1C Final Study Guide PDF - Newborn and Pediatric Clinical Chemistry

Learning Outcomes - Newborn 1. Define the adaptive changes that occur in the newborn. At birth, newborns undergo rapid adaptation to extrauterine life. Key changes include initiation of respiration due to lung surfactant enabling alveolar expansion and gaseous exchange. Circulatory...

Learning Outcomes - Newborn 1. Define the adaptive changes that occur in the newborn. At birth, newborns undergo rapid adaptation to extrauterine life. Key changes include initiation of respiration due to lung surfactant enabling alveolar expansion and gaseous exchange. Circulatory shifts involve closure of the ductus arteriosus, redirecting blood flow to the lungs for oxygenation. Immature organs, such as the kidneys and liver, gradually develop their full function over the first months of life. 2. Describe the developmental changes that occur throughout childhood. Development includes weight doubling by 4-6 months, renal function maturation over the first year, and liver maturity at 2-3 months. Hematopoiesis transitions from fetal to adult hemoglobin. Rapid bone growth occurs in early years and puberty, with endocrine changes driving sexual maturation and secondary sexual characteristics development. 3. Discuss the problems associated with collecting blood from small children. Challenges include small blood volumes, which limit sample collection, and the increased risk of anemia from frequent draws. Narrow-gauge needles and expertise are required to avoid hemolysis. Capillary samples, though easier to collect, risk contamination by interstitial fluid, leading to altered analyte concentrations. 4. Understand the role of point-of-care testing in pediatric settings. POCT allows rapid bedside results with minimal sample volume, benefiting critical situations. However, its limitations include lower precision compared to laboratory analyzers, higher costs, and potential errors in results for conditions like hypoglycemia. Common pediatric POCT tests include glucose, electrolytes, and hemoglobin. 5. Summarize the changes that occur in children with regard to electrolyte and water balance, endocrine function, liver function, and bone metabolism. ○ Electrolyte and Water Balance: Kidneys regulate salt and water poorly at birth, leading to potential imbalances like hypernatremia or hyponatremia. Total body water decreases from 80% at birth to 60% by one month. ○ Endocrine Function: Endocrine changes support growth and development, including thyroid and adrenal axis maturity. Disorders like congenital hypothyroidism require early intervention. ○ Liver Function: Immature bilirubin metabolism leads to neonatal jaundice, often treated with phototherapy. Liver enzymes and metabolic markers help diagnose conditions like galactosemia.  ○ Bone Metabolism: Vitamin D deficiency risks rickets; calcium and phosphorus levels are tightly regulated. Periods of rapid growth heighten these demands. 6. Explain how drug treatment and pharmacokinetics differ between children and adults. Differences stem from variations in absorption, metabolism, and clearance. Neonates have slower liver enzyme activity and immature renal function, altering drug clearance rates. Dosing often relies on weight or surface area adjustments. 7. State the procedures and test methods used to diagnose inherited metabolic diseases. ○ Newborn Screening: Tests like tandem mass spectrometry detect metabolic disorders (e.g., phenylketonuria, galactosemia). ○ Urine Reducing Substances: Identifies sugars like galactose in urine for diagnosing galactosemia. ○ Enzyme Assays and Genetic Tests: Confirm enzyme deficiencies and mutations. 8. Correlate laboratory results to pediatric disorders of the immune system. Immune system immaturity at birth results in vulnerability to infections. Disorders include immunodeficiencies like severe combined immunodeficiency (SCID), diagnosed via lymphocyte counts or specific antigen testing. 9. Interpret laboratory test results associated with genetic diseases in pediatric patients. ○ Cystic Fibrosis: Diagnosed with sweat chloride tests and CFTR gene mutation analysis. ○ Galactosemia: Identified by elevated galactose levels in blood or urine. ○ Inborn Errors of Metabolism: Detected through abnormal metabolites in blood or urine. 10. Apply knowledge of clinical chemistry to answer chapter case study questions. Example: For a child presenting with lethargy and weight loss, elevated glucose levels and symptoms point to diabetes mellitus. Lab tests like fasting glucose and HbA1c confirm the diagnosis. Exam: Newborn and Pediatric Clinical Chemistry Instructions: The exam consists of 30 questions, including multiple choice, fill-in-the-blanks, true/false, and case study questions. Answer all questions to the best of your knowledge. Multiple Choice Questions (Choose the best answer for each question.) 