RA100 - Blood, Skin, Eyes, Heart, GI Tract

Blood Characteristics

bright red in arteries, dark red in veins, 8% of body weight, 55% of blood is plasma

Blood Functions

supplies cells & tissues with oxygen & nutrients for growth, repair & other life activities
transports waste products including CO2
WBC, antibodies & other protective substances provide important defense against damage from injury & disease
helps regulate & equalize body temp by distributing heat to other body parts
transports hormones
helps maintain acid-base balance
maintains own volume & composition by forming clots

RBC

normal count 4.2-5.9M, life span approx 120 days,

effects of radiation on RBCs

radiation has a life-shortening effect on RBCs and can cause injury to the walls of blood vessels, which could result in hemorrhage. Fewer RBCs also results in less hemoglobin, leading to less O2 in tissue and a build up of CO2

HgB

Hemoglobin. Normal 12-16 F & 13.5-18 M. AVG 15gm/100dL

HCT

Hematocrit. 45-52% M & 37-48% F. Stop radiotherapy if HCT falls below 30%

Anemia

decrease of RBCs or decreased concentration of HgB, resulting in decreased ability to transport O2 & CO2.

symptoms: pale skin, light colored mucous membranes & nail beds, fatigue, dyspnea, hypoxia, low BP, rapid heart rate

Aplastic Anemia

chemical poisons (exposure): lead, drugs, benzene, arsenic, nitrogen mustard, gold. sometimes caused by overexposure to xray & other forms of radiation ***failure of blood cell production due to aplasia (malfunction of formation of red bone marrow cells)***

Pernicious Anemia

lack of mature RBCs caused by inability to absorb B12

Hemolytic Anemia

excessive destruction of RBCs - drug induced, autoimmune, mismatched blood

Sickle Cell Anemia

sickle shaped RBCs and accelerated hemolysis interfere with O2 transport, obstruct capillary flow, and cause fever, severe joint and ab pain

Hemolysis

alteration, destruction, or dissolving of RBCs causing HgB to be released into medium of cell suspension

Secondary Anemia

simple loss of blood or a defective formation of HgB caused by diseases. other causes are malignant tumors, infections, liver cirrhosis, thyroid deficiency & chronic kidney disease

Leukemia

increase in cancerous white blood cells, malignant leukocytes fill the marrow and bloodstream.

acute=immature, develops quickly, fatigue, bruise easily, get infections often

chronic=mature, develops slowly, may not know sick until abnormal routine blood test

AML (acute myeloid) CML (chronic myeloid)

ALL (acute lymphoid) CLL (chronic lymphoid)

Leukocytes

A type of WBCs. More radiosensitive than RBCs.

Effects of radiation on WBCs

1. dec number of circulating WBCs - injury

2. inc number of WBCs - reaction to injury. inflammation, temp rise

   1. continuous drop in WBCs - body succumbs to infection

leukopenia

reduction in number of circulating WBCs (abnormally low count of neutrophils)

WBCs

white blood cells. Normal count 4500-10500/mm3. lifespan 9 hours. stop radiotherapy when WBC count falls below 2000/mm3

***bacterial infections usually raise WBC while viruses usually lower***

types of WBCs

neutrophils - phagocytosis of bacteria & fungi, 54-62%

eosinophil - parasites, allergic inflammatory response, 1-3%

lymphocyte B cell - antibody to germs

lymphocyte T cell - return functionality of immune system to normal after infection, 25-33% (total B & T cells)

monocyte - present pathogens to T cells so they are recognized and killed, 3-7%

basophils - only WBC circulating around body, 1%

PLT

platelets. normal count 150k-350k/mm3. lifespan 8-10 days. stop radiotherapy when platelet count falls below 50K/mm3.

Thrombocytopenia

reduction in circulating platelets. if too low, blood won’t clot, excessive internal bleeding, could hemorrhage & bleed to death

Methods to reduce effects of treatment on blood

1. megavoltage radiation spares bone marrow

2. shield bone whenever possible

   1. careful monitoring & charting of blood values to show trends

Skin functions

protection of tissues

component of immune system

excretion of waste

sensory information

vitamin d production

***largest organ & most common cancer***

skin layers

epidermis, dermis, subcutaneous

What percentage of patients receiving radiation therapy will have observable skin reactions?

