What is Hyperchloremic Acidosis?
The pH scale, which measures how acidic or basic a substance is, normally ranges from 7.35 to 7.45 in our bodies. If the pH drops below this range, it’s referred to as acidosis. On the other hand, if it rises above this, it’s called alkalosis. There’s a specific type of acidosis called hyperchloremic acidosis. This condition happens when the pH dips below 7.35 and at the same time, there’s an excessive amount of chloride in the body.
It’s essential to understand how our bodies maintain a stable pH by using a buffering system. The primary pH buffer in the human body involves bicarbonate and carbon dioxide (HCO3/CO2). Here’s what the process looks like:
* H (hydrogen) + HCO3 (bicarbonate) <-- --> H2CO3 (carbonic acid) <-- --> CO2 (carbon dioxide) + H2O (water)
Bicarbonate acts to increase the pH (making it more alkaline), while carbon dioxide decreases the pH (making it more acidic). So, a rise in bicarbonate or a drop in carbon dioxide levels will make your blood more alkaline. However, a fall in bicarbonate or a rise in carbon dioxide causes your blood to become more acidic. The lungs manage carbon dioxide levels through breathing, while the kidneys regulate bicarbonate levels by reabsorbing it from urine back into the blood. Therefore, hyperchloremic metabolic acidosis happens when there’s a decrease in bicarbonate levels in the blood.
During health checkups, when there’s a suspicion of metabolic acidosis, doctors often calculate something called the anion gap. It is computed like this:
* Serum anion gap = (Amount of sodium in blood) – [(Amount of bicarbonate + Amount of chloride in blood)]
The anion gap is an approximation used to find out how much of certain substances (that are usually not directly measured) exist in the blood. Since there are always such substances, this gap is never expected to be zero. Protein called albumin is the main unmeasured substance that affects this gap. A healthy anion gap usually lies between 8 to 16 mEq/L (a unit of concentration). A higher gap is linked to conditions such as kidney failure, ketoacidosis (a complication of diabetes), lactic acidosis (a buildup of lactic acid in the body), and certain toxic exposures. A normal anion gap acidosis is characterized by a lower than normal bicarbonate concentration.
What Causes Hyperchloremic Acidosis?
Your body is usually excellent at maintaining a balance of ions – charged atoms needed for various bodily functions. However, particular conditions can cause imbalances, like if you lose bicarbonate, a negatively charged ion. In this situation, your body compensates by increasing the amount of another negatively charged ion, chloride, outside of your body’s cells. This event results in a condition known as a narrow anion gap, which means that your body is in a neutral electrical state. However, this doesn’t fix the problem that caused the increased acidity in your body.
On a similar note, if there’s too much chloride in your body, it may push bicarbonate into the body’s cells. To figure out what exactly is causing a narrow anion gap, doctors may test for hyperchloremic acidosis by conducting a urine anion gap test. The urine anion gap is a test that measures the difference between the sum of the sodium and potassium levels in your urine and its chloride levels using the following formula:
Urine anion gap = (Sodium level + Potassium level) – Chloride level
This urine anion gap essentially approximates how much ammonium, a measure of the body’s acidity, is being excreted in the urine. Your kidneys normally respond to an increase in your body’s acidity by excreting more ammonium. Hence, a urine anion gap result between 20 and 90 mEq/L suggests that the kidneys aren’t excreting enough or just the right amount of ammonium. This could be due to kidney-related issues, such as a condition called distal renal tubular acidosis. On the other hand, a negative urine anion gap result between -20 and -50 mEq/L implies the body is excreting a lot of ammonium. This situation is often seen in conditions not related to the kidney’s function, like severe diarrhea. A urine anion gap result close to zero does not indicate any specific condition.
Risk Factors and Frequency for Hyperchloremic Acidosis
The number of people who have hyperchloremic acidosis, a condition that affects the body’s acid levels, is uncertain. The frequency and spread of this disease depends on its cause. Similarly, the rates of illness and death associated with this disease also depend on its cause.
