Common learninG
ISSUES
PBL TEST 1 2014
Carbon Dixoide (CO2)
• Normally 23-30 mmol/L
• CO2 excreted into blood as bicarbonate-> NOT THE SAME
THING AS PCO2
• Regulated by the kidneys; rough guide for acid-base studies
• Increased: COPD, severe vomiting, primary cause of
metabolic alkalosis; kidney compensation in respiratory
acidosis
• Decreased: Starvation, diabetic ketoacidosis, diarrhea,
dehydration; primary cause of metabolic acidosis and a
response to respiratory alkalosis, loop diuretics,
BMP vs. CMP
• BMP/Chem-7:
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Sodium
Chloride
Potassium
CO2/Bicarbonate
BUN
Creatinine
Glucose
• CMP/Chem-12:
• Same as BMP plus:
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AST
ALT
Albumin
Bilirubin
Alkaline Phosphatase
Chloride (Cl)
• Normally 98-106mEq/L
• Major extracellular anion; follows Na to maintain
electroneutrality
• Increased: Diarrhea, hyperalimentation
• Decreased: Vomiting, renal disease, diabetic ketoacidosis
• Normally Cl values will not change by themselves; will
accompany shifts in either HCO3 or Na
creatinine
• In chronically unstable patients acute changes in renal
function can make real time evaluation of GFR difficult
• Cystatin C may be used for chronic kidney disease
• Clearance: amount of filtrate made
• Amount of blood to be filtered and ability of glomeruli to filter
Creatinine
• Normally <1.1 mg/dl
• Measures blood flow through kidneys (used to approximate
GFR)
• Increased: Renal failure, false positive seen in diabetic
ketoacidosis
• Decreased: Muscle wasting, (MINIMAL effect from liver
disease)
creatinine
• Catabolic product of creatine phsophate used in skeletal
muscle contraction, depends on muscle mass
• Excreted by kidneys and is directely proportional to renal
excretory function; serum levels should be constant
• Used to diagnose impaired renal function
• Unlike BUN it is minimally affected by hepatic function
• Approximation of GFR
• Suggest chronic disease
Glucose
• Normally 80-140 mg/dl
• Slight increase normal with aging
• Increased: DM, Cushing’s syndrome, pancreatitis, thiazide
diuretics, stress, steroids
• Decreased: Liver disease, insulin overdose, malnutrition,
sepsis, endocrine tumors, renal failure
• HIGHLY dependent on time of day, if pt was fasting, etc. HbA1c
is a better determinant of long-term glycemic controls.
Potassium (K)
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Normally 3.5-5 mEq/L
Major intracellular cation
Hemolysis may falsely elevate level
Increased: Renal failure, Addison’s disease, dehydration, ACE
inhibitors, Spironolactone
• Decreased: Diuretics, NG suctioning, vomiting, diarrhea,
metabolic alkalosis
Sodium (Na)
• Normally 136-145 mmol/l
• Major cation in extracellular space (was a question last year); major
determinant of extracellular osmolarity
• Increased: Diabetes inspidius, exessive sweating, Cushing’s syndrome, burns
• Decreased: Excess body water/excess intake (CHF, renal failure, small cell lung
cancer, brain disorders), hypothyroidism, vomiting, diarrhea, pancreatitis, SIADH
• Regulated by aldosterone; increased levels will stimulate ANP (Atrial naturietic
factor is stimulated by +Na), ADH (antidiuretic hormone, increased levels will
decrease levels of Na)
BUN
• Shock, dehydration, congestive heart failure, excessive protein
catabolism
• GI bleeding
• If kidney disease is unilateral and other kidney can take on role then
BUN won’t be affected
• Ureteral and urethral obstruction
• Liver disease decreased BUN (urea cycle takes place in the liver)
• Can be normal if there is liver and kidney disease
BUN
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10-20 mg/dL adult
Child and infant 5-18 mg/dL
Newborn 3-12 mg/dL
Rough and indirect measurement of renal function and GFR also a
measure of liver function
• Amount of urea nitrogen in the blood
• Urea is an end product of protein metabolism and digestion
• Elevated bun or azotemia
BUN (BLOOD Urea Nitrogen)
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Normally 10-20 mg/dl (adults)
Indirect measure of GFR and liver function
Increased: Renal failure, CHF, aminoglycosides
Decreased: Starvation, liver failure
BUN:Creatinine >20 suggests dehydration
BUN:Creatinine >30 suggests GI bleed
HEMATOCRIT
• Decreased levels: anemia (reduced number of RBCs), elevated white counts,
pregnancy, cirrhosis, hemolytic anemia (destruction of RBCs), iron/dietary
deficiency, bone marrow failure. Renal failure kidney makes EPO, collagen
vascular disease, anemia
• Increased levels:, erythrocytosis, polycythemia, dehydration, macrocytic