25%

Desquamation

Dry - skin surface becomes dry and begins to peel off in flakes. skin is scaly and itchy

Moist - weeping, painful, skin sloughing

Epilation

loss of hair due to exposure to radiation. new hair begins to grow in about 2 weeks post treatment. usually finer & different color

erythema

“red skin” caused by capillary congestion brought on by the dilation of the superficial capillaries

radiodermatitis

older term used to describe radiation reactions to the skin, “altered of impaired skin integrity”

telangiectasia

dilation of previously small or terminal vessels of an organ. sometimes seen in patients receiving high dose radiation to skin tissue. characterized by short purplish streaks

acute skin reactions

occurs in patients receiving radical, conventionally fractionated radiotherapy and follows a fairly predictable series of stages. will appear within 24 hours after single dose of aobut 450cGy. faint pink blush may appear (precedes main erythema)

latent period

interval between the effects of radiation and when it becomes visible

skin reaction stages

stage 1 - first degree erythema, 10-14 days following start of treatment, after dose reaches 1000-2000cGy. epilation begins and is reversible. no treatment indicated

stage 2 - around 4200cHy, bright red erythema (looks like sunburn). dry desquamation phase. keep area clean, reduce friction, no heatig pad, use cornstarch

stage 3 - 4800-5500cGy, erythema deeps to purple hue. moist desquamation. sweat glands may be destoryed and epilation may be permanent. patient feels ill and miserable

***stage 4 - very high, acute doses of radiation 6500cGy+ and is NOT a normal skin reaction. complete destruction of dermis & epidermis. healing is unlikely. treatment usually plastic surgery

OAR

organs at risk

chronic radiation dermatitis

late reactions to radiation injury to skin. after acute reaction, skin will show radiation effects for a long time

ischemia - deficiency of blood supply

pigmentation - from light to dark brown and patchy

thickening - may heal with considerable fibrosis of dermis layer, leathery feel with loss of elasticity

telangiectasia - broken capillaries

late ulceration - skin easily traumatized, healing is slow

secondary malignancy - radiation is carcinogenic!

necrosis - tissue death of treated areas

Skin tolerance dose

TD 5/5 = 5500cGy, telangiectasia

TD 50/5 = 7000cGy, necrosis & ulceration

management of skin reactions

no treatment of mild erythema

dry desq - wear cotton, silk, loose clothes, avoid heat/cold and chemical irritants, don’t itch, no deodorant or talcum powder

wet desq - neosporin ok, cleanliness important to prevent infection, no steroids they restrict bloodflow which is needed to heal, nurse may recommend 1% solution of gentian violet as protective coat

other issues regarding radiation induced skin reactions

pressure - from glasses, stiff collars, etc

heat - avoid! room temp only

infection - any suspected inf must be brought to dr attention

drugs - may affection radiosensistivity (doxorubicin/adriamycin/cisplatin)

diabetic patients - prone to sepsis, wounds heal slowly

washing - cleanliness essential. bathe daily in tepid water, no strong soaps, can use baking soda 1tsp per pint of water. showers preferable to bath to eliminated UTIs

shaving - avoid hot water & aftershaves. use electric shaver

drying - use soft clean towels and pat skin dry, avoid friction

clothing - loose natural fibers best

reactions - therapist should check & note if occuring too quickly

sun - keep treated area covered

high doses in limbs - leave a strip untreated if possible to avoid formation of tight inelastic bands of fibrous tissue from forming

factors influencing amount of skin damage

dose

site

vascularity of area

type of skin - light or dark

volume

fractionation

quality - of beam

field gap

Eye lens

most sensitive structure of the body

cataract formation

may be seen at doses as low as 100-200cHy to the lens. 500cGy+ cause significant cataract. treated like any other cataract. eye shields recommended

conjunctivitis

inflammation of conjunctiva (lines eyelids and surface of eye) seen at relatively low doses

keratisis

inflammation of cornea seen at doses around 2500-3000cGy - visible red veins that later darken to violet.

another complication is inhibition of lacrimal gland secretions. first inc in secretions, then diminished and become increasingly viscous. eyelids could stick together. loss of tears results in inc risk of infection

Iritis

inflammation of iris causing it to be dull and swollen with sluggish reactions. diminished vision, pain, tearing. wearing dark glasses helpful

eye tolerance dose

lens TD 5/5 1000cGy, TD 50/5 1800cGy, cataract

retina TD 5/5 4500cGy, TD 50/5 6500cGy, blindness

can radiating lens cause blindness?

