Clin Path MCQ1

Cardiovascular + Respiratory Systems

left sided heart failure effect on respiratory system

increased pulmonary pressure —> pulmonary oedema —> dyspnoea, tachypnoea, crackles

right sided heart failure effect on respiratory system

secondary to pulmonary hypertension —> from chronic hypoxia or interstitial lung disease

congenital heart disease effect on respiratory system

abnormal shunts (e.g. patent ductus arteriosus) —> over circulation of lungs —> congestion, respiratory distress

pericardial disease (tamponade) effect on respiratory system

decreased cardiac output —> poor pulmonary perfusion, hypoxia

patterns and appearance of bronchopneumonia

cranioventral consolidation, moist, firm, exudate-filled airways

patterns and appearance of pleuropneumonia

severe cranioventral pneumonia, fibrin on pleura, pleuritis

patterns and appearance of pleuritis

fibrin, adhesions, thickened pleura

patterns and appearance of emphysema

enlarged, overinflated alveoli, air bubbles in interlobular septa or subpleura

patterns and appearance of atelectasis

dark red, firm collapsed tissue often lobular and sunken

patterns and appearance of fibrinous inflammation

acute, yellow-tan fibrin exudate, easily peeled from serosal surfaces

patterns and appearance of fibrous inflammation

chronic, dense, fibrous tissue, firmly adhered

cause of cranioventral pulmonary lesions

aerogenous dispersion, gravity, airflow patterns favour pathogen settlement e.g. Bronchopneumonia, aspiration pneumonia

cause of caudodorsal pulmonary lesions

haematogenous, area with good blood supply e.g. Embolic pneumonia, metastatic neoplasia

cause of diffuse (interstitial) pulmonary lesions

viral, toxic, or allergic aetiologies, alveolar septa affected e.g. interstitial pneumonia

cause of focal/nodular pulmonary lesions

granulomas, neoplasia, abscesses e.g. TB nodules, metastases, embolic abscesses

cause of right middle lobe pulmonary lesions

predisposed to aspiration e.g. aspiration pneumonia

what is a restrictive respiratory issue

decreased lung compliance/expansion

restrictive respiratory pathology

pleural effusion, pulmonary fibrosis, oedema, mass

restrictive respiratory pathophysiology

decreased tidal volume, normal/increased respiratory rate

restrictive respiratory blood gasses

decreased PaO2, normal or decreased PaCO2 = type I respiratory failure

restrictive respiratory clinical signs

tachypnoea, shallow breathing, shortness of breath when lying down

what is an obstructive respiratory issue

airway narrowing or obstruction

obstructive respiratory pathology

asthma, chronic bronchitis, laryngeal paralysis

obstructive respiratory pathophysiology

increased airway resistance, air trapping

obstructive respiratory blood gases

decreased PaO2, increased PaCO2 = type II respiratory failure

obstructive respiratory clinical signs

expiratory dyspnoea, wheezing, prolonged expiration

pathogenesis of strangles (equine)

streptococcus equi equi causes lymph node abscessation and rupture

clinical signs of strangles (equine)

fever, mucopurulent nasal discharge, dyspnoea, lymphadenopathy (LN enlargement)

laryngeal paralysis pathogenesis

denervation of cricoarytenoid muscle (especially the left recurrent laryngeal nerve - longer path, looping around aortic arch in chest before ascending larynx = more susceptible to injury/degeneration)

laryngela paralysis clinical signs

inspiratory stridor (roaring), dyspnoea, poor performance

brachycephalic airway syndrome pathogenesis

congenital stenotic nares, long soft palate, hypostatic trachea

brachycephalic airway syndrome clinical signs

stertor (low pitched, noisy breathing sound), cyanosis, syncope, sleep apnoea

aspiration pneumonia pathogenesis

inhalation of food, milk or vomit —> chemical and bacterial injury

aspiration pneumonia clinical signs

productive cough, halitosis, dyspnoea, fever, commonly in right middle lobe

pulmonary oedema pathogenesis

increased hydrostatic pressure (LSHF), increased permeability (toxins), decreased oncotic pressure

