Tag Archives: genetic

MS and bipolar disorder: understanding the link

22/02/2026 Gavin Giovannoni

The association between multiple sclerosis (MS) and depression is well-established. Are people with MS also at risk of developing bipolar disorder?

Key points

Bipolar disorder is significantly more common in people with MS than in the general population.
This is not merely a byproduct of the stress of chronic illness; it also has to do with changes in the brain, caused by MS, that affect mood as well as physical function.
Mood symptoms may be caused by MS lesions, disease-related inflammation, or medications (steroids in particular).
Differentiating ‘primary’ (organic) mania from ‘secondary’ (MS-related) mania is crucial to ensure the correct diagnosis and treatment.
Key features that distinguish MS-related mania from organic mania include:
- Late onset, often after age 35–40 years, or onset associated with MS disease progression
- Weak or absent family history of bipolar disorder
- Lack of response to standard treatments for bipolar disorder
Treatment for people with MS who experience bipolar disorder is available and effective. With coordinated care, they can successfully manage their symptoms.

MS affects movement, sensation and other bodily functions, but it also impacts the brain systems involved in thinking, emotions and behaviour. Here, I discuss the relationship between MS and bipolar disorder, a mental health condition that causes episodes of unusually high mood (mania or hypomania) and low mood (depression). Bipolar disorder has received less attention than depression in people with MS, despite its substantial effect on quality of life, treatment adherence and prognosis.

For some people with MS, symptoms of bipolar disorder appear for the first time as their disease develops. In others, existing mood symptoms may be made worse by inflammation, brain lesions or medications used to treat MS. This article explains why bipolar symptoms occur in MS, how they may present, how they can be recognised early and how they can be effectively managed.

How common is bipolar disorder in MS?

Research consistently shows that bipolar disorder is more common in people with MS than in the general population. In the general population, bipolar disorder affects roughly 1–2.4% of people. In MS, studies report current and lifetime prevalence rates of about 3% and 8%, respectively. This means people with MS have approximately double or even treble the usual risk.

Importantly, this increased risk is not simply because people with MS interact with healthcare systems more frequently than the general population, which increases the likelihood of mental health conditions being detected (we call this the ‘admission rate’ bias). Nor is it merely a byproduct of the stress of chronic illness (which might explain depression). Large studies that compare people with MS to similar individuals without MS still show a higher rate of bipolar disorder in the MS group. This suggests the association is real and probably related to changes in the brain caused by MS.

What factors cause MS-related mania?

Researchers believe there are three main mechanisms that drive cognitive and behavioural changes in MS; they can occur alone or together.

MS lesions that affect mood-regulating circuits
inflammation and immune changes
treatment-related factors.

Understanding these mechanisms allows clinicians to distinguish MS-related mania from ‘primary’ (organic) psychiatric illness and to deliver appropriate management.

MS lesions that affect mood-regulating circuits

This mechanism disrupts the ‘hardware’ that controls mood. MS causes inflammation and lesions (scarring) in the brain. Areas that are especially important for controlling emotions and behaviour include:

the right orbitofrontal cortex (OFC) – involved in regulating social behaviour, judgement and impulse control
the temporal lobes – important for memory and emotional processing
the white-matter pathways that connect these regions with deeper emotional and reward centres such as the amygdala and thalamus.

If MS lesions interfere with these circuits, the balance between emotional impulses and rational control can be disrupted. This may lead to behaviours that are characteristic of mania, including disinhibition (reduced ‘internal brakes’), uncontrolled emotions, euphoria (unusually elevated mood) and impulsivity. This pattern is sometimes called secondary mania (mania caused directly by a brain condition such as MS).

There is evidence that right-sided frontal or temporal injury leads to mania-like behaviours in other conditions (e.g. stroke, traumatic brain injury, tumours).

Understanding right- and left-sided brain functions

Consistent with literature on secondary mania from stroke or tumours, MS-associated mania is most often associated with right-sided brain lesions. The right hemisphere is dominant for processing negative emotions and withdrawal behaviours, while the left hemisphere processes positive emotions and approach behaviours. A lesion in the right hemisphere may impair the processing of negative emotions, leading to an unopposed ‘positive’ or euphoric affect (‘highs’) driven by the intact left hemisphere.

Inflammation and immune changes

During MS relapses or periods of immune activation, inflammatory molecules disrupt how brain cells communicate (think of it as a disruption to the brain’s ‘software’). One important system involved is the kynurenine pathway, which controls how the body uses tryptophan (an amino acid essential for the creation of compounds such as serotonin and melatonin).

