Common learninG ISSUESPBL 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:• Sodium• Chloride• Potassium• CO2/Bicarbonate• BUN• Creatinine• Glucose

• CMP/Chem-12:• Same as BMP plus:• 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)• 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• 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)• 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, polycythemia, dehydration, macrocytic anemias,living at altitude, congenital heart diseases (response to hypoxia), COPD

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• 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• 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• Measures RBC• Hemoglobin• Hematocrit• RBC Indices• WBC count• Blood smear• Platelet count• Mean platelet volume

CBC• Mean corpuscular volume ( MCV)• 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

• 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

• 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:• NTD, ABDOMINAL WALL DEFECTS• MULTIPLE FETUSES• THREATENED ABORTION• FETAL DISTRESS OF CONGENITAL ANOMALIES• FETAL DEATH

ALPHA FETOPROTEIN• 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

APGARClinical 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