Renal Medicine Flashcards
What organs are in the peritoneal cavity ?
Stomach
Liver
Small intestine
Large intestine (bar the rectum)
Spleen
The kidney is a _______________ organ.
retroperitoneal
exists outside of the peritoneal cavity
located behind the abdomen
What spinal level are the kidneys located in?
T12 - L3
Both kidneys are on the same level. True or false
False
the right one is lower than the left
The renal _______ is both the entry and exit for the kidneys
renal hilum
What surrounds the kidneys?
the renal capsule
Peri-renal fat capsule
renal fascia
What is the function of the urether?
to take urine away from the kidney to the bladder
What is the function of the urethra?
to remove urine from the bladder
Where does urine collect?
urine collects in the pelvis
Blood flow to the cells of the kidney is small. This is due to __________.
capillary size
What maintains the microvasculature of the kidneys?
prostaglandin
For patients with compromised renal function, why should special care be taken when prescribing NSAIDs?
NSAIDs inhibit prostaglandin synthesis
this can compromise microvasculature of the kidneys
What is the function of the bowmans capsule?
filtration of blood from glomerular capillaries
this is one of the first steps to urine synthesis
Arterial supply of the kidneys is supplied by the _________.
renal artery
Venous drainage of the kidneys is performed by ___________.
the renal vein
Where are the adrenal glands located?
“north pole” of the kidneys
Ad- means next to in latin
(Ad)renal- thus adrenal glands are next to the kidneys
Where are donor kidneys usually located?
they are usually located in the pelvis
Give examples of unusual renal anatomy
Horseshoe kidneys (a U- shape; more common in males than females)
Donor kidney
Polycystic kidney
What is a horseshoe kidney?
renal fusion
this is when the two kidneys are fused together
What is the unit of activity in a kidney?
nephron
Briefly describe the blood supply of the nephron
Afferent arteriole (from the renal artery) which then forms the glomerulus; from the glomerulus blood leaves through the efferent arteriole to supply the rest of the nephron
What are the components of the nephron?
Bowmans capsule
glomerulus (specialised bundle of capillaries responsible for filtration of blood)
proximal convoluted tubule
loop of henle
distal convoluted tubule
What is the renal corpuscle ?
blood filtering component of the nephron
consists of bowmans capsule and glomerulus
What is the purpose of the knotted structure of the glomerulus?
causes an increase in pressure
Aside from the knotted structure of the glomerulus, the capillaries of the glomerulus have another quality that facilitates production of urine. What is it?
they are permeable
glomerular basement membrane - separates the podocytes from the endothelial cells and contributes towards selectivity of molecules that can pass through
Small molecules filter out of the glomerular walls into the _____________ in the form of a filtrate
bowmans capsule
Give examples of small molecules that filter out of the glomerulus
water
glucose
ionic salts
ammonia (toxic agent)
Large molecules cannot filter through the glomerulus walls. Give examples of such molecules
Proteins
red blood cells (prevents loss of RBCs and maintains osmotic pressure)
The pressure across the glomerulus is altered by …
the efferent arteriole vasoconstriction or vasodilation
How can you identify the presence of protein in the urine?
upon shaking it becomes frothy
What is the glomerular filtration rate?
volume of blood passing through the glomeruli per minute
amount of filtrate produced per minute
(glomerular filtrate)
What is the path of the filtrate after leaving the renal corpuscle?
