Renal

Question 1

Describe the kidneys

Answer 1

Sited at the back level with last thoracic and 12th lumbar vertebrae. Partially protected by 11th and 12th ribs. Rt kidney slightly lower then left. Adrenal gland sit on top of each kidneys. Embedded in fat and connective tissue.

Question 2

What is the glomerulus ?

Answer 2

Sited at beginning of nephron.Where vascular filtration occurs. A positive pressure is created by efferent arteriole being narrower than the afferent. Filtration is dependent on positive pressure.

Question 3

What does a drop in blood pressure cause for filtration pressure ?

Answer 3

Results in a loss. BP = CO x SVR so potential causes could relate to cardiac output through loss of circulating volume or poor cardiac function. Reduced BP detected in carotid sinus stimulates sympathetic nervous system which causes renin release from juxtaglomerular cells of the kidney. Kidneys release renin from stimulation of the juxtaglomerular cells or macula densa cells.

Question 4

How is renin released into the bloodstream ?

Answer 4

Drop in BP. Renin released from kidney via juxtaglomerular and macula densa cells. Renin travels to the liver where angiotensinogen is converted into angiotensin I. Angiotensin I travels to lungs where it is affected by angiotensin converting enzyme and converts into angiotensin II. This leads to vasoconstriction and the release of anti diuretic hormone from posterior pituitary gland and release of aldosterone from adrenal glands.

Question 5

What does aldosterone do ?

Answer 5

Regulates BP by ..
IncreasIng sodium retention in the blood stream and enhance excretion of potassium in urine. Promoting sodium reabosrption helps body to retain water, increasing blood volume.
Also when aldosterone levels rise kidneys reabsorb more water leading to elevated blood volume and BP, the aldosterone influences kidney water reabosprtion.

Question 6

What does an anti diuretic hormone do ?

Answer 6

Causes increase in water reabsorption in the collecting duct of the nephron. Stimulates aquaporins (water channels)
Water is reabsorbed into circulatory system.

Question 7

What is a nephron ?

Answer 7

Functional unit of the kidneys

Question 8

What are the functions of the kidney ?

Answer 8

Dispose of waste - nitrogenous waste(urea) end product of protein breakdown, uric acid (results from nucleic acid), metabolism (creatinine)
Toxins, drugs, excess ions
Regulatory function - maintain homeostasis -
fluid and electrolyte balance, acid - base balance PH, production of renin to maintain BP, production of erythropoietin to stimulate RBC production, conversion of vit D to its active form.

Question 9

Define AKI

Answer 9

Acute kidney injury is an abrupt decline in glomerular filtration with failure of the kidneys to excrete the waste products of metabolism & inability to maintain electrolyte & acid-base homeostasis. Potentially reversible.

Question 9

What are the key issues associated with AKI ?

Answer 9

Rapid decline in kidney function, within hours or day - build up of nitrogenous waste in blood, alteration in fluid and electrolytes balance, decreased GFR.

Question 10

What are the 3 causes of AKI ?

Answer 10

Prerenal, intrarenal / intrinsic, postrenal

Question 11

Describe prerenal cause of AKI

Answer 11

Causes decrease in effective blood flow to kidneys and GFR (glomerular filtration rate). Caused by hypovolaemia, hypotension, stenosis, heart and liver failure

Question 12

Describe intrarenal / intrinsic cause of AKI

Answer 12

Disease processes or damage directly to structure of kidney. Glomerular nephritis, interstitial nephritis, haemolytic uremic syndrome, Henoch Schoenlein purpura and some nephrotoxic medications can cause this

Question 13

Describe postrenal causes of AKI

Answer 13

Downstream of the kidney, most often occurs as consequence of UT obstruction. Caused by blocked urinary catheter, benign prostatic hyperplasia, obstructive uropathy in children.

Question 14

What are the common causes of AKI in children ?

Answer 14

Post cardiac surgery and stem cell transportation patients.
Hypoxia/ischemia and nephrotoxin induced AKI - causes in neonates and CYP.

Question 15

How do you detect AKI ?

Answer 15

Rise in serum creatinine of 26 micromole/ Lor greater within 48 hours.
50% or greater rise in serum creatinine known or presumed to have occurred in past 7 days. fall in urine output 0.5ml/kg/hr for more than 6 hours adults, 8 hours children. 25% or greater fall in eGFR in CYP in past 7 days

Question 16

How do you identify the cause of AKI ?

