w/c 20-Jan-14 Flashcards

(86 cards)

1
Q

Treatment option for local therapy of a tumour that cannot be resected.

A

Radiotherapy.

Also used for pain control (bone cancer/ bone mets)

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2
Q

How does radiotherapy work?

A

Ionising radiation. 1. Direct damage 2. Indirect Damage

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3
Q

How does radiotherapy cause indirect damage?

A

Free radicals- more efficient than direct damage. Heats and therefore damages DNA

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4
Q

The use of radiation is the Gray. How many Grays are required to cause cell death?

A

10 Grays: Intermitotic death

Tissues with high proliferative rate express radiation damage relatively quickly

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5
Q

Which is more efficient at repair; tumour cells or normal body cells?

A

Normal body cells are better at repair than tumour cells.

This helps therapeutically.

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6
Q

What is the significance of Fractionation?

A

Total dose of radiation used to treat a tumour is divided into a number of fractions
- Spares normal tissues, allows repair and repop

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7
Q

How does Fractionation lead to increased tissue damage? (2 things)

A

Fractionation increases damage to tumour because of REOXYGENATION of cells and REDISTRIBUTION of cells into radiosensitive phases of cell cycle

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8
Q

What are the 4 ‘R’s of Radiation therapy?

Which ONE is a negative effect?

A
  1. Repair (tumour cells less able to repair DNA damage)
  2. Repopulation (negative effect)
  3. Reoxygenation
  4. Redistribution
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9
Q

What are the general principles of Reoxygenation?

A

Tumours often have a necrotic centre. A single dose of RT would kill of healthy oxygenated tumour cells but may not affect the hypoxic cells.
Death of vascularised cells will make room for SURVIVING HYPOXIC CELLS. (Then next fraction kills these)

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10
Q

Which stage of the cell cycle is most suspectible to Radiotherapy? What is the significance of this?

A

Significance: Redistribution (therefore Fractionation)
Most sensitive to Least sensitive
M>G2>G1>ES>LS
i.e. LATE S PHASE = MOST RESISTANT

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11
Q

Which particles are used in the linear accelerator?

A

Strontium-90
Iridium-192
Linerar accelerator higher technical maintenance but higher accuracy c.f. Cobalt-60 unit

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12
Q

Differences between electron beam and photon beam? (Penetration ability)

A

ELECTRON BEAM Various energies possible
Rapid dose reduction. Penetration 1.5-5.6cm, single fields
PHOTON BEAM: High penetration. Slow dose reduction, CT-based planning!

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13
Q

One use of radiation therapy is curative/ definitive. What is the other goal of RT?

A

Palliative i.e. pain reduction in osteosarcoma/ bone mets

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14
Q

When might RT be used as a post SX adjuvant TX?

A

MCT, Soft tissue sarcoma, Feline vaccine-associated sarcoma

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15
Q

When might RT be used as a primary TX?

A

Brain tumour, tumour of head and neck, MCT.

2/3 Nasal tumours= carcinomas

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16
Q

Prognosis of squamous Cell Carcinoma in dogs?

and in cats?

A
MIddle ages dogs, prognosis is SITE DEPENDENT.
Rostral: local control-->cure
Tonsillar < 10% survival after 1 yr
IN CATS = V.V AGGRESIVE 
Cauliflower shaped
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17
Q

Which type of biopsy should be taken for diagnosis of feline ISS

A

Feline injection site sarcoma: mesenchymal.
ALWAYS INCISIONAL BIOPSY.
The have to do radiotherapy after otherwise reoccurance

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18
Q

Adverse effects of RT Tx may not be apparent until the irradiated cells attempt ____

A

Mitosis.
Acute effect will resolve (rapidly dividing tissue)
Late effects (>6MNTS) can be permanent (slowly dividing tissue i.e. brain, bone, muscle, retina, CNS)

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19
Q

When do the acute side effects peak in RT Tx?

A

After the third week of radiation.
8-10 DAYS
Normal tissue reactions: inflamm of MM, dermatitis, keratitis, conjuctivitis, CNS.
Dermatitis: target cells: Stratum Basale (also alopecia)

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20
Q

Anorexia as a side effect to RT Tx is common in what species?

A

Cats (parenteral feeding?)

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21
Q

Treatment of RT Tx side-effects of brain demyelination

A

Corticosteroids

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22
Q

Where should the biopsy site be to avoid compromising subsequent treatment?

A

Biopsy site should lie within likely surgical field so biopsy site may be excised with the tumour

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23
Q

What direction of incisional should be made for biopsies on limbs? why?

A

Longitudinal incision when on tails of limbs. Since these incisions are easier to resect during future surgical procedures

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24
Q

In what type of tumour might pre-malignant change be an indication for prophalactic surgery?