Filtrate enters proximal convoluted tubule
Enters loop of henle
continues to the distal convoluted tubule
then enters collecting duct
arrives at the ureter
What is the function of the surrounding vasa recta?
they carry blood to the venules (eventually reaches the renal vein)
Describe what occurs at the loop of henle
1.) water moves out of the descending loop of henle down its concentration gradient and then into the vasa recta
2.) salts are actively pumped out of the ascending loop of henle to make a highly concentrate “salty” medullary interstitium (the interstitial fluid in the medulla)
- ascending loop makes the medulla salty
3.) the concentration of the ultrafiltrate and the interstitium is equal at the base of the loop of henle)
4.) ascending arm of the loop of henle is impermeable to water and thus ultrafiltrate remains concentrated
The collecting duct connects the nephrons to the ________.
pelvis
The collecting duct is prone to _______________ of water
reabsoprtion of water
further concentrating urine
What is the function of the collecting duct? How is this made possible?
water conservation
this is made possible by the loop of henle as it essentially makes the medulla of the kidney “salt” hence water leaves the collecting duct
Renal tubules consist of …
Proximal convoluted tubule
loop of henle
distal convoluted tubule
Renal tubules of multiple nephrons connect to a common ____________.
collecting duct
How is GFR controlled?
vasoconstriction and vasodilation afferent arteriole which controls the glomerular pressure to rise/ fall (respectively)
Capillaries that surround the renal tubules are known as …
peri-tubular capillaries
How is the permeability of the collecting duct regulated?
ADH (anti-diuretic hormone)
cause kidneys to release less water
upregulation of aquaporins present on collecting duct
ADH causes even more water to be reabsorbed in the collecting duct
How are collecting ducts able to allow water to be reabsorbed back into the blood?
they contain aquaporins which are small proteins that open up to allow water to be reabsorbed
What are the functions of the kidney ?
Osmolality homeostasis (ADH)
Reabsorption (water, glucose, amino acids, electrolytes)
excretion (urea, creatinine)
pH balance
blood pressure regulation- renin angiotensin
Endocrine- erythropoietin, vitamin D activation.
Why is kidney disease associated with bleeding disorders?
this is because clotting factors are very pH sensitive (physiological maintenance of pH by kidneys) so pathological changes to kidneys mean that pH balance is disrupted
Disruption of pH balance means that clotting factors will not woek
What is the function of EPO (erythropoietin) ?
stimulated synthesis of RBC in bone marrow
A drop in blood pressure or fluid volume causes the release of __________ from the kidney
renin
the juxtaglomerulus is sensitive to blood flow coming into the glomerulus
What is the function of the renin protein?
renin converts angiotensinogen to angiotensin I
Where is angiotensinogen produced?
liver
Angiotensin I is converted by ______________ to produce angiotensin II
ACE
Angiotensin converting enzyme
Where is ACE produced?
produced in the lungs
What is the function of angiotensin II?
acts on the adrenal glands to stimulate the release of aldosterone (mineralcorticoid in the zona glomerulosa of the adrenal cortex- most superficial layer of the adrenal cortex)
Angiotensin II also acts directly on blood vessels and stimulated vasoconstriction (narrorwing)
this all works to increase blood pressure
What is the function of aldosterone? (include sites of action of aldosterone)
salt retention
acts on the kidneys to stimulate reabsorption of salt (NaCl) and water
Acts on the late distal tubule and the collecting duct, favouring water and sodium reabsorption
List some instances that can lead to a blood pressure drop
loss of fluid
burns
bleeding
Why are ACE inhibitors used to treat heart failure?
in heart failure, the heart is unable to effectively pump blood around the heart.
This can be exarcebated arterial/ venous resistance (vasoconstriction)
ACE inhibitors prevent release of aldosterone which increases blood pressure as well as preventing angiotensin II which stimulates vasoconstriction.
This can be detrimental in a patient with congestive heart failure thus, vasodilator drugs such as ACE inhibitors are useful
Describe the process that stimulates release of ADH hormone
rise in plasma osmolality is detected by the hypothalamus (dehydration, less water in blood)
posterior pituitary gland is then stimulated to release ADH hormone
ADH functions stimulating the opening of aquaporins on the collecting duct
Water moves out of the collecting duct and is then reabsorbed into circulation
Where is ADH synthesised and released from?
posterior pituitary gland
Give examples of renal function tests
glomerular tiltration rate
urea (measure presence in blood)
creatinine (measure presence in blood)
electrolytes Na+, K+
What should the normal glomerular filtration rate be ?
