What is Xanthochromia?
Xanthochromia is a term that comes from the Greek word “xanthos,” meaning yellow. It was initially coined to describe the pink or yellow coloration of cerebrospinal fluid (CSF), which is the fluid surrounding your brain and spinal cord. This color change is caused by different concentrations of colored compounds like oxyhemoglobin, bilirubin, and methemoglobin, which are usually products of red blood cell breakdown.
In today’s medical field, xanthochromia is most commonly understood to be the yellow color that occurs when bilirubin, a waste product, is present in the CSF. If the CSF turns yellow due to the presence of bilirubin, this is known as xanthochromia.
There are currently two ways to diagnose xanthochromia: the traditional method, which involves simply looking at the fluid, and a more sensitive and specific method called spectrophotometry, which uses light to measure the amount of bilirubin in the fluid.
What Causes Xanthochromia?
Xanthochromia, a condition that gives a yellowish tint, is caused by too much bilirubin – a substance produced when the body breaks down red blood cells using an enzyme called oxygenase. This event mainly happens in a specific area of the brain, lined by a type of white blood cell called a macrophage.
Several conditions can lead to xanthochromia. Some common ones include acute brain bleeding, brain tumors, infections, conditions that result in too much protein in the brain fluid (more than 150 mg/dL), and severe body-wide jaundice (when bilirubin levels in the blood are more than 10 g/dL).
Detecting xanthochromia in the brain fluid is usually used to diagnose subarachnoid hemorrhage, a condition involving bleeding in a specific area of the brain. This is especially useful when a regular head scan (Computed Tomography or CT) appears normal.
Risk Factors and Frequency for Xanthochromia
Xanthochromia is a condition that can be caused by several different problems, so its actual prevalence is not known. However, it’s often associated with the rupture of an aneurysm within the brain, leading to a type of stroke called subarachnoid hemorrhage (SAH). In the United States, between 9 to 15 out of every 100,000 people experience this type of stroke each year, but the rates can be different depending on the location. Factors that increase the risk of this stroke include high blood pressure, smoking, drinking alcohol, using certain types of drugs, and having certain genetic traits.
Xanthochromia can happen really quickly after an SAH, even within two hours. About 12 hours after the rupture of an SAH, more than 90% of people will show signs of xanthochromia in their cerebrospinal fluid (CSF), and this can last for up to 4 weeks. SAH is usually diagnosed using an imaging test like a CT scan or CT angiogram of the brain.
However, sometimes these scans might miss the presence of SAH, which happens in fewer than 1% of cases. In these situations, looking for xanthochromia in the CSF can be helpful. This method has proven to be highly accurate (100% sensitivity and 99% specificity) when a testing method called spectrophotometry, as used by the United Kingdom National External Quality Assessment Service, is applied.
Signs and Symptoms of Xanthochromia
Xanthochromia is a condition that can be linked to a variety of health issues. One of the most serious conditions associated with it is called a subarachnoid hemorrhage (SAH), although it is relatively uncommon. SAH is a serious health risk because it can lead to severe health complications including sudden death or disability if it is not quickly diagnosed and treated. Patients with SAH usually experience very intense headaches, often described as the worst headache of their life.
- The headaches are sudden and reach maximum intensity usually within the first hour of onset
- Associated symptoms can include stiffness in the neck, nausea, vomiting, sensitivity to light or sound, but rarely acute neurological issues
It can be challenging for medical professionals to differentiate between headaches caused by SAH and headaches from less serious causes.
Testing for Xanthochromia
If a subarachnoid hemorrhage, a dangerous type of stroke, is suspected, a non-contrast CT scan of the head (NCHCT) is usually the first test done. This scan is most effective within the first six hours after the stroke symptoms start.
However, if the CT scan doesn’t clearly show a stroke, doctors might need to do a test called a lumbar puncture. This is where a small amount of cerebrospinal fluid (CSF), the fluid that surrounds your brain and spinal cord, is taken out of your lower back for testing.
