Question

A child is admitted to the hospital unit with a diagnosis of pyloric stenosis, On admission, the nurse would expect to see which electrolyte imbalance? A. Hypokalemia B. Hypernatremia C. Hyperchloremia D. Hypomagnesemia

Short answer

The nurse would expect to see Hypokalemia (A) as the electrolyte imbalance in a child admitted with a diagnosis of pyloric stenosis.

Step-by-step solution

Understanding Pyloric Stenosis

Pyloric stenosis is a condition where the pylorus muscles, which connect the stomach to the small intestine, thicken and obstruct gastric emptying. This can lead to forceful vomiting, which can result in a loss of gastric contents, including hydrochloric acid.

Recognizing the Result of Vomiting on Electrolytes

Frequent vomiting could lead to a loss of gastric acid which is rich in hydrogen and chloride ions. Loss of acidic gastric contents may cause a metabolic alkalosis, which generally presents with hypokalemia and hypochloremia as the body tries to compensate by retaining bicarbonate.

Identifying the Correct Electrolyte Imbalance

Given the typical presentation of pyloric stenosis and the associated vomiting, it would be expected that hypochloremia and/or hypokalemia could occur. Since hypochloremia is not an option, the most likely imbalance would be hypokalemia.

Key concepts

Pyloric Stenosis

Pyloric stenosis is a pediatric condition characterized by the narrowing of the pylorus, the passage that connects the stomach to the duodenum. This narrowing occurs because of the hypertrophy and hyperplasia of the muscular layers of the pylorus, which leads to obstruction and difficulty for food to pass from the stomach to the small intestine.

Typical symptoms include projectile vomiting in infants, which usually occurs following feeding, and can lead to weight loss and dehydration. This forceful vomiting is due to the stomach muscles contracting against the narrowing pylorus. As a result, infants with pyloric stenosis may seem hungry frequently and may show signs of distress related to feeding.

Diagnosis of pyloric stenosis is often achieved with the use of ultrasound imaging, where the thickened pyloric muscle is visualized. A physical exam may also reveal a palpable 'olive-like' mass in the right upper quadrant of the infant's abdomen. It's essential for healthcare providers to be aware of these signs and symptoms for prompt diagnosis and treatment, which typically involves surgical intervention known as pyloromyotomy.

Electrolyte Imbalance

Electrolyte imbalance refers to the disruption in the levels of electrolytes in the body, which are minerals that help regulate a range of physiological functions. Key electrolytes include sodium, potassium, chloride, calcium, and magnesium. These minerals are critical for maintaining fluid balance, muscle contractions, and neural activity.

When it comes to vomiting, such as in cases of pyloric stenosis, there is often a loss of stomach acids, which are high in hydrogen and chloride ions. This loss can lead to an imbalance in the body's electrolytes, particularly chloride and potassium, resulting in conditions such as hypochloremia and hypokalemia.

Hypokalemia, or low potassium levels, can cause muscle weakness, cramping, and fatigue, and severe cases may affect the heart function. Hypochloremia, or low chloride levels, often occurs together with hypokalemia, and can complicate alkalosis. It is important for nursing and medical staff to monitor the electrolyte levels in patients with conditions that cause frequent vomiting to avoid severe complications.

Metabolic Alkalosis

Metabolic alkalosis is a condition characterized by a higher than normal pH level in the body's tissues due to the accumulation of bicarbonate or a loss of hydrogen ions. One of the primary drivers of metabolic alkalosis is the prolonged vomiting of gastric contents, which include hydrochloric acid (HCl).

When the body loses too much hydrochloric acid, it results in a decrease in the level of acidity in the blood, tipping the balance towards alkalinity. The kidneys compensate by increasing the retention of bicarbonate ions, a base, and the loss of hydrogen and chloride ions, leading to the symptoms of alkalosis. These may include confusion, muscle twitching, hand tremor, light-headedness, nausea, and vomiting.

To treat metabolic alkalosis, the underlying cause must be addressed. In the case of pyloric stenosis, this would involve correcting the electrolyte imbalances, rehydrating the patient, and eventually surgery to correct the obstruction. Monitoring the patient's blood gas levels and electrolytes helps guide the treatment and ensure the successful management of the condition.