anemias,living at altitude, congenital heart diseases (response to hypoxia), COPD
• Values NOT reliable immediately after hemorrhage-a question last year;
percentage of total blood volume taken up by RBCs hasn’t changed. The value
will only decrease after fluid repletion
• Know figure 2-17, it was on last year’s exam
• Indications for transfusions (normally 24%)vary with age
Hematocrit
• Normal Values: Male 42-52% (.42-.52) Female 37-47% (.37-.47); Critical <15% or >60%
• Indirect measurement of RBC number and volume; regularly measured in a CBC
• Percentage of total blood volume made by RBCs; ratio of the height of the RBC column
after centrifugation compared to total height of column
• Approximately 3* Hgbn values under normal circumstances
• Women have lower values than men; also decreases with age
HEMOGLOBIN
• Measure of total amount of Hgb in peripheral blood-oxygen
carrying capacity of blood
• Women and elderly-decreased values
• Changes in plasma volume accurately reflected by Hgb
concentration (overhydration will increase, dehydration will
increase)
• Slight diurnal variation in Hgb levels (highest in the morning)
• Causes of high hgb: smoking, altitude
• Decreased levels (hypochromic): anemia (reduced number of
RBCs), elevated white counts, pregnancy, cirrhosis, hemolytic
anemia (destruction of RBCs), iron/dietary deficiency, bone
marrow failure. Renal failure kidney makes EPO, collagen
vascular disease, anemia
• Increased levels (hyperchromic):, erythrocytosis,
Platelet count
• Platelet count
• Number of platelets formed in bone marrow of megakaryocytes
• Adult/child 150,000-400,000
• Newborn/ premature infant: 100,000-300,000
• Infant 200,000-475,000
• Counts <100,000= Thrombocytopenia; >400,000=thrombocytosis; >1 million=
thrombocythemia
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Even pts with elevated blood platelet counts experience bleeding, because functions like aggregation
may be abnormal
Thrombocytopenia causes spontaneous bleeding, causing petechiae (small bruising) and echymoses
(large bruises)
• Survival in blood is 7-9 days
Platelet count
• Causes of thrombocytopenia: reduced production (bone marrow failure,
tumor); sequestration of platelets (hypersplenism), accelerated
destruction of platelets (antibodies, infections, drugs), disseminated
intravascular coagulation, hemorrhage,dilutional, thrombotic
thrombocytopenias like HELLP (eclampsia= hemolysis, elevated liver
enzymes, low platelet count).pernicious anemia (B12 is necessary for
platelet production)
• Causes of thrombocytosis: malignancys (leukemia, lymphoma, solid
tumors of the colon); polycythemia vera; postsplenectomy (it’s the
spleen’s job to destroy old “senescent” RBCS), rheumatoid arthritis, iron
deficiency anemia
RBC Count/erythrocyte count
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Normal findings: Adult male: 4.7-6.1; Adult female 4.2-5.4
Number of cicularing RBCS in 1 mm3 peripheral venous blood
Production is stimulated by erythropoeiten
Abnormal or old RBCs destroyed by the spleen; intravascular injury
like atherosclerotic plaques shortens the RBC life
• Overly active spleen will also destroy RBCs
• Anemia= 10% less than normal values
CBC
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Measures RBC
Hemoglobin
Hematocrit
RBC Indices
WBC count
Blood smear
Platelet count
Mean platelet volume
CBC
• Mean corpuscular volume ( MCV)
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Average volume or size of a single RBC
Divide hematocrit by total RBC count (Hct*10%/RBC)
Large “macrocytic”: folic acid or B12 deficiency
Small “microcytic”: iron deficient anemia or thalassemia
• RBC
• # circulating RBC
• Normal life span 120 days
• Lysed and extracted from circulation by spleen
CBC
• Mean corpuscular hemoglobin
• Measure of average weight of hemoglobin within RBC
• Hgbn*10/RBC
• Mean corpuscular hemoglobin concentration (MCHC)
• Average concentration or % of hemoglobin within RBC
(Hgbn*100/Hct)
• RBC distribution width
• Indicates variation of size of RBC
• Important in classifying anemias
CBC
• Blood smear
• Information concerning drugs and diseases that affect RBCs and
WBCs
• Examines RBC, platelet, and WBC
• White count
• Neutrophils, basophils, eosinophils, monocytes, lymphocytes
White Blood Count
• Normally 5,000-10,000
• Differential provides more clues to cause than overall count
does
• Increased: Infection, inflammation, leukemia, trauma, stress
• Decreased: Bone marrow failure, vitamin B12 deficiency
Cause of Increased Differentials