Inflammation increases the activity of an enzyme called indoleamine 2,3-dioxygenase. This shifts tryptophan away from serotonin production towards production of quinolinic acid, a substance that overly stimulates nerve cells through NMDA receptors (N-methyl-D-aspartate receptors). This ‘excitatory overload’ can lead to symptoms like those seen in primary mania, such as agitation, mood instability, sleep disturbance and racing thoughts.

The kynurenine pathway in inflammation-induced pathology of the central nervous system. Activation of IDO in peripheral immune cells (e.g. macrophages) or in the brain leads to production of kynurenine. This is converted to kynurenic acid in astrocytes and to quinolinic acid in microglia. Kynurenic acid can block the release of glutamate and dopamine, contributing to cognitive dysfunction. Quinolinic acid, by contrast, can increase glutamate release, which contributes to neurodegeneration. Figure modified from Haroon et al.

3-HAO, 3-hydroxy-anthranilic acid oxygenase; IDO, indoleamine-2,3-dioxygenase; KAT II, kynurenine aminotransferase II; KMO, kynurenine-3-monooxygenase; NMDA, N-methyl-D-aspartate.

This pathway is one of the clearest biochemical links between MS inflammation and bipolar-type symptoms.

Treatment-related factors

Some medications used in MS influence mood and may contribute to manic symptoms.

Steroids

High-dose intravenous methylprednisolone, typically 1000 mg/day for 3–5 days, is the most common cause of drug-induced mania in MS. Up to 12% of people treated with corticosteroids experience symptoms of mania, and nearly 65% of those with psychiatric side effects present with a mix of mania and psychosis.

A history of prior steroid-induced mood changes, female sex, older age and higher steroid doses increase risk. Steroid-induced mania typically appears 3 − 4 days after starting treatment (median 11 days in some studies) and may involve:

severe insomnia
pressured speech
irritability or agitation
grandiosity
psychosis in severe cases.

Symptoms usually resolve when the dose is tapered (within roughly 3 weeks), but they can persist longer in individuals with underlying bipolar disorder. I therefore try to avoid treating MS relapses with steroids. However, this is not always possible.

Other agents that may cause mania

Amantadine, used for fatigue, can trigger mania in susceptible individuals.
Modafinil and methylphenidate, also used for fatigue, have been linked to sudden switching between manic and depressive symptoms.
Cannabinoids may destabilise mood or cognition.
Interferons more commonly cause depression than mania, but irritability, aggression and mania have been reported. The risk of new psychiatric symptoms is low, and patients with stable mood disorders can usually tolerate interferons with careful monitoring.
Fingolimod is linked to mood changes; severe rebound inflammatory activity after discontinuation could theoretically trigger mania.

Diagnosis of MS-related mania

Distinguishing between primary bipolar disorder, secondary MS-related mania and steroid-induced mania can be difficult. Accurate diagnosis is essential for effective management, as treatment for one form may exacerbate another. Below are some of the ‘atypical’ features of MS-related mania that deviate from classic bipolar disorder.

Late onset of symptoms

Primary bipolar disorder usually begins in adolescence or early adulthood. In contrast, secondary mania associated with MS can appear later, often after age 35–40 or during disease progression. A manic or psychotic episode may sometimes be the first manifestation of MS, occurring months or years before a neurological diagnosis.

Mania coinciding with an MS relapse

A sudden change in mood, sleep or behaviour that coincides with new neurological symptoms (e.g. numbness, vision changes, weakness) may indicate that inflammation or new lesions are affecting mood circuits. There may also be evidence of disease progression from MRI scans.

Weak family history

Primary bipolar disorder often runs in families; the absence of a family history suggests a secondary cause (i.e. MS-related pathology).

Disproportionate cognitive decline

Impulse control and executive functions, such as planning, organising and paying attention, are impaired – possibly reflecting frontal lobe involvement.

Mania as an MS relapse

A minority of patients present with isolated psychiatric symptoms (mania, psychosis, delirium) as the only manifestation of a relapse. MRI often reveals new frontal or temporal lesions, even when motor or sensory signs are absent.

Lack of response to standard treatments

Failure to respond to standard mood stabilisers, or paradoxical worsening with antidepressants, warrants a re-evaluation for organic causes.