90-120 ml/min /1.73 m2
should be above 60 ml/min at all times
<60 ml/min indicative of kidney disease
<15ml/min indicative of kidney failure
50-70% of kidney function can be lost before urea/creatinine levels are increased. True or false. What is the implication of this?
True
therefore, raised urea is an indication that kidney “failure” has been going for a while
List the major reasons of renal function tests
calculate kidney functions and provide treatment accordingly
denote progress of kidney functions during treatment
aid the situation of hydration
Urinanalysis (urine dip) is used to aid the diagnosis of the following diseases:
UTI
Diabetes
Kidney disease
What information does the urinanalysis provide?
pH
blood
nitrites
WBC
protein (frothy)
glucose
specific gravity
What are the means of performing urinanalysis?
urine microscopy
urine culture
urine cytology
What information can you gather from urine microscopy?
used to detect red blood cells, organisms, cell casts (renal disease), crystals (stone disease)
How do cell casts form ?
cells casts form when myoglobin and other metabolic products of distal tubule and collecting ducts of the nephrons are bound to Tamm-Horsfall mucoprotein.
Tamm-Horsfall mucoprotein + myoglobin/ other DT and CD metabolic products
these casts can be found in the urine
What is the use of urine cultures?
to determine specific organisms to target antibotic therapy in infective disease
What is the use of urine cytology?
used to identify abnormal transitional epithelial cells- warrants further investigation for malignancy
What is acute renal injury?
acute decline in GFR from baseline with or without oliguria /anuria
(urine output may be affected or not essentially)
What is oliguria?
< 500 ml of urine per hour made
<0.5ml/kg/hour
What is anuria?
<100 ml of urine per day
Acute renal injury was previously known as…
acute renal failure
Causes of acute renal injury (AKI) are split into the following categories:
Pre-renal
Renal
Post-renal
Pre-renal causes of AKI are usually due to …
problems with blood flow into the kidney
Give examples of pre-renal causes of AKI
Hypovolaemia
haemorrhage
sepsis
ACEi (RA stenosis renal artery stenosis)
Why are ACEi contraindicated for pre-renal AKI?
ACEi are usually contraindicated for patients with hypotension
ACEi can exacerbate the low volume of blood that reaches the kidneys in these patients ?
Give examples of renal causes of AKI ?
acute tubular necrosis
glomerulonephritis
interstitial nephritis (injury inside the tissues of the kidney)
vascular disease
Renal causes of AKI are usually due to …
nephron destruction
NSAIDs can cause renal AKI. Briefly explain how.
NSAIDs - loss of prostaglandins; prostaglandins regulate vasodilation of a glomerular level
loss of protection from vasoconstrictor hormone effects
microvasculature integrity compromise?
Give examples of post-renal causes of AKI
Tumour
Urinary retention (drug induced or infection e.g. herpes)
Urolithiasis (urinary stone)
Post renal causes of AKI are usually due to …
obstructions
What are the presentations of AKI ?
reduced urine output
vomiting
dizziness
orthopnoea (sense of breathless ness relieved by sitting or standing)
pulmonary oedema (lungs fill up with fluid)
peripheral oedema
hypotension - low BP because fluid has escaped the lung s
tachycardia
What are the risk factors for AKI
age (paracetamol)
chronic renal disease
diabetes
radiocontrast
drugs (NSAIDs, ACEi)
trauma
haemorrhage
sepsis
drug OD
surgery
What diagnostic tests can be carried out for AKI diagnosis?
