The 13 most dreadful neurological disorders…and the groups standing up to them

Neurology embodies some of the most dreadful diseases known to man. Every neurological disorder is disheartening, each characterised by unique frustrations for patients and their families. It is difficult to quantify the distress and misery these afflictions impose on their victims, and even harder to appreciate the despair and anguish they evoke in those who care for them.

Brain Art. Ars Electronica on Flikr. https://www.flickr.com/photos/arselectronica/7773544158

It is clearly hard to compare the impact of different neurological diseases. Some neurological disorders however stand out because of the consternation their names evoke, and the terror that follows in their wake. These diseases come with unimaginable physical and psychological burdens, and crushing demands on human and material resources. They impose either a debilitating morbidity, or a hasty mortality.

Neural pathways in the brain. NICHD on Flikr. https://www.flickr.com/photos/nichd/16672073333

The nervous system ailments in the list below pose exacting therapeutic challenges, resistant as they are to all attempts at treatment or cure. This list sets out to emphasise the urgency for neuroscience to find a remedy for each of them, but it does not intend to belittle the horror of the disorders omitted from it. The choice of the number 13 is, sadly, self-evident. Here then are the top 13 most dreadful neurological disorders…all with gold links to the associations helping to defeat them.

Working Brain. Gontzal García del Caño on Flikr. https://www.flickr.com/photos/euskalanato/2052487054

Ataxia

Ataxia, in lay terms, is incoordination. This typically manifests as an unsteady gait and clumsiness. Ataxia converts all activities of daily living into burdensome chores. Whilst many types of ataxia are preventable or reversible, primary ataxias are progressive and carry a dismal outlook. In this category are Spinocerebellar ataxia (SCA)Friedreich’s ataxia, and Ataxia telangiectasia. You may read more about ataxia in these previous blog posts: The 43 spinocerebellar ataxias: the complete checklistsOld drugs, new roles?, and Will Riluzole really be good for cerebellar ataxia?

Brain tumours

Brain cancers hardly need any description. They are either primary, arising from the brain cells, or metastatic, spreading to the brain from other organs. Some primary brain cancers, such as meningiomas and pituitary tumours, are, relatively, treatable. Many others are unfortunately ominously malignant. The most dreadful in this category is surely the spine-chilling glioblastoma multiforme. You may check out these previous blog posts for more on these tumuors: Calming the rage of brain tumours: hope for a dreaded cancerMaggots, viruses and lasers: some innovations for brain tumoursand Are steroids detrimental to survival in brain tumours?

Peripheral neuropathy

Peripheral neuropathy is ubiquitous in the neurology clinic. Neuropathy may result from reversible situations such as overindulgence in alcohol, uncontrolled diabetes, or Vitamin B12 deficiency. Neuropathy is often just a minor inconvenience when it manifests with sensory symptoms such as tingling and numbness. It may however be debilitating when it presents as limb paralysis, or complicated by major skeletal deformities. At the severe end of the spectrum of neuropathy are the hereditary forms such as Charcot Marie Tooth disease (CMT) and Familial amyloid polyneuropathy. Read more in these blog posts: The 52 variants of CMT… and their practical checklistsWhat’s looming at the frontline of peripheral neuropathy? and Will a pill really hold the cure for CMT?

Creutzfeldt Jakob disease (CJD)

CJD is the most iconic of the prion diseases. These disorders are as horrendous as they are enigmatic, defying categorisation as either infections or neurodegenerative diseases. More puzzling is their ability to be either hereditary and acquired. CJD exists in the classic or variant form, but both share a relentlessly rapid course, and a uniformly fatal end. You may read more in these previous blog posts titled Final day of ANA 2015- Prions center stage, and What are the links between Prion diseases and Parkinsonian disorders?

Dementia

Dementia is the scourge of longevity. Its name strikes terror because it insidiously colonises the cells that make us who we are. The most prominent dementia is Alzheimer’s disease, but it has equally dreadful companions such as Frontotemporal dementia (FTD) and Dementia with Lewy bodies (DLB). Read more on dementia in these blog posts: How bright is the future for Alzheimer’s disease?Alzheimer’s disease: a few curious things, and Alzheimers disease and its promising links with diabetes.

Dystonia

Dystonia marks its presence by distressing movements and painful postures. At its most benign, dystonia is only a twitch of the eyelid (blepharospasm) or a flicker of one side of the face (hemifacial spasm). At the extreme end, it produces continuous twisting and swirling motions, often defying all treatments. The causes of dystonia are legion, but the primary dystonias stand out by their hereditary transmission and marked severity. Read more on dystonia in these blog posts: Why does dystonia fascinate and challenge neurology? and Making sense of the dystonias: the practical checklists.

Huntington’s disease (HD)

Huntington’s disease is an iconic eponymous neurological disorder which is marked by the vicious triumvirate of chorea, dementia, and a positive family history. It is an awful condition, often driving its victims to suicide. It is a so-called trinucleotide repeat expansion disorder, implying that successive generations manifest the disease at an earlier age, and in more severe forms (genetic anticipation). You may read more on HD in the previous blog post titled What are the prospects of stamping out Huntington’s disease? 