Genetic considerations

Is the risk solely environmental (inflammation/lesions), or do MS and bipolar disorder share a genetic root? The Major Histocompatibility Complex (MHC) on chromosome 6 is the primary genetic risk factor for MS (specifically the HLA-DRB1*15:01 allele). Interestingly, Genome-Wide Association Studies have suggested that the MHC region is also involved in bipolar disorder and schizophrenia.
There is some evidence that, in certain familial clusters, a gene located near the HLA locus (possibly involving the HLA-DR2 antigen) could confer susceptibility to both autoimmune demyelination and bipolar disorder. Other studies have indicated the opposite: that specific MS risk alleles in the HLA region are associated with decreased schizophrenia risk. The results are therefore mixed; some haplotypes may increase the risk of severe mental illness, while others appear protective against it. It is likely that environmental factors (inflammation, lesion burden) play a greater role than genetics in most cases.

There is some evidence that, in certain familial clusters, a gene located near the HLA locus (possibly involving the HLA-DR2 antigen) could confer susceptibility to both autoimmune demyelination and bipolar disorder. Other studies have indicated the opposite: that specific MS risk alleles in the HLA region are associated with decreased schizophrenia risk. The results are therefore mixed; some haplotypes may increase the risk of severe mental illness, while others appear protective against it. It is likely that environmental factors (inflammation, lesion burden) play a greater role than genetics in most cases.

Management

Treatment of MS-related mania depends on the cause.

Steroid-induced mania

If steroids triggered the symptoms, the steroids should be tapered or discontinued if safe.
Short-term antipsychotic medications, such as quetiapine, olanzapine or risperidone, can help stabilise mania symptoms. Quetiapine has the added benefit of aiding sleep, which is commonly disrupted in people with MS. Use of low-dose benzodiazepines during the steroid course can help to reduce the insomnia that often precedes or triggers mania.

Mania caused by MS inflammation

If mania is part of an organic, MS relapse, treating the inflammation is important. High-dose steroids may then be necessary, even though they can in other circumstances cause mania.
This crucial distinction underscores the need for close coordination between neurology and psychiatry.

Mood swings

Lithium is still the gold standard mood stabiliser and is generally safe for psychiatric management in MS. The anticonvulsants valproate, lamotrigine and carbamazepine are useful alternatives in people with MS; they treat both the mania and other MS-related comorbidities, such as neuropathic pain and trigeminal neuralgia.

Managing future steroid treatment

People with a known history of bipolar disorder or steroid-induced instability may benefit from:

starting a low-dose mood stabiliser (e.g. lithium) before the steroid course
adding an antipsychotic temporarily (e.g. olanzapine)
using sleep support (e.g. low-dose benzodiazepines) to prevent insomnia (a common trigger for mania).

Long-term management

Any MS patient presenting with new-onset mania requires a comprehensive workup, including MRI (to check for new frontal/temporal lesions) and a review of recent medication changes, rather than a direct referral to psychiatry. Ongoing coordination between neurologists and psychiatrists is, however, essential. A neurologist might misinterpret mania as ‘euphoria’ related to frontal lobe damage (pseudobulbar affect), while a psychiatrist might miss the neurological signs of an MS relapse that is driving the mood change. Screening tools (e.g. Mood Disorder Questionnaire) may help identify individuals at higher risk but should not replace clinical judgement.

Recognising the distinguishing features of MS-related mania allows clinicians to intervene promptly, reduce misdiagnosis and optimise care. With integrated neurological and psychiatric management, most people with MS experiencing bipolar symptoms can achieve stable, effective control of their mood and maintain a high quality of life.

Reference

Haroon, E et al. Psychoneuroimmunology meets neuropsychopharmacology: translational implications of the impact of inflammation on behavior. Neuropsychopharmacology Rev; 2011:1–26.

Pregnancy and childbirth, Women's health

Concerns about parenting

18/04/2023 Gavin Giovannoni

Being disabled or unemployed because of MS does not mean you cannot be a good parent. Here I cover some of these practical considerations as well as the steps you can take to reduce the potential risk of your child developing MS.

Can I be a good parent if I become disabled from my MS?

