B7.010 LG Syncope Flashcards
what is syncope
transient loss of consciousness with loss of postural tone
usually from hypoperfusion of the brain
abnormal tilt test
drop in systolic of > 20 or in diastolic of > 10, or experiencing lightheadedness or dizziness is abnormal
primary causes of syncope
neutrally mediated reflex (60%) -vasovagal -carotid sinus syndrome -situational (cough, postmicturition) orthostatic hypotension (15%) -drug induced -primary ANS failure -secondary ANS failure cardiac arrhythmias (10%) structural cardiopulm (5%)
signs of SNS adrenergic failure
orthostatic hypotension
male ejaculatory failure
signs of SNS cholinergic failure
anhidrosis
signs of PNS failure
dilated pupils fixed HR sluggish urinary bladder atonic large bowel male erectile failure
hereditary causes of diffuse autonomic neuropathy
familial amyloid polyneuropathy
hereditary sensory autonomic neuropathies
Fabry disease
porphyrias
acquired causes of diffuse autonomic neuropathy
- primary: idiopathic or have autonomic neuropathy as a characteristic feature of the disease process
- secondary: identifiable cause may lead to autonomic neuropathy
- neurodegenerative diseases like parkinson’s
primary autonomic neuropathies
pandysautonomia idiopathic distal small fiber neuropathy Homes-Adie syndrome Ross syndrome chronic idiopathic anhidrosis amyloid neuropathy postural orthostatic hypotension syndrome (POTS)
secondary autonomic neuropathies
diabetes uremic neuropathy hepatic disease B12 def toxic and drug induced neuropathy alcohol infections (Chagas, HIV, leprosy, diphtheria) autoimmune (celiac, Sjogren, RA, GBS, LEMS, IBD, paraneoplastic) drug mediated
diagnostic testing options for autonomic function
cardiovagal function sudomotor function vasomotor function gastric emptying test urodynamic tests for bladder function
cardiovagal function
HR variability
baroreflex sensitivity
sudomotor function
sweat testing (nerves that regulate sweat glands) thermoregulatory sweat test
vasomotor adrenergic function
tilt table testing for orthostatic intolerance
non medical management of orthostatic hypotension
hydration, avoid heat exercises abdominal binders tilt up bed increase salt in diet
meds for orthostatic hypotension
B blockers (POTS) flourinef midodrine droxidopa
management of autonomic neuropathy
treat the cause
+
symptomatic treatment
digestive: smaller meals, add fiber, laxatives
urinary: hydration, empty bladder frequently at set times, oxybutynin for bladder spasms, bethanechol for bladder emptying
excessive sweating: glycopyrrolate, botulinum toxin
HR: b blockers
sexual: sildenafil, lubricant
how do anticholinergics cause orthostatic hypotension
tachycardia leading to decreased venous return of heart
vasodilation with decreased venous return
off target blockage of ganglionic cholinergic transmission
depression of central vasoconstrictor center
typically at high dose
postural hypotension w amitriptyline
alpha blockade association TCAs antagonize: -M -a1 -H1
Ross Syndrome
cranial postganglionic PNS and SNS dysfunction with autonomic disturbances
triad: tonic pupils, areflexia, anhidrosis
cause unknown, maybe autoimmune
can be progressive
neuropathy associated with amyloidosis
bilateral, symmetric, small fiber peripheral neuropathy
generalized autonomic failure
large fibers ok (motor, proprioception)
most common systemic amyloidosis
light chain (AL) amyloidosis caused by plasma cell dyscrasia, not hereditary
why can chest/abdominal involvement be seen in length dependent neuropathies
second longest nerves located there (after leg nerves)
