Volume 195 - Issue 6
Practical neurology: a case-based series
Authors: Leo Davies and Craig S Anderson
Med J Aust 2011; 195 (6): 328. || doi: 10.5694/mja11.10912
Published online: 19 September 2011
Published online: 19 September 2011
A practical guide to common and important problems in clinical neurology
It has been a long-held perception that neurology is a descriptive discipline, limited to careful diagnostic assessment but offering few therapeutic options for the care of patients, who are generally the responsibility of other medical practitioners. To some extent, these testaments hold true today: there has been distressingly little progress in the treatment of common and disabling neurodegenerative diseases — in particular, Alzheimer’s disease and motor neurone disease — despite tantalising clues to their aetiology. Major gaps remain in the availability of comprehensive specialist services, such as acute-care stroke units, despite nearly two decades of evidence from randomised trials supporting the benefit of such models of service delivery.
However, considerable advances in many areas have transformed neurology into a very active discipline. For example, although the initiating factors for multiple sclerosis remain hidden, knowledge of the pathophysiological mechanisms has enabled development of treatments that target specific aspects of the immune system. The prognosis for young adults diagnosed with this chronic disease is, therefore, much more optimistic than it has been in the past. The development of sophisticated imaging technologies has radically increased the diagnostic certainty of a wide range of neurological conditions. Where neurologists once had to incrementally improve their diagnostic certainty by doing postmortem examinations months or years after a clinical encounter, there is now a range of investigations that can be used to determine the location and pathophysiological basis of lesions during life. This gives us a window of time during which therapeutic intervention may reverse an underlying process. The improvement in imaging techniques such as computed tomography, magnetic resonance imaging and ultrasound has dispelled much of the mystery of the neurological examination. Clinical neurophysiology, once a laboratory curiosity, is now widely available as the standard procedure to reliably diagnose nerve injuries and muscle disease. This technology has also enabled better use of surgical and medical therapies for conditions such as carpal tunnel syndrome, radiculopathies, and inflammatory myopathies and neuropathies.
On a background of advances in neuroscience and neuroimaging has come enormous growth in the availability of therapeutic compounds. The pharmacology of neuroscience probably had its birth in the development of combination levodopa and dopa-decarboxylase inhibitor therapy for Parkinson’s disease in the 1960s. This was the first specifically targeted neuropharmacological treatment and heralded the subsequent arrival of a range of compounds that target specific receptors in the nervous system. In addition, recently developed high-potency biological compounds such as monoclonal antibodies offer the potential for unprecedented levels of efficacy, but those which target specific receptors in the immune system carry the risk of catastrophic side effects such as fatal opportunistic infection. The complexity of available therapies has meant that both doctors and patients need to be well informed to make appropriate management decisions.
The unsung heroes of neurological therapies are epidemiological studies and clinical trials — these have formed an evidence base for practice that goes beyond knowledge derived from biological rationale, case series analyses and pattern recognition. Until recently, for example, every stroke admission provoked an arcane discussion about the role of heparin and/or aspirin, and other interventions to “thin the blood”. It took large, well controlled studies to show that the risks of such therapies, other than aspirin, outweighed any potential benefits in the acute-care setting. Similarly, such studies have debunked neurological dogma over the hazards of blood-pressure lowering in acute stroke and have established that such therapy is the most efficacious medical treatment for improving long-term outcomes. Large-scale clinical trials are usually funded by pharmaceutical companies, yet important questions have been, and will continue to be, solved by academics who work in collaboration and use public funding. Given that governments spend so much on health care, often with poor supporting evidence for how it should be best spent and monitored, the level of funding for such studies, and medical research in general, is parsimonious.
Practical neurology is a series of articles that examine common and important problems in clinical neurology in the context of advances in basic neuroscience and neurological investigations. The quality of evidence that supports the available therapeutic options (see Box) is also included.
Despite the advances in this discipline, neurology remains one of the bastions of clinical medicine, where simple but finely tuned bedside skills can readily establish a diagnosis, prognosis and management plan. The cases presented in this series therefore emphasise key aspects of patient history and clinical signs, which are still the most cost-effective way of establishing a neurological diagnosis and making management decisions.
Grading system for recommendations in Practical neurology*
Grade A: “Excellent” — evidence from large randomised controlled trials (RCTs), or systematic reviews with meta-analyses of multiple RCTs
Grade B: “Good” — one or more RCTs with limitations, or high-quality and persuasive non-randomised cohort studies
Grade C: “Satisfactory or poor” — non-randomised case series and opinions of experts
* Adapted from the National Health and Medical Research Council.1
Competing interests
No relevant disclosures.
References
- National Health and Medical Research Council. NHMRC levels of evidence and grades for recommendations for developers of guidelines. Canberra: NHMRC, 2009. 0_CHDBEFHA