L32: Syncope (Swift) Flashcards
(64 cards)
1
Q
Presyncope
A
An incomplete form of syncope often involving hindlimb or generalized weakness
2
Q
Seizure
A
- Abnormal excessive paroxysmal synchronous discharge in a population of neurons
- a dysfunction of grey matter which may be primary or secondary to metabolic abnormality
- can be tonic/clonic or psychomotor
3
Q
Narcolepsy/cataplexy
A
- animal collapses into sleep or muscle paralysis respectively
- can be induced by excitement or eating
- can be roused by stimulation
- often many times daily
- inherited forms in poodles, labs, dobies
4
Q
Neuro vs. cardiac localization
A
Neuro: usually occurs at rest, takes long time to recover, assoc. with seizures
Cardio: usually occurs with excitement, recovers quickly
5
Q
PE in syncope/seizure patients
A
- mm color
- pulses: hypo or hyper kinetic?
- jugular veins: pulses and distention
- neuro deficits?
- auscultation (gallop rhythm? Murmur?)
6
Q
PDA –> pulses?
A
Hyperkinetic pulse
7
Q
Pulmonic stenosis –> pulses?
A
Weak, attenuated pulses
8
Q
What can cause gallop rhythm?
A
DCM, HCM
9
Q
2 things assoc. with Left basilar mumur
A
Aortic or pulmonic stenosis
10
Q
Things to assess when you hear a murmur
A
1) Loudness (I-VI)
- grade III is as loud as heart sounds
2) point of maximal intensity
3) radiation
4) timing
5) character (does it get louder or quieter, or equally loud?)
11
Q
Ddx for collapse (categories)
A
Cardiac** Resp Peripheral vascular Haematological Metabolic Endocrine Muscular Neurological Skeletal Neuromuscular Iatrogenic
12
Q
Resp. Causes of collapse
A
Hypoxia (upper or lower tract dz, pleural dz) Pulmonary hypertension (ie. HWD) Hyperventilation Cough Oslerus osleri
13
Q
Peripheral vascular dysfunction causes of collapse
A
- neurocardiogenic syncope (vasovagal syncope)
- carotic sinus hypersensitivity (ie. Pulling on leash causes bradycardic event)
- postural hypotension (BP low after lying down)
- hyperventilation
14
Q
Neurocardiogenic syncope
A
Simultaneous Vasodilation and bradycardia, often in response to adrenergic surge
-mismatch between what body wants to do and what HR and BP are doing
15
Q
Haemotological disorders causing collapse
A
- anemia
- polycythemia (thick blood)
- myeloproliferative diseases
16
Q
Endocrine disorders causing collapse
A
- hypo (causes collapse) and hyperadrenocorticism (causes hypertension, arrhythmias)
- DM (both hypo or hyerglycemia)
- phaeochromocytoma (release of epi/norepi can cause sudden tachycardia and collapse)
- hypothyroidism (usually causes just weakness)
- DKA
17
Q
Muscular disorders causing collapse
A
- polymyositis
- muscular dystrophy
- myopathy 2ary to hypoK, steroids, or myotonia
- labrador and retriever myopathy
- mitochondrial myopathy
18
Q
Polymyositis
A
A systemic, noninfectious, maybe IM, inflammatory muscle disorder
-may be acute or chronic and progressive
19
Q
Neuro disorders causing collapse
A
- cerebral emboli/thrombi/hemorrhage
- space occupying lesions
- atherosclerosis
- seizures
- vestibular or cerebellar dz
- spinal trauma
- narcolepsy/cataplexy
20
Q
Skeletal disorders causing collapse
A
- degenerative joint dz
- polyarthritis
- hypertrophic osteodystrophy
- bilateral ACL rupture
21
Q
Neuromuscular disorders causing collapse
A
- myasthenia gravis
- botulinism
- peripheral polyneuropathies
22
Q
Iatrogenic causes of collapse
A
- Digoxin (CHF drug that can cause bradyarrhythmias)
- Vasodilators
- Quinidine (used to control A fib in horses)
23
Q
Syncope
A
Sudden transient loss or depression of consciousness and postural tone resulting from transient and diffuse cerebral malfunction with spontaneous recovery
-often due to deprivation of energy substrates (glucose or oxygen) as a result of decreased or brief cessation of cerebral blood flow
24
Q
Congenital cardiac causes of collapse
A
- obstruction to outflow (AS, PS, atrial tumor, valvular endocarditis)
- cyanotic heart disease (tetralogy of fallot, VSD/PDA)
- severe AV valve dysplasia
25
How does obstruction of outflow --> collapse?
Body needs more blood in circulation but heart can't push against the obstruction to increase outflow. As a result, the body vasodilates and BP plummets
26
Heart is perfused during systole or dyastole?
Dyastole
27
Why have hard time perfusing the heart with AS?
