From the Research
The correct answer is A. Hypokalaemia. In gastric outlet obstruction, persistent vomiting leads to significant loss of gastric contents, which are rich in hydrochloric acid. This results in metabolic alkalosis due to the loss of hydrogen ions. As the body attempts to compensate for this alkalosis, the kidneys excrete potassium ions in exchange for hydrogen ions to maintain electrical neutrality, leading to hypokalaemia. Additionally, the direct loss of potassium in vomitus contributes to the potassium depletion. Patients typically present with a hypochloremic, hypokalemic metabolic alkalosis, often called a "contraction alkalosis" because the loss of fluid volume concentrates the remaining bicarbonate. This electrolyte disturbance can cause muscle weakness, cardiac arrhythmias, and other symptoms if severe.
Key Points
- The most common electrolyte disturbance in gastric outlet obstruction is hypokalaemia, as seen in the study by 1.
- Metabolic alkalosis is a result of the loss of hydrogen ions from the stomach, leading to an increase in bicarbonate levels.
- Treatment involves correcting the underlying obstruction, rehydration with normal saline to correct the volume depletion and chloride deficit, and potassium replacement, as discussed in the study by 2.
- It is essential to address the underlying cause of the gastric outlet obstruction, whether it be malignant or benign, to prevent further complications and improve patient outcomes, as highlighted in the study by 3.
- The study by 4 also supports the idea that gastric outlet obstruction can have various causes, and it is crucial to identify the underlying cause to provide appropriate treatment.
Management
- Correcting the underlying obstruction is crucial in managing gastric outlet obstruction.
- Rehydration with normal saline and potassium replacement can help alleviate symptoms and prevent further complications.
- In some cases, endoscopic or surgical intervention may be necessary to relieve the obstruction, as discussed in the study by 5.