COMMON LEARNING ISSUES

PBL TEST 1 2012

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

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

ANTINUCLEAR ANTIBODY (ANA)

Used to diagnose systemic lupus erthematosus

(SLE) and other autoimmune disease

ANA is a group of protein antibodies that react

against cellular nuclear material

Normal findings negative at 1:40 dilution

ARTERIAL BLOOD GASES

Monitor patients on ventilators, monitor critically

ill nonventilator patients, establish preoperative

baseline parameters, and regulate electrolyte

therapy

pH –log[H+]• Acids normally found in blood: carbonic, dietary,

lactic and ketoacids• Elevated indicates alkalosis• Decreased indicates acidosis

BLOOD GASES

PCO2• Measure of partial pressure of carbon dioxide in the

blood• Measure of ventilation• 10% free floating in plasma, 90% carried by RBCs• Respiratory component of acid-base determination• Co2 and pH are inversely proportional

BLOOD GASES

HCO3- or CO2 content• Measure of the metabolic component of the acid-base

equilibrium• Regulated by the kidney• Directly proportional to pH• In alkalosis kidneys excrete more into the urine to lower pH

PO2• Pressure of oxygen dissolved in plasma• Indirect measure of O2 content• Determines effectiveness of oxygen therapy• Determines the force of oxygen to diffuse across the pulmonary

alveoli membrane

BLOOD GASES

Oxygen saturation• Percentage of hemoglobin saturated with oxygen• As PO2 decreases so does saturation of hemoglobin

Oxygen content• The amount of oxygen in the blood• Nearly all of it is bound to hemoglobin

Base excess/deficit• Amount of • anions in the blood, bicarbonate being the largest• Also hemoglobin, proteins, phosphates• Negative base excess indicates acidosis, positive alkalosis

BLOOD GASES

Alveolar to arterial oxygen difference• If gradient is abnormally high there is a problem in

diffusing oxygen across the alveolar membrane (thickened or edematous) or unoxygenated blood is mixing with oxygenated

• Thick walls due to edema, fibrosis, and RDS• Mixing occurs with septal defects, shunts or

underventilated alveoli still being perfused

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

Performed by a banding technique, pairing similar chromosomes

based on size, 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

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• Large: folic acid or B12 deficiency• Small: 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

Mean corpuscular hemoglobin concentration• Average concentration or % of hemoglobin within

RBC

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

CBC

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

Mean platelet volume• Measure volume of large number of platelets to

evaluate platelet disorders especially thrombocytopenia

CREATININE, BLOOD

. Normal Findings:

A. Elderly: Decrease in muscle mass may cause decreased values

B. Adult: Male: 0.6-1.2 mg/dL Female: 0.5-1.1 mg/dL

C. Adolescent: 0.5-1.0 mg/dL

D. Child: 0.3-0.7 mg/dL

E. Infant: 0.2-0.4 mg/dL

F. Newborn: 0.3-1.2 mg/dL

---creatinine clearance

1. used to measure the GFR of the kidneys

2. Normal Findings:

A. Adult (<40 yrs): Male: 107-139 mL/min Female: 87:107 mL/min

B. Values decrease 6.5 mL/min/decade of life after age 20 yrs with decline in GFR

C. Newborn: 40-65 mL/min

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

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

ERYTHROCYTE SEDIMENTATION RATE

no-n-specific test used to detect illnesses associated with acute and

chronic infection, inflammation, advanced neoplasm, and tissue necrosis or

infarction

Measure rate at which RBC settle in saline solution or plasma per unity

time

RBC will settle faster with illness

Male up to 15 mm/hr

Female up to 20 mm/hr

Child up to 10 mm/hr

New born 0-2 mm/hr

ESTROGEN FRACTION

EstradiolSerum (pg/mL)

Urine mcg/ 24 hr

Child <10 <15 0-6

Adult male 10-50 0-6

Adult female

Follicular phase

25-350 0-13

Midcycle peak 150-750 4-14

Luteal phase 30-450 4-10

postmenopausal

<20 0-4

ESTROGEN FRACTION

estriol Serum (ng/mL) Urine mcg/ 24 hr

Male, child, postmenopausal

1-11

Follicular phase 0-14

Ovulatory phase 13-54

Luteal phase 8-60

1st trimester <38 0-800

2nd trimester 38-140 800-12,000

3rd trimester 31-460 5000-12,000

ESTROGEN FRACTION

Total estrogen serum Urine mcg/ 24hr

Male or child 4-25

Female not pregnant

4-60

1st trimester 0-800

2nd trimester 800-5000

3rd trimester 5000-50,000

ESTROGEN FRACTION

Evaluate sexual maturity, menstrual problems, and fertility

problems

Evaluate males with gynecomastia or feminization

In pregnancy it indicates feto-placental health or tumor

marker

FSH and LH stimulate ovaries to make estradiol (E2)• Peaks during ovulatory phase of menstrual cycle• Menopausal status, sexual maturity, fertility problems,