LV can become thickened (more tissue to perfuse). If a tachycardic event occurs, HR increases and dyastole (the time when heart is perfused) gets shorter. Lack of perfusion can --> hypoxia
28
4 parts of tetralogy of fallot
- pulmonic stenosis
- RV hypertrophy
- large VSD
- overriding of the aorta
*creates resistance between pulmonary and systemic circulation
29
Consequences of tetralogy of fallot
- reduced pulmonary blood flow (fatigue, shortness of breath)
- generalize cyanosis due to mixing of blood from R and L ventricles
30
Mm in reverse shunting PDA
- peripheral mm can look normal while core mm will look cyanotic
- secondary to blood entering the brachiocephalic trunk
31
If have severe AV valve dysplasia, will demonstrate syncopal episode when?
When become very stressed
32
What things cause cyanosis?
Pulmonary hypertension
| Pulmonic stenosis + VSD
33
Acquired cardiac diseases causing collapse
- severe AV valve dz
- systolic dysfunction - DCM
- pericardial disease
- pulmonary hypertension
- certain arrhythmias
34
What arrhythmias can cause collapse?
Bradyarrhythmias: 3rd degree AV block, and less commonly 2nd degree or sick sinus syndrome
Tachyarrhythmia: V tach and certain supraventricular arrhythmias
35
What is dilated in DCM?
LV and LA
36
4 main categories of ddx for collapse
1) cardiovascular
2) respiratory
3) internal medicine (haematological, metabolic, endocrine)
4) neuromuscular skeletal
37
Treatment of ventricular tachycardia that is affecting CO
- turn off anesthetic gases
- make sure oxygenated
- give IV lidocaine
- consider K if lidocaine doesn't work
- other drugs: short acting beta blocker, esmolol, sotalol
38
Class 1 anti-arrhythmic drugs
Sodium channel blockers (ie. Lidocain, procainamide, etc.)
*used for muscles of ventricle
39
Class 2 anti-arrhythmics
Beta blockers
-esmolol, atenolol, propranolol, metopralol
*used for regulating SA and AV nodes
40
Class 3 anti-arrhythmics
K channel blockers
-sotalol, amiodarone
*used for muscles of ventricle
41
Class 4 anti-arrhythmics
Ca channel blockers
-diltiazem, verapamil, nefedipine
*used for regulating SA and AV nodes
42
Pimobendan
Increases contractility and dilates peripheral vascular system (vasodilator)
43
V tach can --> CHF
:)
44
Signs of atrial fibrillation on ECG
- no p waves
- supraventricular
- irregular
- fast (ie. 200 bpm)
45
How can neoplasia cause pericardial effusion?
Tumor rubbing up against heart wall can rupture vessels or obstruct lymphatic drainage to pericardium --> effusion
46
Causes of syncope (cardiac)
1) poor output (due to decreased contractility, poor diastolic filling with tachycardia, or reduced diastolic filling due to loss of atrial contraction)
2) undiagnosed ventricular arrhythmia
47
Treatment aims of preventing cardiac syncope
- slow HR
- convert to normal sinus rhythm
- provide inotropic support
- control CHF
- goal of drugs = prolong AV nodal refractory period
48
Tx of A fib
- digoxin
- Ca channel blocker (diltiazem)
- beta blockers (don't use if CHF present; beware of negative inotropic actions)
- goals = control rate and rhythm; want to slow HR
49
Collapse that is preceeded by exercise, stress, cough, gagging, vomition, urination, or defecation is more likely to represent SYNCOPE than SEIZURE
:)
50
Pulse pressures are reduced with:
Poor CO often caused by systolic failure, aortic stenosis, pericardial effusion, or tachyarrhythmias
51
Pale mm (cyanosis) could be caused by:
Poor CO, often due to severe arrhythmias or poor contractile function ie. DCM
52
Ascites in heart failure is:
Modified transudate
53
Muscular and neuromuscular disorders tend to cause:
Episodic weakness and collapse
54
One of the most common cardiac causes of syncope
Advanced AV block
55
Dogs with advanced degenerative mitral valve disease can develop neurocardiogenic bradycardia, often in dogs with pulmonary hypertension. Causes episodic syncope/collapse
:)
56
T: any cause of hypoxia can cause syncope
:)
57
Hyperventilation results in:
Cerebral arterial vasoconstriction and peripheral vasodilation reducing cerebral perfusion
58
Drugs that can cause iatrogenic syncope
- Digoxin (toxicity can cause heart block, AV dissociation, or slow junctional rhythm)
- diuretics (due to volume depletion)
- vasodilators
- quinidine (can cause severe arrhythmia)
59
How does hypoadrenocorticism cause syncope?
- hypovolemia
- hyponatremia
- hyperkalemia
60
How does hypothyroidism cause syncope?
2ary to bradycardia or peripheral neuropathies
61
How does postural hypotension cause syncope?
Both systolic and diastolic pressures fall
62
Metabolic disorders --> syncope?
```
Hypo or hypercalcemia
Hypo or hyperglycemia
Hypo or Hyperkalemia
Hyponatremia
Acidosis
Hyperthermia
Hepatic encephalopathy
```
63
Hypercalcemia is most often caused by
- neoplasia
- hypoadrenocorticism
- renal disease
- primary or secondary hyperparathyroidism
- bone mets
64
Dogs with hepatic encephalopathy often have seizures following high protein meals (may be 2ary to congenital PSS or hepatic insufficiency and cirrhosis)
:)
