Cancer
Antimetabolites
1. "counterfeit metabolites" 2. impairs cell division
Motor and sensory deficits caused by cancer or chemo
1. Compression of nerves 2. Thinning of bone, increasing fracture risk 3. pain from bone metastasis 4. peripheral neuropathy from chemo 5. chemo brain - altered cognition
Most common side effects of Multikinase inhibitors
1. Hypertension 2. nausea, vomitting, diarrhea, constipation 3. mucositis 4. mild neuthropenia/thrombocytopenia
Three classifications of the TNM cancer staging
1. Primary Tumor (T) 2. Regional Lymph Nodes (N) 3. Distant Metastasis (M)
Teach chemo patients with mucositis to follow these mouth care guidelines
1. Soft-bristled toothbrush or mouth sponge 2. rinse with plain water or saline frequently 3. rinse after meals, at bedtime, increase to every 2 hours then to 1 hour 4. avoid alcohol mouthwash 5. keep oral hygiene equipment clean 6. dentures in only at meals
Drugs that promote purine excretion
1. allopurinol 2. rasburicase 3. febuxostat
Acute side effects of radiation on the brain
1. alopecia, radio dermatitis of scalp 2. ear irritation 3. cerebral edema 4. nausea and vomiting 5. somnolence syndrome
Two common side effects common regardless of the radiation site
1. altered taste sensations 2. fatigue
Acute side effects of radiation on the abdomen and pelvis
1. anorexia 2. nausea and vomiting 3. diarrhea and proctitis 4. cystitis 5. vaginal dryness/vaginitis
Nerve-damaging drugs that can cause chemotherapy-induced peripheral neuropathy (CIPN) include
1. antimitotics 2. platinum-based drugs
Nursing priority for patients receiving BRMs
1. assess for complications of systemic inflammation
important care for patients with diarrhea
1. assess peri area - clean and dry 2. hydration status - electrolytes (potassium, mag)
Late side effects of radiation on the breast and chest wall
1. atrophy 2. fibrosis of breast tissue 3. lymphedema
Molecularly targeted therapy
1. biologic agents that target specific cancer cells 2. have less impact on normal cells
Thalidomide
1. biologic response modifier 2. reduces VEGF, which is needed to maintain blood supply to the tumor, causing malnourishment to the tumor and death of cancer cells
What preventive drug therapy is given to reduce infection risk in patients receiving chemotherapy?
1. biological response modifiers (BRMs) 2. growth factors to stimulate bone marrow production of immune cells
For patients with SIADH monitor for these signs of fluid overload
1. bouding pulse 2. JVD 3. crackles in lungs 4. increasing peripheral edema 5. reduced urine output
interferons
1. cell-produced proteins 2. slow tumor cell division 3. stimulate growth and activation of NK cells 4. cause cancer cells to resume normal function/appearance 5. inhibit oncogene expression
Extravasation management may include
1. cold compress to area 2. warm compress to area 3. antidote injection
Monoclonal antibody therapy
1. combines actions from immunotherapy and targeted therapy to help treat specific cancers 2. target specific antigens, bind to them 3. prevent cell division 4. make tumor cells more sensitive to chemo
superior vena cava syndrome
1. compression or obstruction of the thin walls of the superior vena cava by tumor growth or clots leading to congestion
Low spinal compression can cause
1. constipation 2. incontinence 3. difficulty starting, stopping urine
Effect of chemotherapy on blood components
1. destroys circulating blood 2. reduces replacement due to bone marrow suppression 3. reduces circulating leukocytes, erythrocytes, platelets 4. causes neutropenia, hypoxia, increased risk for infection, fatigue, impaired clotting 5. extreme risk for sepsis
Topoisomerase inhibitors
1. disrupt enzyme essential to DNA synthesis and cell division 2. leads to DNA breakage and cell death
Important considerations for oral chemotherapy
1. do not skip doses - can cause resistance 2. nurses wear PPE equipment 3. biohazardous - discard according to policy
Teaching points for patients with fatigue
1. encourage light exercise to promote energy 2. treat reversible causes such as anemia and depression 3. fatigue journal of when most tired, active periods 4. rest before important activities 5. do not ignore fatigue 6. nutrition - high calorie, high protein foods (yogurt, small amounts packed with calories)
Nursing priority for drug therapy with patients taking antiemetics for CINV
1. ensure adequate control to prevent uncontrollable nausea and vomiting 2. make sure given before chemotherapy 3. teach patient to continue even when CINV seems to be controlled
These biological response modifiers are used as supportive treatment for chemotherapy induced anemia, fatigue, and renal failure
1. epoetin alfa (epogen procrit) 2. darbepoetin alfa (aranesp)
Acute side effects of radiation on the chest and lung
1. esophagitis and pharyngitis 2. taste changes 3. pneumonia
What are the three interacting factors that influence cancer development?