Motor neurone disease (MND) 

Also known as Amyotrophic lateral sclerosis (ALS), MND is simply devastating. Recognising no anatomical boundaries, it ravages the central and peripheral nervous systems equally. MND creeps up on the neurones and causes early muscle twitching (fasciculations) and cramps. It then gradually devours the nerves resulting in muscle wasting, loss of speech, ineffectual breathing, and impaired swallowing. It is no wonder that one of the most read post on this blog is titled Is neurology research finally breaking the resolve of MND? Other previous blog posts on MND are The emerging links between depression and MNDWhat is the relationship of MND and cancer?Does diabetes protect from MND?, and MND and funeral directors-really?

Multiple sclerosis (MS)

Multiple sclerosis is a very common disease, and gets more common the further away you get from the equator. It is the subject of intense research because of the devastation it foists on predominantly young people. Many drugs now ameliorate, and even seem to halt the progression of, relapsing remitting MS (RRMS). This is however not the case with primary progressive MS (PPMS) which, until the introduction of ocrelizumab, defied all treatments. There are many contenders vying for the cause of MS, but the reason nerves in the central nervous system inexplicably lose their myelin sheaths remains elusive. You may read more on MS in these blog posts: The emerging progress from the world of MS , What are the remarkable drugs which have transformed the treatment of MS?, and Is low vitamin D a cause of multiple sclerosis?

Muscular dystrophy 

Muscular dystrophy is an umbrella term that covers a diverse range of inherited muscle diseases. The most devastating, on account of its early onset and unrelenting progression, is Duchenne muscular dystrophy (DMD). Adult neurologists will be more familiar with late onset muscular dystrophies such as Myotonic dystrophy and Facioscapulohumeral muscular dystrophy (FSHD). Read more on muscular dystrophy in these previous blog posts: How is neurology stamping out the anguish of Duchenne? and The A–Z of limb girdle muscular dystrophy (LGMD).

Rabies

Rabies, a rhabdovirus, is a zoonosis-it is transmitted to man by a wide range of animals such as dogs, bats, racoons, and skunks. It is the quintessential deadly neurological disease, popularised by the Steven King book and film, Cujo. Rabies manifests either as the encephalitic (furious) or the paralytic (dumb) forms. It wreaks havoc by causing irritability, hydrophobia (fear of water),  excessive sweating, altered consciousness, and inevitably death. Whilst there are vaccines to protect against rabies, a cure has eluded neuroscientists. This blog is yet to do justice to rabies but it is, at least, listed in the post titled What are the most iconic neurological disorders? But you could better by checking neurochecklists for details of the clinical features and management of rabies.

Spinal cord injury

Nothing is quite as heart-wrenching as the sudden loss of body function that results from spinal cord trauma. This often causes paralysis of both legs (paraplegia), or all four limbs (quadriplegia). This life-changing disorder is often accompanied by loss of control over bowel and bladder functions, and complications such as bed sores and painful spasms. You may read about the heroic efforts to treat spinal cord injury in the blog posts titled 6 innovations in the treatment of spinal cord injury and Head transplant, anyone?

Tetanus

Tetanus is an eminently preventable disease, now almost wiped out in developed countries by simple immunisation. It however continues its pillage and plunder in the developing world. It strikes young and old alike, often invading the body through innocuous wounds. Tetanus is caused by tetanospasmin and tetanolysin, the deadly toxins of the bacterium Clostridium tetani. The disease is classified as generalised, localised, cephalic, or neonatal tetanus. It is characterised by painful spasms which manifest as lockjaw (trismus), facial contortions (risus sardonicus), trunkal rigidity (opisthotonus), and vocal cord spasms (laryngospasm). The disease is awfully distressing and, when advanced, untreatable. It is a stain on the world that this avoidable disorder continuous to threaten a large number of its inhabitants. Check neurochecklists for more on the pathology, clinical features, and management of tetanus.

 

Light brain. Mario D’Amore on Flikr. https://www.flickr.com/photos/kidpixo/3470448888

As for all lists, this will surely be subject to debate, or perhaps some healthy controversy. Please leave a comment.

How is innovative neurology research energising myasthenia?

Myasthenia gravis (MG) is one of the best characterised neurological disorders. The hallmark of MG is fatigable weakness. This manifests as intermittent ptosis (droopy eyelids), diplopia (double vision), and limb weakness. There are two main types-ocular MG affects just the eyes and eyelids, and generalised MG affects the body, including the bulbar functions of  breathing and swallowing.

By Doctor Jana - http://docjana.com/#/nmj, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=46835961
By Doctor Jana – http://docjana.com/#/nmj, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=46835961

 

The problem in MG is straightforward lack of communication; the nerves and muscles aren’t talking to each other. The two meet up at the neuromuscular junction (NMJ) where the nerves send packages of acetylcholine to bind with acetylcholine receptors (AChR) on the surface of the muscles. The muscles usually acknowledge this by contracting and producing action, but in MG this response is blocked by antibodies to the acetylcholine receptor (AChR antibodies). Like all culprits, it has wily accomplices such as anti-muscle specific kinase (anti-MUSK) antibody.

