Transcript lab_ex_41A
Urinalysis & Electrolytes Ex 41A Urine Definitions specific gravity compares the relative weight of water to the weight of other elements water = 1 (1ml of water=1g) iron = 7.85 (in other words, iron is 7.85x more dense than water) gold = 19.3 potassium = 0.85 would a pure potassium tablet float or sink in water? pH Urinalysis Dipstick color changes when urine is placed on a test strip. each pad reacts with a color change to different chemicals squares vary depending on manufacturer so be careful Leukocytes, nitrite, urobilinogen, protein, pH, blood, ketones, bilirubin, glucose Urinalysis: Normal normal range comments color clear to yellow •color due to urochrome, a metabolite of hemoglobin breakdown •urine is usually darker when urine output is low odor slight musky to asparagus •the subway smell comes from bacteria breaking down urea to ammonia specific gravity 1.001-1.030 •higher when urine output is low (dehydration) •if > 1.035 possible diabetes or radioopaque dye sodium —— •high concentration with dehydration pH 4.5-8.0 (ave. 6.0) •acid with high protein consumption •alkaline with high flora consumption wastes urea, uric acid, creatinine •urea from protein breakdown •uric acid from purine (DNA) breakdown •creatinine from muscle metabolism other solutes •potassium, phosphate, sulfate, calcium, magnesium, bicarb, etc. Abnormal Urine abnormality cause glycosuria •high serum glucose (>250-300), exceeds rate of reabsorption by PCT •diabetes albuminuria •disruption of glomerular filtration membrane allows plasma protein albumin to pass through •physiologic: exertion, pregnancy, high protein intake •pathologic: HTN, diabetes, trauma, bacterial toxins, etc ketonuria •ketones in urine are a sign of excessive fat metabolism •gives urine a fruity, alcohol smell •diabetes, weight loss, starvation hematuria •red blood cells in urine •urine can be normally red from beets, red dyes, some drugs •nephrolithiasis (kidney stones), infections, trauma, disruption of filtration membrane Abnormal Urine abnormality cause bilirubinuria •due to accumulation of biliruben in the blood due to liver disease •cirrhosis of liver, hepatitis, gall stone obstruction of CBD urobilinogen •none could mean renal disease or biliary obstruction •increased could mean hepatitis, cirrhosis, biliary disease pyuria •white blood cells in the urine •causes urine to look cloudy and consistency is thicker •bladder infection (cystitis), kidney infection (pyelonephritis) hemoglobinuria •presence of hemoglobin (sign of hemolysis) •hemolytic anemia, transfusion reactions, burns Urine Micro cause epithelial cells •normal, due to shedding of cells along the urinary tract casts •caused by accumulation of materials in the tubules which eventually gets flushed out •WBC casts, RBC casts white blood cells •indicates either a bladder or kidney infection red blood cells •indicates either an infection or stones crystals •accumulation of solutes combined with deydration can cause crystals to precipitate and eventually form stones • uric acid and calcium stones are the most common Dipstick Colors Leukocytes normal is white (neg) any purple color is positive pyuria: leukocytes in urine cystitis: bladder infection pyelonephritis: kidney infection Dipstick Colors Nitrite normal is white (neg) any pink color is positive measures chemical produced by gram negative rods like E. Coli Dipstick Colors pH large range from 4.5 to 8.0 depends on what diet is like low pH: high protein diet, ketoacidosis uric acid can precipitate in acidic urine high pH: vegetarian diet phosphates precipitate in alkaline urine Dipstick Colors Protein normal is negative proteins cannot pass through glomerulus can be a normal condition after strenuous exercise, during pregnancy, excessive protein consumption Dipstick Colors Glucose normal is negative filtered load of glucose exceeding the maximal tubular reabsorptive capacity Dipstick Colors Ketones normal is negative may be present during fasting, diabetes, etc. Dipstick Colors Urobilinogen a small amount is normal may be present during fasting, diabetes, etc. Dipstick Colors