Answers to Self Assessment Questions

Transcription

1 Answers to Self Assessment Questions 1. Which of the following findings is supportive of the diagnosis of multifocal motor neuropathy (MMN): A. Absence of conduction block (CB) on nerve conduction studies B. Elevated protein concentration in cerebral spinal fluid C. Elevated titers of serum IgM*** D. Positive therapeutic response to corticosteroid therapy Answer C: Elevated titers of serum IgM are common in patients with MMN and this finding is considered supportive criteria for the diagnosis of MMN based upon joint guidelines from the European Federation of Neurological Societies (EFNS) and Peripheral Nerve Society (PNS) (Answer C is correct). Response to corticosteroids, absent findings of conduction block on nerve conduction studies, and the presence of elevated protein in cerebral spinal fluid are not established criteria from the EFNS/PNS guidelines and these findings do not support diagnosis (Answers A, B, and D are incorrect). 2. Which of the following is a characteristic finding in patients with MMN: A. Impaired muscle grip strength in both left and right hands B. Intolerable neuropathic pain in the lower extremities C. Persistent fatigue*** D. Progressive respiratory decline Answer C: Clinical studies recognize persistent fatigue as a common complication experienced by those with MMN (Answer C is correct). Patients with MMN typically do not complain of intolerable neuropathic pain, nor do they have respiratory decline (Answers B and D are incorrect). Weakness with grip strength is typically asymmetric and not symmetrical (Answer A is incorrect). Reference: Merkies IS, Faber CG. Fatigue in immune-mediated neuropathies. Neuromuscul Disord. 2012;22(Suppl 3):S203-S207.

2 3. MMN differs from amyotrophic lateral sclerosis (ALS) by the presence of which of the following: A. Upper motor neuron signs B. Bulbar findings C. Predominant sensory findings D. Asymmetrical weakness with wrist extension*** Answer D: Patients with MMN typically demonstrate asymmetrical weakness upon wrist extension (Answer D is correct). Sensory involvement is uncommon for those with MMN, but is often experienced by those with ALS (Answer C is incorrect). Upper motor neuron signs and bulbar findings are characteristics of ALS, but not MMN (Answers A and B are incorrect). Reference: Meuth SG, Kleinschnitz C. Multifocal motor neuropathy: update on clinical characteristics, pathophysiological concepts and therapeutic options. Eur Neurol. 2010;63(4): Which of the following is recommended first-line treatment for MMN: A. Therapeutic plasma exchange B. Prednisone orally once daily C. Methylprednisolone intravenously once daily D. Intravenous immune globulin (IVIg)*** Answer D: Clinical guidelines from the European Federation of Neurological Societies (EFNS) and the Peripheral Nerve Society (PNS) endorse IVIg as a first-line treatment for MMN (Answer D is correct). Corticosteroids, including prednisone and methylprednisolone, are not recommended (Answers B and C are not correct). Therapeutic plasma exchange has failed to demonstrate a consistent benefit for the treatment of MMN and is not recommended (Answer A is incorrect). 5. CK is an otherwise healthy man, 40 years of age, (weight 165 lbs [75 kilograms]) recently diagnosed with MMN. Which of the following is an appropriate treatment regimen for IVIg induction therapy: A. 2 g/kg given over 5 days*** B. 1 g/kg given over 5 days C. 0.5 g/kg given over 5 days D. 0.4 g/kg given over 5 days

