Chronic inflammatory demyelinating polyneuropathy (CIDP) is a neurological disorder which causes loss of the fatty myelin covering of large nerves (demyelination). This slows down the speed at which the nerves can transmit electrical impulses. People with CIDP develop weakness and sensory disturbances, but not always in equal measure. CIDP is a pain for the afflicted, and a veritable nightmare for the neurologist.
The diagnostic process for CIDP includes some rather uncomfortable tests such as nerve conduction studies and lumbar puncture (spinal tap). CIDP is however a most rewarding disease to treat because many people respond to immune treatments such as steroids, intravenous immunoglobulins (IVIG), or plasma exchange (PE).
The diagnosis of CIDP is however not straightforward. The results of the tests are not always clearcut, and a lot of sifting and sorting goes into nailing the diagnosis. And even when the diagnosis is eventually made, there is a very long list of potential causes of CIDP which often require treatment on their own merit. Worryingly, some of these conditions make the treatment of CIDP difficult. And this is where IgG antibodies play a nasty role in CIDP.
Neurologists are now recognising that a subset of people with CIDP have IgG4 antibodies which greatly influence the clinical presentation and the treatment of CIDP. Anti-contactin antibody is one such antibody, but by far the most important is anti-neurofascin 155 (NF155). What do we know about this antibody? How does it influence the course of CIDP? To answer these questions, below are 10 important things we now know about CIDP associated with anti-NF155.
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is as complicated to articulate, as it is to manage. CIDP is the result of an inflammatory attack against myelin, the fatty layer that encases large nerves. The damage to the myelin sheath considerably slows down the speed at which nerves transmit electrical impulses. This leads to limb weakness, sensory impairment, and a host of other symptoms.
The diagnosis of CIDP is made on the basis of a clinical examination, nerve conduction studies (NCS), spinal fluid analysis, and countless blood tests. If this convoluted diagnostic process is hair-tearing, the treatment is even more perplexing.
There are 2 major CIDP treatment conundrums. The first is whether to start the treatment with steroids, or with intravenous immunoglobulins (IVIg). The second conundrum is what to do when the patient fails to respond to both of these first line CIDP treatments. Two recent papers have now come to the rescue, and they hope to settle, once and for all, these two major neurological puzzles.
1. Choosing steroids or IVIg as 1st line treatment
The first line treatment for CIDP is usually a toss-up between steroids and intravenousimmunoglobulins (IVIg). This is because neurologists had no way of telling who will do well on steroids, and who will respond to IVIg. Until now, that is. A recent report in the Journal of Neurology, Neurosurgery and Psychiatry (JNNP) set out to understand what patient characteristics predict response to IVIg. The authors studied >200 people with CIDP treated with IVIg, and reported that 1/4 did not respond. These IVIg non-responders had the following features:
The presence of pain
Association with other autoimmune diseases
A difference in the severity of weakness between the arms and the legs
The absence of anti-myelin associated glycoprotein (anti-MAG)
The authors conclude that people with CIDP who have the features above should start their treatment with steroids rather than IVIg. This surely beats tossing a coin.
2. Choosing rituximab as 1st line treatment
Choosing the 2nd line treatment of CIDP is comparatively easy; swap between IVIG and steroids, or go for plasma exchange (PE). Rituximab, a monoclonal antibody, is now also recognised as an effective treatment for CIDP. Conventional practice is to use this expensive treatment only when both IVIg and steroids fail. A recent paper however suggests that people with CIDP who also have IgG4 antibodies do not respond to either IVIg or steroids. On the bright side however, they do well when treated with Rituximab. The paper in the journal Neurology is titled Rituximab in treatment-resistant CIDP with antibodies against paranodal proteins. The authors studied only 4 patients, but the number was enough for them to suggest that patients with CIDP, who also have IgG4 antibodies, should be treated with Rituximab. Makes sense to me, if the alternative is predictable failure.
Now that some light has been shone on the treatment of CIDP, the next stage is to see how things work at the coal face. Do you have any feedback on CIDP treatment? Please leave a comment.
Medical futurists predict that scientific advances will lead to more precise definition of diseases. This will inevitably result in the emergence of more diseases and fewer syndromes. This case is made very eloquently in the book, The Innovators Prescription. Many neurological disorders currently wallow at the intuitive end of medical practice, and their journey towards precision medicine is painfully too slow. Neurology therefore has a great potential for the emergence of new disorders.
In the ‘good old days’, many diseases were discovered by individual observers working alone, and the diseases were named after them. In this way, famous diseases were named after people such as JamesParkinson, Alois Alzheimer, and GeorgeHuntington. For diseases discovered by two or three people, it didn’t take a great stretch of the imagination to come up with double-barrelled names such as Guillain-Barre syndrome (GBS) or Lambert-Eaton myasthenic syndrome (LEMS).
