I’m working on a health & medical multi-part question and need the explanation and answer to help me learn.
1. Kidney stones occur when solid material blocks the flow of urine in the renal system.If left untreated,
kidney stones can lead to renal failure. You are a Nephrologist treating a patient who has already
had one kidney removed. The patient is experiencing nausea, vomiting, and swelling of the
extremities (edema.) An MRI shows a kidney stone that has completely blocked the ureter of the
remaining kidney. Please explain how the kidney stone would lead to the patient’s edema.
In answering this question, walk your way through the following logic:
A. Consider the anatomy of the renal system; blocking the ureter would mean fluid backs up where?
B. Which of the factors that determines NFP of the glomerular capillaries would be affected by the
back-up? How would that factor change (increase/decrease)?
C. How would NFP of the glomerular capillaries change? Would this mean more/less fluid stays in
the blood? Use the NFP equation (glomerular capillary version) to defend your answer!
D. If more/less fluid stays in the blood (as you indicated in part 3,) how would that change P H of
the systemic capillaries?
E. How would NFP of the systemic capillaries change? Why would this cause edema? Use the NFP
equation (systemic capillary version) to defend your answer!
2. Let’s make sure we have the basics down first…
? What is the physiologically normal value of blood/ECF pH? If a patient were acidotic, how
would their pH change? If a patient were alkalotic, how would their pH change?
? What are the physiologically normal values for blood/ECF P CO2 and bicarbonate?
? What is the difference between an acid-base disturbance of respiratory vs. metabolic origin?
? If a patient has a respiratory acid-base disturbance, will their body try to compensate using
respiratory or metabolic mechanisms? How about for a metabolic acid-base disturbance?
? If a patient is acidotic, and their body partially compensates for the disturbance, in which
direction will their pH change? How about for a partially-compensated alkalosis?
? How do we know if a patient has fully compensated for an acid-base disturbance?
Expert Solution Preview
Introduction: In this set of questions, we will explore two medical topics. The first question revolves around the relationship between kidney stones and edema in a patient. We will discuss the anatomical and physiological changes that occur due to the blockage of the ureter by a kidney stone, ultimately leading to edema. The second question focuses on acid-base disturbances and their physiological implications. We will cover the normal values of blood/ECF pH, P CO2, and bicarbonate, as well as the difference between respiratory and metabolic acid-base disturbances and the body’s compensatory mechanisms.
1. Kidney stones occur when solid material blocks the flow of urine in the renal system. If left untreated, kidney stones can lead to renal failure. You are a Nephrologist treating a patient who has already had one kidney removed. The patient is experiencing nausea, vomiting, and swelling of the extremities (edema). An MRI shows a kidney stone that has completely blocked the ureter of the remaining kidney. Please explain how the kidney stone would lead to the patient’s edema.
A. Consider the anatomy of the renal system; blocking the ureter would mean fluid backs up where?
When the ureter is blocked by a kidney stone, fluid backs up into the renal pelvis and the kidney itself.
B. Which of the factors that determines NFP of the glomerular capillaries would be affected by the back-up? How would that factor change (increase/decrease)?
The factor affected by the back-up would be the hydrostatic pressure in the glomerular capillaries (PGC). It would increase due to the accumulation of fluid in the renal pelvis and kidney.
C. How would NFP of the glomerular capillaries change? Would this mean more/less fluid stays in the blood? Use the NFP equation (glomerular capillary version) to defend your answer!
Net filtration pressure (NFP) of the glomerular capillaries would increase due to the increased hydrostatic pressure in the glomerular capillaries (PGC). According to the NFP equation (NFP = PGC – (πGC + PBC)), if PGC increases, and assuming πGC (colloid osmotic pressure) and PBC (Bowman’s capsule pressure) remain constant, NFP increases. This would result in more fluid filtration from the blood.
D. If more fluid stays in the blood (as indicated in part C), how would that change the pH of the systemic capillaries?
An increase in fluid staying in the blood would lead to decreased hydrogen ion concentration (H+) in the blood, resulting in an increased pH, making the blood more alkalotic.
E. How would NFP of the systemic capillaries change? Why would this cause edema? Use the NFP equation (systemic capillary version) to defend your answer!
The increased fluid filtration from the glomerular capillaries would lead to an increase in the hydrostatic pressure in the systemic capillaries (PSC). According to the NFP equation (NFP = PSC – (πSC + PBS)), if PSC increases and assuming πSC (colloid osmotic pressure) and PBS (interstitial fluid pressure) remain constant, NFP increases. This increased NFP in the systemic capillaries causes fluid accumulation in the interstitial spaces, leading to edema.
2. Let’s make sure we have the basics down first…
– What is the physiologically normal value of blood/ECF pH? If a patient were acidotic, how would their pH change? If a patient were alkalotic, how would their pH change?
The physiologically normal value of blood/ECF pH is around 7.4. If a patient were acidotic, their pH would decrease below 7.4. If a patient were alkalotic, their pH would increase above 7.4.
– What are the physiologically normal values for blood/ECF P CO2 and bicarbonate?
The physiologically normal values for blood/ECF P CO2 (partial pressure of carbon dioxide) are around 35-45 mmHg. The physiologically normal values for bicarbonate (HCO3-) in blood/ECF are around 22-28 mEq/L.
– What is the difference between an acid-base disturbance of respiratory vs. metabolic origin?
An acid-base disturbance of respiratory origin is primarily caused by changes in the levels of carbon dioxide (CO2) in the blood, leading to alterations in the bicarbonate (HCO3-) levels to compensate. A metabolic acid-base disturbance, on the other hand, is primarily caused by changes in the bicarbonate levels, leading to alterations in the levels of carbon dioxide to compensate.
– If a patient has a respiratory acid-base disturbance, will their body try to compensate using respiratory or metabolic mechanisms? How about for a metabolic acid-base disturbance?
For a respiratory acid-base disturbance, the body will try to compensate using renal (metabolic) mechanisms to adjust bicarbonate levels. In a metabolic acid-base disturbance, the body will try to compensate using respiratory mechanisms to adjust carbon dioxide levels.
– If a patient is acidotic, and their body partially compensates for the disturbance, in which direction will their pH change? How about for a partially-compensated alkalosis?
If a patient is acidotic and their body partially compensates, their pH will increase (move towards normal) due to the compensatory increase in bicarbonate levels. In the case of a partially-compensated alkalosis, the pH will decrease (move towards normal) due to the compensatory decrease in bicarbonate levels.
– How do we know if a patient has fully compensated for an acid-base disturbance?
A patient is considered to have fully compensated for an acid-base disturbance when the pH returns to the normal physiological range (around 7.4) while both the bicarbonate and carbon dioxide levels are also within their normal range.