A

Dermatitis on ear/nose tips. Pre-malignant change for squamous cell carcinoma.
Also gonadectomy is prophalactic

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25
The most active part of the tumour is normally situated at__
Normally situated at the periphery, incomplete excision leaves the most aggressive cells behind
26
When is lavaging the surgical site, with buffered saline indicated?
Only when contaminated e.g. perforation of a viscus. NEVER to remove seeded tumour cells (cell specific binding!)
27
Why are vascular occlusion techniques especially important when excising a Sarcoma?
Sarcomas metastasis by haematogenous spread (c.f. carcinomas= lymphatics). Ligation of venous/lymphatic drainage should be performed before ligation of arterial supply
28
Which type of tumour are normally removed by radical local excision?
Sarcomas. Tumour removed together with margins that extend into adjacent facial planes which are undisturbed by tumour growth. Tumours that result in the formation of a pseudocapsule
29
What is local excision? Example of a tumour where this would be indicated?
Tumour is removed through its natural capsule, immediate boundaries or with the minimum of adjacent tissues e.g. lipoma, histeocytoma (benign with no tendency for local infiltration)
30
Define heart failure
Inability of the heart to maintain a normal cardiac output at normal filling pressures
31
5 potential causes of heart failure
1. Pump failure (Systolic failure) 2. Volume overload 3. Pressure overload 4. Arrhythmias 5. Diastolic failure
32
Potential causes of volume overload (in cardiology)
Chronic increase in amount of blood that must be pumped by a given cardiac chamber. Due to either shunting of blood (VSD, PDA), regurgitation of blood (mitral insufficiency), aneaemia or increase metabolic demand
33
Which of the 5 potential causes of heart failure would aortic/pulmonary thrombosis be most likely to cause?
Pressure overload due to systemic or pulmonary hypertension (increase resistance)
34
Hypertrophic cardiomyopathy is an example of which of the 5 types of heart failure
``` Diastolic failure (impaired ventricular filling) c.f. dilated cardiomyopathy= failure of contraction= pump/systolic failure ```
35
Which autocrine mechanism is said to be chronically activated during heart failure?
Sympathetic stimulation is chronically activated. i.e. Sympathetic dominance mediated by cardiac beta-effects/ alpha-effects Increase HR/ Contractility and increase vascular resistance
36
Which endocrine effects are activated as a result of heart failure?
RAAS system, ADH, Natriuretic peptides (ANP) in response to ventricular stretch.
37
What effect does Angiotensin II have on vasculature?
ANGIO-TENSIN is a VASOCONSTRICTOR Also leads to aldosterone release form the zona glomerulosa of adrenal cortex leading to sodium/water retention therefore fluid retension and increase in vascular resistance
38
What can cause a dilutional hyponatraemia? | When in heart failure does this occur?
Non-osmotic ADH release. Free water retention in excess of sodium. Normally late stage heart failure; triggered by marked drop in blood pressure
39
Role of Natriuretic peptides in heart failure
Might site of manufacture, storage and release of ANP is the myocardium. Released in response to ventricular stretch
40
Volume overload leads to ___ hypertrophy
Eccentric hypertrophy (=maladaption)
41
Pressure overload leads to _____ hypertrophy
Concentric hypertrophy (=maladaption)
42
Starlings hypothesis states that normally there is a net ____ of fluid at the ARTERIAL end and a net ____ of fluid at the VENOUS end
Starling forces: Equilibrium of fluid exchange between hydrostatic and oncotic pressures ARTERIAL END: NET LOSS VENOUS END: NET GAIN
43
Right sided heart failure leads to
Increased vascular hydrostatic pressure therefore less gain of fluid at venous end = congestion
44
How can vasculitis lead to congestion/oedema
Vasculitis: Increased vascular permeability
45
Cavalier King Charles Spaniels are very predisposed to which cardiac pathology?
Mitral value insufficiency. Systolic murmur loudest caudal LEFT (remember PAM)
46
Which side would the tricuspid valve be heard (in the case of a murmer)
Caudal RIGHT
47
Larger horses are most likely to develop which cardiac abnormality?
Atrial fibrillation c.f. with ponies = septal defects
48
Difference between pale mucous membranes and cynotic membranes
Cyanosis indicates adequate haemaglobin but insufficient oxygen. Pale MM indicates poor peripheral circulation (vasoconstriction or anaemia)
49
What are the DDx for venous congestion e.g. jugular pulses or in horses long time for raised vein to drain?
- Heart failure | - Tumour in the mediastinum
50
Normal oral MM colour for horses
Salmon pink
51
What do the S1 and S2 heart sounds indicate?
s1: lub. start of systole (closure of AV valves) s2: dub. end of systole (closure of pulmonic/aortic valves)
52
What causes the 'dub' sound of heart beat?
s2= end of systole, start of diastole. | Closure of pulmonary and aortic valves
53
A sound between s2 and the next s1 is indicitative of