Today, however, new diseases emerge as a result of advances made by large collaborations, working across continents. These new diseases are named after the pathological appearance or metabolic pathways involved (as it will require an act of genius to create eponymous syndromes to cater for all the scientists and clinicians involved in these multi-centre trials). This is unfortunately why new disorders now have very complex names and acronyms. Take, for examples, chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) and chronic relapsing inflammatory optic neuropathy (CRION). It is a sign that we should expect new neurological diseases to be baptised with more descriptive, but tongue-twisting, names.
New disease categories emerge in different ways. One is the emergence of a new disorder from scratch, with no antecedents whatsoever. Such was the case with autoimmune encephalitis, a category which has come from relative obscurity to occupy the centre stage of eminently treatable diseases. I have posted on this previously as What’s evolving at the cutting edge of autoimmune neurology and What are the dreadful autoimmune disorders that plague neurology?Other disease categories form when different diseases merge into a completely new disease category, or when a previously minor diseases mature and stand on their own feet. These are the stuff of my top 8 emerging neurological disorders.
This huge monster is ‘threatening’ to bring together, under one roof, diverse disorders such as tuberous sclerosis complex, epilepsy, autism, traumatic brain injury, brain tumours, and dementia. You may explore this further in my previous blog post titled mTORopathy: an emerging buzzword for neurology.
4. Hepatitis E virus related neurological disorders
A field which is spurning new neurological disorders is neurological infections, and Hepatitis E virus (HEV) is in the forefront. We are now increasingly recognising diverse Hepatitis E related neurological disorders. HEV has now been linked to diseases such as Guillain Barre syndrome (GBS) and brachial neuritis. And the foremost researcher in this area is Harry Dalton, a hepatologist working from Cornwall, not far from me! And Harry will be presenting at the next WESAN conference in Exeter in November 2017.
Multisystem proteinopathy is a genetic disorder which affects muscles and bone, in addition to the nervous system. It is associated with Paget’s disease of the bone and inclusion body myositis, with implications for motor neurone disease (MND) and frontotemporal dementia (FTD). Quite a hydra-headed monster it seems, all quite complex, and perhaps one strictly for the experts.
7. GLUT-1 deficiency syndromes
GLUT-1 stands for glucose transporter type 1. Deficiency of GLUT-1 results in impaired transportation of glucose into the brain. GLUT-1 deficiency syndrome presents with a variety of neurological features such as dystonia, epilepsy, ataxia, chorea, and a host of epilepsy types. It starts in infancy and is characterised by a low level of glucose and lactic acid in the cerebrospinal fluid. Expect to hear more on this in the near future.
8. Progressive Solitary Sclerosis
And this is my favourite paradigm shifter. Neurologists often see people with brain inflammatory lesions and struggle to decide if they fulfil the criteria for multiple sclerosis (MS). The current threshold for concern is when there have been two clinical events consistent with inflammation of the nervous system, or their MRI scan shows involvement of at least two different sites of the nervous system. Well, dot counting may soon be over, going by this paper in Neurology titled Progressive solitary sclerosis: gradual motor impairment from a single CNS demyelinating lesion. The authors identified 30 people with progressive clinical impairment arising from a single inflammatory nervous system lesion. The authors were convinced enough to recommend the inclusion of this new entity, progressive solitary sclerosis, in future classifications of inflammatory disorders of the central nervous system. Move over progressive MS, here comes progressive SS. Neurologists will surely have their job cut out for them.
Do you have any suggestions of emerging neurological disorders? Please leave a comment
Neurology is a broad specialty covering a staggering variety of diseases. Some neurological disorders are vanishingly rare, but many are household names, or at least vaguely familiar to most people. These are the diseases which define neurology. Here, in alphabetical order, is my list of the top 60 iconic neurological diseases, with links to previous blog posts where available.
The Neurology Lounge has a way to go to address all these diseases, but they are all fully covered in neurochecklists. In a future post, I will look at the rare end of the neurological spectrum and list the 75 strangest and most exotic neurological disorders.
Anti VGKC antibody encephalitis is caused by two different antibodies called LGI1 and Caspr2. The immunology laboratory would however only test for these two if the ‘generic’ VGKC test is positive. Neurologists are understandably left scratching their heads when both tests turn out to be negative. Not any more, going by a report in Neurology titled The relevance of VGKC positivity in the absence of LGI1 and Caspr2 antibodies. The judgment is out: a positive VGCK antibody test is not significant if both LGI1 and Caspr2 are negative. What a relief.
Many acquired neurological disorders have a way of dragging genetics into their fold. Such is the case it seems with anti NMDA receptor encephalitis. This is the case with the GRIN-1 gene which codes for an NMDA receptor subunit. Mutations in this gene results in visual impairment, intellectual disability, and eye movement disorders. This is reported in Neurology by Josep Dalmauand colleagues in a paper titled Delineating the GRIN1 phenotypic spectrum. It is appropriate that the authors call this the genetic sibling of NMDA receptor encephalitis.
