Lithium Carbonate Toxicity: Causes, Symptoms, and Treatment

Introduction:

The lithium-ion used as a medication belongs to the monovalent cation family that was approved in 1970 by the United States Food and Drug Administration as medication to stabilize moods. Although the mechanism of the drug acts is unknown, it is still a potent drug that shows potential effects on mania with a very low dosage index. It stabilizes the mood and is commonly preferred for treating bipolar disorder.

How Does Lithium Carbonate Work?

The exact effect of lithium and its mechanism in the body is unknown, but some of the actions that are believed to be a hypothesis are the following effects:

• It causes the depletion of brain cortisol (the primary stress-releasing hormone in the brain), resulting in a lack of responsiveness to alpha-adrenergic stimulation.

• By reducing the responsiveness of the neurons to the neurotransmitters as it acts on adenylate cyclase and G protein, causing an inhibitor effect that prevents the opening of the ionic channels.

• Stimulates the release of serotonin from the hippocampus of the brain.

• Shows similar effects on sodium and potassium, affecting the cell membrane potential and ion transport.

What Causes Lithium Carbonate Toxicity?

Lithium carbonate toxicity occurs when there is an excessive intake of this drug. The factors that increase lithium intake in the body are:

• Increased intake of lithium carbonate.

• Decreased or impaired excretion of lithium from the body.

How Common Is Lithium Carbonate Toxicity?

According to a study conducted between the years 1997 to 2013, the patients showing recurrence of lithium intoxication along with changes in the kidney were assessed. The study showed that almost 96 out of 1340 cases showed greater levels of lithium, more than 1.5 mmol/l (micro molecular liter/liter). A handful of patients experienced recurrent episodes, in which 34 percent of cases were admitted to intensive care units (ICU), and 13 % needed kidney dialysis for renal filtration. However, the death rates were very low.

How Does Excessive Lithium Carbonate Toxicity Occur?

Lithium toxicity can occur due to two reasons: excessive medication intake or lack of excretion of the drugs. The excessive intake occurs due to:

• It occurs commonly as an attempt to commit suicide or accidental intake, which results in acute or acute to chronic overdose conditions. One of the other reasons includes increasing the lithium dosage by patients over time.

• The impairment in the excretion of lithium: multiple reasons prevent the excretion of lithium from the system, and they include:

1. The excretion of lithium was affected by various systemic reasons like vomiting, fever, diarrhea, less water intake, low sodium diet, congestive heart failure, etc., which causes sodium depletion in the body resulting in lithium reabsorption.

2. Drugs that reduce the kidney's filtering capacity as prolonged lithium intake can induce a condition called nephrogenic diabetes that increases the signs and symptoms of lithium toxicity.

Lithium carbonate toxicity can be classified into three different types, and they are:

• Acute overdose.

• Acute overdose of patients under chronic therapy.

• Chronic overdose.

How Was Lithium Carbonate Administered Clinically?

Lithium carbonate as a drug was administered in the 1800s as lithia, a water-based solution for treating maniac and gout disorders, which later was administered as tablets; on the administration of these medications, clinical signs of tremors and weaknesses were becoming evident by the end of 1898, which eventually led to the first case of lithium poisoning.

What Are the Clinical Signs of Lithium Carbonate Poisoning?

Clinically lithium poisoning results in the following side effects affecting the organs, and they are:

• Effect on the Nervous System: The symptoms of toxification in the nervous system include shivers, rapid involuntary eye movements, hyperreactive body language, and ataxia that causes a lack of coordination in speech, balance, etc. Patients also show symptoms of confusion and delirium. Although these symptoms are nearly reversible, the symptoms existing over more than a year never tend to resolve.

• Kidney Toxicity: These symptoms of toxicity affecting the kidneys are the most common aftermath of lithium carbonate poisoning, which affects the concentration of urine, drug-induced diabetes insipidus of the kidney, nephrotic syndrome, and sodium-losing nephritis.

• Effect on the Heart: The symptoms on the heart are very mild and not particularly specific, but almost every patient administered lithium showed a flattening of the T wave. The other symptoms include dysfunction of the sinus node, long QT wave, and defects in conduction between two ventricles and U wave. However, these symptoms can be reversed at the cessation of the medication.

• Effect on the Digestive System: The symptoms in the gastrointestinal tract occur within one hour from the intake of the drug and are often seen as a symptom of an acute drug overdose.

• Effect on the Hormones: The administration of lithium affects the thyroid gland causing a gradual reduction in the production and eventually slowing down the release of thyroid hormones resulting in hypothyroidism. Cases of hyperthyroidism are also seen to be associated with lithium toxicity.

How Is Lithium Carbonate Poisoning Evaluated?

Patients with lithium toxicity are monitored closely for cardiac output through an electrocardiogram, assessing the oxygen levels and monitoring the renal output. In addition, blood tests are done to study blood glucose, serum lithium levels, and thyroid-stimulating hormones. The normal serum lithium level is around 0.6 to 1.2 meq/lit (micro equivalent per liter).

How Is Lithium Carbonate Poisoning Treated?

Lithium carbonate poisoning can be treated in three ways, and they are:

• Decontamination: It is the first step of treatment and is done by administering activated charcoal. However, activated charcoal and lithium do not effectively bond, and charcoal helps eliminate the other substances ingested with lithium. Oral administration is preferred as gastric lavage and is the most preferred treatment choice.

• Elimination: The most indicated method of removal of lithium in blood is through hemodialysis, mainly in patients with renal failure. Although stomach lavage is considered, it should never replace renal dialysis.

• Disposition: All patients with lithium poisoning should be admitted and monitored despite the results showing normal serum levels.

1. Patients are indicated for admission in the intensive care unit at the development of moderate to severe symptoms.

2. The serum level of lithium is monitored every six hours.

3. The patient should not be allowed to be discharged unless the serum level shows less than 1.5mEq/l (milliequivalent/liter).

What Are the Conditions Similar to Lithium Toxicity?

The conditions that appear similar to lithium toxicity are:

• Sharp fall in blood sugar levels.

• Alcohol toxicity.

• Dementia - frequent loss of memory.

• Depression.

• Other toxicities like heavy metals, mercury, and neuroleptic drugs.

• Stroke.

• Ischemia (a clinical condition characterized by loss of blood supply to the body or a particular organ due to obstruction of blood vessels).

• Delirium (a state of uncoordinated mind with confused thinking).

Conclusion:

Lithium chloride toxicity is a clinical condition that affects all body organs, resulting in symptoms ranging from mild to severe conditions like nausea, vomiting, tremors, fatigue, lethargy, confusion, tachycardia, delirium, agitation up to coma, hypotension, seizure, hyperthermia. However, when treated with obvious evidence of symptoms, lithium toxicity can be prevented from fatality. Lithium carbonate toxicity can be reversed by administering the patient serotonergic drugs and following all the treatment guidelines.