1. exposure to carcinogens 2. genetic predisposition 3. immune function
Results of sepsis and disseminated intravascular coagulation
1. extensive bleeding from multiple sites 2. clots blocking vessels, decrease blood flow 3. pain 4. strokelike manifestations 5. dyspnea 6. tachycardia 7. reduced kidney function 8. bowel necrosis
These biological response modifiers are used as supportive treatment for chemotherapy induced neutropenia
1. filgrastim (neupogen) 2. Pegfilgrastim (Neulasta)
Interventions for patients with SIADH
1. fluid restriction 2. increased sodium intake 3. drug therapy
Side effects of TKI (Tyrosine Kinase Inhibitors)
1. fluid retention 2. electrolyte imbalances 3. bone marrow suppression
Side effects of interleukins
1. generalized inflammatory reactions 2. fluid shift, capillary leak 3. edema *flu-like symptoms
interleukins
1. help regulate inflammation and immunity (these are large group of substances the body makes) 2. can be synthesized as anticancer drugs
Biologic response modifiers (BRM)
1. help the body recognize cancer cells as foreign so the immune system will destroy them 2. improve immune function 3. enhance ability to repair and replace cells damaged by cancer treatment
Interventions for TLS
1. hydration - dilutes potassium levels and increases kidney flow rates 2.
Angiogenesis inhibitors side effects
1. hypersentivity 2. hyperglycemia 3. bone marrow suppression 4. anemia, neutropenia, thrombocytopenia
Growth factors to stimulate red blood cell and platelet production comes with these risks:
1. hypertension 2. blood clots 3. strokes 4. heart attacks
Most common side effects of vascular endothelial growth factor/receptor inhibitors (VEGFRIs)
1. hypertension 2. impaired healing 3. bone marrow suppression, neutropenia, thrombocytopenia
Antimitotic agents
1. interferes with microtubule formation and action 2. mitosis
Two common types of BRMs used as cancer therapy
1. interleukins 2. interferons
Tumor lysis syndrome
1. large numbers of tumor cells are destroyed rapidly 2. intracellular components release in bloodstream faster than can be eliminated 3.
CIPN commonly results in
1. loss of sensation in hands and feet 2. orthostatic hypotension 3. erectile dysfunction 4. neuropathic pain 5. loss of taste discrimination 6. severe constipation
Side effects of hormonal manipulation
1. masculinizing effects in women 2. stop in menstruation 3. breast tissue shrinks 4. fluid retention 5. acne 6. hypercalcemia 7. liver dysfunction 8. increased risk of venous thromboembolism
Grading of Malignant Tumors: G2
1. moderately differentiated 2. retain some of characteristics of normal cells 3. have more malignant characteristics than G1
These aspects of personal hygiene cannot be deferred for neutropenic patient, even if the patient is very tired and does not feel well.