4. ECT for anti-NMDA receptor encephalitis
The typical treatment of autoimmune encephalitis revolves around steroids, intravenous immunoglobulins (IVIg), and plasma exchange. Neurologists, when pushed to the wall, may use heavy duty agents such as Rituximab and Cyclophosphamide. Because anti-NMDA receptor encephalitis may be associated with ovarian teratomas, neurologists may make the difficult trip across the border to consult their gynaecology colleagues. I thought these were all the treatment options for anti NMDA receptor encephalitis until I read this case report, again in Neurology, which reported an excellent response to Electroconvulsive therapy in anti-NMDA receptor encephalitis. A no-brainer then if you see neurologists exchanging pleasantries with psychiatrists: they are the ECT experts. It is just a case report for now, but well-worth thinking about when all else fails.
Neurologists have always known that autoimmunity accounts for many nervous system disorders. A classical example is Sydenham’s chorea or St Vitus dance. This movement disorder develops after rheumatic fever, and is caused by antibodies to the bacterium called Streptocccus. The modern-day resurrection of this condition is called paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections. I know, too long, but just call it PANDAS. A great acronym I must say, quite unlike ABGA which stands for anti basal ganglia antibody syndrome, an umbrella term for many movement disorders provoked by external agents.
A third group of neurological diseases are more sinister because the antibodies are generated by cancer cells. These paraneoplastic neurological syndromes are legion and protean, requiring a high index of suspicion to diagnose. Most frustrating for neurologists is that the cancer itself may not emerge for several years after the diagnosis of a paraneoplastic syndrome. Notorious for this cloak and dagger behaviour is small cell lung cancer (SCLC). Because of the potential consequences, neurologists deploy their heavy duty imaging scans such as positron emission tomography (PET) scans. They then lie low, year after year, waiting to nab the devious cancer as soon as it shows up.
In recent years, a completely different class of disorders has attained notoriety and infamy in the form of autoimmune encephalitis. These disorders often pretend to be infectious diseases, but they totally disregard the antibiotics and antiviral agents the neurologist attacks them with. By subterfuge and subversion they disable ion channels and receptors to cause havoc in the brain. And nobody has described such havoc better than Susannah Cahalan in her book Brain on Fire: My Month of Madness.
Autoimmune encephalitis may fester for weeks, years or decades, evading detection by its duplicitous behaviour, and by the increasing number of antibodies that may be responsible. There are however three main culprit antibodies which neurologists are now getting a grip on:
These conditions are all potentially fatal but eminently curable; this underlies the importance of recognising and treating them very early. A recent paper in Lancet Neurology summarises the clinical approach to autoimmune encephalitis(pdf).
Autoimmune neurology is a rapidly evolving field. I will review recent developments in this area in a second post to follow shortly titled What’s breaking at the cutting edge-of autoimmune neurology?
Neurologists breathe guidelines. And they churn them out at a breathtaking pace. It is extremely difficult keeping up with what’s in, what’s out, and what’s back in again! Often the new guidelines add nothing new, or the important points are buried in sheafs of text justifying the guidelines.
But we can’t get away from them. How then do neurologists keep up, short of becoming paranoid? By becoming obsessive! In developing neurochecklists I had no idea keeping up with the guidelines would be a challenging task because they are released in quick succession. I have looked back to see which are the latest practical guidelines, released in the last 12 months or so. Here they are by disease… but be quick before the guideline-masters revise them…again!
The American Academy of Neurology (AAN) and the American Epilepsy Society published their 1st seizure management guidelines in Neurology. Among the key recommendations are to inform patients of a 2-year recurrence risk of 21-45%, and that a nocturnal seizure is among the usual culprits that increase the risk. The vexing question of whether to treat a 1st unprovoked seizure remains that-vexing.
Not to be outdone, the International League Against Epilepsy (ILAE) released it’s evidence-based guidelines and recommendations for the management of infantile seizures. Published in Epilepsia in late 2015, it shows that Levetiracetam is tops for both focal and generalised seizures. It also confirmed the hard-earned place of Stiripentol alongside Valproate and Clobazam for Dravet syndrome. It is open access so well-worth a detailed look.
Duchenne muscular dystrophy (DMD)
Steroids are now standard treatment in Duchenne’s muscular dystrophy (DMD). A recent practice guideline update on corticosteroids in Duchenne’s highlights this, and it also indicates the strength of evidence for the different benefits. There is Level B evidence that steroids improve strength and lung function, and Level C for delaying scoliosis and cardiomyopathy. Enough to encourage any doubters out there.