Signs and Symptoms of Hyperchloremic Acidosis
Hyperchloremic acidosis is a condition that does not necessarily have any immediate effects linked to hyperchloremia. However, acidosis itself can lead to multiple health issues. People often experience headaches, fatigue, nausea, and vomiting. If the acidosis worsens, it can result in lethargy, unconsciousness, heart instability, or even heart failure. A noticeable increase in the rate of breathing is expected as the body tries to lower levels of carbon dioxide to balance out the acidosis. Over time, however, this could result in muscle exhaustion and difficulty in breathing.
During a physical inspection, doctors may notice changes in mental state, increased heart rate and breathing rate, use of additional muscles during respiration, neurological problems, muscle weakness, heart rhythm disorders, heart murmurs, or abnormal sounds during respiration such as wheezing or crackling.
Testing for Hyperchloremic Acidosis
When you’re feeling unwell, the first step a doctor will take is to speak with you about your symptoms and to check you physically. This will help them to understand what might be wrong. Hyperchloremic acidosis, which is a condition where there is too much chloride in your blood leading to acid levels to rise, can often be easily identified if it is caused by loss of a substance called bicarbonate from the stomach or from certain medications.
To look for signs of infection, the doctor might take a blood sample to check your white blood cell count. This is known as a complete blood count, or CBC. The blood sample will also look at hemoglobin and hematocrit values, which can help the doctor determine if you have the right amount of fluid in your body or if you’re dehydrated.
The doctor will also likely check for the levels of different salts in your blood, including sodium, potassium, and chloride– this is called a complete metabolic panel. These tests help the doctor calculate a number known as the anion gap value, which is important in cases of hyperchloremic acidosis.
To confirm if the acidosis is metabolic, meaning it is caused by either too much acid in the body or not enough base, an arterial blood gas measurement would be needed. This test helps to determine the pH level or acidity of your blood.
In addition, a urinary anion gap test could be performed. This test measures substances in your urine and is important in understanding more about the cause of hyperchloremic acidosis. It specifically looks at the amount of ammonium that your body is getting rid of through your urine.
In some cases of hyperchloremic acidosis known as distal renal tubular acidosis, the urine might have a high pH level, meaning it is more alkaline than usual, and a positive urinary anion gap. In proximal renal tubular acidosis, another type of this condition, your urine pH will usually be less than 5.3 and the result from the urinary anion gap test could vary.
Treatment Options for Hyperchloremic Acidosis
If you have a condition called hyperchloremic acidosis, the first goal of treatment is to uncover and address the underlying issue that led to it. In some severe cases, patients may become too weak to breathe on their own and need a mechanical ventilator to assist with breathing. This often involves the ventilation machine forcing a more rapid breathing pattern to help lower the acidity in the body. If the trigger for this condition is related to your digestive system, intravenous (IV) fluid, commonly known as “normal saline,” is often used to prevent dehydration from diarrhea or other loss of fluid from the intestines.
Besides keeping you hydrated, your doctors also need to monitor your electrolytes – minerals essential for body function – and replace them if needed. A key electrolyte of interest in this case is potassium. To help a little more with the high acid levels, bicarbonate – a substance that can counteract acid – is also added to the saline fluids until the root cause of the problem is addressed.
In a disorder called proximal renal tubular acidosis, which affects your kidney’s ability to manage acid and base balance, you might need substantial amounts of bicarbonate, vitamin D, and potassium. If another type of acidosis called hypokalemic distal renal tubular acidosis (when your kidneys don’t properly remove acid from the body and you have low levels of potassium in your blood), direct alkali administration (such as bicarbonate) is given to manage the high acid load and to match the amount of bicarbonate in urine and the body’s production of acid. Potassium supplements are also important in this scenario.
If you have yet another kind of acidosis, known as hyperkalemic distal renal tubular acidosis (similar to hypokalemic, but you have high levels of potassium in your blood), it’s vital to uncover whether there’s any blockage in the urinary system. If there’s a concern about fluid overload, your doctor could administer diuretics – which help your body produce more urine – with potassium. Occasionally, when the acidosis does not respond to conventional treatments, it might be necessary to consider dialysis therapy – a process which helps clean your blood when your kidneys can’t do the job.