pulmonary oedema clinical signs

moist cough, frothy fluid, crackles, tachypnoea

bovine tuberculosis pathogenesis

Mycobacterium bovis causes granulomatous pneumonia

bovine tuberculosis clinical signs

chronic cough, weight loss, lymph node enlargement, caseous nodules

equine exercise induced pulmonary haemorrhage pathogenesis

high pulmonary capillary pressures during exercise causes rupture

equine exercise induced pulmonary haemorrhage clinical signs

post-exercise epistaxis, poor performance, tracheal blood

pneumothorax pathogenesis

air leaks into pleural space —> lung collapse

pneumothorax clinical signs

sudden dyspnoea, reduced dorsal lung sounds, hyperresonance

pleural effusion pathogenesis

accumulation of fluid in pleural space (e.g. hydrothorax, chylothorax, haemothorax)

pleural effusion clinical signs

muffled lung sounds, tachypnoea, ventral dullness

what does sustained excessive preload cause

volume overload e.g. mitral or aortic regurgitation

what does sustained excessive afterload cause

pressure overload e.g. aortic stenosis, hypertension

what does altered contractility cause

dilated cardiomyopathy, infarction, myocarditis

what does rate/rhythm disturbances cause

AV bocks, atrial fibrillation, tachyarrhythmias

mechanisms of LSHF

pulmonary venous congestion —> pulmonary oedema

clinical signs of LSHF

dyspnoea, cough, exercise intolerance, pulmonary crackles

RSHF mechanism

systemic venous congestion —> ascites, oedema

RSHF clinical signs

ascites, jugular distension, hepatomegaly, peripheral oedema

forward (acute) heart failure mechanism

inadequate CO —> poor tissue perfusion

forward (acute) heart failure clinical signs

lethargy, pale MM, syncope, cold extremities

backwards (congestive) heart failure mechanism

inadequate venous drainage —> fluid accumulation

backwards (congestive) heart failure clinical signs

dyspnoea (LSHF), ascites (RSHF), oedema

what does sympathetic stimulation cause

increased HR, increased contractility, vasoconstriction = increased afterload

what does RAAS activation cause

vasoconstriction, Na/H2O retention = increased preload/afterload

what does ADH increase cause

water retention = increased preload

what does increased atrial natriuretic peptide (ANP) and B-type ANP cause

vasodilation, natriuresis = decreased preload and afterload

describe valvular endocarditis

bacterial infection —> vegetative valve lesions

valvular endocarditis clinical signs

fever, new murmur, thromboembolism, lethargy

describe valvular endocardiosis

degeneration of AV valves (especially mitral valve)

valvular endocardiosis clinical signs

cough, murmur, syncope, pulmonary oedema

describe stenosis (e.g. pulmonic stenosis)

narrow valve —> outflow obstruction

stenosis clinical signs

systolic murmur, cyanosis, exercise intolerance, right ventricular hypertrophy

define thrombus

a solid clot formed in situ from platelets and fibrin. May occlude vessels.

define thromboembolism

detached thrombus that travels through the bloodstream adn lodges distally

define embolism

any intravascular material (thrombus, fat, air, tumour) that occludes a vessel

pathology of dilated cardiomyopathy

chamber dilation, systolic failure

chamber size of dilated cardiomyopathy

thin walls

function affected of dilated cardiomyopathy

enlarged, goboid ventricles

common breeds affected by dilated cardiomyopathy

large breed dogs

clinical signs of dilated cardiomyopathy

weak pulse, systolic murmur, arrhythmias, congestive heart failure

hypertrophic cardiomyopathy pathology

left ventricle wall thickening, diastolic dysfunction

hypertrophic cardiomyopathy wall thickness

thick walls

function affected by hypertrophic cardiomyopathy

decreased filling = stiff ventricle

common species affected by hypertrophic cardiomyopathy

cats (esp. Main Coons and Ragdolls)

clinical signs of hypertrophic cardiomyopathy

thromboembolism, dyspnoea, sudden death