Blood tests:
creatinine (increased)
urea (increased)
FBC (anaemic, EPO)
metabolic acidosis (venous/arterial)
Urine:
urine output <0.5ml/kg/hour for 6 hours
urinanalysis
urine culture
Other:
fluid challenge
catheterisation
ultrasound
CXR- chest xray
ECG
Explain how AKI can cause tented T waves on an ECG
[T waves represent repolarisation of the ventricles- influx of K+ ions]
With AKI; K+ ions are not removed effectively, this can begin to affect cross membrane potentila
Docile membrane can then become suddenly reactive and extra heart beats are observed
T waves become large; these are known as Tented T waves (more repolarisation of the membranes)
Give examples of management for pre-renal cause of AKI
volume expansion
vassopressor (used in hypotension to increase BP)
Diuretic (overload) manages the effects of other medication used to treat pre renal AKI
renal replacement
Why are diuretics administered in management of pre-renal AKI ?
this is to prevent the overload of fluids that can occur with treatments such as fluid overload, vasopressin.
they are given to maintain a non-oligouric state - renal failure with an output of 1ml/kg per hour after the first day
the same reason applies to renal and post-renal causes of AKI
fluid replacement can lead to an overload thus diuretics are given
Give examples of management of renal causes of AKI
treat underlying cause
volume expansion
diuretic (overload)
renal replacement
Give examples of management of post-renal causes of AKI
catheterisation
obstruction relief
diuretic (overload)
renal replacement
What is chronic kidney disease (CKD)?
either a pathological abnormality of the kidney such as haematuria and/or proteinuria or a reduction in GFR to <60ml/minute/1.73m2 for >/= 3 months duration
haematuria refers to blood in the urine
What increases the risk of CKD?
ageing
diabetes (increasing prevalence of CKD in diabetes)
HTN (increasing prevalence of CKD in HTN)
____ % of diabetes patients are on renal replacement therapy
40
____% of HTN patients are on renal replacement therapy
33
Name some other conditions that can lead to CKD
polycystic kidney disease
obstructive uropathy
lupus
amyloidosis (build up of protein called amyloid in the organs)
Focal seogmental glomerulonephritis
What is the presentation of CKD?
Fatigue (anaemia; lack of EPO)
Oedema
Nausea and vomiting
Pruritus
Anorexia- loss of appetite
Arthralagia- deposition of crystals in joints
Prostatic hyperplasia
Multiple infections
Bleeding tendency- pH disturbance affects activity of clotting factors
Secondary hyperparathyroidism
Hiccups!
Explain why secondary parathyroidism is a consequence of CKD
Extra phosphorus is present as a result of failing kidneys. Increased phosphorus presence may cause increased binding of calcium ions hence there are less available calcium ions.
This will cause the compensatory overproduction of parathyroid hormone to mobilise Ca2+ from the gut and bone
List investigations that can be carried out to aid CKD diagnosis
Serum creatinine
Urinalysis (microscropy, cytology and culture)
Urine protein
Renal ultrasound
eGFR (amount of filtrate produced per minute/ amount of blood being filtered)
Renal biopsy
Abdominal xray
Abdominal CT/MRI
What is stage 1 CKD?
kidney damage with normal or increased GFR >/= 90ml/min/1.73m2
What is stage 2 CKD?
kidney damage with a mild decrease in GFR 60-89ml/minute/1.73m2
What is stage 3a CKD?
kidney damage with a moderate decrease in GFR, 45-59ml/min/1.73m2
What is stage 3b CKD?
kidney damage with a moderate decrease in GFR, 30-44ml/min/1.73m2
What is stage 4 CKD?
kidney damage with severe decrease in GFR, 15-29ml/min/1.73m2
What is stage 5 CKD?
kidney failure (end stage kidney disease), with GFR <15ml/min/1.73m2
When is the best time for dental treatment for patients with CKD?
the day after dialysis
the day before dialysis- the blood is at its worst
Haemodialysis can predispose patients to blood borne viruses. What considerations should be made
risk of dialysis hepatitis for patient increases
risk to dental professional providing treatment
Effect on liver; this can affect possible prescriptions e.g. no NSAIDs (increased risk of toxicity)
Risk of bleeding when liver is affected
LA consideration for liver disease; amide LA metabolised by the liver
Why are NSAIDs contraindicated for CKD?
