A newborn is diagnosed with PKU. What is the primary treatment?
Fluid restriction
Iron supplementation
High-protein diet
Phenylalanine-restricted diet
The Correct Answer is D
Phenylketonuria (PKU) is an autosomal recessive disorder caused by a deficiency of the hepatic enzyme phenylalanine hydroxylase. This leads to the toxic accumulation of the amino acid phenylalanine, which causes irreversible neurological damage and intellectual disability. Screening occurs via a neonatal heel stick shortly after birth.
A. Fluid restriction: There is no physiological basis for limiting fluid intake in infants with PKU. Adequate hydration is necessary for metabolic stability and renal function. Treatment focuses on the chemical composition of the intake rather than the total volume of fluid consumed.
B. Iron supplementation: While maintaining general nutrition is important, iron does not affect the metabolic pathway of phenylalanine. PKU management is specifically concerned with amino acid metabolism rather than hematological parameters. Iron status is managed independently of a PKU diagnosis.
C. High-protein diet: Standard high-protein foods like meat, dairy, and eggs are extremely high in phenylalanine and are strictly forbidden. Consumption of these foods would lead to a rapid rise in neurotoxic levels of the amino acid. A high-protein diet is contraindicated for these patients.
D. Phenylalanine-restricted diet: The mainstay of therapy is a life-long diet that limits phenylalanine while providing enough tyrosine and other essential nutrients. This involves special medical formulas and low-protein foods to maintain blood levels within the therapeutic range. This prevents cognitive impairment.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
The Apgar score is a rapid assessment tool used to evaluate the newborn's extrauterine transition and physical condition immediately after birth. It measures five parameters: heart rate, respiratory effort, muscle tone, reflex irritability, and color. Scores are used to determine the need for resuscitative efforts in the delivery room.
A. Immediately only: A single score at birth does not reflect the infant's response to initial stabilization or spontaneous recovery. The transition process is dynamic and requires sequential monitoring to identify trends in neonatal vigor. A one-minute-only assessment is clinically insufficient.
B. At 10 minutes only: Waiting 10 minutes to perform the first assessment would delay critical life-saving interventions for an infant in respiratory or cardiac arrest. The initial minutes are the most vulnerable period for a newborn. Clinical assessment must begin within sixty seconds of birth.
C. After feeding: Apgar scoring is an emergency assessment of vital functions and is completely unrelated to the infant’s nutritional intake. Feeding occurs much later after the infant has been deemed stable. The score is a measure of physiological survival, not digestive capability.
D. At 1 and 5 minutes: The one-minute score assesses how the infant tolerated the birthing process, while the five-minute score evaluates their success in adapting to the environment. If the five-minute score is less than 7, assessments continue every five minutes for up to 20 minutes. This is the standard clinical timing.
Correct Answer is B
Explanation
Metformin is a biguanide that improves insulin sensitivity in peripheral tissues and inhibits hepatic gluconeogenesis. In PCOS, hyperinsulinemia stimulates the theca cells to produce excess androgens, leading to hirsutism and anovulation. Reducing insulin levels helps restore the normal hormonal balance required for follicle maturation.
A. Block ovulation: Metformin is actually used to induce or restore regular ovulation in PCOS patients by correcting the underlying metabolic dysfunction. It is not a contraceptive and does not suppress the pituitary-gonadal axis. Improved insulin levels allow the body to resume a normal ovulatory menstrual cycle.
B. Decrease insulin resistance: By enhancing the action of insulin at the cellular level, metformin lowers circulating insulin concentrations. This reduction decreases the stimulus for ovarian androgen production, which is the primary driver of PCOS symptoms. It addresses the metabolic root cause of the syndrome, improving systemic health.
C. Reduce estrogen levels: PCOS is often characterized by "unopposed estrogen" due to a lack of progesterone from anovulation. Metformin's primary role is not the direct reduction of estrogen, but rather the management of insulin signaling. Restoring ovulation through metformin use will eventually lead to healthier progesterone-estrogen ratios.
D. Stimulate LH surge: Metformin does not directly act on the anterior pituitary to trigger a luteinizing hormone surge. Instead, it creates an internal environment where the dominant follicle can develop naturally. The LH surge eventually occurs as a secondary result of restored follicular health and proper estrogen feedback.
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