This is difficult to answer and depends on how disabled you are, the nature of your disabilities and whether you have support. For example, some patients who are wheelchair users, or close to being wheelchair users, when they give birth manage to nurse and look after their children. On the other hand, some patients with cerebellar problems find it very difficult to bathe, change and feed their babies due to poor coordination and tremor. If you have advanced MS, the decision to start or extend your family needs to be discussed with your partner. If necessary, ask an occupational therapist to assess you and discuss all the issues relevant to you becoming a parent. Disability per se is not a reason not to have children, but it does raise important issues that need careful consideration. The decision to have children needs to be taken by you and not by your HCP.

If I become disabled or unemployed because of MS, will I be able to support my children?

This is another difficult question, and the answer depends on your circumstances. In the modern era having children and supporting them is expensive, but most high-income countries have social safety nets to protect you and your family in times of adversity. We now have effective DMTs that prevent or delay disability, so deciding to have children is easier than it was in the pre-DMT era.

What is the risk of my children getting MS?

MS is not a genetic disease in the Mendelian sense that you pass on to your children with a well-defined inheritance pattern. However, there are genetic factors that increase your risk of getting MS. In high-prevalence countries such as the UK, the lifetime chances of a woman developing MS is about 1 in 375 ̶ 400; for a man, it is close to 1 in 750 ̶ 800. However, for a daughter whose mother has MS, the risk is close to 1 in 40, and for a son, it is lower than 1 in 80. In some studies, the latter risk is no higher than the background rate. If the father has MS, the risk of his daughter developing MS is about half the risk of mother ̶ daughter pairing, i.e. 1 in 70. For a son of a father with MS, the risk is likely lower than this, but the results across studies are inconsistent.

Can I prevent my children from getting MS?

Based on the known and modifiable risk factors for MS, you should try and keep your children vitamin D replete. To do this, you will likely need to supplement your children’s vitamin D intake as follows:

for children less than 2 years of age, 600 IU per day
for children 2 ̶ 10 years of age 2,000 IU per day
for children above 10 years of age, 4,000 IU vitamin D3 per day (the same dose we recommend for adults).

Other modifiable risk factors are childhood and adolescent obesity and smoking. We estimate that about 15 ̶ 20% of new or incident new cases could potentially be prevented by eliminating obesity and smoking in the general population. I must stress that these suggested interventions are based on studies that show associations between the risk factors and MS but may not necessarily be cause and effect. I should also point out that most people with all the risk factors for MS will not get the disease. This implies that the development of MS involves other random factors, or bad luck, that can’t necessarily be modified.

The issues raised above show you how complex the management of MS has become, which is why there is a push for people with MS to be managed in specialist MS units.

References

Krysko KM et al. Treatment of women with multiple sclerosis planning pregnancy. Curr Treat Options Neurol 2021;23:11.

Other articles in this series on Pregnancy and childbirth
Planning for pregnancy
Managing MS during pregnancy
Preparing to give birth
Breastfeeding if you are on a DMT

DMTsSafety, Monitoring MS

How can I reduce my chances of adverse events on specific DMTs?

10/01/2023 Gavin Giovannoni

The complications associated with immunosuppression vary from DMT to DMT. You will find it helpful to understand what investigations to expect before and during treatment and how these may vary depending on the DMT(s) you are considering.

Key points

Numerous tests are carried out at the start of your treatment (baseline); these include blood, urine and tests for a range of infections.
Some patients will need tests or procedures specific to their DMT that are inappropriate for everyone with MS – for example, vaccination against some infections; pregnancy and/or genetic counselling; prevention of cardiovascular complications; and management of infusion reactions.
Ongoing monitoring is required for many but not all of the above factors.
All licensed MS DMTs have had a thorough risk ̶ benefit assessment, and their benefits are considered to outweigh the potential risks.

Standard tests … and why we do them

If you have read the article on immunosuppression, you will know that immunosuppressive DMTs may reduce white blood cell counts and antibody responses to vaccines and increase the likelihood of some infections and cancers. However, we can reduce the risk of many complications associated with long-term immunosuppression (we use the shorthand ‘de-risk’). This article explains what needs to be done at the start of DMT administration (baseline) and during subsequent monitoring. The specifics, however, vary from DMT to DMT.

Baseline tests

Tests at baseline (before starting DMT administration) include full blood count, platelets, liver, kidney and thyroid function tests, and a urine screen. Recording baseline immunoglobulin levels is particularly important if you are about to start an anti-CD20 therapy (ocrelizumab, ofatumumab or rituximab) so that we have a reference level for future comparisons.

