What is Millard-Gubler Syndrome?
Millard-Gubler syndrome (MGS), also referred to as facial abducens hemiplegia syndrome or the ventral pontine syndrome, was first identified in 1858 by two French doctors, Auguste Louis Jules Millard and Adolphe-Marie Gubler. They discovered MGS, a complex condition where a single-sided injury in the lower part of a brain area called the ‘pons’ affects both nerve bundles for facial control (VII cranial nerve) and bundles of nerves responsible for the movement of the body – the corticospinal tract fibers.
The condition develops due to an issue in the front part of the ‘pons’, involving the nerves that control facial movements on the affected side and the corticospinal tract on the opposite side. This results in facial paralysis on the affected side, and partial paralysis, or ‘hemiplegia’, on the opposite side of the body. In some instances, the sixth cranial nerve, or CNVI, might also be involved, even though this wasn’t a symptom seen in the original patients diagnosed by Millard and Gubler.
The problem in MGS emerges above the area where pyramidal and spinothalamic tracts – groups of nerve fibers – criss-cross. This means that the symptoms affecting cranial nerves are on the same side of the injury, while symptoms affecting limbs are on the opposite side, leading to what is called a ‘crossed brain stem syndrome’.
Regularly, MGS comes along with other neurological issues like partial numbness (hemiparesthesia) and unsteady, clumsy movements (cerebellar ataxia) on the side of the body opposite to the injury as several nerve tracts are located close to the facial nerve nucleus. Such a syndrome may occur due to injuries, tumors, infections, or the disintegration of the protective sheath surrounding nerve fibers, which is known as demyelination.
What Causes Millard-Gubler Syndrome?
Millard-Gubler syndrome (MGS), a neurological condition, can have many different causes, and these can change based on a person’s age. In younger people, it’s often due to tumors, bacterial infections like neurocysticercosis and tuberculosis, viral infections like rhombencephalitis, diseases that cause damage to the protective covering of nerve fibers like multiple sclerosis, and other conditions that result from the immune system attacking the body’s own cells, such as neuro-Behçet’s disease.
In older individuals, MGS is typically caused by problems with the body’s blood vessels, such as a stroke (either hemorrhagic, which involves bleeding, or ischemic, caused by a blockage) that affects the posterior circulation, the part of the brain’s blood supply that includes the brainstem. In MGS, this usually happens due to blockage of a specific artery in the brainstem. A hematoma (a solid swelling of clotted blood) near the brainstem or a mass taking up space can also cause MGS. Any other damage to the base of the brainstem, like a deformed blood vessel, can lead to MGS, particularly if it has recently bled.
Risk Factors and Frequency for Millard-Gubler Syndrome
The causes of MGS, a neurological condition, can vary, which in turn affects how common it is. We have some information about how often MGS occurs due to brainstem strokes, but information about other causes is mostly found in individual case reports.
It’s important to note that strokes affecting the back portion of the brain (including the brainstem where MGS can occur) are not as common as strokes affecting the front portion. Although the latest detailed data we have is nearly ten years old, it tells us that strokes in the back portion of the brain account for up to a quarter of all strokes. One recent report found that almost 20% of stroke patients who were treated with clot-dissolving medication had strokes in the back portion of the brain.
Compared to patients with strokes in the front portion of the brain, patients with strokes in the back portion of the brain had lower scores on a stroke severity scale, fewer heart-related risk factors, and a much lower risk of bleeding after treatment. The risk of death was higher in patients with strokes in the back portion of the brain, though the difference was not statistically significant.
Lastly, if we look more specifically at strokes in the pons (a part of the brainstem), they constitute 20% of all brainstem strokes and 7% of all strokes where the brain’s blood supply is interrupted.
Signs and Symptoms of Millard-Gubler Syndrome
If you suspect you might have a brainstem lesion, including a stroke, there are several steps doctors typically follow to assess the situation. First, they’ll take a very detailed history. This includes looking at any risk factors you might have for a stroke, checking if you’ve had similar episodes in the past, checking your medication, and asking about when your symptoms started. This information is important because it might affect whether you’re eligible for certain treatments like IV clot-busting drugs or interventional neuroradiology procedures.