Answer 16

Urine dipstick (test for blood, protein, leucocytes, nitrates, glucose)
Referral to nephrology team with no cause of AKI and dipstick results of haematuria and proteinuria without UTI or catheter trauma.
Ultrasound.

Question 17

What is chronic kidney disease ?

Answer 17

Irreversible, long term chronic condition.
Decline in kidney function, over many years. Failure of homeostasis occurs as disease progresses, increased risk of other conditions esp cardiovascular disease, mortality and morbidity.

Question 18

What are the major causes of CKD ?

Answer 18

Hypertension and diabetes because they damage blood vessels. A good blood supply is essential for kidney function.
Glomerular disease polycystic kidney disease.

Question 19

Which ethnicity is more likely to develop CKD ?

Answer 19

Black and Asian

Question 20

What are the causes of AKI in CYP ?

Answer 20

Congenital disorders, renal dysplasia with reflux, obstructive uropathy, glomerular disease, congenital nephrotic syndrome, tubulo interstitial disease, renovascular disease polycystic kidney disease, metabolic, malignancy

Question 21

What does the diagnosis of CKD require ?

Answer 21

Decline of kidney function for 3 months or more AND
Evidence of kidney damage (e.g. albuminuria or abnormal biopsy) OR
GFR <60 mL/min/1.73 m2
Urine, bloods, imagining, histology (biopsy), signs (oedema, hypertension)

Question 22

What is the pathophysiology of CKD ?

Answer 22

Decline in nephron numbers - adaptive hyperfiltration at glomerulus leads to increased activation of renin angiotensin aldosterone system (increases BP) and increased glomerular permeability (albuminuria proteinuria).
Inflammation and fibrosis and glomerulus tubules. More nephron death = progression.

Question 23

What is estimated eGFR ?

Answer 23

Key indicator of estimated renal function based on serum creatinine level, age, sex and race. Declines with age.
Normal - 100ml/min/1.73m2
Normal above 90 or above 60

Question 24

What is albumin : creatinine ratio ?

Answer 24

Used with eGFR to risk stratify patients.
Urinealbumintocreatinine ratio(ACR) is also known as urine microalbumin or microalbuminuria. It is defined by a rise in urinary albumin loss to between 30 and 300 mg day. Timed urine collections may be inaccurate and therefore ACR is used; ranges vary between adults and children.
Patients with CKD are classified depending on level of eGFR, and the amount of protein present in the urine. This information forms the basis of CKD staging which is used for planning follow up and management. The higher the stage (G1->G5) and the greater the amount of protein present in the urine (A1->A3) the more “severe” the CKD.
Patients are classified as G1-G5, based on the eGFR, and A1-A3 based on the ACR (albumin : creatinine ratio)

Question 25

What are the stages of CKD ?

Answer 25

1 - Kidney damage with GFR >90, no symptoms
2 - Kidney damage, mild GFR 60 -89
3 - Moderate, GFR 30 -59
4 - Severe GFR 15 -29 prepare for new kidney
5 - Kidney failure GFR <15 replacement kidney

Question 26

What are the symptoms of CKD ?

Answer 26

In late stages become symptomatic. Swollen feet, hands, fatigue, shortness of breath, blood in urine, urinary frequency, insomnia, itchy skin, muscle cramps, headache, erectile dysfunction.
Advanced kidney disease - increased risk of infection.

Question 27

What is the management of early CKD ?

Answer 27

Management of risk factors, e.g. blood sugar, blood pressure
Screening for cardiovascular disease
Lifestyle change if necessary, e.g. diet, smoking, exercise, weight
ACE inhibitor or ARB may be beneficial
Dietary modification to control fluid and electrolyte levels, e.g. low potassium diet
Regular monitoring of eGFR and appropriate prescribing

Question 28

What is haemodialysis ?

Answer 28

Blood removed from body and passed through machine to be filtered. Creatinine and other waste removed as well as excess fluid and electrolytes. Often performed at a dialysis centre
Usually three sessions per week
Each session around 4 hours

Question 29

What is an AV fistula ?

Answer 29

An arteriovenous fistula is a vein surgically connected to an artery (AV graft)
Over several months the vein enlarges, making it suitable for high flow rates needed during dialysis.

Question 30

What is peritoneal dialysis ?

Answer 30

Uses peritoneum to filter blood. Performed at home, every day. 4/5 bag changes required each day. Permanent catheter in the abdomen - risk of peritonitis.

Question 31

What are some complications of CKD ?

Answer 31

Sodium retention and volume overload, hyperkalaemia, metabolic acidosis, increased phosphate, PTH, decreased serum calcium, calcitriol, anaemia