Therapeutic plasmapheresis

Successful Emergency Management of a Dog with Ventilator-Dependent Acquired Myasthenia Gravis with Immunoadsorption

A one-year-old, female intact Samoyed, 12.5 kg, was presented with coughing for 2 weeks, progressive appendicular and axial muscle weakness, megaesophagus and labored breathing for 5 days. There was no improvement with standard treatment. Acquired myasthenia gravis was suspected and the dog was referred with increasing dyspnea. At presentation, the dog showed a severely reduced general condition, was non-ambulatory and showed abdominal and severely labored breathing. A marked hypercapnia (PvCO2 = 90.1 mmHg) was present in venous blood gas analysis. The serum anti-acetylcholine receptor antibody test was consistent with acquired myasthenia gravis (2.1 nmol/L). The dog was anesthetized with propofol and mechanically ventilated with a Hamilton C1 ventilator. Immunoadsorption was performed with the COM.TEC® and ADAsorb® platforms and a LIGASORB® adsorber to eliminate anti-acetylcholine receptor antibodies. Local anticoagulation was performed with citrate. Treatment time for immunoadsorption was 1.5 h with a blood flow of 50 mL/min. A total plasma volume of 1.2 L was processed. Further medical treatment included intravenous fluid therapy, maropitant, esomeprazole, antibiotic therapy for aspiration pneumonia and neostigmine 0.04 mg/kg intramuscularly every 6 h for treatment of acquired myasthenia gravis. Mechanical ventilation was stopped after 12 h. A percutaneous gastric feeding tube was inserted under endoscopic control on day 2 for further medical treatment and nutrition. A second treatment with immunoadsorption was performed on day 3. Again, a total plasma volume of 1.2 L was processed. Immediately after this procedure, the dog regained muscle strength and was able to stand and to walk. After 6 days, the dog was discharged from the hospital. This is the first report of immunoadsorption for emergency management of a dog with acute-fulminant acquired myasthenia gravis. Immunoadsorption may be an additional option for emergency treatment in dogs with severe signs of acquired myasthenia gravis.

Temporal Dynamics of MOG Antibodies in Children With Acquired Demyelinating Syndrome

Background and Objective

The spectrum of myelin oligodendrocyte glycoprotein (MOG) antibody–associated disorder (MOGAD) comprises monophasic diseases such as acute disseminated encephalomyelitis (ADEM), optic neuritis (ON), and transverse myelitis and relapsing courses of these presentations. Persistently high MOG antibodies (MOG immunoglobulin G [IgG]) are found in patients with a relapsing disease course. Prognostic factors to determine the clinical course of children with a first MOGAD are still lacking. The objective of the study is to assess the clinical and laboratory prognostic parameters for a risk of relapse and the temporal dynamics of MOG‐IgG titers in children with MOGAD in correlation with clinical presentation and disease course.

Methods

In this prospective multicenter hospital-based study, children with a first demyelinating attack and complete data set comprising clinical and radiologic findings, MOG-IgG titer at onset, and clinical and serologic follow-up data were included. Serum samples were analyzed by live cell-based assay, and a titer level of ≥1:160 was classified as MOG-IgG–positive.

Results

One hundred sixteen children (f:m = 57:59) with MOGAD were included and initially diagnosed with ADEM (n = 59), unilateral ON (n = 12), bilateral ON (n = 16), myelitis (n = 6), neuromyelitis optica spectrum disorder (n = 8) or encephalitis (n = 6). The median follow-up time was 3 years in monophasic and 5 years in relapsing patients. There was no significant association between disease course and MOG-IgG titers at onset, sex, age at presentation, or clinical phenotype. Seroconversion to MOG-IgG–negative within 2 years of the initial event showed a significant risk reduction for a relapsing disease course. Forty-two/one hundred sixteen patients (monophasic n = 26, relapsing n = 16) had serial MOG-IgG testing in years 1 and 2 after the initial event. In contrast to relapsing patients, monophasic patients showed a significant decrease of MOG-IgG titers during the first and second years, often with seroconversion to negative titers. During the follow-up, MOG-IgG titers were persistently higher in relapsing than in monophasic patients. Decrease in MOG-IgG of ≥3 dilution steps after the first and second years was shown to be associated with a decreased risk of relapses. In our cohort, no patient experienced a relapse after seroconversion to MOG-IgG–negative.

Discussion

In this study, patients with declining MOG-IgG titers, particularly those with seroconversion to MOG-IgG–negative, are shown to have a significantly reduced relapse risk.