gynecomastia, feminization syndromes, and tumor mark for ovarian tumors

ESTROGEN FRACTION

E1 or estrone is major circulator after menopause

E3 (estriol) major estrogen in pregnant female assess placental function

and fetal normality, produced by placenta from estrogen precursors rising

values are good declining values mean fetoplacental deterioration,

preeclampsia/eclampsia, diabetes mellitus, anencephaly, death,

dysmaturity

Increased levels liver necrosis, adrenal tumor, hepatic cirrhosis,

hyperthyroidism

Decreased: turners, failing pregnancy, hypothryoidism or pituitarism,

stein-leventhal syndrome, menopause, anorexia nervosa

MATERNAL SCREEN TESTING

Potential birth defects or serious chromosomal/genetic

abnormalities

Women over 35 for downs, NTD, or abdominal wall defects

Double test hCG and AFP

Triple AFP, hCG, and estriol

Quadruple AFP, hCG, inhibin A, and estriol

With trisomy 21 AFP levels are 25% lower than normal hCG 2x

higher

Inhibin A just like hCG

PARTIAL THROMB OPLASTIN T IME (PT T)

Assess the intrinsic system and common pathway of clot formation

and to monitor heparin therapy

First phase of reactions is intrinsic system: factor XII forms complex

on subendothelial collagen

Extrinsic factors include thromboplastin

Prothrombin becomes thrombin converts fibrinogen to fibrin

Plasmin degenerates

Evaluates fibrinogen II (prothrombin, V, VIII, IX, X, XI, and XII

If any of these exist in inadequate quantities then PTT is prolonged

PTT

Vitamin K deficiency can prolong PTT II, IX, and X are

dependent

Coag factors are made in the liver so hepatocellualr

disease will prolong

Heparin inactivates prothrombin (II) no thromoplastin

Monitor heparin whose effects are short-lived if too

much is given protamine sulfate can reverse

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

PROTHROMBIN TIME

Adequacy of extrinsic system and common pathway

Activation of factor X in the presence of factor V

and phospholipid and calcium

Stimulates platelet aggregation and converst

fibrinogen to fibrin in clot stabilization

Factors I (fibrinogen) II (prothrombin), V, VII, and

X

PT

Hepatocellular liver disease (cirrhosis, hepatitis, neoplastic

invasive processes) I, II, V, VII, IX, X

Obstructive biliary disease bile necessary for fat absorption

decreases A,D,E and K are all fat soluble II, VII, IX, X all

dependent on vitamin K, differentiate from liver disease because

it responds to vitamin K

Coumarin ingestion (warfarin) interfere with vitamin K

associated factors; effects long lasting, can be fixed by vitamin K

RHEUMATOID FACTOR

Negative <60 units/mL

Used in the diagnosis of RA

RA: morning stiffness for 6 weeks, pain in at least one joint,

swelling in at least 1 joint, symmetric bilateral joint swelling,

presence of subcutaneous nodules, radiographic changes

Abnormal IgG made in synovial joints

IgG and IgM along with fc attack abnormal IgG

Immune complexes are activated and joint destruction begins

RF

Tests mainly for identification of IgM

Must be found in greater than 1:80 dilution

SLE may also give false positive

Tuberculosis, chronic hepatitis, infectious

mononucleosis and subacute bacterial endocarditis

may give false reading

Does not disappear in remission

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

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

Can be normal if there is liver and kidney disease

AMNIOCENTESIS

Performed on women whose pregnancies are high

risk (diabetic, obese, older)

