Differential diagnosis of central chest pain Flashcards
What are the two branches of the autonomic nervous system?
sympathetic and parasympathetic
What effect does sympathetic nerve stimulation have on the heart?
Increase heart rate
Increase contractility
What effect does parasympathetic nerve stimulation have on the heart?
Decrease heart rate
How do visceral afferent fibres travel?
- pain fibres travel to spinal cord alongside sympathetic nerves
- (visceral) reflex afferents (e.g. from baroreceptors) travel mainly in the vagus nerve (some in CN XI)
How do autonomic and afferent nerves reach the heart?
Cardiac plexus
How do sympathetic nerve fibres get from the CNS from the organs?
presynaptic fibre (connects between CNS and ganglion)
ganglion synapse between axon of presynaptic and postsynaptic
postsynaptic fibre connects ganglion and organ
Where do pre-synaptic sympathetic fibres from the brain travel via?
inferiorly via the spinal cord tracts
Where do pre-synaptic sympathetic fibres from the brain exit the spinal cord?
exit the spinal cord in one of T1-L2/3 spinal nerves (thoracolumbar)
What can sympathetic pre-synaptic fibres do once they leave the spinal cord?
1) go into the ganglion of that level & synapse
2) travel superiorly in the sympathetic chain to another ganglion & synapse
3) travel inferiorly in the sympathetic chain to another ganglion & synapse
4) pass straight through the sympathetic chain ganglion without synapsing, as abdominopelvic splanchnic nerves ,to synapse in one of the prevertebral ganglia of the abdomen (e.g. celiac ganglion)
5) pass straight to the adrenal medulla without synapsing as an abdominopelvic splanchnic nerve (directly stimulating adrenaline release)
Where do cardiopulmonary splanchnic nerves innervate?
sympathetic nerves to heart & lungs
To a midline organ what will the sympathetic innervation be like?
bilateral sympathetic innervation
What does the cardiac plexus contain?
sympathetic fibres
parasympathetic fibres
visceral afferent fibres
How do parasympathetic signals from the CNS reach the organs?
presynaptic fibre (connects between CNS and ganglion)
ganglion - synapse between axon of presynaptic neurone and cell body of postsynaptic neurone
postsynaptic fibre (connects between ganglion and organ)
What are the differences between sympathetic and parasympathetic signals from the CNS?
the neurotransmitters
Sympathetic:
pre-synaptic=acetylcholine
post-synaptic=norarenaline
parasympathetic:
pre-synaptic=acetylcholine
post-synaptic=acetylcholine
How many parasympathetic ganglia are there in the head?
4
How do parasympathetic signals reach the organs?
through CN III, CN VII, CN IX, CN X, pelvic splanchnic nerves to organs of the lower abdomen, pelvis and perineum
What can be the cause of somatic pain?
o muscle
o joint
o bony
o intervertebral disc
What is the character of somatic pain?
sharp, well localised, stabbing
What can be the cause of visceral pain?
o heart and great vessels
o trachea
o oesophagus
o abdominal viscera
What is the character of visceral pain?
dull, aching, nauseating, well localised
What is radiating pain?
felt in a particular area (site of origin) and spreads
What is referred pain?
pain only felt at remote site to origin
Describe the propagation of a probing stimulus to the chest at the T5 dermatome
” skin mechanoreceptors stimulated in T5 dermatome, AP is propagated centrally, passes through right T5 posterior rootlets and sensation reaches consciousness
What separates the parietal and frontal lobes?
central sulcus
What lies anterior to the central sulcus and what is its function?
precentral gyrus (somatomotor area of the brain)- brings about contractions of the body wall
What lies posterior to the central sulcus and what is its function?
post-central gyrus (somatosensory area)- where APs are brought into consciousness
Describe the pain characteristic of herpes zoster (shingles)?
pain and blistering in a dermatomal pattern
pain precedes blisters
What kind of structures are parietal pleura and fibrous pericardium?
Body wall structures therefore somatic pain
Name some causes of dull, visceral chest pain
tracheitis oesophagitis angina MI gastritis cholecystitis hepatitispancreatitis aortic aneurym (of arch)
What is significant about the structure of the right side of the mediastinum?
Vagus nerve is always on the lateral aspect of the tracheal, passes posterior to the root of the lung
What is significant about the structure of the left mediastinum?
vagus nerve crosses the aorta not the trachea
o gives of branch which goes underneath the ligamentum arteriosum (recurrent laryngeal nerve)
What is the function of the azygous vein?
drains blood from each intercostal space into the SVC
What is associated with each intercostal space?
a sympathetic ganglion
What is the function of abdominopelvic splanchnic nerves?
relay sympathetic into abdomen
How will pain signals reach the brain?
visceral afferent will reach the brain by travelling alongside sympathetic nerves (cardiopulmonary splanchnic nerves)
ascend in spinal cord to reach consciousness in post-central gyrus
What is the mechanism behind referred pain?
somatic sensory fibres are also plugging into the spinal cord at the same place
If pain is radiating from a somatic structure where will it be felt?
within that dermatome
If pain is radiating from a visceral structure where will it be felt?
the dermatomes supplied by the spinal cord levels at which the cardiac visceral afferents enter the sympathetic chain/spinal cord
What is the character of radiating pain from a visceral structure?
even though it radiates to a body wall it will still be dull, aching and poorly localised
Where will cardiac referred pain be felt?
upper limbs, back, neck or jaw
What are the most common sites for coronary atherosclerosis?
- LAD
- RCA
- circumflex
- left mainstem
What is the pattern of dominance in most individuals?
right coronary artery is dominant
Which vessels can be taken in CABG?
- great saphenous vein
- radial artery
-internal thoracic (mammary) artery
used by pedicle- one end is attached to its anatomical origin but the other is plugged in
What is the arterial blood supply of the inter ventricular septum?
LAD and posterior inter ventricular artery