Nephrology Flashcards
Causes of Hypertension?
Chronic kidney disease (CKD) because the kidneys do not filter out fluid. excess leads to hypertension
Cushing's syndrome, hyperthyroidism, hypothyroidism , acromegaly, Conn's syndrome or hyperaldosteronism, renal artery stenosis (from atherosclerosis or fibromuscular dysplasia), hyperparathyroidism
Obesity
pregnancy
Alcohol
Drugs
Why could one kidney be smaller than the other?
The kidney is damaged because of a faulty drainage system, usually a condition called reflux nephropathy
Birth defect
damage the kidney, such as glomerulonephritis
narrowing in the artery supplying the kidney with blood
- What are the causes of renal artery stenosis and what is the relationship to hypertension?
is a narrowing of arteries that carry blood to one or both of the kidneys. Most often seen in older people with atherosclerosis (hardening of the arteries),
can worsen over time and often leads to hypertension (high blood pressure) and kidney damage
This narrowing of the renal artery can impede blood flow to the target kidney, resulting in renovascular hypertension – a secondary type of high blood pressure
- Describe what happens to sodium after it has been filtered into the kidney tubule and its importance for the homeostasis of other substance.
It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide.
Aldosterone stimulates sodium reabsorption and potassium excretion in the distal (convoluted) tubule of the kidney and possibly enhances some sodium reabsorption in the proximal portion as well
Describe the difference between pre-renal and post-renal failure, with examples.
Post-renal acute kidney injury, which used to be called acute renal failure, occurs when an obstruction in the urinary tract below the kidneys causes waste to build up in the kidneys. It is not as common as intrinsic acute kidney injury (AKI) or acute tubular necrosis (ATN).
Generally it occurs because of damage to the kidney tissue caused by decreased kidney blood flow (kidney ischemia) from any cause (e.g., low blood pressure), exposure to substances harmful to the kidney, an inflammatory process in the kidney, or an obstruction of the urinary tract that impedes the flow of urine. AKI is diagnosed on the basis of characteristic laboratory findings, such as elevated blood urea nitrogen and creatinine, or inability of the kidneys to produce sufficient amounts of urine.
AKI may lead to a number of complications, including metabolic acidosis, high potassium levels, uremia, changes in body fluid balance, and effects on other organ systems, including death.
- What is creatinine? How is it processed by the kidney?
Is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass).
Is removed from the blood chiefly by the kidneys, primarily by glomerular filtration,
but also by proximal tubular secretion.
Little or no tubular reabsorption of creatinine occurs. If the filtration in the kidney is deficient, creatinine blood levels rise.
- Describe the role of sodium transport in the nephron and its importance for homeostasis of water and electrolytes.
It is very efficient, since more than 25,000 mmoles/day of sodium is filtered into the nephron, but only ~100 mmoles/day, or less than 0.4% remains in the final urine.
Sodium is the major positively charged electrolyte in extracellular body fluid. The amount of sodium in the fluid influences its volume, which in turn determines blood volume and blood pressure.
- Why is hydrochlorothiazide used to treat hypertension?
reduces blood volume
acts on the kidneys to reduce sodium (Na+) reabsorption in the distal convoluted tubule.
- What would be the consequence of drinking a large volume of water?
, fluid outside the cells has an excessively low amount of solutes, such as sodium and other electrolytes, in comparison to fluid inside the cells, causing the fluid to move into the cells to balance its concentration. This causes the cells to swell
Swollen brain cells may also apply pressure to the brain stem causing central nervous system dysfunction. Both cerebral edema and interference with the central nervous system are dangerous and could result in seizures, brain damage, coma or death
- What would be the consequence of losing a large quantity of salt from the body, e.g. in diarrhoea ?
Signs and symptoms of hyponatremia can include altered personality, lethargy and confusion. Severe hyponatremia can cause seizures, coma and even death.
- Describe the normal process by which the kidneys maintain normal blood pH. How are H+ and HCO3- reabsorbed or excreted?
The kidneys maintain acid-base homeostasis by regulating the pH of the blood plasma. Gains and losses of acid and base must be balanced. Acids are divided into “volatile acids”[13] and “nonvolatile acids”.[
In the lumen The H+ combines with HCO3− to form carbonic acid (H2CO3)
In the epithelial cell
H2CO3 readily dissociates into H+ and HCO3−
HCO3− is facilitated out of the cell’s basolateral membrane
- In which parts of the renal tubule do these processes occur? What other substances must be transferred at the same time?
Lumen :
In the lumen The H+ combines with HCO3− to form carbonic acid (H2CO3)
Luminal carbonic anhydrase enzymatically converts H2CO3 into H2O and CO2
CO2 freely diffuses into the cell
In the epithelial cell
Cytoplasmic carbonic anhydrase converts the CO2 and H2O (which is abundant in the cell) into H2CO3
H2CO3 readily dissociates into H+ and HCO3−
HCO3− is facilitated out of the cell’s basolateral membrane
- What would happen to the amount of H+ secreted into the tubule if the activity pf the Na+/K+/ATPase were increased? Are there diseases or other conditions that might enhance the activity of this Na+pump?
Metabolidc diseases, Metbaolic alkalosis etc
Renal compensation for metabolic alkalosis, , consists of increased excretion of HCO3− (bicarbonate), as the filtered load of HCO3− exceeds the ability of the renal tubule to reabsorb it.
- Would you expect to see any changes in the patient’s breathing pattern?
rapid and shallow breathing.