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

ECHOCARDIOGRAPHY

Normal findings: normal position, size, and

movement of cardiac valves and heart muscle wall,

normal directional flow of blood within the heart

chambers

Performed to evaluate heart wall motion and detect

valvular disease, evaluate heart during stress testing

and identify and quantify pericardial fluid

Ultrasound procedure to evaluate structure and

function of heart

ECHO

M-mode echocardiography recording of amplitude and rate of

motion in real time

Two dimensional ultrasonic beam moved within one sector of the

heart 3D gives better image of heart wall and valves

Color flow: direction and velocity of blood flow within heart and

great vessels for valve function in regards to regurgitation

Septal defects, perfusion, valvular heart disease, prolapse, stenosis,

subaortic stenosis, tumors, aneurysm

Perflutren (definity or optison) provides enhancement of borders

OXIMETRY

>95% is normal

Monitors arterial oxygen saturation in patients at risk for

hypoxemia. Surgery, cardiac stress testing, mechanical

ventilation, heavy sedation, lung function testing or trauma

Non-invasive measures home many hemoglobin have oxygen

attached to them

Fetal oxygen saturation monitoring: if heart is in distress but

saturation is fine you can avoid c-section, placed on cheek

between 30 and 70%

EATING DISORDERS

Anorexia nervosa: refusal to maintain body weight (BMI below 17.5), afraid of

appearing fat, frequently staving but in denial, lacking insight, brought in by family

members, failure to make expected weight gain as child or adolescent, amenorrhea,

loss of libido or potency in men, depressive mood, irritability, social withdrawal,

insomnia, decreased libido, self-induced vomiting or purging, excessive exercise, use of

diuretics or appetite supressants

Increased corticotropin releasing factor, cortisol, growth hormone, serotonin,

decrease diurnal cortisol fluctuation, LH, FSH, TSH

Bradycardia, hypotension, arrhythmias, cardiomyopathy

Hypokalemia, hypochloremic metabolic alkalosis, increased BUN, edema

Dry skin dental carries, delayed gastric emptying, constipation, anemia, osteoporosis

FREMITUS

Palpable vibrations transmitted through the bronchopulmonary

tree to the chest wall as the patient is speaking. To detect use ball

or ulnar surface of hand to optimize vibration in bones of hand.

Repeat 99 or one one one

Is decreased or absent when the voice is soft or when the

transmission of vibrations from larynx to chest is impeded.

Causes of faint fremitus: very thick chest walls, obstructed

bronchus, COPD, fibrosis, pleural effusion, pneumothorax or

infiltrating tumor

HYPER-RESONANCE

Very loud, lower pitch, longer duration

Generalized hyper-resonance may be heard over

the hyper-inflated lungs of COPD or asthma, but it is

not reliable

Unilateral hyper-resonance suggests a large

pneumothorax or large air filled bulla in lung

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)

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

VITAL SIGNS

Doppler method detects arterial blood flow

vibrations, converts them to systolic normal for

males is 70 mmHg at birth 85 at 1 month and 90 at 6

months

Pulse is best found at femoral artery

VITAL SIGNS

age Average heart rate

Range

Birth 0-2 140 90-190

0-6 130 80-180

6-12 115 75-155

VITAL SIGNS

Fever can raise respiratory rates by 10 respirations per

minute for each degree centigrade of fever

Temperature rectal, oral and auditory canal (rectal in infants)• Usually above 99 degrees until after 3 years• May approach 101 in normal children in late afternoon after

vigorous activity• Above 100 <2-3 months may be a sign of a serious infetion

Respiratory rate 30-60 per minute• Birth – 2 months >60/minute cutoff• 2-12 months >50/ minute cutoff

VERTEX PRESENTATION

Presentation of any part of the fetal head during

birth

Head/neck in flexion so chin is pushed against

chest

May be different degrees of flexion

CONGENITAL ADRENAL HYPERPLASIA

Refers to disorders of adrenal steroid biosynthesis

that result in glucocorticoid and mineralcorticoid

deficiencies

Because of deficient cortisol biosynthesis,

increases in ACTH occurs, inducing adrenal

hyperplasia and overproduction of steroids that

precede blockage of enzyme production

21-hydroxylase (CYP21) deficiency is the most

common (95%)

CAH

Failure of CYP21 and 17 hydroxyprogesterone and

progesterone to 11 deoxycortisol and 11

deoxycorticosterone respectively with deficient

cortisol and aldosterone is to replace

Aim of treatment for class in 21 hydroxylase

deficiency is to replace glucocorticoids and

mineralcorticoids, suppress ACTH and androgen

overproduction and allow for normal growth and

sexual maturation in children

SOUTHERN BLOT

Used for identifying DNA sequences on gels

Produced when DNA on a nitrocellulose blot of an

electrophoretic gel is hybridized with a DNA probe

BMP VS. CMPBMP/Chem-7:

• Sodium• Chloride• Potassium• CO2/Bicarbonate

• BUN• Creatinine• Glucose

CMP/Chem-12:• Same as BMP plus:

• AST• ALT• Albumin• Bilirubin• Alkaline Phosphatase

SODIUM (NA)Normally 125-145 mmol/l

Collect in red top tube

Increased: Diabetes inspidius, exessive sweating,

Cushing’s syndrome

Decreased: Excess body water (CHF, renal failure,

small cell lung cancer, brain disorders),

hypothyroidism, vomiting, diarrhea, pancreatitis

CHLORIDE (CL)Normally 97-107 mEq/L

Collect in tiger top tube

Increased: Diarrhea, hyperalimentation

Decreased: Vomiting, renal disease, diabetic

ketoacidosis

POTASSIUM (K)Normally 3.5-5 mEq/L

Collect in red or tiger top tube

Hemolysis may falsely elevate level

Increased: Renal failure, Addison’s disease,

dehydration, ACE inhibitors, Spironolactone

Decreased: Diuretics, NG suctioning, vomiting,

diarrhea, metabolic alkalosis

CARBON DIXOIDE (CO2)

Normally 23-29 mmol/L

Collect in tiger tube top; don’t expose to air

CO2 excreted into blood as bicarbonate

Increased: COPD, severe vomiting

Decreased: Starvation, diabetic ketoacidosis,

diarrhea, dehydration

BLOOD UREA NITROGEN

Normally 5-20 mg/dl

Collect in tiger top tube

Increased: Renal failure, CHF, aminoglycosides

Decreased: Starvation, liver failure

BUN:Creatinine >20 suggests dehydration

BUN:Creatinine >30 suggests GI bleed

CREATININENormally <1.1 mg/dl

Collect in tiger or red top tube

Measures blood flow through kidneys

Increased: Renal failure, false positive seen in

diabetic ketoacidosis

Decreased: Muscle wasting, liver disease

GLUCOSENormally 80-140 mg/dl

Collect in red or tiger top tube

Slight increase normal with aging

Increased: DM, Cushing’s syndrome, pancreatitis,

thiazide diuretics

Decreased: Liver disease, malnutrition, sepsis,

endocrine tumors

AST/ALTAspartate Aminotransferase:

• Normally 7-42 IU/L• Increased: Liver disease,

muscle trauma, burns• Decreased: Vitamin B6

deficiency, dialysis• AST>ALT in alcoholic

hepatitis

Alanine Aminotransferase:• Normally 1-45 IU/L• Increased: Liver disease,

billary obstruction• ALT>AST in viral hepatitis

ALBUMINNormally 3.5-5 g/dl

Collect in tiger top tube

Best lab test for measuring protein

Decreased: Malnutrition, nephrotic syndrome,

alcoholic cirrhosis, inflammatory bowel disease,

metastatic cancer, leukemia, Hodgkin’s disease

BILIRUBINNormally 0.3-1 mg/dl

Collect in tiger top tube

Increased: Liver damage, hemolysis, billary

obstruction

ALKALINE PHOSPHATASENormally 25-160 IU/L

Collect in tiger top tube

Increased: Liver disease, billary obstruction, bone

tumors, healing fracture, hyperparathyroidism,

hyperthyroidism

Decreased: Malnutrition, excessive vitamin D

intake, pernicious anemia, zinc deficiency

WHITE BLOOD COUNTNormally 4500-11,000

Differential provides more clues to cause than

overall count does

Increased: Infection, inflammation, leukemia

Decreased: Bone marrow failure, vitamin B12

deficiency

CAUSE OF INCREASED DIFFERENTIALS

Basophils: Leukemia, s/p spleenectomy

Eosnophils: Allergies, asthma, parasites

Lymphocytes: Viral infections, leukemia

Monocytes: Bacterial infections, protozoan

infections, ulcerative colitis

Neutophils: Bacterial infection, noninfectious

tissue damage, metabolic disorders

H & HHematocrit: ~40-50% (lower in women, higher in

men)

The percentage of blood that is RBCs

Decreased with anemia and blood loss

Hemoglobin: ~12-16 g/dl (lower in women, higher

in men)

Does not acurately reflect acute bleeding because

plasma and RBC lost at same rate

COAGULATION STUDIES

Collect in blue top tube

PT: 11.5-13.5 second

INR: 0.8-1.4

Higher with mechanical heart valves or history of

thromboembolitic disease or atrial fibrillation

INR is now the standard measure reported

CAUSES OF POSITIVE VALUES ON UA

Bilirubin: Jaundice, hepatitis, fecal contamination

of sample

Blood: Stones, BPH, infection, Foley cath

Glucose: DM, pancreatitis, steroids

Ketones: Starvation, high fat diet, diabetic

ketoacidosis, vomiting, diarrhea, asprin overdose

CAUSES OF POSITIVE VALUES ON UA

Leukoesterase: UTI• Leukoesterase plus nitrates: 75% of UTI• Neither LE or nitrates: 92% not UTI

Protein: Renal failure, CHF