No! only cataracts. other parts of the eye like retina, optic chiasma, optical nerve can cause blindness

during which treatments is the heart given substantial doses of radiation?

internal mammary nodes

carcinoma of the lung

mediastinum of pts with hodgkins disease (not as common)

radiation induced changes of heart depend on

total dose, fraction size, portion of heart treated, chemotherapy drugs used, presence of heart disease/family history, age, weight, blood pressure, smoking, cholesterol

synergistic cardio toxicity

seen in radiotherapy patients receiving concurrent chemo. can be minimized by well prepared plan to omit some chemo cycles pre & post radiation

acute pericarditis

inflammation of pericardium, membrane enclosing heart. presents with fever, tachycardia, sub-sternal pain and pericardial friction/rub. cardiac silhouette widened on xray. changes in heart sounds - scraping or grating noise. 4000cGy over 4 weeks to major portion of heart. not common

chronic pericarditis

radiation induced chronic pericarditis usually manifested by chronic constructive changes associated with myocardial & endocardial fibrosis in heart or with varying degrees of effusion. latent period about 6 months to several years. symptoms: dyspnea, chest pain, venous distention, pleural effusion

heart tolerance dose

TD 5/5 = 4000cGy (whole)

TD 50/5 = 5000cGy

pericarditis

3 salivary glands

sublingual

submandibular

parotid

largest salivary gland

parotid

mucous membrane tissue type

epithelial (stratified squamous)

xerostomia

dry mouth

most radiosensitive part of GI tract

small intestine

mucosal reactions

initially 1st degree erythema reactions. at about 1000cGy, slight reddening of area and inc in secretions. may be some edema. above 2000cGy, markedly red with discomfort. impairment of function begins (cell damage, tissue damage, system damage, related systems affected)

stomatitis

canker cores

salivary gland secretions

clean and protect teeth and gums from infection. reduction results in inc potential for infection.

peg tube

feeding tube inserted through ab wall into stomach

oral cavity reactions

fractions of about 180-200cGy/day common. at 2000cGy, xerostomia and loss of taste with edema and erythema.3000-3500cGy (2-3 weeks) viscosity of saliva increases, food & debris adhere to teeth & gums. amt and pH of saliva decreases becoming more acidic. can see patches of white pseudo membrane. 5000cGy+ (4-5 weeks) membrane becomes yellow and separates leaving a raw painful surface. breaths smells. smokers & drinkers affected more. STRESS ORAL CARE. reactions subside in about a month. immobilization is critical (bite block)

thrush

yeast like fungi grows on mucosa. independent of dose. spreads quickly, even outside treatment area. must be treated immediately. most common infection in oral cavity of radiotherapy patients

magic mouthwash

mild analgesic mouthwash, needs prescription. can help patients eat. xylocaine, pain reliever, antiinflammatory

oral cavity cancer diet

light, soft, high calorie foods, high in protein. milk & milk products, pudding & custards, eggs, cheese, yogurt, soups (room temp - esp beans & pea), protein supplements & vitamins. avoid spicy foods, hot drinks, alcohol & smoking. eat numerous small meals, gargle 10x day, blend food, boost milkshakes. must keep weight up

saliva substitutes

salivart, xerolube, oralube

esophagus tolerance dose

TD 5/5 5500cGy

TD 50/5 6800cGy

clinical stricture/perforation

esophagitis

pain on swallowing. antacids, soft diet & xylocaine viscous before meals may help. subsides 7-10 days. watch for candidiasis

stomach tolerance dose

TD 5/5 5000cGy

TD 50/5 6500cGy

ulceration and perforation

stomach reactions

doses of about 1600cGy in 10 days cause reduction of secretions (enzymes, HCL, and mucus). complaints of nausea & pain. as dose increases, dypoacidity, dyspepsia (diff digestion & spasms), bleeding & hematemesis (vomit blood) with anemia

compazine

anti-nausea drug

marijuana also used

intestine reactions

surface epithelium of small intestine renewed every 24-48 hours. significant dose results in loss of protective and absorptive functions. diarrhea and potential for infection follow. diarrhea very fluid, can lead to dehydration and loss of food, vitamins, electrolytes (avitaminosis). severe reactions associated with passage of blood and slime, ulceration & obstruction due to adhesions

anti-diarrheal drugs

lotomil, imodium at increased OTC dosingr

rectum reactions

acute reaction characterized by spasmodic contractions of anal sphincter with pain & persistent desire to empty the bowel with involuntary, ineffectual straining efforts (tenesmus). patient believes diarrhea, but only passing mucus.

radiation proctitis - inflammation of last 6 inches of rectum

if severe reactions, pt may be given a 2 week rest

intestine & rectum tolerance doses

intestine & colon TD 5/5 4000cGy, TD 50/5 5500cGy. Obstruction perforation, fistula

rectum TD 5/5 6000cGy, TD 50/5 8000cGy. Stenosis, necrosis, severe proctitis, fistula

GI diet (not oral)

light, low fat, bland, low-residue diet. drink plenty of fluids, avoid all roughage. no spicy food, alcohol, milk, or other flatulence producing foods

GTV

gross tumor volume. what you can palpate and see

CTV

clinical target volume. add margin to get microscopic disease

PTV

planning target volume. account for margin of human error