Serum protein electrophoresis is done for patients considering starting interferon-beta; having a so-called monoclonal gammopathy (an abnormal immunoglobulin) is a contraindication to starting an interferon-beta formulation in people with MS. The drug has been associated with a form of capillary leak syndrome, leading in rare cases to death from an adult respiratory distress syndrome.

The table below summarises the routine investigations required at baseline; subsequent sections provide further detail.

Tests routinely carried out at the start of treatment (baseline).
AHSCT, autologous haematopoietic stem cell transplantation; CMV, cytomegalovirus; CSF, cerebrospinal fluid; DMT, disease-modifying therapy; EBV, Epstein ̶ Barr virus; ECG, electrocardiogram; FBC, full blood count; HIV, human immunodeficiency virus; HPV, human papillomavirus; JCV, JC virus; LFTs, liver function tests; MMR, measles/mumps/rubella; MRI, magnetic resonance imaging; PCP, pneumocystis pneumonia; PML, progressive multifocal leukoencephalopathy; TB ELISpot, tuberculosis enzyme-linked immune absorbent spot; TFTs, thyroid function tests; U&E, urea and electrolytes; VZV, varicella zoster virus.

Infection screening

At our centre, we screen for a relatively large number of infectious diseases so that we can treat any subclinical infection before starting a DMT. This is particularly relevant for HIV-1 and 2, hepatitis B and C, syphilis and tuberculosis (TB).

Screening for the JC virus (JCV), which causes progressive multifocal leukoencephalopathy (PML), is only really needed for people with MS considering starting natalizumab. Even if you are JCV positive, you can be treated with natalizumab for 6 ̶ 12 months and sometimes longer if you are prepared to take on the risk of PML and the extra monitoring required to detect PML early.

We only check measles/mumps/rubella (MMR) status in patients without documentation of full vaccination as children. We check varicella zoster virus (VZV) status before starting immunosuppression and vaccinate seronegative individuals. Currently, we are still using the live VZV vaccine. This will change, and we will likely be offering all people with MS in the UK the component inactive VZV vaccine (Shingrix, that has had its licence extended) to reduce the chances of zoster reactivation in all adults starting immunosuppression. This new Shingrix indication is similar to the pneumococcal vaccine (Pneumovax). Our centre is only recommending Pneumovax in patients about to start an anti-CD20. However, when Shingrix becomes available on the NHS, it will make sense to bundle this with the Pneumovax and make it routine for all people with MS before starting immunosuppressive therapy. Please check with your healthcare team which products are available locally.

Routine tests and monitoring for Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are only needed for subjects undergoing autologous haematopoietic stem cell transplantation (AHSCT), which causes profound short-term immunosuppression that can result in CMV and EBV reactivation. CMV reactivation also occurs with alemtuzumab, so this needs to be considered when investigating patients who develop complications after receiving alemtuzumab (please see Opportunistic infection in MS).

For patients starting long-term immunosuppression, it is advisable to screen for active human papillomavirus (HPV) infection (by cervical smear or vaginal swab) and for warts or active infection with molluscum contagiosum. Warts are caused by HPV skin infection; molluscum contagiosum is due to a relatively benign pox virus that typically affects young children but occasionally affects adults. Warts and molluscum contagiosum can spread rapidly in patients receiving alemtuzumab, so I recommend treating these skin infections before starting immunosuppression for MS.

Vaccinations

We encourage all patients to be vaccinated against COVID-19 and seasonal flu; outside the flu vaccine season, we remind people to get vaccinated during the next vaccine season.

Hepatitis B, meningococcal and Haemophilus influenzae vaccines are considered only for people with MS who are at high risk of infection and have not had these vaccines as part of a national vaccine programme, i.e. healthcare and laboratory workers for hepatitis B, school and university students and military recruits for meningococcal vaccine and paediatric patients for Haemophilus influenzae.

The issue around having the HPV vaccine as an adult is more complex. For example, in the UK, the NHS does not cover the cost of the vaccine for people over 25. In addition, most people have only had the quadrivalent vaccine (Gardasil-4), which covers about two-thirds of the strains that cause cancer. Some people with MS may want to upgrade their immunity with the polyvalent vaccine (Gardasil-9) that covers over 95% of the cancer-causing strains of HPV. For more information on HPV vaccination, please see Case study: cervical intraepithelial neoplasia (CIN) and ocrelizumab.