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Basophils: Leukemia, s/p spleenectomy
Eosnophils: Allergies, asthma, parasites
Lymphocytes (B cells/T cells): Viral infections, leukemia
Monocytes: Bacterial infections, protozoan infections,
ulcerative colitis
• Neutophils: Bacterial infection, noninfectious tissue damage,
metabolic disorders
ALPHA-FETOPROTEIN
• NORMAL FINDINGS < 40 ng/mL
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Child < 30 ng/mL
• Ranges vary by week of gestation normally detected at 10 weeks
• Peak levels at 16-18 weeks
• DECREASED LEVELS:
• TRISOMY 21
• FETAL WASTAGE
• INCREASED LEVELS:
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NTD, ABDOMINAL WALL DEFECTS
MULTIPLE FETUSES
THREATENED ABORTION
FETAL DISTRESS OF CONGENITAL ANOMALIES
FETAL DEATH
ALPHA FETOPROTEIN
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USED AS A SCREENING MARKER INDICATING INCREASED RISK FOR BIRTH DEFECTS (NEURAL TUBE, BODY WALL,
AND CHROMOSOMAL)
PRODUCED BY FETAL LIVER AND YOLK SAC IF THERE IS A BODY WALL DEFECT THE AFP WILL LEAK INTO AMNIOTIC
FLUID AND IS PICKED UP BY MATERNAL SERUM
ALSO ASSOCIATED WITH TUMOR MARKERS, HEPATOMA, TERATOMA, HODGKINS, LYMPHOMA, AND RENAL CELL
CARCINOMA
karotype
• Study an individual’s chromosome makeup to determine chromosomal defects
associated with disease or risk for developing disease
• Congenital or acquired because of duplication, deletion, translocation,
reciprocation, or genetic rearrangement
• Indicated with family hx of disease or advanced maternal age
• Performed by a banding technique, pairing similar chromosomes based on size
(arranged largest to smallest), location of centromere, banding patterns
• Congenital anomalies, growth and mental retardation, infertility, delayed
puberty, hypogonadism, amenorrhea, ambiguous genitalia, CML, neoplasm
recurrent miscarriage, turner, klinefelter, downs
hCG
• <5 for non-pregnant people, used to diagnose pregnancy, increases throughout
pregnancy, can be detected as early as 10 days post conception
• Secreted by placental trophoblast
• Immunologic test: high risk of false positive
• Beta subunit characteristic of hCG
• Radioimmunoassay: blood test for beta
• Radioreceptor assay performed in one hour reliable
• Ectopic pregnangy, hydatiform mole, and choriocarcinoma can produce
• Liver cancer cells as well
amniocentesis
• Performed on women whose pregnancies are high risk
(diabetic, obese, older); usually at 24-25 weeks (earliest
possible is 12-14 weeks)
• Indicate fetal maturity, distress, risk for RDS, genetic and
chromosomal abnormalities, sex, NTD
• Lung maturity (lecithin and sphingomyelin ratio) lecithin is a
major constituent of surfactant 2:1 indicates maturity; at 35
weeks rapidly increases
amnio
• Phosphatidyglycerol (PG) small component of surfactant,
produced by mature lung alveolar cells appear at 35 weeks
• Lamellar body count: produce by type II pneumocytes,
represent the storage of surfactant
• Microviscosity: aggregates dependent on L/S ratio and degree
of saturation of fatty acid side chains, high early decreases
later
amnio
• Rh isoimmunization: assess levels of bilirubin in amniotic fluid,
indicates severity of hemolytic anermia in Rh-sensitized pregnancy
higher bilirubin, lower fetal hemoglobin, early delivery or blood
transfusion may be indicated
• Anatomic abnormalities: increased AFP neural crest abnormality
• Fetal distress: pale, straw colored fluid tinged with green, yellow
indicates blood incompatibility, yellow-brown may be intrauterine
death red is blood contamination
Gravida-para
• Gravida = total number of pregnancies
• Para = or outcomes of pregnancies
• Often after you will see notations F (full-term), P (premature), A
(abortion), L (living child)
Twin pregnancies= 1 pregnancy. So a woman who has had one set
of twins= G1P2
apgar
• Key assessment of newborn immediately after birth 5
components take at 1 and 5 minutes after birth based on 0,1,
or 2, total score is 0-10, five minute score of 8+ move on to
full exam
• 1 minute score 8-10 normal, 5-7 some nervous system
depression 0-4 severe depression requiring immediate
resuscitation
• 5 minute score 8-10 normal, 0-7 high risk for subsequent
central nervous system and other organ dysfunction
APGAR
Clinical sign
0
1
2
Heart rate
absent
<100
>100
Respiratory effort
Absent
Slow and
irregular
Good, strong
Muscle tone
Flaccid
Some flexion of
arms and legs
Active movement
Reflex irritability
No response
Grimace
Crying vigorously,
sneeze or cough
color
Blue/pale
Pink body, blue
extremities
Pink all over