Case Conference

1
Case Conference

• Vipul Ganatra, MD

2
Case 1

• 54 yr old AA male presents to the ER with 2 week
  h/o worsening left shoulder pain. Also c/o
  arthralgias for about a month, particularly the
  left hip.
• Had a negative left hip X-ray one month ago and a
  bone scan 2 weeks earlier.
• He did not c/o fever or chills, night sweats or
  other symptoms.
• Earlier ED eval 10/10 lt shoulder pain, sharp,
  non-radiating in character, aggravated by
  passive/active range of motion.

3
Case 1

• Orthopedic surgery was consulted in the ER.
• L shoulder films unremarkable
• Patient underwent arthroscopic ID of the left
  shoulder and partial synovectomy for presumptive
  Dx of septic arthritis.
• Post-operatively ID consulted

4
Case 1

• PMH
• ESRD
• HTN
• Failed cadaveric kidney transplant in 10/2002
• S/P placement of a Gore-Tex loop AV graft, right
  arm for dialysis access in 3/03 with subsequent
  thrombectomy x 2.

5
Case 1

• MEDS
• Cefazolin 1 gm q 12hrs.
• Clonidine
• Benadryl
• Labetalol
• Procardia

6
Case 1

• ALLERGIES
• Codeine causes nausea
• SOCIAL HISTORY
• Non-smoker, non-alcoholic, no h/o IDU
• FAMILY HISTORY
• Positive for HTN

7
Case 1

• P/E
• Vitals 97.1-70-120/76
• Lt. Shoulder dressing C/D/I
• LABS
• WBC 13.1, HH 12 36, Plt cnt 265.
• BUN/Cr 51/8.7, ESR 68, CRP 28.6
• Synovial fluid WBC 37,700 and RBC 38,000 with
  99 polys.
• Lt shoulder OR swab grew S. aureus
• BC x1 grew gram positive cocci in clusters.

8
Case 1

• Recommended
• changing cefazolin to vancomycin and adding
  rifampin pending susceptibilities.
• Repeat BC
• Echocardiogram and tagged WBC scan
• Ultrasound right forearm AV graft.

9
Case 1

• TTE was negative for any vegetation.
• US of the forearm showed a pseudoaneurysm and
  fluid collection on the posterior aspect.-
  Vascular surgery was consulted.
• Final BC grew MSSA
• Vancomycin was switched to nafcillin 2gm q 4
  hours.
• Graft excision planned

10
Hemodialysis Access Infections

• Infectious complications of the vascular access
  are a major source of morbidity and mortality
  among HD patients.
• Incidence of vascular access-related infection is
  the highest when central venous dialysis
  catheters are used.
• Native AV fistulas carry the lowest risk of
  infection.
• PTFE AV grafts carry a higher risk of serious
  vascular access related infections compared to
  fistula.

Nassar et al. Kidney Internat 2001 60 1-13
11
Hemodialysis Access Infections

• In 1995, US national survey, conducted by CDC
  showed that only 22 of HD patients had a native
  AV fistula.
• In the US PTFE AV grafts have gained popularity
  as they are easy to place at sites where it is
  surgically unfeasible to create a native AVF.
• They are associated with high rates of thrombosis
  and infection than fistula.

Raju S Ann Surg 1987 206 666
12
Hemodialysis Access InfectionsPost-operative
Infection

• Risk of PTFE infection starts at the time of
  surgical placement.
• In one study an initial 30-day graft infection
  rate of 6 in 208 patients undergoing PTFE
  placement was reported.
• Femoral location of PTFE grafts is associated
  with higher postoperative wound infections.

Zibari GB et al, AmJ Kidney Dis 199730 343-48
13
Hemodialysis Access Infections

• Risk factors for PTFE graft infection are as
  follows
• - Repetitive cannulation of the graft for
  dialytic purposes.
• - Difficulty in cannulation of the graft.
• - Perigraft hematoma formation.
• - Prolonged post dialysis bleeding from the
  graft.
• - Break in the sterile technique.

Zibari GB et al, AmJ Kidney Dis 199730 343-48
14
Hemodialysis Access Infections

• Pain. irritation, tenderness, redness warmth etc.
  are symptoms signs of local infection.
• Lack of such symptoms signs does not exclude
  the possibility of clinically silent graft
  infection, especially in cases of unexplained
  sepsis, leucocytosis or FUO.

15
Nassar et al. Kidney Internat 2001 60 1-13
16
Hemodialysis Access Infections

• Conservative excision of infected segments of
  PTFE grafts is associated with high rates of
  recurrent infection necessitating total graft
  excision.
• Old clotted PTFE AV grafts are have been
  recognized to harbor occult bacterial infection
  that can lead to serious infectious
  complications.

Nassar GM et al. Semin Dial 2000 131-3
17
Hemodialysis Access InfectionsClotted graft
infection

• These infections are silent and often difficult
  to diagnose.
• In one study 20 HD patients with old clotted PTFE
  grafts who presented with fever(15 patients) or
  fever and clinical signs of sepsis(5 patients) in
  whom the source was not localized to any organ
  system.

