An elderly patient has been having copious vomiting for several days and has become lethargic and weak. His mucous membranes are dry. He has poor skin turgor. Lab work shows: sodium of 145, ABGs: pH 7.58, PCO2 38, HCO3 38, PO2 95, SO2 98. Which response best explains the patient’s lethargy and weakness?
The hypokalemia brought on severe muscle spasms, causing exhaustion.
Due to his low potassium, his cells rely on glycolysis.
Due to the hypokalemia, his cells are hyperpolarized.
The hypernatremia caused cellular dehydration, leading to lethargy.
The Correct Answer is D
Choice A rationale
Hypokalemia can cause muscle weakness and cramps, but it does not typically lead to severe muscle spasms causing exhaustion. The patient’s symptoms of lethargy and weakness are more likely related to electrolyte imbalances and dehydration rather than muscle spasms.
Choice B rationale
While low potassium levels can affect cellular metabolism, the primary issue here is not glycolysis. The patient’s symptoms are more consistent with dehydration and electrolyte imbalances rather than a metabolic shift to glycolysis.
Choice C rationale
Hypokalemia can cause cells to become hyperpolarized, leading to muscle weakness and decreased reflexes. However, the patient’s symptoms of lethargy and weakness are more likely due to dehydration and electrolyte imbalances rather than cellular hyperpolarization.
Choice D rationale
Hypernatremia, or high sodium levels, can cause cellular dehydration, leading to symptoms such as lethargy and weakness. The patient’s lab results and clinical presentation are consistent with hypernatremia-induced cellular dehydration, which explains his symptoms.
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View Related questions
Correct Answer is A
Explanation
Choice A rationale
Elevated blood ammonia levels are a common consequence of liver dysfunction, particularly in conditions like cirrhosis and alcoholic liver disease. The liver is responsible for converting ammonia, a byproduct of protein metabolism, into urea, which is then excreted by the kidneys. When the liver is damaged, it cannot effectively perform this function, leading to elevated blood ammonia levels. High ammonia levels can cross the blood-brain barrier and cause hepatic encephalopathy, which manifests as confusion, memory loss, and asterixis (a flapping tremor of the hands). These neurological symptoms are consistent with the patient’s presentation.
Choice B rationale
An increased white blood cell count typically indicates an infection or inflammation. While infections can occur in patients with liver disease due to a compromised immune system, the symptoms described (increased blood glucose, blurred vision, memory loss, and asterixis) are more indicative of hepatic encephalopathy rather than an infection.
Choice C rationale
Elevated blood urea nitrogen (BUN) levels can occur in liver disease, but they are more commonly associated with kidney dysfunction. BUN is a measure of the amount of nitrogen in the blood that comes from the waste product urea. While liver dysfunction can affect BUN levels, the symptoms described are more specifically related to elevated ammonia levels and hepatic encephalopathy.
Choice D rationale
A decreased platelet count, or thrombocytopenia, is a common finding in liver disease due to splenic sequestration and decreased production of thrombopoietin. However, thrombocytopenia does not directly cause the neurological symptoms described in the patient. The symptoms of increased blood glucose, blurred vision, memory loss, and asterixis are more specifically related to elevated ammonia levels and hepatic encephalopathy.
Correct Answer is C
Explanation
Choice A rationale
Hyperkalemia can cause weakness and fatigue, but it is not directly related to acute coronary syndrome (ACS). ACS is primarily associated with chest pain and other cardiac symptoms.
Choice B rationale
Experiencing chest pain when climbing a flight of stairs may indicate stable angina, which is a form of chronic coronary artery disease. However, it does not meet the criteria for ACS, which involves more severe and persistent symptoms.
Choice C rationale
Persistent and severe chest pain when at rest is a hallmark symptom of acute coronary syndrome (ACS). This condition requires immediate medical attention as it can lead to myocardial infarction (heart attack) or other serious complications.
Choice D rationale
Paroxysmal nocturnal dyspnea (PND) is a symptom of heart failure, not acute coronary syndrome (ACS). While heart failure can coexist with ACS, PND alone does not indicate ACS4.