Lastly, be aware that certain medications can trigger this type of acidosis and should be avoided or used with caution. Some can cause the loss of bicarbonate through the digestive system, including calcium chloride, magnesium sulfate, and cholestyramine. Certain medications related to kidney acidosis include streptozotocin, lead, mercury, arginine, valproic acid, gentamicin, ifosfamide, and outdated tetracycline. Those associated with distal renal tubular acidosis include amphotericin B, toluene, nonsteroidal anti-inflammatory drugs, and lithium.
What else can Hyperchloremic Acidosis be?
When doctors are trying to diagnose hyperchloremic acidosis, which is a type of acid buildup in the body, they also consider other conditions that might cause similar symptoms. These conditions include:
- Non-anion gap metabolic acidosis (another type of acid buildup)
- Vitamin D deficiency
- Renal tubular acidosis (a kidney disorder that causes acid buildup)
- Vitamin D resistance
- Chronic diarrhea or other conditions that cause a loss of bicarbonate (a substance that helps manage body pH)
- Monoclonal gammopathy and myeloma (types of blood cell disease)
- Secondary hyperparathyroidism (an overactive parathyroid gland, which regulates calcium)
- Chronic hypocalcemia (long-term low calcium levels)
- Lowe syndrome (a rare genetic disorder affecting various body parts)
- Sickle cell disease (a genetic disorder that affects red blood cells)
- Obstructive uropathy (blockage in the urinary tract)
- Fabry disease (a genetic disorder affecting cells’ ability to break down certain fats)
- Metachromatic leukodystrophy (a genetic nervous system disorder)
- Methylmalonic acidemia (a genetic disorder causing a buildup of certain organic acids and toxins)
Doctors need to carefully consider these other possibilities and order appropriate tests to make an accurate diagnosis.
What to expect with Hyperchloremic Acidosis
The outlook for a condition known as hypochloremic metabolic acidosis, which involves a low level of chloride and an increased acidity in the blood, largely depends on what caused the condition in the first place. If doctors can effectively manage the underlying cause, patients usually do quite well.
However, hyperchloremic metabolic acidosis, which is a high level of chloride in the blood leading to increased acidity, can be harmful, particularly to older people or those with existing heart or lung (cardiopulmonary) problems.
Possible Complications When Diagnosed with Hyperchloremic Acidosis
If hyperchloremic acidosis, a condition of high chloride levels in the blood, is not treated adequately, it can lead to a systemic acid-base imbalance known as acidemia. This imbalance can trigger irregular heart rhythms, which could be deadly, and thus increase the risk of death. Additionally, if the blood’s pH drops below 7.2, it can negatively affect the heart’s normal contraction, which could further exacerbate the risk of heart fibrillation, a serious heart rhythm disorder, and heart failure. A quickened breathing pace or tachypnea, often a response to acidosis, can tire out the respiratory muscles if it persists, which could ultimately lead to respiratory arrest if not rectified promptly.
Common Risks:
- High chloride levels in the blood
- Acidemia triggering irregular heart rhythms
- Potential fatality due to disrupted heart rhythm
- A decline in the blood’s pH negatively affecting heart’s contraction
- Increased risk of heart fibrillation and heart failure
- Exhaustion of respiratory muscles due to persistent rapid breathing
- Potential respiratory arrest if not treated quickly
Preventing Hyperchloremic Acidosis
Several medications can worsen or even cause a condition called hyperchloremic metabolic acidosis, which is a type of acid buildup in the body. If any such medications are identified, they should be stopped right away. Depending on the levels of a mineral called potassium in the patient’s blood, the patient may be advised to follow a diet that is either high in potassium or low in potassium. The amount of water the patient should drink also depends on their body’s overall fluid balance. The doctor will guide the patient in adjusting these factors to manage their condition.
