More than Skin-deep - Muscle and Nerve Lab

21 August 2023

Did you know that your muscles and nerves tell a story?

Our highly specialised Muscle and Nerve Laboratory was established in 1978 - and since the early 90s, Kathy Cash and Bernice Gutschmidt have been the dynamic duo helping to uncover each patient’s unique story.

This specialised testing is particularly beneficial in the treatment and management of patients who may present with mild to debilitating symptoms of muscle weakness, pain, cramping, pins and needles, numbness, and sometimes non neuromuscular symptoms.

Samples and surgeons

Skeletal muscle and peripheral nerve samples are received from surgeons across the metropolitan public and private hospital network; each sample must be surgically removed using specific protocols.

When the muscle samples arrive in the lab, they’re dissected into multiple, smaller portions of muscle fibres of specific orientation, carefully glued onto pieces of cork, and snap-frozen with the aid of liquid nitrogen to ensure they remain perfectly preserved for analysis.

Sural nerve samples (the nerve which gives sensation to the lower outside leg, foot, and ankle) must also meet stringent specifications during surgical removal.

On arrival in the lab the nerve sample is subdivided into smaller segments that are placed into various fixatives; for one, the nerve is attached to a stainless-steel weight to prevent its contraction.

The art of analysis

Frozen sections are the mainstay of muscle tissue and cell analysis (histology) and are manually produced in a cryostat, in contrast to other human tissues which are predominantly processed into paraffin wax. Enzyme histochemistry, immunohistochemistry and special stains are applied to these frozen sections to demonstrate patterns of staining and reactions that demonstrate if the patient has a primary muscle disease or a secondary nervous system cause for their symptoms.

Microscopically, the enzyme histochemistry almost looks like art!

Kathy and Bernice have also perfected the unique skill of “teasing” single myelinated nerve fibres, achieved by microdissection, using very fine forceps. The fibres are finer than a human hair. It is artistry and intricacy of the highest order.

The team must select only 30 fibres (from a possible 30,000) that accurately represent what is taking place within the whole nerve- it’s a technique that takes years of experience to master.

Each preparation is then microscopically analysed, with every fibre telling a part of the story. Different diseases will exhibit unique patterns of degeneration under the microscope.

Bernice Gutschmidt and Kathy Cash.

Refining processes

Kathy has been with the organisation for fifty years- starting out in Anatomical Pathology, and her passion for her work is evident.

"I’ve been doing this for so long, it has afforded me the opportunity to modify and create techniques that not only improve test turnaround times but also improve the histological microscope slide preparations, to facilitate interpretation by the reporting pathologists."

Bernice has been with the organisation for 35 years; her contribution to the lab’s transition to an automated immunohistochemical platform in 2005 has been integral to the service they now provide.

A changing landscape

Over time Kathy and Bernice have noticed a change in disease classifications. The need for diagnosis of muscular dystrophies has declined due to an increase in the genetic testing of blood and the prevalence of more inflammatory conditions. They attribute this to developments in research and awareness around muscle (and nerve) disease indicators.

Kathy says, "We now see mainly systemic autoimmune inflammatory diseases with many subgroups. We’re finding as time goes by that pathologists are now armed with increased knowledge due to advances in serological and radiological testing (MRI), which contributes to a more comprehensive understanding of these disorders, and which collectively assists in optimal interpretation. This has led to new treatments, such as immunotherapies in addition to the usual steroids as a first line of treatment".

Bernice adds, "Consequently, the number of patients referred by neurologists has lessened but we’ve seen an increase in rheumatologist referred, reflecting this emerging group of inflammatory muscle disorders. We also have more antibodies available to us that didn’t even exist back in the early 80s and 90s".

The lab currently runs inflammatory, metabolic and dystrophy screens on muscle biopsies, which can comprise up to 30 antibodies. Although costly, some patients will require screening of all 30 to ensure nothing is missed when pursuing a diagnosis.

Bernice says, "We throw everything at diagnosing our patients’ conditions because it’s what they deserve; it is incredibly satisfying to follow the patient journey and sample from start to finish."

Multi-state service

While based in South Australia, this reference laboratory doesn’t just look after South Australians; Bernice and Kathy also receive partially pre-prepared samples from the Northern Territory and Newcastle, NSW. It’s a specialised service that is only provided by SA Pathology in this state.

Interested in partnering with our Muscle and Nerve Laboratory? Contact us today.