Hyperchloremic Acidosis: Causes, Symptoms, Diagnosis, and Treatment

Introduction:

The human body maintains an acid-base balance to help maintain equilibrium. The term pH (potential of hydrogen) refers to whether a substance is acidic, alkaline, or neutral. pH is measured on a scale from 0 to 14. For example, a pH between 0 and 7 is acidic, whereas a pH between 7 and 14 is considered alkaline. The average blood pH is between 7.35 and 7.45. The lungs and kidneys maintain this range. Any disease or condition can alter the pH levels to below or above normal states, altering the acid-base balance in the body, which, when left untreated, can be fatal.

How Is pH Maintained in the Body?

The lungs and kidneys play a pivotal role in maintaining the acid-base balance. Bicarbonate (HCO3) and carbon dioxide (CO2) are essential elements that help maintain chemical equilibrium. HCO3 is alkaline, whereas CO2 is acidic. Therefore, when HCO3 levels rise, or CO2 levels fall, it makes the blood more alkaline, whereas a fall in HCO3 levels or an increase in CO2 levels makes the blood more acidic. The levels of CO2 are regulated by the lungs, whereas the kidneys regulate the HCO3 levels. The lungs decrease CO2 when acid levels rise, increasing the speed of respiration (hyperventilation), thereby pushing CO2 out of the body. Similarly, kidneys prevent bicarbonate excretion by reabsorbing it more in the urine and returning it to the body.

What Are Acid-Base Disorders of the Body?

Acid-base disorders are of two types, namely:

• Respiratory Acid-Base Disorders: Lung diseases or breathing disorders that affect respiration cause changes in the pH by altering the CO2 concentration, leading to respiratory acidosis (low pH) and respiratory alkalosis (high pH).

• Metabolic Acid-Base Disorders: Kidney diseases, severe vomiting, and diarrhea, metabolic diseases like diabetes, electrolyte imbalances, or ingestion of specific drugs or toxins can affect metabolism, causing pH changes. This state of the body can cause metabolic acidosis (low pH) or metabolic alkalosis (high pH).

How Does the Body Compensate for a State of Acidosis or Alkalosis?

When the body goes into respiratory acidosis, it compensates by the opposite mechanism in which it attempts metabolic alkalosis to bring back the equilibrium. Similarly, when the body experiences respiratory alkalosis, it attempts to compensate by metabolic acidosis.

What Is Hyperchloremic Acidosis?

Hyperchloremic acidosis is when the body has high levels of chloride ions due to loss of bicarbonate from the body, which occurs in conditions like severe diarrhea. It is a disease state that occurs in response to a loss of bicarbonate rather than increased acid production or build-up. Bicarbonate loss causes a shift of chloride ions from the cells into the bloodstream, causing hyperchloremia.

What Are the Causes of Hyperchloremic Acidosis?

Hyperchloremic acidosis occurs due to a variety of reasons, like:

• Gastrointestinal (GI) Reasons: Loss of bicarbonate can occur due to medical conditions that affect the digestive system, like severe diarrhea, long-term use of laxatives or stool softeners, and pancreatic fistula (an abnormal connection between the pancreas and other organs).

• Renal Reasons: Kidney-related reasons for bicarbonate loss include acidosis of tubules in the kidney or chronic use of carbonic anhydrase inhibitors (used for management of glaucoma of the eye and other conditions).

• Exogenous Reasons: Supplements like ammonium chloride and hydrochloric acid combine with bicarbonate in the body to maintain a neutral pH, thereby depleting the bicarbonate stores in the body, ultimately causing acidosis.

What Are the Symptoms of Hyperchloremic Acidosis?

People affected with hyperchloremic acidosis do not have any symptoms due to the condition but rather show signs related to the cause. However, the condition causes an increase in the breathing rate to expel CO2, which is the opposite mechanism for bringing back the acid-base balance. However, in long-standing cases, it causes weakness of lung muscles and respiratory failure.

The signs and symptoms noticed in people with hyperchloremic acidosis include:

• Headache.

• Nausea and vomiting.

• Confusion.

• Fatigue.

• Increased heart rate.

• Rapid breathing.

• Stupor (altered level of consciousness).

• Muscle weakness.

• Cardiac murmurs (sounds produced when blood pumps through the heart valves).

• Cardiac arrhythmias (irregular heartbeat).

• Wheezing (a whistling or rattling sound heard during breathing).

• Rales (abnormal sounds heard while examining unhealthy lungs).

• Ronchi (low-pitched lung sounds due to accumulation of fluid or mucus in the respiratory system).

What Are the Complications of Hyperchloremic Acidosis?

Untreated cases of acidosis can cause the pH levels to drop below 7.2, causing life-threatening complications affecting heart contractions and leading to heart failure. Also, rapid breathing, which occurs as a compensatory mechanism, can cause weakness of the respiratory muscles, leading to respiratory arrest.

How Is Hyperchloremic Acidosis Diagnosed?

The doctors first conduct a physical examination and note the signs and symptoms. Then, they may further order specific diagnostic tests to confirm the condition, which includes:

• Arterial Blood Gas Analysis: Arterial blood gas is measured to determine the blood's pH and know if the cause of acidosis is due to a metabolic condition.

• Electrolyte Testing: The levels of electrolytes are determined using basic metabolic panel testing. The test helps confirm the acidic state in the body and also helps assess whether it is respiratory or metabolic acidosis. Besides testing for bicarbonate levels, sodium, potassium, and chloride levels are also checked during the electrolyte testing.

• Complete Blood Count (CBC): A CBC helps determine whether acidosis is due to an infection in the body, known by a rise in the WBC (white blood cell) count.

• Urine Anion Gap: It is a test used to measure the amount of ammonium excreted in the urine, which is an essential measurement in hyperchloremic acidosis patients.

• Additional Tests: Imaging tests like X-rays and CT (computerized tomography) may be required in a few cases to determine the cause of acidosis.

How Is Hyperchloremic Acidosis Managed?

Treatment of hyperchloremic acidosis aims at identifying and treating the cause. In cases of respiratory failure, a ventilator, a device that supports breathing by pumping air into the lungs, is used. Rapid breathing, along with ventilator support, can help reverse metabolic acidosis.

GI (gastrointestinal) reasons, administering the patients with IV (intravenous) saline and necessary electrolytes helps replenish the fluid lost due to severe diarrhea. Bicarbonate is also given in moderate amounts to neutralize the acidic state. Renal causes require more significant amounts of bicarbonate and diuretics to restore a balanced state. However, dialysis may be the preferred option when acidosis does not respond. Medicines that cause hyperchloremic acidosis must be identified, stopped, or used with caution to manage acidosis.

Conclusion:

Hyperchloremic acidosis is when the body turns acidic due to the loss of bicarbonate and increased chloride levels in the bloodstream. When left untreated, it can cause complications like heart and respiratory failure. Identifying the cause of the condition and treating it can help reduce the impact of acidosis on the body. A healthcare team consisting of doctors has to work as a unit to reduce patient mortality.