What is BRASH Syndrome?
The term ‘BRASH’ is an acronym that describes a specific medical condition. This situation arises when a certain type of medication, known as AV nodal blockers, reacts with kidney dysfunction, resulting in very slow heart rate (bradycardia) and high levels of potassium in the blood (hyperkalemia). The acronym stands for Bradycardia, Renal Failure (kidney failure), AV nodal blockade (using medication that inhibits certain electric signals in the heart), Shock, and Hyperkalemia. This is a relatively new term, but the link between these medicines and kidney failure has been known for a long time.
Medications known as beta-blockers and calcium channel blockers have been widely used since the 1960s to treat conditions like coronary artery disease (blockages in the heart arteries), high blood pressure (hypertension), and irregular heart rate (atrial fibrillation). These medications work by affecting the AV node, a part of the heart’s electrical system, which leads to reduced heart rate. Like many other drugs, AV nodal blockers can cause side effects like tiredness, dizziness, sleep disorders, and difficulty in breathing (dyspnea). However, BRASH syndrome is a less known side effect that can cause serious health problems, potentially leading to cardiovascular collapse (heart failure) and failure of multiple bodily systems, if not identified and treated correctly.
What Causes BRASH Syndrome?
This syndrome is a unique condition that is becoming more common due to a combination of factors: aging population and the introduction of new drugs aiming to improve heart performance. This condition leads to extremely slow heart rates due to the combined effects of a blockage in the heart’s electrical system (AV nodal blockade) and kidney failure. This creates a harmful cycle of a very slow heart rate and elevated levels of potassium in the blood (hyperkalemia). Despite being common, it’s believed that it often goes unnoticed, leading to incorrect diagnoses, particularly in intensive care units (ICU).
Risk Factors and Frequency for BRASH Syndrome
This condition, which has recently been named, is still largely unknown. Based on case reports though, it seems to be more common in older people who have heart and kidney problems. The risk becomes even greater if the patient is taking many AV node-blocking drugs. Medications such as ACE inhibitors and angiotensin receptor blockers also increase the risk because they make developing a sudden kidney injury and high potassium levels more likely.
Signs and Symptoms of BRASH Syndrome
People who experience this syndrome may have symptoms that differ greatly from person to person. These can go from a very slow heartbeat without any other symptoms to a severe condition called cardiogenic shock, which requires strong medications to raise blood pressure and treatments to clean the blood (hemodialysis). Despite these differences, everyone with this syndrome will have an unusually slow heartbeat. This syndrome is often triggered by decreased blood flow to the kidneys. As such, a person’s medical history might reveal recent stomach or intestinal illness, being dehydrated, changes in medication, or other factors that raise the risk of acute kidney injury. It is important to understand that the role of medications that slow down the heart rate (AV nodal blockers) in this syndrome is not dependent on the dose taken.
Testing for BRASH Syndrome
An EKG, or electrocardiogram, is an important tool in diagnosing a condition known as BRASH syndrome, which causes an abnormally slow heart rate. Even though EKGs are useful, the typical patterns seen with high potassium levels (or hyperkalemia) might not be present in BRASH syndrome patients.
Hyperkalemia, which can also result in slow heart rate, usually displays distinct changes on an EKG. As potassium levels rise, the EKG shows changes in pattern, such as pointed T waves and a prolonged PR interval followed by a wider QRS complex – all these patterns reflect how your heart’s electrical activity is behaving. However, in BRASH syndrome, these changes are often not visible.
In addition to EKG, a detailed look at your blood chemistry, known as a comprehensive metabolic panel, can provide more clues. This test can reveal if your potassium levels are too high, even if the increase is small. Increased potassium levels are harmful to the heart and can cause it to beat slower.
A case study even showed a patient with BRASH syndrome who had only a slightly high potassium level. However, most recorded cases demonstrated higher potassium levels, generally ranging from 5.5 to 7.0 mEq/L. No matter the degree of increase, too much potassium in your blood is harmful to your heart and can lead to a slower heart rate.
Acute kidney injury, where your kidneys suddenly stop working as they should, is another common finding in BRASH syndrome. Even if these patients have borderline kidney function to begin with, there will be a noticeable drop in the kidneys’ filtering capacity (also known as glomerular filtration rate or GFR) and an increase in the levels of waste products in the blood, such as BUN (blood urea nitrogen) and creatinine. This kidney injury often leads to a buildup of acid in the body (a condition known as acidosis).
Other lab tests may be performed based on each patient’s individual symptoms. Any abnormalities found in these tests may help doctors pinpoint what triggered the BRASH syndrome, which will, in turn, help with treatment planning.
Treatment Options for BRASH Syndrome
Often when dealing with this syndrome, which is a group of symptoms without a clear, singular cause, doctors usually focus on treating the most severe symptom. This could be two potentially life-threatening conditions – a slow heart rate (bradycardia) or high levels of potassium in your blood (hyperkalemia).
Both of these conditions may need immediate treatment, but most people find their condition improves with the right support.
Calcium is usually given immediately if you have low levels of calcium in your blood (hypocalcemia), as it can make hyperkalemia worse. There’re two types of calcium treatments – calcium chloride or calcium gluconate. While calcium chloride has more calcium, calcium gluconate is usually the preferred option because it’s easier on the body when given through an IV.
