What is the role of plasma exchange in the treatment of pediatric atypical hemolytic uremic syndrome (aHUS)?

Updated: Nov 12, 2018
  • Author: Robert S Gillespie, MD, MPH; Chief Editor: Craig B Langman, MD  more...
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Answer

Therapeutic plasma exchange (TPE), which is also called plasmapheresis, was previously the preferred plasma therapy for aHUS, although its efficacy was never confirmed in controlled clinical trials. [21]

TPE removes the patient's plasma and replaces it with fresh frozen plasma (FFP) or a similar product. Albumin should not be used for replacement because it does not contain the vWF metalloproteinase or complement factors, except in the case of pneumococcal-associated hemolytic-uremic syndrome or neuraminidase mediated hemolytic-uremic syndrome (see above).

TPE can be performed using a cell-separator device or a special plasma filter used on a CRRT machine, both of which require specially trained staff to operate. Both methods work well, and local availability is the main selection factor. TPE requires a central venous catheter for vascular access.

No consensus or evidence-based guidelines guide therapy dose or schedule. Most clinicians use a tapering schedule, with several daily sessions followed by alternate-day treatments. Intervals between treatments are extended based on patient response. Individual regimens widely vary. Some authors advocate twice-daily TPE for refractory cases, but note that the benefit of this approach cannot be confirmed. [22]

TPE can lower the serum creatinine because it removes the patient's serum and replaces it with serum from donors with a normal creatinine value. This does not necessarily mean the patient's renal function is improving. Platelet count is a more reliable marker of response.

In theory, FFP may contain some large vWF multimers. Some authors advocate using cryoprecipitate-reduced plasma. However, multiple TPE sessions with cryoprecipitate-reduced plasma alone may deplete other coagulation factors and put the patient at risk for bleeding. Consider using FFP for at least some exchanges.

The role of plasma therapy in pneumococcal-associated hemolytic-uremic syndrome is controversial. Donor plasma may contain antibodies to the T antigen, which, in theory, could worsen the hemolytic process. Alternately, plasma exchange may remove neuraminidase and decrease the amount of circulating anti–T antibody. Some authors advocate plasma exchange using albumin replacement, since albumin does not contain antibodies.


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