3 Answer A: Clinical guidelines from the European Federation of Neurological Societies (EFNS) and Peripheral Nerve Society (PNS) endorse IVIg 2 g/kg administered over 2 to 5 days as inductive therapy for MMN. (Answer A is correct). An induction regimen of of 1 g/kg, 0.5 g/kg, and 0.4 g/kg given over 5 days are all incorrect based upon clinical guideline recommendations. (Answers, B, C, and D are incorrect). 6. ZG is a man, 53 year years of age, with MMN with progressive disease who has failed to respond to 3 separate courses of IVIg therapy. Which of the following would be an appropriate treatment alternative for ZG: A. Therapeutic plasma exchange B. Corticosteroids C. Cyclophosphamide*** D. Subcutaneous immunoglobulin (SCIg) Answer C: For patients unresponsive to IVIg, cyclophosphamide may be considered; although risk for toxicity limits widespread use (Answer C is correct). Clinical guidelines do not recommend corticosteroids or therapeutic plasma exchange (Answers A and B are incorrect). Subcutaneous immunoglobulin (SCIg) is used to treat patients who are responsive to maintenance IVIg therapy, but wish to transition to subcutaneous therapy. It is not recommended for induction therapy and is not a good option in a patient unresponsive to IVIg therapy (Answer D is not correct). 7. Which of the following is an appropriate maintenance therapy for a patient with MMN: A. Intravenous immunoglobulin 1 g/kg dosed once monthly*** B. SCIg 1 g/kg dosed once daily C. Prednisone 60 mg orally once daily D. Therapeutic plasma exchange once monthly Answer A: Clinical guidelines from the EFNS/PNS recommend IVIg as maintenance therapy for patients with MMN. Appropriate maintenance regimens include IVIg 1 g/ kg given once monthly (Answer A is correct). Prednisone and therapeutic plasma exchange are

4 not recommended maintenance therapies (Answer C and D are not correct). SCIg is an option for the maintenance treatment of MMN, but a dose of 1 g/kg once daily is incorrect because this is typically dosed on a weekly, and not a daily, basis (Answer B is incorrect). 8. For patients undergoing induction therapy with immune globulin for MMN, which of the following parameters should be closely monitored as part of a treatment plan: A. Kidney function*** B. Liver function test C. Serum concentration of IgM D. B lymphocyte count Answer A: Patients undergoing immunoglobulin therapy are at risk for kidney injury and markers of kidney function should be closely monitored (Answer A is correct). Immunoglobulin products carry a labeled warning for the risk of acute kidney injury. Routine monitoring of liver function tests and B lymphocyte counts with IVIg therapy are not suggested (Answers B and D are not correct). While serum concentrations of IgM may vary in patients being treated with IVIg, routine monitoring of IgM as a marker of immunoglobulin treatment responsiveness is not of benefit (Answer C is not correct). Reference: Van Schaik IN, van den Berg LH, de Haan R, Vermeulen M. Intravenous immunoglobulin for multifocal motor neuropathy. Cochrane Database Syst Rev. 2005;18(2):CD Which of the following medications work by inhibiting complement factor 5 and preventing formation of the membrane attack complex (MAC): A. Eculizumab*** B. Interferon beta-1a C. Rituximab D. Infliximab Answer A: Eculizumab is a complement factor 5 inhibitor and prevents the formation of the MAC. (Answer A is correct). Interferon beta-1a is a cytokine modulator, rituximab inhibits B cells by binding to CD20 antigen on B cells, and infliximab is a tumor necrosis factor-α antagonist (Answers B, C, D are incorrect).

5 Reference: Umapathi T, Hughes RA, Nobile-Orazio, Léger JM. Immunosuppressant and immunomodulatory treatments for multifocal motor neuropathy. Cochrane Database Syst Rev. 2012;4:CD Based upon available clinical evidence, which of the following biological therapies may be beneficial for the treatment of patients with MMN: A. Rituximab*** B. Fingolimod C. Natalizumab D. Infliximab Answer A: Current clinical evidence suggests rituximab is an effective treatment for some patients with MMN (Answer A is correct). There is no datum supporting the use of fingolimod or natalizumab for the treatment of MMN (Answers B and C are not correct). A few patients with MMN have been treated with infliximab; however, the concern regarding reports of new onset peripheral neuropathy makes it a less attractive clinical option (Answer D is not correct). Reference: Umapathi T, Hughes RA, Nobile-Orazio, Léger JM. Immunosuppressant and immunomodulatory treatments for multifocal motor neuropathy. Cochrane Database Syst Rev. 2012;4:CD