If your heartbeat doesn’t get faster within five minutes of getting calcium, doctors might give you another dose. If the problem continues, another drug known as epinephrine can be introduced. This drug won’t just increase your heart rate but also help move potassium back into your cells, which can help manage hyperkalemia.
There are also other treatments used that help move potassium back inside our body’s cells or enhance the body’s ability to get rid of potassium. Insulin, a hormone that regulates blood sugar levels, can help reduce potassium levels in the blood. To prevent low blood sugar (hypoglycemia) caused by insulin, dextrose, a type of sugar, is given at the same time. Another drug called albuterol, often used in inhalers, can be nebulized and given to help shift potassium back into the cells. The induced increased heart rate caused by albuterol could be beneficial in this condition.
Once your immediate life-threatening conditions are under control, doctors will then need to find and deal with the root cause, typically indicated by your medical history. It’s quite common that people coming in with this condition are actually dehydrated (hypovolemia), so doctors will often use an ultrasound to determine the level of fluids needed.
How much IV hydration you need also depends on your initial pH (a measure of acidity in your body). It’s common to have an acid state in this condition, which is why some doctors suggest using sodium bicarbonate (a type of baking soda) in your IV fluid for hydration. Sodium bicarbonate can potentially reduce the need for urgent dialysis (a procedure to remove waste products and excessive fluids from your body).
An alternative way to lower potassium levels in your blood is to increase its excretion via the urine, a process known as kaliuresis. This is usually achieved through the use of different kinds of diuretics, which help your body to get rid of excess fluid. However, this treatment usually requires careful replenishment of the fluids removed through the diuretics to maintain a balance.
In cases when you aren’t producing urine, emergency dialysis may be needed to help remove excess potassium from your body.
Finally, if you have hypotension (low blood pressure) and don’t respond to intravenous (administered into a vein) fluids, doctors might start you on vasopressor medications. These are a group of drugs that constrict (narrow) your blood vessels, causing your blood pressure to rise, which will enhance your organ’s blood supply. Medications like epinephrine or isoproterenol might be introduced in these cases.
What else can BRASH Syndrome be?
BRASH syndrome can confuse doctors because it has a lot of the same signs and symptoms as AV nodal blocker toxicity which happens when too much of a certain drug is taken, as well as hyperkalemia, which is a high level of potassium in your blood. It’s crucial to tell these conditions apart because they each need a different treatment. Clues from the patient’s medical history can help doctors figure out if it’s really BRASH syndrome. Usually, these patients are taking their medications as prescribed. A quick blood test can also help. If the patient has low blood sugar, it might be due to beta-blocker toxicity. If they have high blood sugar, it could be due to calcium channel blocker toxicity. If their potassium level is not disrupted, then it could be due to an overdose of certain medications.
Doctors already know that hyperkalemia, or high potassium levels, can cause a slow heart rate. But usually, this only happens if the potassium levels are higher than 7 mEq/L. With potassium levels between 5.5 to 6.5 mEq/L, an EKG might show peaked T waves. If the potassium levels are moderately high between 6.5 to 7.0 mEq/L, the EKG might show a flattening of P waves and a prolonged PR interval. It’s only when the potassium levels surpass 7.0 mEq/L that there are changes in the QRS complex on the EKG and a slow heart rate. But these specific heart rhythm changes are often not seen in patients suffering from BRASH syndrome.
What to expect with BRASH Syndrome
BRASH syndrome, a medical condition characterized by a number of symptoms, usually responds well to basic treatment in its milder forms. However, in more severe cases, it might need more intense treatments like hemodialysis (a process to remove waste and extra fluid from your blood when your kidneys can’t adequately do the job) or transvenous pacing (a procedure to regulate your heart beat).
Quick detection of this condition improves the chances of a better outcome and reduces the need for these more intense treatments. The seriousness of the accompanying acute kidney injury (sudden and temporary loss of kidney function) and hyperkalemia (too much potassium in your blood) are key factors that influence the outcome of the condition.
Possible Complications When Diagnosed with BRASH Syndrome
The problems that can come from this syndrome can vary. They can be as serious as kidney failure, which may need a treatment called hemodialysis to clean the blood, or heart distress that may need drugs to increase blood pressure or a heart pace setting. If this syndrome isn’t addressed, an increase in potassium levels in the blood can result in cardiac arrest, or heart failure.
Below are some potential complications:
- Kidney failure which may need hemodialysis
- Heart distress that may need medication to increase blood pressure or a procedure to regulate heart pace
- Increased potassium in the blood leading to heart failure, if not treated
Preventing BRASH Syndrome
Patients should be aware of the warning signs for arrhythmia, a condition where the heart does not beat normally. These signs can include feeling lightheaded, fainting, or symptoms that may suggest sudden kidney failure. The latter may appear as an excessive build-up of fluid in the body or producing less urine than usual.
AV nodal blockers are medications which are often prescribed for many different ailments. Patients taking these medications should be informed about the possibility of experiencing this syndrome as a side effect. This awareness can assist in the quick recognition and treatment of any adverse reactions that may occur.