Next, the doctor will look for certain symptoms that might point to a brainstem problem. These include:
- Any changes to your vision (like blurred vision, double vision, new blind spots)
- Difficulty chewing
- Asymmetry of the face
- Changes in hearing
- Feeling off balance
- Difficulty with coordination or tremors
- Difficulty swallowing
- Slurred speech
- Changes in tongue mobility
- Tremors
- Changes in the way you walk or stay balanced
Your doctor will also want to know if you’ve had any headaches recently.
In certain cases, such as Millard-Gubler Syndrome, doctors look for specific combinations of symptoms like facial weakness on one side and weakness in the arm and leg on the other side. Sometimes, a syndrome like this might also include difficulties with eye movement.
Doctors will also consider non-stroke causes for your symptoms. For instance, general feelings of unwellness might suggest an infection, while symptoms that come and go might indicate a disease like MS. Likewise, slow, progressive changes might hint at a tumor.
A clinical examination then looks for particular signs. For instance, if the facial nerve is involved, you might have weakness in your facial muscles and might not be able to close your eye on the affected side. If the abducens nerve (which controls eye movement) is involved, you might have double vision and difficulty looking outwards with the affected eye. You might also have weakness in the arm and leg on one side. Sensation in the face and limbs, however, is typically unaffected in Millard-Gubler Syndrome.
Testing for Millard-Gubler Syndrome
If you have symptoms that suggest a cerebrovascular event (a sudden loss of blood flow to a part of your brain), doctors may suspect a condition called Millard-Gubler syndrome (MGS). MGS often presents like a stroke, so the first response is to start stroke protocols immediately. This means treating it as a medical emergency because in stroke cases “time is brain” – the quicker we treat you, the better your chances of recovery. Treatments like clot-dissolving drugs or procedures to physically remove the clot (thrombolysis or embolectomy) may be options, depending on how long ago your symptoms started.
Your doctor will want to urgently get a picture of your brain, as with any suspected stroke. A CT scan can usually be done very quickly in the emergency department, but although it’s fast, its detail may not be good enough to see the exact problem. However, it can perform two important jobs: 1) detect if there’s bleeding in your brain causing your symptoms, and 2) help decide risk levels if you’re being considered for treatments like thrombolysis, thrombectomy, or embolectomy.
Another imaging option is a brain MRI, which can provide more detailed views of your brain than a CT scan. With an MRI, where the stroke has occurred can show up as a bright white area, while the surrounding brain tissue will look darker. There are different types of MRI sequences – T1, T2/FLAIR – however, these are less sensitive than the bright white and dark areas in identifying acute stroke. The spot where the stroke happened can be quite small, which carries the risk of it being missed unless thin slices of the brain are taken for the imaging. Sometimes, even with these measures, initial scans may still not show the stroke.
Other conditions such as tuberculomas and cysticercus granulomas (types of brain infections), or other mass formations, could be detected through an MRI scan. In these cases, a special dye called gadolinium is often needed. Another way to visualize the brain is by using angiography, which is particularly useful to spot any narrowing or blockages in the basilar artery, a major blood vessel at the base of the brain.
Treatment Options for Millard-Gubler Syndrome
The treatment for MGS, or Millard-Gubler syndrome, largely depends on what is causing the condition. In some instances, patients might show multiple symptoms and need immediate but careful treatment, along with multiple approaches to therapy from different healthcare professionals.
In many cases, MGS can be traced back to an acute episode like a stroke. If this is the case, the treatment for MGS will be similar to the standard treatment for strokes. Patients having a stroke in the area of the brain controlling the circulation at the back can be treated with various stroke therapies, one being intravenous thrombolysis, a treatment that dissolves harmful clots in blood vessels. A recent study found patients that had this treatment for strokes in the back part of the brain had a lower risk of bleeding post-treatment compared to those patients with strokes occurring in the front part of the brain. The study also found a higher death risk among those with strokes at the back of the brain, but didn’t find a notable difference between these two groups.
People with MGS experience a type of facial paralysis called lower motor neuron facial palsy. This affects one whole side of the face, on the same side as the brain injury, and the person might not be able to fully close their affected eye. It’s very important to protect the eye in this situation to prevent dryness and further injury. This might involve the use of eye drops, such as artificial tears or other lubricants, during the day and a special eye ointment at night. Wearing an eye patch can also help protect the eye from irritants, injuries, and dryness. Treatments for ‘lagophthalmos’, the inability to fully close the eye, could include placing a small weight made of gold, the patient’s own tissue from the temporalis fascia (a muscle in the head), or platinum chains on the eyelid to help it close.