NSAIDs inhibit production of prostaglandins which are involved in maintenance of the integrity of microvasculature of the kidney
Local anaesthesia is safe for patients in CKD except when?
except when there is a severe bleeding tendency
pH balance disruption can affect clotting factor integrity
You should avoid arteriovenous fistulas arm to minimise the risk of …
fistula infection
thrombophlebitis (inflammatory process that causes blood clot to form and block vein)
phlebitis - inflammation of the vein
What is renal osteodystrophy?
it is a complication of CKD which causes weakens bones
Explain why renal osteodystrophy occures?
it is usually secondary to hyperparathyroidism
its is a compensatory mechanism where there is an overproduction of parathyroid hormones which causes mobilisation of calcium from the bone and gut
Less calcium is available as a result of kidney disease/ injury (crystal formation with phosphorus) and a compensatory mechanism leads to weakened bones
What are some dental considerations of renal osteodystrophy secondary to hyperparathyroidism (weakened bones)?
- loss of lamina dura on intraoral radiograph
- (hyperparathroidism) causes brown tumours to grow on gingiva
- osteomalacia in adults - weakened bone (due to loss of calcium)
Loss of calcium in children leads to rickets
Briefly describe how IV dialysis takes place
- a fistula can be created in the arm
- blood passes through an exchange column, fresh, new material is pumped in and toxic material is removed
What is ambulatory dialysis ?
peritoneal dialysis?
the lining of the abdomen is used to filter the blood.
the dialysis tube is connected to the abdomen as opposed to a fistula
the gut surfaces acts as exchange membranes
not as effective as IV dialysis
Why are transplant kidneys placed in the pelvis?
this is because it is easy to connect the kidneys to the ileac artery and veins
the transplanted ureter is connected to the home ureter
What are the dental considerations of a kidney transplant?
Steroid cover- immunosuppresant, anti-inflammatory; risk of infection e.g. oral candidiasis
Dental treatment should be completed before transplant if possible
Gingival hyperplasia due to cyclosporin (immunosuppresant)
Increased risk of tuberculosis
increased risk of basal cell carcinoma
Urine leaves the bladder via the …
urethra
What is the urothelium?
this is the lining of the urinary tract
this includes the bladder, ureter, renal pelvis and urethra
What is a urinary tract infection?
this is an invasion of the urothelium by bacteria
What is the cause of most acute cases of UTIs?
90% cases caused by E.coli
An infection of the bladder is know as …
cystitis
An infection of the ureter or kidney is knowns as …
pyelonephritis
What are the risk factors for UTIs?
female (distance between urinanatomy and outside world, hormones)
diabetes
obstruction
foreign bodies (catheter)
What are the symptoms of cystitis (bladder infection)?
urinary frequency
urgency of micturition (urination)
dysuria (sensation of burning)
+/- haematuria (blood in urine)
What are the symptoms of pyelonephritis
pyrexia (fever)
loin pain
rigors
(sepsis type symptoms)
What are the main stay treatments for UTIs?
[cystitis and pyelonephritis)
antibiotics
What is pyonephrosis?
this is where there is a collection of pus in the collecting system (including renal pelvis) due to an obstruction
Surgical emergency and requires drainage with MRI/ultrasound guidance
Supprative infection of upper urinary tract due to obstruction of the ureter
What is urolithiasis?
formation of calculi in the urinary tract (kidney stones)
80% of calculi formed in kidneys are _________ based.
calcium based
What causes urolithiasis (kidney stones) ?
super-saturated urine around nucleus
dehydration?
