With respect to plasma exchange therapy:
- (a) What are the physical principles of plasma exchange therapy?
- (b) What substances can plasma exchange effectively remove?
- (c) List 5 acute conditions where therapeutic plasma exchange is indicated.
- (d) List 4 common complications of this therapy, excluding catheter-related complications
Answer and interpretation
(a) What are the physical principles of plasma exchange therapy?
- Separation of plasma from blood cells by centrifugation or membrane filtration
- Reinfusion of cells plus autologous plasma or another replacement solution eg albumin
- Removes large molecular weight substances
(b) What substances can plasma exchange effectively remove?
- Pathogenic auto-antibodies
- Immune complexes
- Myeloma light chains
- Cholesterol-containing lipoproteins /triglycerides
(c) List 5 acute conditions where therapeutic plasma exchange is indicated.
- Myasthenic Crisis
- Goodpasture’s Syndrome with pulmonary haemorrhage
- Hyperviscosity syndromes
— Waldenstrom’s Macroglobulinaemia
- Wegener’s Granulomatosis with pulmonary haemorrhage
- Guillain-Barre Syndrome/Acute Inflammatory Demyelinating Polyradiculopathy
- Antiphospholipid Antibody Syndrome
- HELLP syndrome
- Multiple sclerosis
- HIV-related neuropathy
- Paraneoplastic syndromes
- Rapidly progressive glomerulonephritis
- Renal transplant rejection
- Coagulation inhibitors
- Auto-immune haemolytic anaemia
- Overwhelming sepsis syndromes eg meningococcaemia
- Reye’s syndrome
- Paraquat poisoning
(d) List 4 common complications of this therapy, excluding catheter-related complications
- Hypotension due to excess fluid removal +/ inadequate volume replacement
- Citrate-induced hypocalcaemia
- Anaphylactic/transfusion reactions to fresh frozen plasma replacement solution
- Coagulation abnormalities due to removal of clotting factors not replaced when albumin replacement used.
- Removal of useful immunoglobulins and complement which can in theory lead to an immunodeficient state.
- Drug removal – especially drugs with high protein-binding and low volume of distribution. Potential problems in the diseases in which therapeutic plasma exchange is used are cyclophosphamide and azathioprine.
- Pyrogenic reactions
- Vasovagal reactions