MMR is a live vaccine given in childhood (see MMR vaccine: to vaccinate or not? ). Owing to vaccine hesitancy, however, many people do not receive this vaccine as children. Therefore, if an adult with MS is about to start immunosuppressive therapy and has not been vaccinated against MMR, we advise them to do so. This is particularly important for people about to start natalizumab because these viruses are neurotropic and can infect the brain. Natalizumab blocks immune response within the brain; hence, exposure to a neurotropic virus could cause serious infection, similar to what we see with the JC virus – which causes PML.

Travel vaccines for people who travel as part of their work or plan to travel shortly need to be considered. In particular, the yellow fever vaccine is a live vaccine (made from a weakened yellow fever virus strain) and it should ideally be given before someone starts on immunosuppressive therapy.

Cardiovascular screening

You may need an ECG (electrocardiogram), to rule out an abnormal heart rhythm or electrical conduction abnormality and to check your left ventricular function (ejection fraction). These abnormalities are a relative contraindication to using the S1P modulators (fingolimod, siponimod, ozanimod, ponesimod), which may affect the conduction of the heart. In patients treated with mitoxantrone, the left ventricular ejection fraction (LVEF) must be done at baseline and regularly monitored because mitoxantrone is toxic to the heart. If the LVEF drops significantly, further dosing of mitoxantrone is contraindicated.

Pregnancy, family planning and genetic testing

Many chemotherapy agents used in AHSCT for ablating (extracting) the bone marrow are toxic to the ovaries and testes. Therefore, patients receive counselling before treatment and can have eggs (oocytes) or sperm banked for future use. Egg banking is also a consideration for women with MS being treated with mitoxantrone. Men receiving mitoxantrone do not need to bank sperm, however, because mitoxantrone does not cross the testes ̶ blood barrier.

Genetic testing is only required at present if you wish to receive siponimod. Siponimod is metabolised by a specific liver enzyme (biological catalyst) with two functional variants – slow metabolising and fast metabolising. People who carry two slow-metabolising variants of the enzyme cannot receive siponimod. Intermediate metabolisers (those that carry one slow- and one fast-metabolising version of the enzyme) receive low-dose siponimod, while those with two fast-metabolising enzymes receive high-dose siponimod.

Protecting against progressive multifocal leukoencephalopathy

I have included magnetic resonance imaging (MRI) and lumbar puncture with cerebrospinal fluid (CSF) testing for JCV among the baseline tests. This is specific to patients at high risk of developing PML who are switching from natalizumab to a depleting immune reconstitution therapy such as alemtuzumab or another therapy that depletes their immune system (e.g. cladribine or an anti-CD20 therapy). These tests are done to exclude asymptomatic PML, which will otherwise be carried over to the new treatment. The effects of these immunosuppressive therapies on your immune system cannot be rapidly reversed, which is a problem because immune reconstitution is needed to clear PML. Most MS centres do not mandate CSF testing in this situation because it does not always reveal the presence of PML. However, I still request this test on my patients to gain as much information as possible on which to base potentially life-changing decisions.

Prophylactic antivirals and antibiotics

Patients in our centre undergoing AHSCT or receiving alemtuzumab will be given antivirals and antibiotics to reduce the likelihood of certain infections. This is particularly relevant for listeriosis, which is a rare infection transmitted via food. We also encourage all our patients to start and maintain a specific diet to reduce the chances of listeriosis. The risk of listeriosis is only present for a short period when both the adaptive and innate immune systems are compromised, that is, for 4 weeks after receiving alemtuzumab, so we recommend antibiotic prophylaxis for 4 weeks. Our online resource provides more information about listeriosis. If you live in the UK, you can order our free listeriosis prevention kit, which contains a booklet (also downloadable) and various practical items to help keep you safe.

Strategies for limiting the risks from immune reconstitution therapies and infusion DMTs.

Infusion reactions

When you use agents that cause cell lysis (breakdown), such as alemtuzumab and intravenous anti-CD20 therapies, the contents of cells cause infusion reactions. To prevent such reactions or reduce their severity, we pretreat patients with corticosteroids, antihistamines and antipyretics. The exact protocols for each DMT differ; for example, ocrelizumab infusion reactions are generally only a problem with the first and second doses; therefore, many centres don’t give steroids with the third and subsequent infusions. The latter was particularly important during the COVID-19 pandemic when it was shown that the recent administration of high-dose steroids increased your chances of severe COVID-19.

