hair follicles
• Colonic contents
1
Di Rocco C, et al. (2006)
capable of contaminating the catheter
and even of reaching the cerebral
ventricles

8. Etiology
• Non-bacterial shunt infections are rare and most
commonly fungal infections ( Candida albicans ), usually
in1
– Premature infants
– immunocompromised patients
1
Baallal H et al.(2013)

9. Presentation
• The clinical presentation can vary greatly depending on
– the site of infection,
– the age of the patient
– the timing of infection (acute or chronic)
• Early CSF shunt infection1
– proximity to a recent the placement of the shunt (days to weeks)
– febrile (>38.5 °C)
– erythema along the shunt track
– have a purulent drainage from the wound
– Visible shunt components
• Chronic CSF shunt infections
– occur weeks to months after the shunt has been placed
– repeated malfunctions (headache, irritability, nausea, vomiting, and
lethargy)
– with or without fever
1
Meftah M et al (2003)

10. Presentation
• Neonates may manifest apneic episodes, anemia,
hepatosplenomegaly, and stiff neck.1
• Less commonly, patients may present with signs of
meningeal irritation or seizures.
1
Greenberg MS (2006)
• A scar over the valve reservoir (or
other shunt component) suggests the
probable infection of the device.
• In peritoneal shunts (VP or LP),
symptoms and signs of infection
related to the abdomen usually are
most prominent.
The photograph shows an
exposed part of a valve
reservoir ( arrow )

11. Presentation
( b ) photograph of the thoracic tract of a VP shunt
showing subcutaneous accumulation of fluid
( arrow )
( a ) Photograph
illustrating skin
reddening along
the thoracic wall in
a child with shunt
infection ( arrow ),
Ref: Complications of CSF Shunting in Hydrocephalus
Prevention, Identification, and Management 2015

12. Presentation
Erythematous paraumbilical
abdominal wound with swelling
• The patients often complain of
abdominal pain and distention, nausea
and vomiting, or constipation.
• On examination, there may be
abdominal tenderness, guarding and
distention in peritonitis or ascites, or a
palpable mass in the case of a
pseudocyst.

13. Presentation
• In VA shunts, early or late features of systemic infection,
sepsis, or endocarditis may be the hallmark of the
presence of valve infection.
• Shunt nephritis, a late form of VA shunt infection, usually
evolves with sepsis, arterial hypertension, hematuria,
and proteinuria.
• In ventriculopleural shunts, infection usually shows up
with pleuritic pain, fever, tachypnea, dyspnea, or other
features of respiratory tract involvement.

14. Prevention
• Meticulous surgical technique and extreme measures of
asepsis are regarded as crucial for the prevention of
shunt contamination.
• Modifications of surgical techniques include
– reduced personnel in the operating room
– Shunting as first case in the day
– use of adhesive drapes on the skin
– double gloving
– no-touching technique
– bathing the valve components with an antibiotic solution
– meticulous wound closure to prevent CSF leakage

15. Prevention
The image shows the extremely
thin skin of a premature infant. The
entire trajectory of the shunt can be
easily viewed.
• Prevention of skin ulceration over the
valve involves
– choosing an adequate cranial site for valve
placement and avoiding prominent zones of
the head, especially in infants and in
debilitated or bedridden patients.
• Association of hair shaving on the
incidence of shunt contamination are
not conclusive.1
1
Broekman MLD et al. (2011); 2
Lund-Johansen M et al. (1994)
• Association of factor such as “experience of the surgeon”
(trainees vs. experienced surgeons) on the infection rate
are also not conclusive.2

16. Prevention
• The preparation of the surgical field is one of the most
important actions to be taken for preventing shunt
contamination. (Venes’s recommendations)1
– Patients are shaved immediately before operation.
– The skin is scrubbed with povidone iodine (Betadine) solution for
10 min and then covered with adhesive drapes.
• Shunt components in a solution of antibiotics prior to
insertion.
• Use of intravenous prophylactic antibiotics.
• Antibiotic-impregnated shunts resulted in a significant
reduction of shunt infection over standard shunts and in
no increase in microbial resistance to antibiotics.2
1
Venes JL (1976); 2
Parker SL et al (2011)