Extracorporeal Therapies in the Emergency Room and Intensive Care Unit

Extracorporeal treatments create opportunity for removing disease causing solutes within blood. Intoxications, renal failure, and immune-mediated diseases may be managed with these treatments, often providing new hope for patients with severe or refractory disease. Understanding solute pharmacokinetics and the limitations of each type of extracorporeal technique can allow for the selection of the optimal treatment modality.

Development of an automated plasmapheresis procedure for the harvest of equine plasma in accordance with current good manufacturing practice

OBJECTIVE

To develop a high-speed, continuous-flow, automated plasmapheresis procedure for the high-volume harvest of equine plasma in accordance with current good manufacturing practice.

ANIMALS

143 horses (predominantly draft breeds) between 3 and 10 years of age at the time of purchase.

PROCEDURES

Adaptations were made to automated plasmapheresis instruments and sterile disposable collection sets, which allowed for dual-instrument, continuous-flow operation. Donor horses were connected to the apparatus via 2 catheters (1 inserted in each jugular vein). The instruments removed whole blood from donors, fractionated the blood, diverted plasma to collection bags, and simultaneously returned concentrated cells to the donors. Plasmapheresis was performed on donor horses at 14-day intervals with a maximum of 22 mL of plasma/kg of donor body weight harvested during each plasmapheresis procedure.

RESULTS

During a 5-year period, 3,240 plasmapheresis procedures were performed and > 50,000 L of sterile equine plasma was harvested in accordance with current good manufacturing practice. Donors typically remained calm during the plasmapheresis procedures and tolerated the procedures well. The high-volume and frequent plasma harvest did not result in sustained hypoproteinemia in donor horses. Adverse events associated with the automated plasmapheresis technique were infrequent, and the recurrence of adverse events was minimized by making minor adjustments to the procedure.

CONCLUSIONS AND CLINICAL RELEVANCE

The automated plasmapheresis procedure described in this report can be used to safely harvest equine plasma or to perform therapeutic plasmapheresis in horses.

Treatment of Three Cats with Hyperviscosity Syndrome and Congestive Heart Failure Using Plasmapheresis

Three cats were evaluated at a veterinary teaching hospital for congestive heart failure (CHF) secondary to hyperviscosity syndrome from plasma cell neoplasia. All cats had severe hyperproteinemia due to hyperglobulinemia. Multiple myeloma or plasma cell neoplasia was diagnosed based on cytopathology and post mortem examination. The cats presented with signs of CHF including acute collapse, tachypnea, increased respiratory effort, and pulmonary crackles. All cats had heart murmurs and echocardiographic signs consistent with hypertrophic cardiomyopathy. An enlarged left atrium was found in all cats and two of three cats also had spontaneous echocardiographic contrast. Plasmapheresis (centrifugal plasma exchange) was performed on all three cats by the removal of whole blood and the infusion of a balanced electrolyte solution while the whole blood was centrifuged and separated. The RBCs were then washed before being readministered to the patient. Plasmapheresis alleviated the clinical signs of CHF (tachypnea) in all three cats. Plasmapheresis should be considered in cases of CHF secondary to hyperviscosity syndrome to rapidly alleviate clinical signs associated with heart failure while diagnosis of the underlying cause is made and appropriate therapy implemented.

Use of therapeutic plasmapheresis in a case of canine immune-mediated hemolytic anemia

OBJECTIVE

To investigate the clinical application and potential utility of plasmapheresis in canine immune-mediated hemolytic anemia.

CASE SUMMARY

A 7-year-old spayed female Maltese diagnosed with immune-mediated hemolytic anemia was initially treated with prednisone, cyclosporine, and received multiple transfusions of packed RBC. Because of the progression of clinical signs despite traditional medical therapy, plasmapheresis was initiated. Plasma immunoglobulin G and immunoglobulin M levels were measured before, during, and after treatment to help determine if there had been a significant decrease in immunoglobulin levels with plasmapheresis. Plasmapheresis was successfully performed over a 2.5-hour period in this dog with minimal complications. Hypocalcemia was identified as a known complication of circuit anticoagulation, and was corrected through calcium supplementation. Post-plasmapheresis there was a decrease in immunoglobulin G and immunoglobulin M levels, and the patient showed clinical improvement. Following discharge the dog had no known complications of therapy, and had complete resolution of the anemia.

NEW OR UNIQUE INFORMATION PROVIDED

Plasmapheresis was performed successfully with minimal complications. Because transfusion requirements appeared to be reduced, and the procedure was well tolerated, there may be a place for this modality in severe cases to act as a bridge until medical therapy takes full effect. Because of the cost of performing this therapy, and the potential requirement for multiple treatments, it should be reserved for selected patients.