What are the risk factors for urolithiasis ?
higher in carnivores- protein
family history
warm climate
metabolic abnormalities
dehydration
previous stone
What is renal colic?
ureteric colic occurs as the stone migrates to the ureter and the ureter then goes into spasm and hyperperistalsis
What are the symptoms of renal colic?
patients writhe pain
“loin to groin”
colic (spasmodic)
nausea and vomiting
tachycardia
What investigations can be carried out to diagnose renal colic?
blood (renal function)
urine dip (haematuria)
CT
IV urogram
What is the treatment for renal colic?
stones that are <5mm mostly pass spontaneously over 6 week period
wait and watch
extacorporeal shock wave lithotripsy (ESWL)- Ultrasound shockwave; smash into pieces, some pieces can get stuck
Ureteroscopy and stone extraction
percutaneous nephrolithotomy (surgery for larger stones)
Where is the prostate located?
the prostate lies inferior to the bladder and surrounds the prostatic urethra
What is benign prostatic hyperplasia?
[hyperplasia- increase in number of cells of a tissue or organ]
this is an increase in an increase in size of the prostate gland. The urethra as a result becomes compressed
- cannot empty the bladder with ease
Patients with benign prostatic hyperplasia usually present with…
lower urinary tract symptoms
What are the voiding lower urinary tract symptoms?
hesitancy
poor streaming
straining
terminal dribbling
What are the storage lower urinary tract symptoms?
frequency
urgency
nocturia (urination at night?)
incontinence
What is the management of benign prostatic hyperplasia?
adrenergic antagonist e.g. tamsulosin
5alpha reductase inhibitors e.g. finesteride
surgery (TURP)- transurethral resection of prostate
What is the most common male cancer?
prostate
95% of prostate cancer are present as what type of cancers?
adenocarcinomas
(glands)
Prostate cancer adenecarcinomas are driven by what hormone?
testosterone
What is the presentation of prostate cancer?
asymptomatic
incidental (craggy prostate)
outflow symptoms
bony pain
What is the management of prostate cancers?
hormonal treatment
transurethral resection of prostate (TURP)
radial prostatectomy (take prostate and surrounding tissues)
radiotherapy
brachytherapy
What is PSA (prostate specific antigen)?
enzyme produced by the prostate
it is often elevated in prostate cancer and benign prostate hyperplasia
it is not a screening test
can be used to monitor the disease
What is the most common type of renal cancer?
renal cell carcinoma
Where does renal cell carcinoma arise ?
in the proximal renal tubule
Renal cell carcinomas are described to be very __________ tumours, as they are metastases.
vascular
How are renal cell carcinomas spread?
direct extension via renal vein
reaches inferior vena cava and then the right atrium
Renal cell carcinomas have “cannonball” metastasis which are…
lung
bone
brain
The mandible is a well known site of renal cell carcinomas. True or false
true
What are the risk factors of renal cancer?
family history
renal cystic disease
smoking
exposure to calcium, lead, asbestos, polycarbons
What is the classic triad of renal cell carcinomas?
Pain
mass (abdominal masss)
blood in urine
The class triad of renal cell carcinomas are now rarely seen (<10% of cases). How are these masses found?
Incidental findings
imaging (CT, MRI) performed for an unrelated reason
Paraneoplastic syndrome caused by renal cell carcinomas is a result of …
increased secretion of Renin and/or EPO
What are the symptoms of paraneoplastic syndrome?
polycythamemia (RBCs take up more space in bone marrow; less space for other cells)
hypertension (renin)
fever
night swats
What is the management of renal cell carcinomas?
surgical - nephrectomy
embolisation (as they are vascular tumours, prevent them from travelling)
chemo/radiotherapy
immunotherapy (monoclonal antibodies)
What is the 5 year survival statistic for stage 1 RCC according to CRUK?
80%
What is the 5 year survival statistic for stage 4 RCC according to CRUK?
5%
Bladder cancer is most commonly what type of cancer?
transitional cell carcinoma TCC
Bladder cancer presents with …
a painless macroscopic haematuria
What is the treatment for bladder cancer?
transurethral resection
cystectomy (removal of bladde)
What are the risk factors for bladder cancer?
male
increasing age
smoking
occupational exposure to rubber, dye, textile industry
A urothelial tumour of the bladder can affect the entire urinary tract. True or false
True
renal pelvis, ureter, urethra, bladder
How is end-stage renal failure treated?
transplant
dialysis
