Renal and Neurologic function

Exam Review

• Reviewing Incorrect Answers: Schedule an appointment to review exam questions, including incorrect answers, questions of concern, and correctly answered questions lacking full comprehension.
• Exam Scores: Scores released after everyone has completed the exam to address potential coding issues.
• Exam Format:
  • 50 questions total.
  • 50 minutes total (1 minute per question).
  • Accommodations provided with proper documentation.
  • No backtracking allowed to mimic licensing exams.
  • Primarily single-response questions with a few fill-in-the-blanks.

Genetic Disorders

• Symptoms of Genetic Disorders: Expected to link symptoms to genetic changes.
  • Example: Marfan Syndrome: Recognize genetic changes based on symptoms like hyperflexibility and pectus excavatum. *Tay-Sachs Disease:
    • Presentation: Unremarkable pregnancy followed by decreased milestones and potential seizures in infancy.
    • Risk Factors: Higher risk in couples of the same ethnicity, particularly Ashkenazi Jewish descent.

Proctoring and Study Guide

• Proctoring Software: Use LockDown Browser without requiring additional downloads.
• Study Guide: A study guide will be provided, and students can ask questions about it.

Contact Information and Availability

• Contact: Available via Zoom or email for questions or review.
• Review Sessions: Email to schedule review sessions.

Acid-Base Regulation

• Respiratory System: Manages pH by altering breathing rate and depth, affecting CO_2 excretion or retention.
  • Decreased respiratory rate: Increased CO_2 and acidity.
  • Quick response but brief effect.
• Renal System: Regulates pH by excreting or retaining hydrogen or bicarbonate in urine.
  • More effective due to permanent removal of hydrogen.
  • Slower response but longer-lasting effect.
• Normal Values:
  • pH: 7.35 - 7.45
  • PaO_2: 95 - 100
  • PaCO_2: 35 - 45
  • Bicarbonate (HCO_3): 22 - 26

Blood Gas Analysis Examples

• pH 7.25, CO2 56, PaO2 99, Bicarbonate 24: Respiratory acidosis, uncompensated.
• pH 7.54, CO2 24, PaO2 98, Bicarbonate 23: Respiratory alkalosis, uncompensated.
• pH 7.36, CO2 54, PaO2 95, Bicarbonate 29: Compensated respiratory acidosis (pH normal).
• pH 7.31, CO2 56, PaO2 99, Bicarbonate 28: Partially compensated respiratory acidosis (pH still acidotic).

Electrolytes

• Sodium (Na): Most abundant cation in extracellular fluid; controls osmolality and water balance.
  • Normal Range: 135 - 145 mEq/L
  • Hypernatremia: Excessive sodium; caused by iatrogenic factors, Cushing's syndrome, deficient water intake, etc.
  • Hyponatremia: Insufficient sodium; caused by diuretic use, GI losses, excessive water intake, liver failure, etc.
• Potassium (K): Primary intracellular cation; critical for electrical conduction, acid-base balance, and metabolism.
  • Normal Range: 3.5 - 5.5 mEq/L
  • Hyperkalemia: Excessive potassium; caused by deficient excretion (renal failure), certain medications, or increased release from cells (acidosis, blood transfusions).
    • Management: Diuretics (for responsive patients), calcium (to stabilize myocardium), insulin and dextrose (to shift K+ into cells), K+ oxalate (to eliminate K+ via GI tract), renal replacement therapy (for life-threatening cases).
    • Indications for Dialysis: Life-threatening hyperkalemia, hyperammonemia, severe metabolic acidosis, significant fluid overload.
  • Hypokalemia: Insufficient potassium; caused by excessive losses (vomiting, diarrhea, diuretics) or increased shifts into cells (alkalosis, excess insulin).
• Calcium (Ca): Important for various physiological processes.
  • Hypercalcemia: Excessive calcium; caused by antacids, supplements, cancer (bone breakdown), or deficient excretion (renal failure).
  • Hypocalcemia: Insufficient calcium; can lead to neonatal seizures.
    • Etiologies: Hypoparathyroidism, alkalosis, pancreatitis, certain medications.

Fluid Balance

• Intracellular Fluid: Fluid inside cells.
• Intravascular Fluid: Fluid in the vascular system.
• Extravascular Fluid: Fluid outside the vascular system (e.g., ascites).
  • Management of Hypotensive, Fluid-Overloaded Patients:
    • Administer albumin or FFP to increase intravascular oncotic pressure.
    • Use diuretics judiciously.
    • Consider the risk of capillary leak in septic patients when administering albumin.

Fluid Abnormalities

• Fluid Excess: Caused by excessive intake or retention; increased ADH increases water reabsorption.
  *Monitoring: Weights (most accurate), INO (intake and output).
• Fluid Deficit: Caused by excessive loss.
  • Manifestations: Weight loss, dizziness.

IV Fluid Solutions

• Isotonic: Same osmolality as intravascular compartment (e.g., normal saline, lactated Ringer's).
• Hypotonic: Lower osmolality; causes fluid shift from intravascular to intracellular/interstitial (e.g., half-normal saline).
• Hypertonic: Higher osmolality; pulls fluid from the interstitial to the vascular space (e.g., D5 normal saline, 3% saline, mannitol).

Edema

• Definition: Result of hydrostatic pressure on the venous side of the capillary, causing fluid movement into the interstitial space.
• Causes:
  • Lack of movement
  • Heart failure
  • Dependent edema
  • Deep vein thrombosis (DVT): Typically unilateral, increases hydrostatic pressure.
• Management:
  • Diuretics
  • Mobilization
  • Compression stockings

Renal System Anatomy and Function

• Components: Kidneys, ureters, bladder, urethra.
• Nephron: Functional unit of the kidney; filters substances; glomerulus filters blood.
• Glomerular Filtration Rate (GFR): Best indicator of renal function.
• Kidney Functions:
  • Regulate urine and fluid volume.
  • Regulate blood pressure (RAS system, ADH).
  • Excrete metabolic waste.
  • Conserve nutrients.
  • Excrete drugs.
  • Convert vitamin D.
  • Maintain pH balance.
  • Synthesize hormones (renin, erythropoietin).
• Kidneys and Hypertension: Kidneys play a significant role in blood pressure regulation.
• Drug Excretion: Adjust medication dosages based on GFR or creatinine clearance to avoid unintended consequences.

Urinalysis (UA)

• Components: pH, specific gravity, urine sedimentation, red blood cells, crystals, casts.
• Casts:
  • Red Cell Casts: Indicate renal tubule bleeding or red cells escaping through the glomerulus (associated with AKI, ATN).
  • White Cell Casts: Indicate an inflammatory process.
  • Epithelial Casts: Indicate degeneration or necrosis of renal tubules.
• UTI and Pyelonephritis:
  • Cystitis: Inflammation of the bladder and urethra, often bacterial.
  • Pyelonephritis: Infection ascends to one or both kidneys, causing edema and potential abscesses or necrosis.
    • Symptoms: Fever and a lot more systemic signs and symptoms. Can also compress the renal artery with resulting ischemia and infarction.