i.e. diastolic murmer. Implies ventricle is not filling properly; poor relaxation. Galloping rhythm e.g. Du-Lub-Dub
54
Murmurs in cats that vary with stress are especially characteristic of
Hypertrophic Cardiomyopathy.
55
What would the radiographic signs of LEFT ATRIAL ENLARGEMENT
Bulge on Caudodorsal aspect on LAT view | Focal bulge on mid left border on DV/VD view
56
Radiographic signs of RIGHT VENTRICULAR enlargement?
Increased sternal contact on lateral view
57
Which type of imaging is best for determining whether an animal is in HEART FAILURE?
Radiology. | Echocardiology is good for diagnosing TYPE of cardiac disease
58
What does BART stand for (in the context of colour dopler)
BLUE-AWAY (from transducer) | RED-TOWARDS (transducer)
59
Best echo view for overview of all 4 chambers?
Right parasternal long axis
60
During cardio echo exam, the aortic value looks like a
Mercedes logo
61
Normal measurements of LA:Ao?
Measure aorta to LA to aorta ratio Aortic: Mercedes logo! Dogs <1.5
62
You would expect an enlargement of the cardiac silhouette with which type of hypertrophy?
Eccentric hypertrophy-enlarged heart (caused by volume overload e.g. mitral insufficiency)
63
What heart disease might cause concentric hypertrophy
NO ENLARGEMENT IN CARDIAC SILHOUETTE. | Pressure load e.g. aortic stenosis
64
Radiographic signs of LEFT-SIDED HEART FAILURE
Pulmonary congestion | Pulmonary oedema
65
Radiographic signs of RIGHT SIDED HEART FAILURE
Hepatomegaly Peritoneal effusion Pleural effusion
66
Cardiomegaly indicators:
Number of intercostal spaces Position of trachea Distance between heart and diaphragm (should not be in contact)
67
Broncho-pneumonia is normally seen on which part of the lung (on radiograph)
Pneumonia is normally seen ventrally. | Pulmonary oedema is normally seen dorsally
68
Different graphs plotted with a) M mode echocardiography and b) spectral doppler
a) M-mode : depth against time | b) Spectral Doppler: Velocity against time graph
69
Normal vertebral heart scale range
VHS: 8.7- 10.7
70
On which radiology view is the apex seen most clearly?
Apex is seen more clearly on the left hand side
71
Murmurs that vary with stress are especially characteristic of which cardiac condition in cats?
Hypertrophic cardiomyopathy (HCM)
72
Which biomarker is increased in heart disease
B-type natriuretic peptides
73
Differentials list for asymptomatic cat with a murmur
HCM, Functional, Systemic hypertension, Hyperthyroidism, Anaemia, Congenital Heart disease. Therefore can rule out a using haematology, blood pressure, t4 concentration, urinalysis (protein in urine?)
74
Which viral agents can cause primary myocarditis?
equine herpes virus, equine viral arteritis (all cause viraemia i.e. blood bourne)
75
How does the size of the QRS complex vary between small animals and large animals?
Small animals: reflects shape/size of ventricular myocardium. Large animals: Extensive Pukinje fibre system. therefore QRS complex doesn't reflect shape/size of ventricular myocardium
76
How can 2nd degree AV block and Atrial fibrillation be differentiated?
2nd degree AV block: P waves without associated QRST complex. REGULAR PATTERN AF: Slow SA node rate, (high vagal tone). VARIABLE refractory periods
77
Difference between ATRIAL FIBRILLATION in Small Animals vs Large Animals
In contrast to SA, equine AF is frequently spontaneous and not due to cardiac disease.
78
What does the loudness of the murmur tell you about the size of the valve defect?
Small defect: Louder murmur (due to higher pressures!) | Large defect: Quiter murmur (lower pressures involved)
79
Majority of septal deficits in horses are down to...
VSD's (Ventricular Septal Deficits) - Over 90%
80
Which type of murmur is considered normal in the horse?
Physiological flow murmur - AORTIC FLOW MURMUR -Quiet, heart base, effect of exercise on murmur variable, The aortic valve is where S2 is loudest
81
Cor pulmonale is associated with what clinical signs?
Those of right heart failure -Jugular distention/pulsations Dyspnoea/Tachypnoea Due to underlying chronic pathology normally hopeless prognosis
82
When a horse has EIPH, the blood normally originates in the
Caudodorsal lung lobes. Capillary stress failure
83
Which type of drugs would be used to treat EIPH?
Diuretic furosamide to reduce circulating volume | Vasodilator - nitric oxide, (ace inhibitors?)
84
Prognosis of a cat with HCM and murmur and elongatewd cardiac silhouette
Normal size left atrium is a good prognostic indicator. | Murmur caused by systolic anterior motion of the mitral valve
85
Cat with severe HCM (enlarged cardiac silhouette and left atrium) is at imminant risk of ___
enlarged left atrium is poor prognostic indicator. | Cat is at imminant risk of arterial thromboembolism. Treat with aspirin or clopidogrel.
86
A cat presents with poydipsia and a very dilated right pupil which doesn't constrict when you shine a light in it. The cat also has a grade 3/6 murmur. What are the DDx?
Blindness in cats highly indicitive of HYPERTENSION. Polydipsea is highly suggestive of renal disease (as is azotemia) Treat hypertension with amlodipine (calcium channel blocker)(