SIDS and SUDEP

Question 1

SIDS

Answer 1

sudden death of infant under one year of age
unexplained death after clinical review, autopsy, and death scene investigation
peak in 2-6 months
more males than females
die during sleep: usually lying prone

Question 2

SUDEP

Answer 2

sudden unexpected death of a patient with epilepsy
not traumatic, drowning, or status epilepticus

Question 3

barriers to physiological research on SIDS

Answer 3

cannot easily study cardiorespiratory physiology in healthy babies
very few babies have died of SIDS while being monitored
no animal model of SIDS
most distinctive research is from autopsies of SIDS cases

Question 4

What neurotransmitter defect is linked to SIDS?

Answer 4

5HT in neurons

Question 5

benefits of studying SUDEP

Answer 5

occurs in a population willing to participate in research
refractory epilepsy patients are frequently monitored in epilepsy units
many good animal models
can study pathophysiology and effect of interventions

Question 6

genes associated with risk of SUDEP

Answer 6

SCN1A and SCN8A: sodium channel
DEPDC5: MTOR pathway
Htr2c: 5HT receptor
Kcna1

Question 7

SUDEP risk factors

Answer 7

high frequency of seizures
generalized seizures
sleep period
70-80% are found in prone position in bed

Question 8

Sinus tachycardia occurs in what percentage of seizures?

Answer 8

80%

Question 9

During an epileptic seizure, does loss of breathing occur prior to or after cardiac asystole?

Answer 9

prior to asystole

Question 10

Dravet Syndrome

Answer 10

severe myoclonic epilepsy of infancy
onset typically at 6 months
prolonged generalized febrile seizures
refractory to treatment
SCN1A mutations seen in about 80% of cases
SUDEP is cause of death in about half of cases

Question 11

pathology of Dravet Syndrome mouse models

Answer 11

50% of animals show spontaneous death
respiratory arrest precedes bardycardia
mice show impaired response to carbon dioxide increase after seizure - 5HT agonist reversed imapirment

Question 12

breathing depends on two sources of tonic drive

Answer 12

wakefulness
chemoreceptor: dependent on carbon dioxide concentration

Question 13

How is breathing regulated by the concentration of carbon dioxide?

Answer 13

increased carbon dioxide lowers pH: acidosis

Question 14

What are the central carbon dioxide/pH chemoreceptors?

Answer 14

5HT neurons

Question 15

5HT neurons

Answer 15

mostly located in raphe nuclei and project to every region
medullary 5HT neurons project to respiratory nuclei
located near largest arteries in the brainstem

Question 16

What happens when 5HT neurons are knocked out?

Answer 16

depressed respiratory response to carbon dioxide
many animals die within the first month of life
lose the ability to arouse from sleep in response to increased carbon dioxide

Question 17

How do seizures affect breathing and neurons in rats?

Answer 17

inhibition of breathing and raphe neurons

Question 18

similarities in SIDS and SUDEP

Answer 18

bilamination of the GCL in the dentate gyrus of some infants
some SIDS victims have SCN1A mutation
SIDS could be caused by seizures, but they are very hard to detect in infants

Question 19

SIDS could be due to what?

Answer 19

SUDEP