Facio-scapulo-humeral muscular dystrophy (FSHD)
Not one I thought had guidelines, but this FSHD diagnosis and management guidelines turned out to be quite useful. The guidelines address four key areas-diagnosis, predictors of severity, surveillance for complications, and treatment. And if you like flow charts, there is an excellent one here. A lot of helpful tips here for example, subjects with large D4Z4 gene deletions are more prone to earlier and more severe disability, and these patients should be reviewed by a retinal specialist.
Multiple sclerosis (MS)
Multiple sclerosis (MS) is one of the most shifty conditions when it comes to guidelines, both diagnostic and management. Take the latest NICE MS guidelines, 39 pages long. All sensible stuff mind you, with time-restricted targets such as 6 weeks for a post-diagnosis follow-up, and 2 weeks to treat a relapse. Mind you, just to keep neurologists on their toes!
MS diagnosis and follow up is often the game of countinglesions on MRI scans. The question of what to count, and when to do so, is addressed in the recent MAGNIMS MS consensus guidelines. More recommendations than guidelines, these did not challenge the sacrosanct MacDonald criteria for dissemination in time, but tinker with dissemination in place. They suggest, for example, that optic nerve lesions be counted. The MAGNIMS consensus guidelines on the use of MRI goes on to stipulate when and how to count lesions throughout the course of MS. Not an easy bedtime read.
Finally, Neurology published guidelines on rehabilitation in MS. Unfortunately there are quite a few qualifying ‘possibles‘ and ‘probables‘ which water down the strength of most of the recommendations. But what else do we have to go by?
The Journal of Neurology, Neurosurgery and Psychiatry (JNNP) published a review of CIDP in February 2015. It covers everything ”from bench to bedside”, but heavily skewed towards the former. It confirms that CIDP is a “spectrum of related conditions”, great news for splitters, and disappointing for lumpers. I personally struggle with the concepts of sensory and focal CIDP, have never diagnosed CANOMAD, but never tire of listening to Michael Lunn on VEGF, or be fascinated by the links between CIDP and POEMSsyndrome. The review, an editors choice, is open access, and is backed by the authority of Richard Hughes; you really have no choice but to read it!
Unruptured intracranial aneurysms
The America Stroke Association (ASA) published new guidelines on management of unruptured aneurysms in a June 2015 issue of Stroke. It gives a comprehensive review of cerebral aneurysms, addressing the “presentation, natural history, epidemiology, risk factors, screening, diagnosis, imaging and outcomes from surgical and endovascular treatment“. It also suffices for a review article. Some recommendations are easily overlooked such as counsel against smoking and monitor for hypertension (evidence level B). Some important recommendations however have weak evidence, for example surveillance imaging after endovascular treatment (evidence level C).
The guidelines still advocate screening if there are 2 or more affected first degree family members. (I confess my threshold is lower than this). The extensive list of at-risk conditions for aneurysms include the usual suspects such as adult polycystic kidney disease and fibromuscular dysplasia. New culprits (at least to me) are microcephalic osteodysplastic primordial dwarfism, Noonan syndrome, and α-glucosidase deficiency.
The American Stroke Association (ASA), along with the American Heart Association (AHA), released their guidelines for the management of spontaneous intracerebral haemorrhage in 2015. There are several additional recommendations to the previous guidelines; these include the recommendation to control hypertension immediately from onset to prevent recurrent haemorrhage.
The ASA/AHA also published their updated guidelines on endovascular stroke therapy in 2015. To to show how important this treatment has become, the debate now is whether to use thrombectomy alone, or after thrombolysis. And the winner is…to use thrombectomy after thrombolysis. The eligibility checklist for endovascular therapy with a stent retriever is thankfully quite short.
OK, I confess these guideline are from 2014, a bit dated. But how often does one think ‘guidelines’ in the context of Friedreich’s ataxia. Furthermore, this Consensus clinical management guidelines for Friedreich ataxia is open access! Published in Orphanet Journal of Rare Diseases, they are the product of 39 experts, and consist of 146 recommendations! They cover everything from sleep, spasticity, and scoliosis to diabetes, dysphagia, and dysarthria. I bet you don’t enquire about restless legssyndrome (RLS) in your patients with FA!
Motor neurone disease (MND)
And hot off the press are the NICE guidelines on motor neurone disease (MND). One thing to mention is its sheer volume- 319 pages long, and containing 123 recommendations! The guidelines targets every aspect of MND care, and it’s futile trying to master it all. Each specialist can really only pick and choose which aspect is relevant to them. There is a lot of balancing of clinical and economic benefits, and this is reflected by questions such as “what are the most clinically- and cost-effective methods of maintaining nutrition…?” The guidelines address several long-standing issues such as the clinically appropriate timing for placing PEG tubes. Whether they add anything really new is however debatable.
Do you have a recent guideline or update to share? Please leave a comment.