1. What is the primary cause of respiratory distress in premature infants? A. Liver immaturity B. Kidney immaturity C. Lack of lung surfactant D. Low birth weight 2. Which organ takes 2-3 months to mature in neonates, significantly impacting bilirubin metabolism? A. Kidney B. Liver C. Heart D. Lungs 3. What is a common method for measuring glucose in pediatric settings? A. ELISA B. Point-of-care testing (POCT) C. Gas chromatography D. Immunoassay 4. Which of the following is a true liver function test? A. ALT B. AST C. Serum albumin D. ALP 5. What is the most significant risk associated with hypernatremia in neonates? A. Diarrhea B. Seizures C. Respiratory distress D. Hepatomegaly 6. What is the primary metabolic disease identified by a newborn screening test? A. Cystic fibrosis B. Diabetes mellitus C. Galactosemia D. Hypercalcemia  7. What is the recommended daily dose of vitamin D for infants to prevent rickets? A. 200 IU B. 400 IU C. 600 IU D. 800 IU 8. Which of the following immune cells are primarily responsible for producing antibodies? A. T cells B. B cells C. Natural killer cells D. Phagocytes 9. What is the primary characteristic of Crigler-Najjar syndrome? A. Hyperbilirubinemia due to hemolysis B. Absence of bilirubin-conjugating enzyme C. Excessive bilirubin excretion in urine D. Impaired albumin synthesis 10. Which sample collection method is often used when venipuncture is difficult in neonates? A. Arterial puncture B. Capillary sample C. Finger stick D. Heel stick Fill in the Blanks 11. The transition from fetal hemoglobin to adult hemoglobin often results in increased _________ in neonates. 12. _________ is a method used to quickly diagnose inborn errors of metabolism by analyzing a small blood sample. 13. In pediatric phlebotomy, the maximum allowable blood draw volume for a term infant per day is _________% of their total blood volume. 14. The _________ system in the hypothalamus controls the secretion of growth hormones and regulates sexual maturation.  15. The failure of neonates to properly metabolize bilirubin often leads to _________ jaundice. True/False 16. Newborns can maintain their blood glucose levels even with a blood glucose concentration below 30 mg/dL. (True/False) 17. Capillary samples collected from neonates are less prone to hemolysis compared to venous samples. (True/False) 18. Cystic fibrosis is detected by analyzing the sweat chloride concentration in affected individuals. (True/False) 19. Point-of-care testing is always more accurate than central laboratory testing for pediatric glucose monitoring. (True/False) 20. Pediatric metabolic pathways for drugs are identical to those of adults by 6 months of age. (True/False) Case Study Questions Case 1: Trevor, a 5-year-old male, presents with fatigue, irritability, and weight loss. A random glucose test shows 250 mg/dL. 21. What is the most likely diagnosis for Trevor? 22. Which follow-up test is required to confirm the diagnosis? 23. If confirmed, what is the primary treatment for this condition? Case 2: A 1-month-old infant presents with respiratory infections and steatorrhea. The older sibling has a genetic condition. 24. What is the probable diagnosis? 25. Which test is performed to confirm this condition? 26. What mutation is typically involved in this condition? Case 3: Jody, a newborn, has a positive newborn screen for galactosemia but did not receive treatment for 35 days. 27. What are the potential complications of untreated galactosemia? 28. What immediate dietary adjustment is needed? 29. How is galactosemia screened in newborns? 30. What enzyme deficiency leads to galactosemia? Answer Key Multiple Choice 1. C - Lack of lung surfactant 2. B - Liver 3. B - Point-of-care testing (POCT) 4. C - Serum albumin 5. B - Seizures 6. C - Galactosemia 7. B - 400 IU 8. B - B cells  9. B - Absence of bilirubin-conjugating enzyme 10. D - Heel stick Fill in the Blanks 11. bilirubin 12. Tandem mass spectrometry 13. 2.5% 14. hypothalamic-pituitary-gonadal 15. physiologic True/False 16. True 17. False 18. True 19. False 20. False Case Study Questions 21. Type 1 diabetes mellitus 22. Fasting plasma glucose or HbA1c test 23. Insulin therapy 24. Cystic fibrosis 25. Sweat chloride test 26. CFTR mutation 27. Hepatic failure, renal tubular damage, cataracts 28. Lactose-free diet 29. Urine reducing substance test 30. Galactose-1-phosphate uridyltransferase deficiency