Treatment of infections in MS

Managing infections is an important part of care for people with multiple sclerosis (MS), a disease of the central nervous system in which the immune system mistakenly attacks healthy tissue in the brain and spinal cord.

Because both infections and MS involve the immune system, they are closely linked. For example, it’s now well-established that infection with the Epstein-Barr virus is a leading risk factor for developing MS. Additionally, people with the disease are more vulnerable to infections and their complications, both due to the disease itself and because many MS treatments suppress the immune system.

Infections can also create inflammation that worsens MS symptoms, which makes prevention, monitoring, and early infection treatment for MS essential.

MS treatments and infection risk

Many disease-modifying therapies (DMTs) for MS work by altering the activity of white blood cells to reduce inflammation and prevent new nerve damage.

Some cause white blood cell depletion, and others alter their function. While effective in reducing disease activity and slowing progression, these therapies can interfere with the immune system’s ability to fight infections. For this reason, people with MS often have an increased risk of infections, especially with long-term DMT use.

Most MS DMTs include warnings about infections, including:

Lemtrada (alemtuzumab)
Mavenclad (cladribine)
natalizumab (sold as Tysabri and others)
teriflunomide (sold as Aubagio and generics)
anti-CD20 therapies, including Kesimpta (ofatumumab), Briumvi (ublituximab-xiiy), Ocrevus (ocrelizumab), and Ocrevus Zunovo (ocrelizumab and hyaluronidase-ocsq)
fumarate therapies, including dimethyl fumarate (sold as Tecfidera and generics), Bafiertam (monomethyl fumarate), and Vumerity (diroximel fumarate)
S1P modulators, including fingolimod (sold as Gilenya and generics), Ponvory (ponesimod), Mayzent (siponimod), and Zeposia (ozanimod)

Older DMTs such as glatiramer acetate (sold as Copaxone and generics) and interferon-based medications are generally safer and not associated with as high of an infection risk.

Data from clinical trials and real-world studies have also shown an association between certain DMTs and serious opportunistic infections, or those that occur primarily in people with weakened immune systems.

One of the most serious examples is progressive multifocal leukoencephalopathy, a potentially life-threatening brain infection caused by a virus that usually doesn’t cause problems in people with healthy immune systems.

Before starting DMTs, patients may be advised to receive certain vaccines, such as the varicella vaccination, and undergo regular blood tests to monitor for infections. Each therapy has its own risk profile, so patients should discuss prevention and monitoring strategies with their healthcare team.

Managing common infections in MS

Both the immune suppression caused by DMTs and MS-related neurological changes can make people with the disease more susceptible to common infections, including:

urinary tract infections
respiratory tract infections

While these infections are generally managed easily at home, people with MS are at an increased risk of serious infections requiring hospitalization. This is especially true in people with progressive forms of MS, who generally have a higher risk of severe infections than those with relapsing-remitting MS.

Urinary tract infections

Urinary tract infections refer to infections in the bladder, urethra, ureters, or kidneys. They are especially common in MS for several reasons:

Bladder issues from MS can cause incomplete emptying of the bladder, allowing bacteria to multiply in the residual urine.
Some patients use a catheter to drain urine, which can introduce bacteria into the urinary tract.
Mobility issues and fatigue in MS may interfere with personal hygiene habits, which can increase the risk of infections.

Typical symptoms of a urinary tract infection include pain or burning during urination, frequent urination, cloudy or strong-smelling urine, and pain in the lower abdomen or back. They are usually treated with a short course of antibiotics such as:

nitrofurantoin
trimethorprim-sulfamethoxazole
fosfomycin
fluoroquinolones, such as ciprofloxacin
cephalexin

Staying hydrated, maintaining good hygiene, and following proper catheter care can help prevent urinary tract infections.

Respiratory infections

People with MS are also more susceptible to respiratory tract infections — or those affecting structures running from the nose, throat, and lungs — such as influenza or pneumonia.

Several factors may contribute to this risk:

Weakness in the breathing muscles can make it harder to clear mucus and foreign particles from the airways, creating an environment for infection to take hold.
Immune suppression from some DMTs can make a person more vulnerable to contagious respiratory infections.
Swallowing difficulties may cause aspiration pneumonia, a bacterial infection that develops when food is accidentally inhaled into the airways.

Respiratory infection treatment for MS can vary depending on the underlying cause, but may include:

antiviral medications may be used for influenza
antibiotics may be prescribed for bacterial pneumonia
supportive care includes rest, hydration, and over-the-counter fever-reducing medications

Prevention strategies are also important for avoiding respiratory infections. These include frequent hand-washing, avoiding people who are sick, and receiving vaccines such as pneumococcal and flu shots as recommended by healthcare providers.

Infection symptoms vs. MS relapses

During an infection, patients may experience inflammation and fever that can cause MS symptoms to temporarily worsen. This is known as a pseudo-relapse, and is distinct from a true MS relapse, which is caused by new inflammation that is actively damaging the brain and spinal cord.

A pseudo-relapse occurs because slight increases in body temperature, such those occurring during a fever or vigorous exercise, can slow the speed at which electrical signals travel along nerves, which is already slower in damaged nerves.

A few factors can help tell them apart:

The presence of infection symptoms, such as fever, cough, or painful urination, suggests a pseudo-relapse.
A pseudo-relapse brings back old symptoms, while new ones indicate a true relapse.
A true relapse typically develops suddenly and worsens over a few days before stabilizing, whereas a pseudo-relapse improves as the infection clears.

Recognizing this distinction is crucial, as treatment differs. While infections are treated with antibiotics and antiviral medications, severe relapses are often treated with corticosteroids, which further suppress the immune system and can worsen an ongoing infection.

Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.