By No machine-readable author provided. S. Jähnichen assumed (based on copyright claims). - No machine-readable source provided. Own work assumed (based on copyright claims)., Public Domain, https://commons.wikimedia.org/w/index.php?curid=423915
By No machine-readable author provided. S. Jähnichen assumed (based on copyright claims). – No machine-readable source provided. Own work assumed (based on copyright claims)., Public Domain, https://commons.wikimedia.org/w/index.php?curid=423915

 

AChR antibodies are produced by a gland in the chest called the thymus. Disturbingly, this rather shabby-looking tissue may become enlarged (thymic hyperplasia), or cancerous (thymoma). The neurologist is therefore quick to request a CT chest scan as soon as MG is confirmed. Alas, the thymus is often normal or even shrivelled, to the delight of the patient who escapes the cardiothoracic surgeon. The neurologist is however ambivalent because surgery often gives a one-off cure, and saves the neurologist from a life-long commitment to monitor toxic treatments. The life of a Neurologist!

With so much known about MG, one would think there is very little on the horizon to put a smile on the faces of people with MG. But this old dog still has a few new tricks, and here are 4 energising reports I came across.

1. Predicting generalisation of ocular MG

By BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=29452230
By BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. “Blausen gallery 2014“. Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=29452230

 

Neurologists are aware that ocular MG could transform to generalised MG, they just don’t know who is at risk. Generalised MG is obviously a worse condition and requires more heavy-duty treatments. After much speculation, a report in JAMA Neurology has found the predictor of MG generalisation. Titled Clinical Utility of Acetylcholine Receptor Antibody Testing in Ocular Myasthenia Gravis, the authors confirmed, for the first time ever, that the risk of generalisation is linked to higher AChR antibody levels. I know, you were expecting some new, cutting-edge test or technology: sorry for the dampener, but sometimes it’s the little things that count. 

2. Linking MG to muscular dystrophy

By Cbenner12 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19555962
By Cbenner12Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19555962

 

Congenital myasthenia is a slightly different kettle of fish from conventional MG. For one, the diversity of genetic mutations that cause congenital myasthenia is mind-boggling; there are >20 genetic forms of MG such as DOK 7, RAPSYN, LAMB 2, and AGRIN. And these all differ in their presentation and response to treatment. An addition to this long list of congenital myasthenic syndromes should therefore normally not be exciting news. But there is something different in the recent report in the journal Brain about GMPPB (you really don’t want to know what this stands for). The paper, titled Mutations in GMPPB cause congenital myasthenic syndrome, opens up a can of worms because GMPPB also plays a role in causing muscular dystrophy. The authors see this as a bridge between myasthenia and muscular dystrophy. All rather complicated stuff, not quite sure what the implications are, but that’s the reason neurologists exist!

3. Leflunomide for drug-resistant MG

By MarinaVladivostok - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=27488894
By MarinaVladivostokOwn work, CC0, https://commons.wikimedia.org/w/index.php?curid=27488894

 

Immunosuppression is the ultimate treatment for MG because it reduces the production of the MG-causing antibodies. And the neurologist has a list, an arm length, of immunosuppressive agents to try. This variety of options is helpful because earlier choices may be ineffective, intolerable, or impractical. Azathioprine, methotrexate, mycophenolate …these roll out easily from the neurologist’s pen. Leflunomide would however sound very strange in neurological circles; it is more familiar to rheumatologists who use it to treat rheumatoid arthritis. Neurologists, ever peeping into the rheumatology recipe book, thought why not try Leflunomide in MG. They reported their findings in Journal of Neurology as Leflunomide treatment in corticosteroid-dependent myasthenia gravis: an open-label pilot study. And the recipe worked; 9 of 15 people with severe, steroid-dependent, MG improved on Leflunomide. Great news for when the going gets tough.

3, 4 Diaminopyridine for anti-MUSK MG

Thankfully not all MG treatment involves immunosuppression. One approach is to prevent the break down of the enzyme (esterase) that breaks down acetylcholine-got it? In this way there will be more acetylcholine available to counter the effect of AChR antibodies. Medications that work in this way are called acetylcoline esterase inhibitors (ACEI). It’s OK to  re-read all this before proceeding!

Pyridostigmine is the quintessential ACEI. But this is not effective in the more severe anti-MUSK MG where typical MG treatments don’t work so well. Neurologists have tried all sorts, including Rituximab, to varying success. What to do when all fails? A paper in the journal Neurology offers some hope that anti-MUSK MG may respond to 3,4 Diaminopyridine. This will be heart-warming news to all neurologists, if they ignore the fact that it is a single case report! But hey, from little acorns grow giant oak trees.

Want to dig deeper into MG? Try this update on myasthenia gravis.