Why it is important
to know about this subject:
1-
Many drugs affect kidney mainly OTC which we are responsible for
2-
Many patient refer to pharmacy regarding their test so we should be able
to interpret it to direct patient to health provider
3-
Pharmacist play crucial role in patient education plan
Bean shaped organ about size of the
fest located near middle of your back below rip cage
Each kidney consist of about one
million functional unite which is nephrone which is composed of 5 main segments
Function of kidney:
1-excretory (urea, uric acid,
creatinine, drugs, products of metabolism)
2-regulatory: acid base balance, water,
and electrolyte.
3- endocrine: erythropoitin, renine,
active form of vit D
How kidney works:
Formation of urine include
1-filtration:
start at glomerulus, content the same as plasma �prot and RBC and WBC,
170-200L /24 hr reduced to 1-2 L OF urine.
2-reabsorbtion:
start at proximal tubules, Na, K, Ca, Mg, water, glucose.
3-excretion:
a-waste
product: urea (protein), uric acid (nuclicacids),creatinin(muscle).
b-Drugs
c-Inorganic
substances
d-Excess
water
Mechanisms that
control kidney function:
FIG
2
Kidney is an organ with huge functional
reserve; this means certain disorder in kidney may not appear unless around 75%
of nephrons are lost
|
Renal function |
Effect |
|
50% |
Many people will have kidney disease
which will get worse if not properly managed |
|
20% |
Serious health problem and kidney
disease |
|
10-15% |
Cannot live long without renal
replacement therapy (dialysis or transplantation. |
Why do kidney fail
Most kidney disease attack nephrone
affecting filtering capacity
Damage can be quickly or slowly
reversible or irreversible
Most common causes of
kidney disease are:
1-
Diabetes: many theories
-High blood
sugar may force capillary in the kidney to filter greater amount of blood than
normal, extra pressure on capillary leaking and filtering membranes thicken
-Increase
blood aggregation, AS in renal arteries, decrease bld flow, nephrone starved of
O2 and die
2-
Hypertension: the higher bld pressure the less blood reaches vital organ,
and kidney and high blood pressure may damage bld vessels.
3-
Congenital kidney disease: poly cystic kidney disease
4-
Poisons or trauma
5-
Drugs especially OTC
6-
Aging: as person gets older body will age, no of functioning nephrone
will decrease, volume and bld flow will decrease, glomerular filtration rate
will decrease, kidney are less able to concentrate and dilute urine in response
to hydration state.
We can classify
kidney diseases to:
1-acute renal failure: sudden drop in
kidney function, which is reversible
2- chronic renal failure: gradual loss
of kidney function (silent kidney disease) and it is irreversible
3-end stage renal disease: total or
nearly total and permanent kidney failure and person here should undergo
dialysis or transplantation
How to know about
kidney disease:
1-
Early stage person may not feel sick at all
2-
First sign may be general. Headache, feeling tired.. Etc
3-
Urination problems: less or more urination, change in urine
color,
4-
Pain in kidney area.. lower back pain .
5-
test s may revel kidney disease by chance and then it is the most
important tool and diagnosis , management and follow up treatment
renal tests :are done to examine
filtration function (protein),secretary capacity (urea , cretinine , uric acid
),and concentrating ability .
most important tests
for kidney function :
|
Test |
Normal value |
Notes |
Limitations |
|
Cretinine conc. in bld |
0.5-1.4 |
Rise in response to renal damage |
May not rise until 50%of renal fxn
lost Not reliable May appear normal in older patient
because muscle mass less |
|
Creatinine clearance |
Men 85-125 ml/minu Women 75-115 ml/minu |
To measure filtration 24 urine collection most prices way to assess renal fxn |
Limitation of urine collection Used for detection of early damage
since value will fall even with just 10% loss of renal function |
|
Blood urea nitrogen |
7-20 mg/dl |
Rise in response to renal damage |
GI hemorrhage and chronic gout may
increase it |
|
Protein in urine |
.05-0.1gm/day |
1st sign is foamy urine first measurable sign of damage , |
Important in diabetic patient follow
up |
|
Specific gravity |
Random : 1.002-1.031 12 Hr fluid restriction: >1.025 |
Compare density of urine to water |
|
Rapid loss of renal function, which may
be reversed if, treated .
Causes :
1-prerenal :caused by circulatory
insufficiency , burns , sever hemorrhage ,volume depletion,hypotension, drugs
that may lead to
a-renal artery constriction(ACE
inhibitor and NSAIDs)
b-volume depletion(diuretics)
c-heart failure (B-blockers 0
all will lead to renal hypo perfusion
and decrease GFR.
If not treated it may lead to acute
tubular necrosis
2-intrensic ARF(ATN)
loss of functional nephrone either due
to nephro toxins or renal ischemia .. decrease bld flow .. decrease O2 supply
� death of nephrone
3-post renal ARF
due to obstruction due to calculi ,
prostrate enlargment and neoplasm of urinary tract
characterized by anuria
usually three phases
are observed inARF :
1-
oligouric � occur within 1-2 days and last from several days to weeks
urine out
put less than 400ml/day
2-
diuretic phase : chch by
increase volume of urine lasts for several days .. patient remain azotemic
3-
3- recovery phase : begin with gradual decline in azotemia may last weeks
to months .
biochemical changes
in plasma in ARF :
increased :
1-
K
2-
Urea
3-
Creatinin
4-
Phosphate
5-
Mg
6-
H+
Decreased:
1-Bicarbonate
2-Calciume
management of ARF :
1-
relief obstruction
2-
control water and electrolyte
3-
strict control of NA and water intake
4-
nutritional support
5-
treatments of underlying disease like HTN, DM
6-
dialysis if needed .
Patient information :
Name : nc
Age :69 years
Wight : 51
Past medical history
:
Biventricular cardiac failure
Ankle edema
Gout
Medication history :
Frusemide 80 mg
on the morning
Isosorbide mono nitrate
20mg twice daily
Captopril 6.25 mg twice daily
Frusemide increase to 120 mg daily
because of ankle oedema
Indomethacin 50 mg three times / day in
previous 21 days .
Present illness :
Admitted complaining of nausea ,loss of
appetite , on examination she was pale and tired looking ,sunken eyes .
Pulse 120 beat /minu
Blood pressure 105/70 lying and 85/60
standing
Diagnosis :
Na and water depletion with consequent
renal hypo perfusion
|
Test |
Result |
Normal value |
|
Na |
131mmol/L low |
135-150 |
|
K |
5.5 mmol/L high |
3.5-5 |
|
Bicarbonate |
17mmol/L low |
22-31 |
|
Creatinine |
312 micromol/Lhigh |
60-110 |
|
Urea |
27.2 mmol/L high |
3.2-6.6 |
|
Mean cell volume |
71 fetolitre low |
77-91 |
|
Osmolality |
306mosml/Kg |
275-295 |
