With the winter chill setting in on Hyderabad and several other parts of Telangana, each hot-water shower left a 25-year-old woman in the state capital panicked and baffled.
Worried over the peculiar problem that mostly lasted a few hours, she decided to consult neurologist Dr Sudhir Kumar at Apollo Hospital in the city.
The young woman explained that she had suffered short-time vision loss in her left eye after a hot-water shower. And it had occurred eight times in the past month as well.
The doctor soon found that it had happened to her last winter as well, but she had ignored it.
She was referred to an ophthalmologist who found nothing wrong with her. “Her family thought she was cooking up the symptoms,” she informed the doctor.
Her husband rejected her requests for a detailed medical inspection. The woman was convinced that she had vision loss — albeit for a few hours — after each hot-water shower.
With her family members refusing to believe her “concocted story”, she decided to go ahead and reached Dr Kumar’s outpatient department.
“On detailed inquiry, I understood she also experienced a similar loss of vision in the left eye after her Zumba sessions. Again, the loss of vision lasted a few hours after exercise, and returned to normal in a few hours. She also reported occasional pins and needles sensations in her hands and feet,” Dr Kumar told South First.
The doctor diagnosed her with multiple sclerosis, “a phenomenon an ophthalmologist had explained 132 years ago. Transient loss of vision on exposure to heat is referred to as Uhthoff’s phenomenon”, he said.
What is multiple sclerosis?
Multiple sclerosis (MS) is a chronic disease that affects the central nervous system (CNS), specifically the brain, spinal cord, and optic nerves. It is an autoimmune disorder, which means that the body’s immune system mistakenly attacks healthy tissues.
It is characterised by the presence of scar tissues (called sclerosis) in the brain and spinal cord.
In MS, the body’s immune system mistakenly attacks and damages the myelin sheath, a protective covering that surrounds nerve fibers in the central nervous system. This damage disrupts the normal flow of electrical impulses along the nerve fibers, causing a wide range of symptoms.
It is also believed that certain risk factors may increase the likelihood of a person developing MS:
Gender: MS is more common in women than in men.
Age: MS is mostly diagnosed in people aged between 20 and 40.
Family history: MS is more common in people who have a family member with the disease.
Geographic location: MS is more common in people who live farther from the Equator.
Smoking: Smoking increases the risk of developing MS.
It is important to note that having these risk factors need not always contribute to developing MS, and many people who have the disease do not have any known risk factors.
Why vision loss?
Multiple sclerosis can affect the optic nerve, which is a bundle of nerve fibers that carries visual information from the eye to the brain. When MS causes inflammation or damage to the optic nerve, it can lead to a range of vision problems.
“The optic nerve is part of the brain. It’s not a separate nerve. The myelin sheath around the optic nerve gets removed and that’s why it is called demyelinating disease,” Consultant Neurologist at Hyderabad’s Yashoda Hospitals Dr Mohan Krishna Narasimha Kumar Jonnalagadda told South First.
Some of the most common symptoms of MS-related optic nerve damage include:
Optic neuritis: This is the inflammation of the optic nerve that can cause sudden, severe vision loss in one or both eyes. Symptoms may include blurred vision, pain with eye movement, and colour vision changes.
Nystagmus: This is a condition in which the eyes make involuntary, rapid movements. It can cause difficulty with depth perception and make it hard to focus on a target.
Diplopia: This is double vision, which can be caused by weakness or dysfunction of the muscles that control eye movement.
Scotoma: This is a blind spot in the visual field, which can be caused by damage to the optic nerve.
Visual acuity loss: This means that the person may have trouble seeing finer details and may have difficulty reading, driving, or performing other visually demanding tasks.
Uhthoff’s phenomenon, also known as Uhthoff’s sign, is a symptom of MS in which an increase in body temperature causes a temporary, worsening of neurological symptoms.
This can include issues like blurred vision, difficulty with coordination, and muscle weakness. “The phenomenon is named after Wilhelm Uhthoff, a German neurologist, who first described it in 1890,” Dr Kumar said.
The exact mechanism behind Uhthoff’s phenomenon is not well understood but it is thought to be related to changes in blood flow in the brain’s affected areas.
Dr Jonnalagadda said the diagnosis is completely clinical. “We have to go by what the patient says such as he or she has lost vision in one eye or is experiencing blurred vision. This vision loss can happen instantly, even within 30 minutes. In 95 percent of the cases, it’s in one eye,” he said.
There are several methods that doctors use to diagnose MS:
Medical history and physical exam: A doctor will ask about symptoms and perform a physical examination for signs of nerve damage.
Neurological exam: A doctor may perform a detailed examination of the patient’s vision, coordination, reflexes, and strength to help identify any neurological problems.
Magnetic Resonance Imaging (MRI): An MRI is a non-invasive test that uses a magnetic field and radio waves to produce detailed images of the brain and the spinal cord. These images can reveal areas of inflammation or damage that may be indicative of MS.
Visual evoked potentials: These tests measure the electrical activity in the brain in response to specific stimuli, such as the flashing of light or a buzzing sound. It can help identify damage to the nerves that control vision, hearing, and sensation.
Spinal fluid analysis: A sample of cerebrospinal fluid can be obtained via a lumbar puncture (spinal tap) to look for certain proteins (oligoclonal bands) that are often found in people with MS.
“So the diagnosis depends on the patients’ complaint, examinations, and his or her cooperation,” Dr. Jonnalagadda added.
It can often be challenging to diagnose MS, as its symptoms can be similar to those of other neurological disorders and it may take time to confirm the diagnosis.
In some cases, doctors may use a combination of tests or repeat them over time to build a more complete picture of the patient’s condition before making a diagnosis.
“For the Hyderabad woman, I ordered two investigations to confirm my suspicion: VEP studies and MRI. VEP studies showed features of optic nerve dysfunction and MRI was diagnostic for multiple sclerosis,” Dr. Kumar said.
Uhthoff’s phenomenon: Treatment
Uhthoff’s phenomenon primarily focuses on managing symptoms and preventing further deterioration of neurological function. There are a few different strategies that can be employed:
Cooling measures: Keeping the body cool during times of increased activity to reduce symptoms. Cooling vests, headbands, and other cooling devices can be used to keep the body temperature down.
Medications: Some medications, such as dalfampridine, can help to improve nerve conduction and reduce symptoms.
Physical therapy: Physical therapy can improve muscle strength and coordination, which can reduce symptoms.
Disease-modifying therapies (DMTs): DMTs such as Interferon beta, Glatiramer acetate, and Natalizumab are used to slow down the progression of MS and reduce the number of flare-ups.
It’s important to note that individual patients may have different responses to different treatments, and it may take some time to find the most effective approach. It’s also important to work with a healthcare provider to develop a treatment plan that works best for the patient.
“Patients with MS are advised to avoid exposure to heat to prevent worsening of the symptoms,” Dr. Kumar added.
“To prevent a relapse, a disease-modifying therapy for a longer period is often suggested, which includes oral tablets, or injections. There is no surgical intervention required,” Dr. Jonnalagadda further explained.