1. mouth care 2. washing of axillary and perineal regions *should be performed every 12 hours
Most common side effects of proteasome inhibitors
1. nausea 2. vomitting 3. anorexia 4. abodominal pain 5. bowel changes 6. decreased taste sensation 7. peripheral neuropathy
Manifestations of spinal cord compression
1. neurologic changes 2. back pain 3. muscle weakness 4. heaviness in arms, legs 5. numbness, tingling in hands or feet 6. inability to sense hot or cold 7. unsteady gait 8. paralysis
Interventions for hypercalcemia
1. oral hydration 2. normal saline when IV hydration needed 3. loop diuretics to promote calcium loss in urine 4. dialysis for life-threatening hypercalcemia 5. bisphosphonates, calcitonin, oral glucocorticoids
Acute side effects of radiation on the head and neck
1. oral mucositis 2. taste changes 3. oral candidiasis 4. oral herpes 5. acute xerostomia (dry mouth) 6. dental caries 7. esophagitis and pharyngitis
Extravasation with vesicants can lead to
1. pain 2. tissue loss 3. infection
nursing priorities for patients with SIADH
1. patient safety 2. restoring normal fluid balance 3. supportive care
Late side effects of radiation on the heart
1. pericarditis 2. cardiomyopathy 3. coronary artery disease
Grading of Malignant Tumors: G4
1. poorly differentiated cells 2. retain no normal cell characteristics 3. difficult or impossible to determine tissue of origin
Grading of Malignant Tumors: G3
1. poorly differentiated cells 2. tissue of origin usually can be established 3. few normal cell characteristics
Precautions taken with patients receiving sealed radiation implants
1. private room with private bath 2. "Radioactive Material" caution door sign 3. lead shield at door, keep door closed 4. carry dosimeter during care 5. lead apron worn during care 6. no pregnant women or visitors under 16 7. half hour visits only 8. 6-foot distance from source 9. Dressings/linens removed after radioactive source is removed
Priority care during chemotherapy
1. protecting patient from life-threatening side effects 2. management of distressing symptoms
Priority care for patients who have undergone cancer surgery
1. psychosocial support* 2. assist patient achieve maximum function* 3. early mobility 4. pain management 5. prevention of infection
Advanced cancers often cause
1. reduced immunity and blood-producing functions 2. altered GI structure and function 3. motor and sensory deficits 4. decreased respiratory function
Effect of SIADH on blood
1. retained water dilutes blood sodium levels 2. weakness, muscle cramps, loss of appetite
Oncologic emergencies
1. sepsis and disseminated intravascular coagulation 2 . syndrome of inappropriate diuretic hormone 3. spinal cord compression 4. hypercalcemia 5. superior vena cava syndrome 6. tumor lysis syndrome
severe complications of hypercalcemia
1. severe muscle weakness 2. loss of deep tendon reflexes 3. paralytic ileus 4. dehydration 5. electrocardiographic changes
Benefits of BRM supportive therapy
1. shorter period of bone marrow suppression 2. patients may be able to tolerate higher doses of chemo, increasing chance for cure
Common manifestations of hypercalcemia
1. skeletal pain 2. kidney stones 3. abdominal discomfort 4. altered cognition 5. nausea, vomiting, fatigue, loss of appetite, constipation, increased urine output
Patients with neutropenia should be taught to report any
1. skin changes - pimple, sore, rash, open skin area 2. cough 3. burning on urination 4. pain around venous access site 5. new drainage from any body area
Acute side effects of radiation on the breast and chest wall
1. skin reactions 2. esophagitis
Most common side effects of EGFRIs (epidermal growth factor receptor inhibitors
1. skin reactions - rash, peeling, issues 2. cardiac effects
Priority nursing intervention for patients with alopecia
1. teach patients how to avoid scalp injury 2. assist in coping with body image change
Results of severe or untreated TLS
1. tissue damage 2. acute kidney injury 3. death 4. hyperkalemia 5. uric acid crystals forming in kidneys
Grading of Malignant Tumors: G1
1. tumor cells well differentiated 2. closely resemble normal cells from which they arose 3. low grade of malignant change 4. malignant but slow growing
Common targeted therapy agents
1. tyrosine kinase inhibitors 2. epidermal growth factor receptor inhibitors (EGFRIs) 3. vascular endothelia growth factor receptor inhibitors (VEGFRIs) 4. multikinase inhibitors 5. proteasome inhibitors 6. monoclonal antibodies
Late side effects of radiation on the head and neck
1. xerostomia 2. dental caries 3. trismus (jaw spasm causing forced closed) 4. osteoradionecrosis (bone death) 5. hypothyroidism
Other drugs used as antiemetics
1. zofran (endo...) 2. steroids 3....