Bilirubin normal is negative if bilirubin is high yellow foam can form when shaking a sample Dipstick Colors Blood normal is negative kidney stone, UTI, bladder tumor, menstruation More on solutes Sulfates normal in urine determined by intake of sulfur containing amino acids (protein) Phosphates normal in urine important for buffering H+ in the collecting duct Chlorides major extracellular anion used to maintain electrical neutrality More on solutes Urea end product from ammonia from amino acid breakdown Uric acid end product from purine breakdown Creatinine part of muscle breakdown from creatine phosphate Microscopic Examination WBC’s Normal men < 2 WBC/HPF women < 5 WBC/HPF WBC’s in urine can be a sign of inflammation along the urinary tract Microscopic Examination Hematuria Not normally found in urine can appear normal or crenated depending on hypertonicity of urine dysmorphic RBC’s can be a sign of glomerular disease Microscopic Examination Epithelial Cells too many squamous cells might be a sign of poor specimen collection transitional cells from renal pelvis, ureters, bladder or urethra large sheets of transitional cells may be a sign of cancer Microscopic Examination Bacteria small amount may be from contamination large amount may be sign of infection Microscopic Examination Crystals Struvite can form in alkaline urine, UTI with ureas producing bacteria (raise pH by increasing free amonia) Uric Acid gout (high serum uric acid concentration) Calcium Oxalate can occur in any urine pH asparagus, ethylene glycol Microscopic Examination Microscopic Examination Casts fragments of material that gets caught in the DCT and collecting ducts usually a sign of pathology hyaline casts made of mucoprotein secreted by tubule cells low urine flow, high salt concentration, low pH RBC casts sign of glomerulonephritis WBC casts indicates pyelonephritis or interstitial nephritis Microscopic Examination Fluid Compartments Fluid and Electrolytes Intracellular All fluid inside of body cells about 40% of body weight high in K+, Phosphaes (HPO4--), protein Extracellular All fluid outside of body cells Plasma, CSF, interstitial fluid and lymphatics make up the ECF about 20% of body weight high in Na+, Cl-, bicarb Comparison Between Fluid Components Acids, Bases and Buffers Buffers resist changes in pH by removing excess H+ or OH- from solution turn strong acids and bases into weak acids and bases Types of buffers carbonic acid active in ECF protein active in ICF and ECF phosphate active in ICF Acids, Bases and Buffers Acidosis pH below 7.35 causes CNS depression to coma if severe Alkalosis pH above 7.45 cases CNS excitability to spasms, convulsion Body can correct these abnormalities through respiratory compensation increase or decrease breathing renal compensation change the way the kidneys handle acids or bases Respiratory Acidosis Cause is elevation of pCO2 of blood Due to lack of removal of CO2 from blood emphysema, pulmonary edema, injury to the brainstem & respiratory centers Treatment (acute phase) ventilation therapy to increase exhalation of CO2 IV administration of bicarbonate (HCO3-) Renal compensation (chronic phase) increase H+ secretion increase HCO3- reabsorption Respiratory Alkalosis Arterial blood pCO2 is too low Hyperventilation caused by high altitude, pulmonary disease, stroke, anxiety, aspirin overdose Treatment (acute phase) breathe into a paper bag or better yet, fix the lung problem Renal compensation (chronic phase) decrease H+ secretion decrease HCO3- reabsorption Metabolic Acidosis Blood bicarbonate ion concentration too low loss of bicarb through diarrhea or kidney dysfunction production of fixed oragnic acids (lactic acid, ketones) kidney failing to remove H+ from protein metabolism Treatment IV administration of sodium bicarbonate correct the cause Respiratory compensation hyperventilation Metabolic Alkalosis Blood bicarbonate levels are too high Cause is nonrespiratory loss of acid vomiting, gastric suctioning, dehydration, excessive intake of alkaline drugs Treatment fluid and electrolyte therapy correct the cause Respiratory compensation hypoventilation