Necrotizing autoimmune myopathy
Earlier identification and treatment initiation
Immune-mediated necrotizing myopathy (IMNM), also called necrotizing autoimmune myopathy (NAM), is a disease that causes severe muscle weakness. Timely diagnosis and treatment is important to improving outcomes, but differentiating IMNM from other myopathies on initial clinical assessment may be difficult because:
Therefore, a positive HMGCR-IgG or SRP-IgG autoantibody result will aid in achieving a shorter time to diagnosis and assist with sorting out these diagnostic challenges.
of IMNM patients will be seropositive for HMGCR-IgG or SRP-IgG
Assess probability of necrotizing myopathy for your patients
Early initiation of immunotherapy results in better outcomes for patients with IMNM, but diagnosis is often challenging. Mayo Clinic has created an online calculator to help physicians assess the probability of IMNM based on their patients’ symptoms. Please note: A calculator based on a statistical model cannot replace sound clinical judgement; thorough understanding of a patient’s history, along with clinical examination and laboratory testing, are still needed for a clinic-sero-pathological diagnosis of IMNM. A study validating the effectiveness of this tool is available here.
An advanced approach to diagnosis
We offer improved clinical assay performance through:
Necrotizing Autoimmune Myopathy
Christopher Klein, M.D., gives an overview of the necrotizing myopathy evaluation. He discusses when this testing should be ordered, how this testing compares to previous testing approaches, and what clinical action can be taken due to the results of this testing.
Articles and resources
In late 2019, after months of looking for a reason for his rapid loss of muscular function, David Voeltz got an answer: he had necrotizing autoimmune myopathy. Today, after nearly two years of treatment, David has a renewed lease on life and keen appreciation for the Mayo Clinic team that confirmed his diagnosis.
This “Specialty Testing” webinar will discuss the diagnosis, pathological understanding, and current best treatment options for necrotizing autoimmune myopathy.
Necrotizing autoimmune myopathy (NAM) is a serious but rare muscle disease strongly associated with autoantibodies to either the protein signal recognition particle (SRP) or the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR). NAM typically manifests with subacute proximal limb muscle weakness and persistently elevated serum creatine kinase (CK) concentrations, but slower onsets can occur and complicate diagnosis.