Intro to Radiology/Labs

ALARA

Acronym for radiation safety

As low as reasonably achievable

Radiolucent

No interference with the flow of x-ray particles

Black on X-ray

Radiopaque

Something lies between the beam of x-ray particles and the cassette that causes the beam to absorb or disperse

White on X-ray

Gas

Type of imaging density:

• Black on XRay

• Lungs

• Trachea

• Bronchi

• Gas in stomach/intestines

fat

Type of imaging density:

• Gray on X-ray

• Soft tissue, around muscle

water

Type of imaging density:

• Whitish, slightly radiopaque on X-ray

• Heart, BV, muscle, diaphragm

Metal

Type of imaging density:

• White on X-ray

• Calcium of ribs, vertebrae, scapulae, clavicles, prostheses, contrast media

PA & Lat upright

Best view of CXR

Order for:

• Fever of unknown origin, infants <6mo w/ fever

• Obvious airway compromise

• Pain w/ SOB

• Suspected aspiration

• Chest pain

KUB

Type of X-ray

• shows ileus, obstruction, neoplasm, gallstones, adhesions, stenosis, hearnias, volvulus & intussesception

upright ABD

Type of X-ray:

• This or L LAT decubitus with upright PA & LAT of chestà important to show bowel gas patterns, anatomical bony structure, soft tissue, bases of lungs

• check for FREE AIR under diaphragmà RED FLAG

perforation

Free air on X-ray under the diaphragm is indicative of…

Avoid contrast

• If cerebral bleed suspected

• Shellfish allergy

• Renal impairment

• If diabetic and on metformin (did not hold)

MRI indications

__ indications:

• For patient with negative plain films

• With continued pain or loss of functional ability (already had plain films)

MRI contraindications

__ contraindications:

• Cochlear implant

• Swan w/ thermodilution tip

• Implanted metal devices

• Foreign body

• Shrapnel

considerations in children

• Joint/bone pain in children, epiphyseal plate fracture is hard to catch

• Correlate clinical exam findings w/ X-ray, if normal but still having pain, splint and refer to ortho

pregnancy

Avoid X-ray/CT in… d/t radiation

specificity

Negative when the disease is not present

True negative

How specific is the test to what I’m looking for?

Sensitivity

Positive when the disease is present

True positive

How fast does this test trigger a positive result

hyponatremia

Excess water

Causes:

• edema

• adrenal insuff

• kidney/liver dx

• HF

• burns

• Meds (Hydrochlorothiazide, morphone, SSRIs)

hypernatremia

Insufficient water

Causes:

• dehydration

• cushing’s disease

• DI

hypokalemia

Causes:

• Diarrhea

• Fluid loss

• Starvation

• Malabsorption

• Alcoholism
  Meds: diuretics, ABX, steroids

hyperkalemia

Causes:

• Renal failure / kidney rejection

• Dehydration

• Hemolysis

• Meds: digoxin, K+ supplements, NSAIDs

bicarb (?)

Chloride has an inverse relation ship with which electrolyte?

hypochloremia

Causes:

• Massive diuresis

• Vomitting

• Prolonged diarrhea

• Over hydration

• H2O intoxication

• Resp. acidosis

hyperchloremia

Causes:

• Dehydration

• Resp. alkalosis

• Metabolic acidosis w/ prolonged diarrhea

• Salicylate toxicity

• DI

decreased co2

Causes:

• Severe diarrhea

• Starvation

• Acute renal failure

• Salicylate toxicity

• DKA

increased co2

Causes:

• Severe vomitting

• Emphysema

• Aldosteronism

• Diuretics

increased BUN

causes:

• impaired renal function d/t

• Dehydration

• CHF

• Salt and water depletion

• Shock

• Stress

• DKA

Decreased BUN

Causes:

• Liver failure

• Low protein diet/malnutrition

• Impaired absorption (celiac)

• SIADH

Increased Cr

Causes:

• impaired renal function

• urinary tract obstruction

• muscle disease

• dehydration

• shock

decreased cr

Causes:

• decreased muscle mass

• inadequate dietary protein

hypoglycemia

Causes:

• Insulinomas

• Liver damage

• Reactive

• Insulin overdose

hyperglycemia

Causes:

• Cushing’s

• Stress

• Pancreatitis

• Steroids

• Obesity

hypocalcemia

Causes:

• hypoparathyroid

• malabsorption

• malnutrition

• alcoholism

hypercalcemia

causes:

• cancers (MM, Hodgkins, lung)

• Excess intake (antacids, vitamin D)

• Parathyroid dx

Hct

Measures % of a given volume of whole blood that is occupied by the erythrocyte

Hgb

Main component of RBCs, transports o2 and co2

MCV

Indicates RBC size

MCHC (mean corpuscular hemoglobin concentration)

Measures average concentration of Hgb in the RBC (color)

More accurate than MCH

MCH (mean corpuscular hemoglobin)

Weight of hemoglobin in RBC (color)

Less accurate than MCHC

RDW

Index of variation of the size of the RBC

Earliest indicator of microcytic or macrocytic anemia

vitamin deficiency

What is elevated RDW always associated with?