The cerebrospinal fluid test will look for something called “xanthochromia”, which can be a sign of a brain bleed or stroke. This test is really accurate—it can correctly identify a stroke with 93% accuracy rate, and when xanthochromia is not present it can rule out a stroke 99% of the time.
Xanthochromia may start showing up in the cerebrospinal fluid 6 to 12 hours after stroke symptoms start. Even if the CT scan doesn’t show a stroke after a few weeks, testing the cerebrospinal fluid for xanthochromia can still be useful. In fact, it can detect a brain bleed up to 3 weeks after it happens.
And even more importantly, the cerebrospinal fluid test can help doctors tell the difference between a real brain hemorrhage and a false alarm caused by a “traumatic tap”, which is when red blood cells accidentally get into the cerebrospinal fluid during the lumbar puncture procedure.
Treatment Options for Xanthochromia
After a patient has been diagnosed with a subarachnoid hemorrhage (SAH) – a type of stroke caused by bleeding into the space surrounding the brain, their doctor will need to work out the next steps for treatment. This diagnosis is typically made based on the presence of a substance called xanthochromia in the cerebrospinal fluid (CSF) – the liquid that protects the brain and spinal cord.
From here, the patient might undergo a magnetic resonance imaging (MRI) scan or a Computed Tomography Angiography (CTA). These are both types of imaging tests that can provide detailed pictures of the brain and its blood vessels. The purpose of these tests is to locate the aneurysm, a bulging of a blood vessel, which is the likely cause of the SAH. This step is crucial in planning for the treatment to prevent further damage.
What else can Xanthochromia be?
When trying to identify xanthochromia, which is a yellowish discoloration, doctors might consider several alternative possibilities that exhibit similar symptoms. These include:
- Bleeds from small brain aneurysms
- Severe high levels of bilirubin, a yellow pigment made during the normal breakdown of red blood cells
- Subarachnoid hemorrhage (SAH), a life-threatening type of stroke caused by bleeding into the space surrounding the brain
- ‘Sentinel’ or warning hemorrhage, a smaller bleed which may come before a major one
- Eating too many carotenoid-rich food such as carrots and spinach
- Conditions that cause high protein levels in the cerebrospinal fluid (CSF), which include cancer spread, brain tumors, Froin’s syndrome, tuberculosis, a specific type of fungal meningitis called cryptococcal meningitis and nerve fiber damage called radicular demyelination
Identifying these alternatives helps doctors give a correct diagnosis.
Possible Complications When Diagnosed with Xanthochromia
Determining the likelihood of having a subarachnoid hemorrhage (SAH) based on a one-time symptom, such as an acute nontraumatic headache, is tricky. There’s no single criteria that dictates whether you need more tests. Performing a lumbar puncture, which involves puncturing the lower back to collect fluid, can help identify SAH. But it’s invasive and the results are often unclear.
Having a head CT scan that shows no signs of SAH doesn’t necessarily mean you don’t have it. However, overusing CT angiography (CTA) can unnecessarily expose patients to radiation. Also, CTA can mistakenly identify aneurysms that aren’t cause for concern, leading to unneeded tests and treatments. A lumbar puncture, on the other hand, is usually helpful for diagnosis and can even eliminate the need for more invasive procedures or consultations with a neurosurgeon. It has a low risk of causing infection, bleeding, and headache after the procedure. Additionally, it’s cost-effective, fast, and can reduce exposure to radiation and contrast dye used in angiography.
- Likelihood of SAH is difficult to determine from a single symptom
- Lumbar puncture can be helpful but is invasive
- Head CT scans can miss SAH
- Overuse of CTA can expose patients to unnecessary radiation
- CTA can lead to unneeded tests and treatments
- Lumbar puncture is cost-effective and fast
- Lumbar puncture can reduce the need for invasive procedures and consultations
