kidney diseases

Question 1

What does the term acute mean with respect to the diseases of the kidney?

Answer 1

Acute diseases of the kidney are quick, and reversible.

Question 2

What does the term chronic mean with respect to the diseases of the kidney?

Answer 2

Chronic diseases of the kidney are slow, and thus irreversible.

Question 3

What is acute renal failure?

Answer 3

Acute renal failure refers to the reduction of the glomerular filtration rate (GFR). Creatinine clearance is reduced and this indicated low glomerular filtration. Acute means that this is reversible.

Question 4

What is nephrotic syndrome? Even though it doesn’t have the title ‘acute’, it is still reversible.

Answer 4

1. Proteins that are never filtered by the glomerulus, are filtered from the blood into the tubules.
2. Proteinuria, or protein deficiency occurs because the rate of excretion of bodily proteins is faster than the liver can produce them again.
3. Low protein in the blood changes the osmotic pressure, and so water wants to rush out of the blood into the interstitial spaces where there is now more protein,by osmosis. This causes oedema and swelling of the entire body.
4. This all happens, because of an initial defect in the glomerulus, that made it leaky and caused protein filtration.

Question 5

What are some diseases that can make the glomerulus leaky enough to cause nephrotic syndrome?

Answer 5

Diabetes melitus, glomerulonephritis, amyloid deposition (amyloids are insoluble fibrous proteins masses).

Question 6

What is acute tubular necrosis?

Answer 6

Acute tubular necrosis is reversible, but occurs as an end result of severe acute renal failure.
The epithelial cells of the tubules require a lot of energy to actively transport ions to and from the blood. Because of this, they have a lot of mitochondria and require lots of oxygen.
So, if the kidneys are deprive of oxygen (ischaemia) even for a short period of time, the tubules are the most vulnerable. Acute tubular necrosis sees the epithelial cells of the tubules die and start to be sloughed off into the tubule lumen, and oedema occurs in the interstitium.
The reason this is acute is because the lost epithelial cells can be replaced as long as oxygen supply is restored to the kidney. Depending on how bad the damage is, it may take weeks to months for the full regeneration to occur.

Question 7

what is glomerulonephritis?

Answer 7

Glomerulonephritis is the inflammation of the glomerulus induced by the accumulation of IgA antibodies, usually after a bacterial infection of some kind. In some cases, it can be caused by direct antibody production towards the glomerulus but this is very rare. The severity of the glomerulonephritis depends on the number of antibodies that have been deposited in the glomerulus.

Question 8

What is one of the characteristic morphological traits of acute glomerulonephritis?

Answer 8

The presence of crescents- crescents are clumps or masses of monocytes, fibrin and epithelial cells that accumulate in the capillary tuft. They are called crescents because they are in the shape of half a moon.

Question 9

What is acute interstitial nephritis?

Answer 9

It seems to be confused with acute renal failure symptomatically. It is the inflammation of the interstitium and tubules because they have been infiltrated by inflammatory cells. It is often caused by drug allergy, like to antibiotics.

Question 10

What is the major issue with the detection of chronic renal failure?

Answer 10

Our kidneys are so efficient that even the loss of one kidney would have no effect on your body, because surviving on one kidney is still more than 100% efficient. Thus, the early stages and middle stages of chronic renal failure are asymptomatic. When you finally start to display symptoms, then chronic renal failure is in its final stages and renal function is less than 10%!

Question 11

What morphological changes occur in the kidney during chronic renal failure?

Answer 11

The kidneys become fibrotic, scarred and shrink in size.

Question 12

So if chronic renal failure is asymptomatic until its late phases, how is it detected?

Answer 12

Often it is detected accidentally, when people go to the doctor and do blood tests for other reasons. The symptoms of low kidney function include nausea, anorexia, anaemia and worstening hypertension. If left untreated, the end stage CRF leads to coma, pericarditis, sepsis and neuropathy.

Question 13

Explain the relationship between high blood pressure and chronic renal failure in the body?

Answer 13

As chronic renal failure gets worst, the kidney becomes more stressed and secretes more renin. Renin causes vasoconstriction of the blood vessels in the body and thus increases blood pressure. Increased systemic blood pressure increases the perfusion to the kidneys, and increased perfusion to failing kidneys causes more damage to the struggling kidney and the cycle continues if not treated.

Question 14

What is the relationship between diabetes mellitus and chronic renal failure?

Answer 14

Diabetes interferes with the immune system and impairs neutrophil functioning. Thus many diabetics present with kidney infections that if unresolved lead to chronic kidney failure.

Question 15

What is the relationship between glomerulonephritis and chronic renal failure?

Answer 15

Glomerulonephritis, if untreated, can lead to chronic renal failure, due to the extensive damage to the glomerulus that cannot be repaired.

Question 16

What is focal and segmental glomeurosclerosis and what is its relationship to chronic renal failure?

Answer 16

FSGS, as it is known, is segmented and random scarring of the glomerulus. It is one of the main causes of nephrotic syndrome and if left untreated can lead to chronic renal failure.

Question 17

What is systemic lupus erythmatosus and what is its relationship to chronic renal failure?

Answer 17

It is an autoimmune disease in which self tolerance is completely lost, and the immune system goes crazy and produces lots of antibodies towards self-tissues of the body, including the tissues of the kidney. In the case of the kidneys, the antibodies tend to deposit themselves in the mesangium. If left untreated, the kidneys can become so irreversibly damaged that chronic renal failure occurs.

Question 18

What is hypertension and what is its relationship to chronic renal failure?

Answer 18

Long-term high blood pressure damages the kidneys and can lead to chronic renal failure. The high blood pressure damages the arterioles of the kidney leading to artheroma of the larger arteries, sclerosis of the arterioles and scarring of the glomeruli and interstitium. The kidneys shrink and become scarred.

Question 19

What is polycystic kidney disease and what is its relationship to chronic renal failure?

Answer 19

It is a rare autosomal dominant disorder in which the kidney, liver, brain and pancreas are prone to getting cysts. The kidney develops super large cysts, so much so that one kidney can weigh up to 4 or 5 kg. This destroys the kidneys and can lead to chronic kidney failure.

Question 20

What is Alport syndrome and its relationship to chronic renal failure?

Answer 20

Alport syndrome is another genetic disorder which leads to faulty type 4 collagen production. Type 4 collagen is the major constituent of the adult glomerular basement membrane. This has many systemic effects, but in the kidney itself causes heamaturia and progresses to end stage renal failure.

Question 21

What is analgesic nephropathy and what is its relationship to chronic renal failure?

Answer 21

The disease in which consumption of certain analgesics containing the molecule phenacetin combined with caffeine. The body metabolises the phenacetin and this forms toxic byproducts that damage the medulla of the kidney, the collecting duct in particular and causes the entire medullary unit to slough off into the renal pelvis.
The kidneys become shrunken and necrotic, and the ureter becomes obstructed by all the sloughed medullary tissue inside it. Chronic renal failure is inevitable at this stage.