RBC, HGB, HCT

Parts of CBC that tell us if the patient is anemic

MCHC, MCV, RDW

Parts of CBC that help us differentiate between anemia types

phagocytes

• Eosinophils

• Neutrophils

• Monocytes

are all ____

leukocytosis

Causes:

• Acute infection

• Steroids

• Surgery - reactive

leukopenia

Causes:

• Radiation

• Chemo

neutrophilia

Causes:

• Infection/inflammation/tissue damage

• Physiologic stress

• Chronic blood loss

• Myeloproliferative disorders

• Meds: steroids, digoxin, sulfonamides, and corticotropin

neutropenia

Causes:

• Severe sepsis

• Viral conditions

• Bone marrow suppression

• Starvation

• Meds: NSAIDs, antimicrobials, TCAs, cimetidine, allopurinol

• Anemia

shift to the left

Elevated WBC and neutrophils is called a …..

Eosinophillia

Causes:

• Allergies

• Hay fever

• Asthma

• Parasitic dx

• Subacute infection

• Addison’s dx

Eosinopenia

Causes:

• Mononucleosis

• HF

• Stress

• Meds: epi, thyroxine

basophilia

Causes:

• inflammation

• allergy

• influenza

• varicella

• TB

• splenectomy

chronic inflammation

What are basophils used to monitor?

basopenia

Causes:

• infection

• neoplasm

• hemorrhage

• hyperthyroidism

• inflammation

monocytosis

Causes:

• bacterial, viral, parasitic infections

• Hodgkin’s dx

• MM

• Inflammation (SLE, RA)

• Recovering from acute infection

Monocytopenia

Causes:

• Not usually significant if other indices are not affected

• Glucocorticosteroids

• Aplastic anemia

lymphocytosis

Causes:

• Mononucleosis

• Viral and bacterial infections

• Smoking

• Thyroiditis

lymphopenia

Causes:

• HIV

• Cushing’s syndrome

• Chronic uremia

• Severe burns/trauma

• Malignancy

• SLE

• Radiation/Chemo/Steroids

thrombocytopenia

Causes:

• Drug induced

• Gestational

• Viral infections

• Purpura

• Pregnancy

• Liver disease

thrombocytosis

Causes:

• Inflammation

• Acute blood loss

• Iron deficiency

• Post-splenectomy

neutrophils

Pyogenic infections

Bacterial

Left shift

eosinophils

Allergic disorders

Parasitic infections

“worms, wheezes, and weird diseases”

basophils

Parasitic infection

Some allergic disorders

lymphocytes

Viral infections (Measles, rubella, varicella, mono)

monocytes

Severe infections by phagocytosis

Increased iron

Causes:

• Thalassemia

• Acute iron poisoning

• Iron-overload

• Lead poisoning

• Multiple transfusions

Decreased iron

Causes:

• Iron deficiency anemia

• chronic blood loss

• chronic disease

• third-trimester of pregnancy

• inadequate absorption

transferrin sat

An index of iron saturation

increased transferrin saturation

Causes:

• Increased intake

• Acute liver disease

decreased transferrin saturation

Causes:

• Iron-deficiency anemia

• Malignant

• Anemia of chronic disease

Ferritin

Measure of iron stores. Reliable and sensitive assessment of body stores

increased ferritin

Causes:

• iron excess from supplementation

• alcoholic liver disease

• malignancy

decreased ferritin

Causes:

• iron deficiency anemia

reticulocyte count

Immature RBCs that circulate in blood for 24hrs before they mature.

Used to measure response to anemia treatment

increased retic count

Causes:

• hemolytic anemia

• 3-4d after hemorrhage

• after treatment for anemia

decreased retic count

Causes:

• Untreated iron deficiency anemia

• Aplastic anemia

• Anemia of chronic disease

• Alcoholism

increased B12

Causes:

• Liver disease

• Obesity

• Diabetes

decreased B12

Causes:

• pernicious anemia

• Malabsorption

• Zollinger-Ellison syndrome (pancreatic or intestinal tumors)

• Insufficiency dietary intake

increased folate

Causes:

• vegetarian diet

decreased folate

Causes:

• inadequate intake w/ alcoholism

• Chronic disease

• malnutrition

• anorexia

• liver disease

thyroid panel indications

__ __ indications:

• heart palpitations/irregular beat

• new onset a-fib

• rapid unexplained weight loss/gain

• nervousness

• insomnia

• unexplained menstrual disorders, myalgia, fatigue, weakness, constipation, HLD, anemia

• family hx - DM, high triglycerides, autoimmune

• Meds: lithium or amiodarone

TSH

Most sensitive test for hypothyroidism and hyperthyroidism