A slow-growing tumor has a mitotic index of less than
10%
Platelets lower than _____ can cause spontaneous and uncontrollable bleeding to occur
20,000
fluid consumption for patients with tumors known to be very sensitive to cancer treatment
3-5 L day before, day of, and for 3 days after cancer therapy
Even small trauma can lead to prolonged bleeding when platelet count is less than
50,000
A fast-growing tumor has a mitotic index of greater than
85%
Cytoprotectants/chemoprotectants
Agents given ahead of or with chemotherapy to decrease the impact of these drugs on normal tissue
The gaining or losing of whole chromosomes and possible structural abnormalities of remaining chromosomes
Aneuploidy
The client receiving brachytherapy with implanted radioactive "seeds" for prostate cancer asks the nurse when these seeds will be removed. What is the nurse's best response? A. "The half-life of radiation in these seeds is so short that it is not necessary to remove them." B. "They will only be removed if their presence is painful or leads to an enlarged prostate gland." C. "When we know for certain that all cancerous cells have been killed, the seeds will be removed." D. "The seeds are small enough to be absorbed by your body and excreted in the urine or stool."
Answer: A Rationale: The seeds are small and painless. The half-life of the radiation source is less than 2 weeks. Thus, it is not necessary for the seeds to be removed because they pose no health hazard to the client or anyone else. They are neither absorbed nor excreted by the body.
Which precaution is most important for the nurse to teach the client who has chemotherapy-induced peripheral neuropathy? A. Avoid taking aspirin or any aspirin-containing products. B. Use a bath thermometer to check bath water temperature. C. Do not use mouthwashes that contain alcohol or glycerin. D. Bathe daily using an antimicrobial soap or gel.
Answer: B Rationale: Peripheral neuropathy reduces the ability to discriminate temperature sensation. It is very easy for a person with neuropathy to be unaware of water temperature and to become injured as a result of water for bathing or showering being too hot. Aspirin, although important to avoid when platelets are low, is not contraindicated with peripheral neuropathy. Alcohol or glycerin mouthwashes are contraindicated for mucositis, not peripheral neuropathy. Bathing with an antimicrobial soap helps prevent infection but does not prevent injury.
The client receiving high-dose chemotherapy who has neutropenia asks the nurse whether he and his wife can have sexual intercourse while he is receiving chemotherapy. What is the nurse's best response? A. "No, this activity will increase the side effects of the chemotherapy." B. "No, the danger of impregnating your wife is too great." C. "Yes, as long as you feel like it and use a condom." D. "Yes, if you do not have an infection."
Answer: C Rationale: Many people do not feel well enough to have sexual intercourse during the months they are taking chemotherapy. This activity is fine as long as the client takes precautions to limit chemotherapy drug exposure to his partner and protects himself from infection and trauma. Wearing a condom reduces chemotherapy drug exposure to his partner (as a result of any drugs
Which pathologic description of a client's tumor does the nurse interpret as being the "most malignant" or "high grade" cancer? A. Poorly differentiated; mitotic index = 20%, euploid B. Moderately differentiated; mitotic index = 50%, euploid C. Undifferentiated; mitotic index = 50%, aneuploid D. Highly differentiated; mitotic index = 10%, aneuploid
Answer: C Rationale: Tumors that closely resemble normal cells are "less malignant," and those that have few normal cell features are "more malignant." Thus, those that are euploid are less malignant and those that are aneuploid, with abnormal numbers or structures of chromosomes, are more malignant. Less malignant cells are highly differentiated, and more malignant cells are poorly or undifferentiated. Cells that divide faster (have a higher mitotic index) are more malignant.
Which change in health status indicates to the nurse that the client's superior vena cava syndrome is worsening? A. The client's systolic blood pressure is rising, and the diastolic pressure is decreasing. B. The client's severe nausea and vomiting no longer responds to antiemetics. C. The client has experienced four nose bleeds in the past 2 days. D. Pedal edema is now present.
Answer: C Rationale: With superior vena cava syndrome, blood flow through the vena cava is compromised as a result of tumor growth. As blood backs up in the venous system drained by the superior vena cave, pressure in the veins increases and nose bleeds (epistaxis) occur easily and more frequently. The increased venous pressure would not increase systolic pressure. Response to antiemetics is not affected by superior vena cava syndrome. Pedal edema could occur in response to a blockage in the inferior vena cava but not the superior vena cava.
Seven warning signs of cancer
C.A.U.T.I.O.N. Changes in bowel or bladder habits A sore that does not heal Unusual bleeding or discharge Thickening or lump in breast or elsewhere Indigestion or difficulty swallowing Obvious change in a wart or mole Nagging cough or hoarseness
A 65-year-old client tells the nurse she does not have mammograms because there is no history of breast cancer in her family. What is the nurse's best response? A. "You are correct. Breast cancer is an inherited type of malignancy and your family history indicates a low risk for you." B. "Performing breast self-examination monthly at home is sufficient screening for someone with your family history." C. "Because your breasts are no longer as dense as they were when you were younger, your risk for breast cancer is now decreased." D. "Breast cancer can be found more frequently in families; however, the risk for general, nonfamilial breast cancer increases with age."