Ongoing monitoring

Once someone has been treated with a DMT, ongoing monitoring is required. What gets monitored and how frequently depends on the individual DMT. For a list of DMTs associated with important adverse events, please see our summary Table in ‘De-risking’ guide: monitoring requirements of individual DMTs.

The regulatory authorities usually put in place specific monitoring requirements, which can differ worldwide. It is important that you also enrol in your national cancer screening programmes. Being on chronic immunosuppression increases your chances of developing secondary malignancies, so please remain vigilant.

Tests carried out regularly as part of ongoing monitoring.
FBC, full blood count; LFTs, liver function tests; MRI, magnetic resonance imaging; PML, progressive multifocal leukoencephalopathy; TFTs, thyroid function tests; U&E, urea and electrolytes.

I want to reassure you that all licensed MS DMTs have undergone a thorough risk ̶ benefit assessment by the drug regulators, and the benefits of these treatments are considered to outweigh the potential risks. On balance, the level of immunosuppression associated with MS DMTs is typically mild to moderate; hence, the complications are relatively uncommon. MS is a serious disease and, if left to run its natural course, would result in most patients becoming disabled. To learn more about the natural course of MS, please read the section entitled What are the consequences of not treating MS?

DMTsSafety, Monitoring MS

‘De-risking’ guide: monitoring requirements of individual DMTs

10/01/2023 Gavin Giovannoni

Before you start taking a disease-modifying therapy (DMT), your MS team will carry out routine tests and investigations, many of which are repeated during subsequent monitoring or before switching to another DMT. The regulatory authorities that license the drugs specify their monitoring requirements. What gets monitored and how frequently depends on the individual DMT.

All licensed MS DMTs have undergone a thorough risk ̶ benefit assessment by the drug regulators, and the benefits of these treatments are considered to outweigh the potential risks. The table below summarises the main monitoring requirements of individual DMTs or DMT classes. For more detailed information, see the post on reducing your chances of adverse events.

AHSCT, autologous haematopoietic stem cell transplantation; CMV, cytomegalovirus; CSF, cerebrospinal fluid; EBV, Epstein ̶ Barr virus; ECG, electrocardiogram; HPV, human papillomavirus; JCV, JC virus; LVEF, left ventricular ejection fraction; MRI, magnetic resonance imaging; PML, progressive multifocal leukoencephalopathy.

Causes and prevention of MS

What is multiple sclerosis?

15/08/2022 Gavin Giovannoni

This is the first of a series of basic lessons to help you understand multiple sclerosis (MS).

Key points

MS is an autoimmune disease in which the immune system attacks the central nervous system.
Its exact cause is unknown; some contributory environmental factors are outlined.
Common manifestations of MS include lesions, relapses and intermittent symptoms, which often worsen with fatigue.
Early treatment is important to help prevent the damage that occurs with MS.

Multiple sclerosis (MS) is an organ-specific autoimmune disease. Autoimmune simply means that the immune system, whose primary role is to fight infections and cancers, goes awry and attacks itself. Organ-specific means that a disease is limited to one organ. So, in the case of MS, the immune system attacks the central nervous system (CNS), which consists of the brain, spinal cord and optic nerves.

Every organ in the body has its specific autoimmune disease. For example:

joints: rheumatoid arthritis
skin: psoriasis
insulin-producing cells of the pancreas: type 1 diabetes
intestines: inflammatory bowel disease
kidneys: autoimmune nephritis (interstitial or glomerulonephritis).

The cause of MS

At present, the exact cause of MS is unproven. MS is a complex disease that occurs due to the environment’s interaction with inherited or genetic factors.¹ Some of the main environmental factors are:

low vitamin D levels or a lack of sunshine
smoking
Epstein–Barr virus (EBV), the virus that causes infectious mononucleosis (glandular fever)
obesity, particularly in adolescence.

What we don’t know is how these genetic and environmental factors interact to cause MS. There are many genetic variants that predispose someone to get MS, but only a minority of people who have these variants will get the disease. Similarly, only a minority of people exposed to environmental risk factors get the disease.

Mechanisms that underlie the common manifestations of MS

Lesions

MS is characterised by inflammatory lesions – areas of damage or scarring (sclerosis) in the CNS – that come and go. The clinical manifestations of MS depend on where these inflammatory lesions occur. If, for example, a lesion involves the optic nerve, it will cause impaired vision; if it involves the brain stem, it causes double vision, vertigo or unsteadiness of gait; a spinal cord lesion leads to loss of feeling, limb weakness or bladder and bowel problems.

