Sudden infant death syndrome (SIDS)

Question 1

Define SIDS.

Answer 1

The sudden death of an infant < 1 year that remains unexplained after a thorough case investigation, including performance of a complete post-mortem, examination of the death scene and a review of the clinical history.

Question 2

Explain the aetiology/risk factors of SIDS.

Answer 2

Many factors have been implicated but none has been proven.

Prolonged QT interval: Is a marker of reduced cardiac electrical stability and is strongly associated with SIDS. Increased sympathetic activity in these infants may be sufficient to cause fatal arrhythmias such as torsades de pointes.

Upper airways obstruction:

• Infants have sites of anatomical and physiological vulnerability such as a shallow hypopharynx and position of the tongue and epiglottis.
• Infants are obligate nasal breathers for the first few months of life and so prone positioning may compress their only airway.

Central apnoea: Infants can have reflex-like apnoeic responses to a number of conditions such as hypoxia, hypoglycaemia, infection and stimulation of the upper larynx (e.g GOR). Such apnoeic responses are probably due to incomplete development of the CNS, increased vagal tone and decreased respiratory muscle reserve.

Thermoregulatory dysfunction: Minor changes in temperature (hot or cold) can induce autonomic dysfunction in infants.

Brainstem dysfunction: Cardiorespiratory function, autonomic mechanisms, chemoreceptor sensitivity and thermoregulation are all controlled by the medullary and related structures of the brain. Autopsy examinations of the brainstems of infants with diagnosis of SIDS have demonstrated hypoplasia or decreased neurotransmitter binding of the arcuate nucleus (medulla).

Question 3

Summarise the epidemiology of SIDS.

Answer 3

SIDS is the most common cause of death in infants aged 1 month to 1 year.

Peak incidence: 1-4 months.

UK incidence: 300 cases/year. M>F

Prevalence: 1.7 cases/1000 live births

Seasonal variation: More common during winter

Question 4

What are the symptoms of SIDS?

Answer 4

SIDS is a diagnosis of exclusion so a thorough history describing the details surrounding the event and examination are required to look for possible medical conditions leading to demise. History should include developmental stage of child, family and social history (including parents’ and siblings’ full names, dates of birth and whereabouts).

Classic presentation:

• Usually occurs during hours of extended sleep (10pm-10am).
• Child is found dead usually in the position the child was put to bed.
• Checks whilst the child was asleep usually revealed no problems.
• Parent may report that the child ‘was not himself or herself’ before going to sleep.
• May report GI or respiratory infection in the weeks preceding death

Alerts for child abuse: Unclear, inconsistent history, unwanted child, poor antenatal/postnatal care, age > 6 months.

Question 5

What are the signs of SIDS?

Answer 5

Fully undress the child and note:

• General condition of child (hygiene, nutrition, growth parameters).
• Signs of illness (vomit, hydration, nasal discharge, rash).
• Signs of trauma, abuse or evidence of bleeding.
• Clothing.

Question 6

What are appropriate investigations for SIDS?

Answer 6

Blood culture should be obtained in all cases.

Depending on history and examination, further microbiological samples may be taken (swabs, SPA, LP) or metabolic samples (blood, urine, CSF) may be required.

Postmorten examination.

Question 7

What is the management for resuscitation in SIDS?

Answer 7

Should always be initiated by paramedic and emergency staff unless clearly inappropriate. Resuscitation should only be discontinued when the most senior paediatrician is present. If there is no detectable cardiac output or sign of cerebral activity for 20 minutes, it is reasonable to withdraw.

Question 8

What should happen following unsuccessful resuscitation in SIDS?

Answer 8

1. Provide support and a calm environment for the family.
2. Allow both parents to spend time with the child, allow photographs if desired.
3. Avoid mention of risk factors which attribute blame.
4. Put in touch with SIDS support groups.

Question 9

What is the information cascade following SIDS?

Answer 9

Parents must be told of the legal requirement to inform the coroner and that the police will wish to visit the place of death and take a statement.

• Immediate: Inform attending consultant paediatrician, coroner, police (if unexpected), duty social worker and police child protection team (if relevant).
• Within 24 hours: GP, paediatric clinical director, emergency consultant, designated doctor and nurse who will cascade to further relevant parties.

Question 10

What is the prevention for SIDS?

Answer 10

• Avoid smoking during pregnancy and by family members during birth.
• Avoid overheating baby, e.g with duvets. Room temperature should be 16-20 degrees.
• Use thin flat sheets that are firmly fastened and will not cover the baby’s head.
• Place the baby on their back to sleeo with their feet touching the foot of the cot.
• Use firm flat bedding; infants are more likely to sleep face down with soft bedding.
• Avoid bed-sharing with parents, especially if parent has drunk alcohol, been smoking or taken medication that makes them drowsy.
• Dummies have been should to decrease the risk of SIDS. In breastfed child, should only be used >1 month to avoid confusion.

Question 11

What are complications associated with SIDS?

Answer 11

Psychological distress in family members.

Plagiocephaly may occur due to ‘back to sleep’, but this can be improved by putting child on their front for ‘tummy time’ when they are awake.

Question 12

What is the prognosis and preventative measures of SIDS?

Answer 12

Future siblings of children who have died from SIDS have a slightly increased risk of SIDS.

The Care Of Next Infant (CONI) programme provides increased support for parents and future siblings.