D. "Breast cancer can be found more frequently in families; however, the risk for general, nonfamilial breast cancer increases with age."
Staging of Cancer (TNM classification): M1
Distant metastasis
Grading of Malignant Tumors: Gx
Grade cannot be determined
Staging of Cancer (TNM classification): N1, N2, N3
Increasing involvement of regional lymph nodes
Staging of Cancer (TNM classification): T1, T2, T3, T4
Increasing size and/or local extent of the primary tumor
Staging of Cancer (TNM classification): M0
No distant metastasis
Staging of Cancer (TNM classification): T0
No evidence of primary tumor
Staging of Cancer (TNM classification): N0
No regional lymph node metastasis
Staging of Cancer (TNM classification): Mx
Presence of distant metastasis cannot be assessed
Staging of Cancer (TNM classification): Tx
Primary tumor cannot be assessed
Priority nursing care for patients with thrombocytopenia
Provide safe environment
Staging of Cancer (TNM classification): Nx
Regional lymph nodes cannot be assessed
Priority teaching intervention during radiation therapy
Skin care!: 1. do not remove ink markings 2. avoid skin irritation from clothing 3. follow radiation department's policy on use and timing of skin care products
Nadir
The time when bone marrow activity and white blood cell counts are at their lowest levels after cytotoxic therapy.
Normal cells most affected by chemotherapy
Those that divide rapidly: 1. skin cells 2. hair, intestinal tissues, spermatocytes, blood-forming cells
What life-threatening effect can interleukins have?
Tissue swelling can affect function of all organs
cytokines
a type of biologic response modifier
The single most important risk factor for cancer is
advancing age (due to decrease in immune strength)
What is a possible issue with receiving monoclonal antibodies?
allergic reactions due to incorporation of non-human proteins
Main side effect to monitor for in any biologic therapy
anaphylaxis
Invasion of the bone marrow by cancer causes
anemia and thrombocytopenia *may also be caused by chemotherapy
Direct sun exposure should be avoided for how long following radiation therapy?
at least 1 year
sepsis and disseminated intravascular coagulation
bacterial invasion of blood stream that triggers extensive abnormal clotting, causing extensive bleeding from many sites
This type of radiation involves internal delivery of radiation and results in a patient that emits radiation for a time that has the potential to harm others
brachytherapy
Typical sites of metastasis of lung cancer
brain, bone, liver, lymph nodes, and pancreas.
Staging of Cancer (TNM classification): Tis
carcinoma in situ
effect of hyperkalemia in severe or untreated TLS
cardiac dysfunction
Priority nursing action for targeted therapy
careful assessment for adverse reactions
People with this type of cancer most commonly report symptoms of this
chemo brain
CINV
chemotherapy induced nausea and vomiting
Adjuvant therapy
chemotherapy used along with surgery or radiation
Acute side effects of radiation on the eye
conjunctival edema and tearing
Proteins that promote cell division
cyclins
This drug may start nausea and vomiting almost as soon as it is administered
dacarbazine
Antitumor antibiotics
damage the cell's DNA and interrupt DNA or RNA synthesis.
Effect of chemotherapy on cells
damages DNA and interferes with cell division
Side effects for patients on hormone manipulation therapy
dependent on hormones manipulated *table 22-7
Assessment of the amount of time it takes for a tumor to double in size is called
doubling time
Side effects of chemotherapy
due to systemic effects: 1. hemorrhagic cystitis 2. cardiac muscle damage 3. loss of bone density 4. anemia 5. neutropenia 6. thrombocytopenia 7. nausea, vomiting, altered bowels 8. alopecia 9. mucositis (open sores on mucous membranes) 10. anxiety 11. sleep disturbances 12. skin changes 13. cognitive function changes
Drug therapy for SIADH
emeclocycline (Declomycin)
Normal chromosome count is referred to as
euploidy
The amount of radiation delivered to a tissue is called
exposure
A serious complication of IV infusion, which occurs when drug leaks into the surrounding tissue.