Relapses

A new MS lesion in a site that is eloquent will cause symptoms and neurological signs; if these last for at least a day, they are called an attack or a relapse. If a lesion occurs in a site not associated with overt symptoms, this is often referred to as a subclinical or asymptomatic relapse. Subclinical relapses can be detected using magnetic resonance imaging (MRI). It is said that for every clinical attack there are 10 or more sub-clinical attacks (new MRI lesions).²

Damage frequently occurs at the site of MS lesions. The inflammation strips the myelin covering the nerve processes and may cut through axons. Axons are the nerve processes that transmit electrical impulses or signals. When the axons are stripped of their myelin sheath, and/or are cut, they can’t transmit electrical signals. This causes loss of function, which manifests with specific symptoms.

*Demyelination: loss of the myelin sheath that insulates nerves, leading to disruption of electrical signals. Image courtesy of* *Timonina*/*shutterstock.com*.

Intermittent symptoms

Surviving axons that pass through the lesion are able to recover function, by synthesising and distributing so-called ion channels across the demyelinated segment or by being remyelinated. Both these processes are not perfect. For example, the new sodium channels may not function normally, so they sometimes fire spontaneously. The spontaneous firing of axons may cause positive symptoms, for example, pins and needles, pain or spasms. The new myelin is typically thinner and shorter than normal and is temperature, fatigue and stretch sensitive.

Stretch sensitivity

If someone with MS has a lesion in their spinal cord, electric shock-like sensations may occur when they stretch the spinal cord by bending or flexing their neck; this is known as Lhermitte’s sign.

Temperature sensitivity

Recurrent symptoms may occur when body temperature rises, for example following fever, exercise or a hot bath. The MS symptoms (which may vary among individuals) disappear when the fever resolves or the body cools down. The temperature sensitivity is often referred to as Uhtoff’s phenomenon.

Fatigue

Symptoms tend to worsen with physical and/or mental fatigue; for example, someone with MS may begin dragging a leg or dropping their foot after 20–30 minutes of walking. This is because the transmission in the functioning nerves, which have been previously damaged, begins to fail. This failure may be related to a lack of energy and/or to temperature changes that occur with exercise.

Worsening MS (also called progressive MS)

If the axons, or nerve processes, above and below an MS lesion die off, the surviving axons may sprout to take over the function of the axons below the lesion. This puts an unnecessary strain on the surviving axons, which makes them vulnerable to die off in the future. A reduction in the number of nerves in a neuronal system reduces the neurological reserve of that system, making it more vulnerable to future attacks. In other words, the ability to recover from future attacks is reduced, and the neuronal pathway is susceptible to delayed degeneration and premature ageing. Clearly, if no treatment is given and focal inflammatory lesions continue to come and go, this will cause worsening of the disease. If enough damage is allowed to accrue, even switching off new inflammatory lesions may not prevent the so-called delayed neurodegeneration. This is why one of the primary principles of managing MS is early treatment to prevent damage from occurring in the first place. We have also discovered that the neuronal systems with the longest nerve fibres, in particular the bladder and legs, are much more susceptible to damage. We think this is simply because the longest pathways provide the greatest scope to be hit by multiple MS lesions.

Ageing and MS

As we get older our nervous systems degenerate. If we live long enough, we will all develop age-related neurological problems, such as unsteadiness of gait, loss of memory, reduced vision, loss of hearing, and poor coordination.

What protects people with MS from becoming disabled and developing age-related neurodegeneration are brain reserve and cognitive reserve. Brain reserve is simply the size of your brain or the number of nerve cells you have. Cognitive reserve, in comparison, relates to how well these nerves function; it is associated with your level of education and how well you enrich your life by using your brain. From about 35 years of age, our brains start to shrink. In MS, this brain shrinkage is in general much greater than normal, and the resulting reduction in brain and cognitive reserve almost certainly primes the nervous system to age earlier. This is one of the reasons why people with MS continue to develop worsening disability later in the course of their disease. This insight is one of the main reasons why we promote early effective treatment of MS to protect and maintain brain and cognitive reserves.

References

Olsson T, et al. Interactions between genetic, lifestyle and environmental risk factors for multiple sclerosis. Nat Rev Neurol 2017;13:25–36 .
Gafson A, et al. The diagnostic criteria for multiple sclerosis: From Charcot to McDonald. Mult Scler Relat Disord 2012;1:9–14