What else can Millard-Gubler Syndrome be?
In simpler words, there are various conditions that share similar signs such as mild paralysis or numbness, referred to as ‘crossed hemiparesis’ or ‘hemianaesthesia’. These conditions all stem from damage to certain parts of the brainstem, above the crossing point of the brain’s signals. Among these conditions are:
- Foville syndrome: This condition is caused by an issue with the lower third of the pons in the brain. It leads to facial paralysis, trouble moving the eyes horizontally, and mild paralysis on one side of the body. It often happens due to a blockage in specific branches of the basilar artery during a stroke.
- Raymond syndrome: Also known as ventral pontine syndrome, this is caused by problems in the upper front part of the pons. Symptoms can include a weak or paralyzed sixth cranial nerve on the same side as the damage, facial weakness, and mild paralysis on the opposite side of the body. The common type of this syndrome presents as paralysis on one side of the body and problems moving the eyes to the side opposite to the affected half of the body.
- Raymond-Cestan syndrome: Caused by damage to the upper back part of the pons, this disorder involves involuntary trembling and loss of muscle coordination on the same side as the damage, paralysis of the face muscles, sensory loss in the face, and mild paralysis and sensory loss on the opposite side of the body.
- Marie-Foix syndrome (lateral pontine syndrome): Blockage of the basilar artery or anterior inferior cerebellar artery, this syndrome causes loss of muscle control, sensory impairment in the face, weakness in the face, hearing loss, dizziness/nystagmus, mild paralysis on the opposite side of the body and numbness of the arms and legs on the opposite side.
- Gasperini syndrome: A rare syndrome caused by damage to the lower part of the pons. It leads to damage to the 5th, 6th, 7th, and 8th cranial nerves on the same side as the damage and sensory loss on the opposite side.
- Brissaud-Sicard syndrome: Extremely rare, it’s caused by damage to certain parts of the pons that can result in facial cramps on the same side as the damage and mild paralysis on the opposite side of the body.
What to expect with Millard-Gubler Syndrome
The outcome largely depends on the severity and cause of the condition. A stroke affecting the vertebrobasilar area (the part of the brain responsible for balance and coordination) may lead to serious damage to the nervous system. An isolated infarction (or blocked blood vessel) in the pons (a part of the brain stem) could potentially have a good outcome if detected and treated promptly.
Patients with smaller lesions (abnormalities or damage in the body tissue) usually have a better chance for improvement.
Possible Complications When Diagnosed with Millard-Gubler Syndrome
People who have experienced a stroke may sometimes have unusual facial or eye area pain, which can feel like a burning “salt and pepper” sensation. These types of strokes usually occur in a part of the brain called the pons. Emotional imbalance, known as emotional dysmetria, can be an after-effect of a stroke in this area, especially if it also involves another part of the brain called the cerebellum.
It’s also possible for restless leg syndrome to develop after a stroke in the pons. Therefore, all patients who’ve had such a stroke should be regularly checked for symptoms of this condition.
In a recent study, a condition called paroxysmal sympathetic hyperactivity was reported to occur about three months after a stroke in the pons. This means strokes in this area can cause various complications. Therefore, if a person with a history of this type of stroke is showing unusual or unexpected symptoms, it should immediately raise suspicion of potential complications.
- Stroke causing burning “salt and pepper” sensation
- Emotional imbalance, known as emotional dysmetria
- Development of restless leg syndrome post-stroke
- Potential for an after-effect called paroxysmal sympathetic hyperactivity
- Need for regular checks for symptoms and complications
Preventing Millard-Gubler Syndrome
Miller Fisher syndrome, commonly referred to as MGS, is often categorized as a type of stroke. Like with every type of stroke, it’s critical to educate patients following the episode. Recent research suggests that the use of technology could enhance this education process. According to a study, tailored interactive computer-based education systems could be more beneficial compared to traditional methods, like handing out information booklets and hosting verbal teaching sessions.
It’s also important to note that if a patient has experienced a stroke as a result of blockage in the part of the brain called the pons (known as a pontine infarct), measures should be taken to prevent another stroke from occurring. This is known as secondary stroke prevention and should apply to anyone who has had this kind of stroke.