17. Work-up
• CSF cultures are the most definitive method of diagnosis
• In cases with high suspicion of shunt infection,
– a shunt tap for isolation of the causative organism
– CSF Studies include CSF glucose, protein, cell counts, culture
(bacterial and fungal), and sensitivities +/- both aerobic and
anaerobic cultures
• Lumbar and ventricular punctures are routinely
performed to isolate these bacteria, but cultures are
usually sterile.1
1
Sivaganesan A et al. (2012)

18. Work-up
• CSF often shows
– a mild to moderate white blood cell count elevation (with
predominantly polymorphonuclear cells).
– Low glucose level
• a glucose ratio (CSF glucose/serum glucose) of <0.4,
– Elevated protein.
• History of fever and ventricular fluid neutrophils >10 %
had a 99 % specificity and 93% positive predictive value
for shunt infection.1
• A recent study showed that CSF vascular endothelial
growth factor (VEGF) levels were associated with the
subsequent development of shunt infection.2
1
McClinton D et al. (2001); 2
Lee JH et al (2012)

19. Work-up
• FBC shows leukocytosis .(75 %)
• Erythrocyte sedimentation rate is rarely normal.
• Blood cultures are positive in less than 1/3 of cases.1
• Elevated C-reactive protein (CRP) levels ¾ cases.2
• Swab C+S of any apparent sites of infection (especially
open wounds).
1
Greenberg MS (2006); 2
Wong GKC et al.(2011)

20. Work-up
• Plain radiographies of the shunt system
– to establish continuity of the shunt hardware.
• Abdominal US or CT-scan
– to assess the peritoneal end in VP shunts
– to demonstrate its complications
• abnormal position of the distal catheter,
• CSF pseudocysts
• CT and MRI1
– Irregular leptomeningeal consistent with meningitis
– Ventricular ependymal enhancement consistent with ventriculitis
• Diffusion- weighted imaging
– Differences in intensity between infected (Debris within the ventricles) and normal
fluid
• Echocardiography in patients with a ventriculoatrial shunt
– to look for vegetations if shunt infection is suspected
1
Wallace AN et al. (2014)
Axial abdominal CT-scan showing
an extraperitoneal subcutaneous
pseudocyst with the distal shunt
catheter in the middle of a fluid
collection

21. OPTIONSOPTIONS
Treatment
removal of the shunt
with re-implantation of a new shunt
immediately at the same time of the
surgery
externalization of the shunt
system followed
by placement of a new shunt
system later
after the CSF becomes sterile
removal of the shunt with
placement of an
EVD followed by shunt re-
implantation at a
later time when the infection has
cleared
intrathecally
antibiotic
therapy
alone
systematically
(consecutive negative CSF cultures, CSF white blood cell
count <10, glucose ratio ( CSF glucose/serum glucose ) of
>0.4,and CSF protein <0.5 g/L).
highest treatment success rate
highest failure rate
(EVD should then be clamped
for 30 min after injection)

22. Treatment: Medical
• Optimal duration of antibiotic
– treatment duration is 10–14 days after the culture
becomes negative.
• for virulent or highly resistant organisms may be longer1
• Choice of antibiotic therapy is generally guided
by2
– the susceptibility patterns of the infecting organism
– degree of antibiotic penetration into the CSF
– previous personal experience
– local practice patterns
• Initial antibiotics should be broad spectrum.
1
Greenberg MS (2006); 2
Ackerman LL (2008)

23. Prognosis
• Prognosis of a CSF shunt infection is dependent
primarily on
– Underlying neurological pathology
• Relatively normal brain organization has a better outcome
than a patient with abnormal morphology especially in the
pediatric population.
– Organisms involved
• Gram-positive organisms correlate with a better prognosis
than Gram-negative ones.
– Inadequate or inappropriate treatment
• can cause recurrent shunt infections (20-30% cases)1
1
Yilmaz A et al (2012)

24. Complications
• Cerebritis with cortical damage
• Polycystic ventricles
• Brain abscess
• Peritoneal CSF malabsorption
• Decreased intellectual performance
• Psychomotor retardation
• Increased risk of seizures and death
• Peritonitis with bowel adhesion or perforation
• Endocarditis
• Nephritis