Ayus JC et al J Am Soc Nephrol 1998 9 1314-17
18
Hemodialysis Access InfectionsClotted graft
infection

• Comparison was made with 21 asymptomatic HD
  patients with clotted PTFE grafts who served as
  control subjects.
• Both febrile patients and control subjects were
  evaluated with indium scans and then subjected to
  surgical removal of the graft.
• Bacterial cultures of the recovered surgical
  material and blood were done simultaneously in
  all study participants.

Ayus JC et al J Am Soc Nephrol 1998 9 1314-17
19
Hemodialysis Access InfectionsClotted graft
infection

• Blood cultures were positive for bacterial
  pathogens in 15 of the 20 febrile patients,
  indicating that serious illness was present.
• In contrast, all of the asymptomatic control
  subjects had negative blood cultures.
• Indium uptake in or around the clotted grafts was
  present on scanning in all 20 patients and in 15
  of the control subjects.

Ayus JC et al J Am Soc Nephrol 1998 9 1314-17
20
Hemodialysis Access Infections

• The importance of the indium scan findings was
  verified when purulent infected material was
  recovered from graft material in all 20 patients
  and in 13 of 15 indium scan-positive control
  subjects. Thus, asymptomatic graft infection
  present in majority of indium controls
• The pathogens recovered from blood culture were
  identical to those cultured from the graft
  material in all patients, strongly indicating a
  causal relationship.

21
Hemodialysis Access Infections

• By far the most frequent pathogens recovered from
  the graft material were S. aureus, followed by
  Staphylococcus epidermidis. Other less frequent
  pathogens were Escherichia coli, Serratia
  marcescens, and Streptococcus pneumonia.

22
Hemodialysis Access Infections

• Indium scan has been shown to be useful in
  vascular graft infection, with overall
  satisfactory sensitivity and specificity
• A variety of lesions other than foci of bacterial
  infection can produce positive results, but an
  intense focal uptake is uncommon in lesions other
  than abscesses and hematomas.

23
Hemodialysis Access Infections

• The indium scan demonstrated a sensitivity of
  100 and a specificity of 75 for graft
  infection.
• The authors therefore advocate indium scanning as
  a diagnostic tool to investigate the possibility
  of graft infection when such suspicion exists in
  the absence of clinically obvious signs.

Ayus JC et al J Am Soc Nephrol 1998 9 1314-17
24
Hemodialysis Access Infections

• Fishbane et al, who found high rates of occult
  bacterial infection in nonfunctioning
  arteriovenous grafts among their HD patients with
  refractory anemia and low serum albumin.
• Excision of the graft led to a decline in serum
  C-reactive protein (CRP) levels and total serum
  ferritin, along with a rise in serum albumin and
  improved responsiveness to erythropoietin.

Fishbane et al, J Am Soc Nephrol, 101402, 1999
25
Hemodialysis Access Infections

• Old clotted PTFE grafts with evidence of
  infection should be surgically excised without
  delay, and systemic antibiotics should be
  administered.
• ?? Should old clotted PTFE grafts be routinely
  excised if there is no evidence of infection is
  found after evaluation??

26
Hemodialysis Access Infections

• There is currently no prospective data to address
  this question appropriately.
• The authors suggest that HD patients with old
  clotted (after 30 days post-op) PTFE grafts
  having risk factors for AV graft infection should
  be actively investigated for infection (indium
  scan) and managed.

Nassar GM et al. Semin Dial 2000 131-3
27
Hemodialysis Access Infections

• These risk factors include
• - DM
• - Immuno-incompetency
• - Renal transplantation
• - Indwelling central venous catheter
• - h/o bacteremia
• - Previous major infection in any organ system
• - Previous AV graft-related infection
• - Previous AV graft-related surgery
• - Fever of unknown origin

28
Hemodialysis Access Infections

• A recent development in the area of the HD access
  is the availability of cryopreserved human
  femoral veins for use as arteriovenous access
  grafts.
• These cryoveins have the ability to
  revascularize, thus allowing the patient to fight
  and resist infection.

Abstract Matsura et al, 24th Annual Meeting of
the Peripheral Vascular Surgery Society, 1999.
29
Hemodialysis Access Infections

• These vein allografts were placed in the setting
  of systemic or local infection.
• The rarity of cryovein-related infection in these
  preliminary reports is promising for patients
  with history of repeated PTFE graft infections
  and exhaustion of dialysis arteriovenous access
  sites.

Abstract Matsura et al, 24th Annual Meeting of
the Peripheral Vascular Surgery Society, 1999.
30
Hemodialysis Access Infections

• In keeping with the same concept, lower rates of
  arteriovenous access-related infection were also
  observed with the use of denatured homologous
  vein grafts, as opposed to PTFE grafts, in a
  prospective randomized multicenter trial.

Bosman PJ et al.Eur J Vasc Endovasc Surg 1998
16 126-132