A 54 year old male presents to the ER with hematemesis (vomiting blood, abdominal distention, confusion and jaundice. Cirrhosis of the liver is diagnosed.
Question: What is the pathophysiology of hepatic encephalopathy and the resultant confusion?
hyperbilirubinemia and jaundice
fluid and electrolyte imbalances
impaired ammonia metabolism
decreased cerebral blood flow
The Correct Answer is C
A. Hyperbilirubinemia and jaundice: Hyperbilirubinemia causes yellowing of the skin and sclera (jaundice). In adults, high levels of bilirubin can cause significant itching (pruritus), but they do not typically cross the blood-brain barrier to cause the acute confusion and neuropsychiatric symptoms seen in hepatic encephalopathy.
B. Fluid and electrolyte imbalances: Fluid and electrolyte disturbances, such as hyponatremia or hypokalemia, can contribute to altered mental status, but they are secondary factors. They may exacerbate confusion but do not explain the core pathophysiology of hepatic encephalopathy.
C. Impaired ammonia metabolism: Liver dysfunction impairs the conversion of ammonia into urea, leading to hyperammonemia. Elevated ammonia crosses the blood-brain barrier and disrupts neurotransmission, resulting in cerebral edema and altered mental status, which manifests as confusion and other neuropsychiatric symptoms.
D. Decreased cerebral blood flow: Cerebral blood flow is typically maintained in hepatic encephalopathy. The confusion is primarily due to neurotoxicity from accumulated substances like ammonia, rather than reduced blood flow. Decreased cerebral perfusion is not the main mechanism.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
A. Hemoptysis: Hemoptysis can occur with bronchogenic cancer but is more commonly a later finding as the tumor erodes into blood vessels. It often indicates more advanced local disease. It is not typically one of the earliest manifestations.
B. Chronic cough: A persistent or worsening cough is one of the earliest and most common signs of bronchogenic cancer. Tumor irritation of the airway stimulates cough receptors before significant obstruction or invasion occurs. This symptom often precedes more severe respiratory findings.
C. Pain on inspiration: Pleuritic chest pain usually develops when the tumor involves the pleura or chest wall. This reflects more advanced disease rather than early cancer. Pain on inspiration is not a typical initial manifestation.
D. Air trapping and over inflation of the lung: Air trapping occurs when a tumor significantly obstructs airflow, creating a ball-valve effect. This represents a later structural consequence of tumor growth. It is not usually present in the early stages of bronchogenic cancer.
Correct Answer is D
Explanation
A. Cigarette smoke: Cigarette smoking is the leading risk factor for lung cancer and is strongly associated with multiple histologic types. Tobacco smoke contains numerous carcinogens that cause DNA damage in lung tissue. Risk increases with duration and intensity of exposure.
B. Arsenic: Arsenic exposure, particularly in occupational or environmental settings, has been linked to an increased risk of lung cancer. Chronic inhalation can lead to cellular damage and malignant transformation. It is a well-established environmental carcinogen.
C. Asbestos: Asbestos exposure is strongly associated with lung cancer and mesothelioma, especially when combined with cigarette smoking. Inhaled fibers cause chronic lung irritation and fibrosis, increasing cancer risk. The latency period can be several decades.
D. Viral infection: Viral infections are not recognized as a primary risk factor for lung cancer. While some viruses are associated with other cancers, they do not play a significant role in lung carcinogenesis. Lung cancer risk is mainly related to environmental and occupational exposures.
E. Radioactive dust: Exposure to radioactive dust, such as radon decay products, is a known risk factor for lung cancer. Inhaled radioactive particles emit radiation that damages lung tissue over time. This exposure is a significant risk, especially in poorly ventilated areas.
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