extravasation (infiltration)
This may be the only assessment finding in patients with the start of serious complications from cancer
fever (100 or higher)
This treatment is used to stimulate production of red blood cells and platelets to improve clotting in patients with bone marrow suppression following chemotherapy.
growth factors, erythropoiesis-stimulating agents (ESAs): 1. darepoetin alfa (Aransep) 2. epoetin alfa (Epogen, Procrit)
Effect of hormonal manipulation for cancer treatment
helps control some types of cancer but does not cure the disease
Growth that causes tissue to increase in size by increasing the number of cells
hyperplasia
Growth that causes tissue to increase in size by enlarging each cell
hypertrophy
meds for diarrhea
imodium, imotal? imotil? limotyl?
Mucositis often develops here
in the entire GI tract, especially mouth *assess mouth and anus
Aim of BRM as supportive therapy for chemotherapy
induce rapid recovery of bone marrow after suppression due to chemo.
Most reliable test for hypercalcemia in cancer patients
ionized calcium levels
Most radiation therapy for cancer uses this type of radiation
ionizing
Reduced immunity and blood-producing functions is most commonly seen in these types of cancer
leukemia, hymphoma, and any cancer that invades bone marrow
Patients with severe rigors in response to interleukin therapy are treated with
meperidine (Demerol)
The assessment of the percentage of actively dividing cells within a tumor
mitotic index
The distinct and recognizable appearance, size, and shape of normal cell types
morphology
Any new or continued cell growth not needed for normal development or replacement of dead and damaged tissues - considered abnormal
neoplasia
This biological response modifier is used as supportive treatment for chemotherapy induced thrombocytopenia
oprelvekin (neumega)
Effect on oncogenes by carcinogenic agents or by events with loss of cellular regulation
overexpression of the the oncogenes, leading to cancer
Term for the classification of tumor chromosomes as normal or abnormal
ploidy
Patient safety measures for patients with SIADH
preventing fluid overload from worsening (causes pulmonary edema and heart failure)
Patients with cancer should have diets high in
protein and carbs
Late side effects of radiation on the lung.
pulmonary fibrosis
The amount of radiation absorbed by the tissue is called
radiation dose
Late side effects of radiation on the brain
radiation-induced fibrosis
Tumors with _____ (slow/rapid) growth usually are more sensitive to chemotherapy.
rapid
Most well known monoclonal antibody for targeted therapy, especially in non-Hodgkin's lymphoma
rituximab (Rituxan)
This biological response modifier is used as supportive treatment for chemotherapy induced leukopenia
sargamostim (leukine, prokine)
Antiemetic drug most often used in chemotherapy
serotonin (5-HT3) antagonists
This biological response modifier is used as supportive treatment for hormone-refractory prostate cancer
sipuleucel-T (provenge) (this is a vaccine)
Late side effects of radiation on the abdomen and pelvis
small and large bowel injury
Mucositis
sores in mucous membranes
This classification of cancer determines the exact location of the cancer and its degree of metastasis at diagnosis.
staging
If hemoglobin higher than 12 patient is at risk of
stroke hold growth factor drugs (epogen)
Priority nursing care for patients with cognitive changes due to chemotherapy
support the patient: 1. listen to concerns 2. teach to avoid behaviors that could further alter cognitive behavior - like alcohol, recreational drug use, activities with risk for head injury
Proteins that limit cell division
suppressor gene products
Priority nursing care for patients experiencing CIPN
teaching them to prevent injury (ie: lack of ability to sense excessive heat, cold, pressure)
Radiation delivered from a source outside of the patient.
teletherapy
Molecularly targeted therapies do not work unless
the cancer cell overexpresses the actual target substance
purpose of hormone manipulation therapy for cancer treatment
to control, not cure
These assessments should be performed every 8 hours for patients with neutropenia.
total patient assessment: 1. skin and mucous membrane inspection 2. lung sounds 3. mouth assessment 4. inspection of venous access device site
Positive sign that cancer treatment is effective
tumor lysis syndrome
secondary cancer prevention
use of screening strategies to detect cancer early, at a time when cure or control is more likely
primary cancer prevention
use of strategies to prevent the actual occurrence of cancer (ie: skin protection during sun exposure to avoid skin cancer)
Chemicals that damage tissue on direct contact
vesicants