Perinatal Asphyxia - NEET PG Pediatrics

Lack of blood flow or gas exchange to or from the fetus in the moments just before, during, or after childbirth is known as perinatal asphyxia. Due to decreased blood flow and/or oxygen to a fetus or child during the peripartum period, perinatal hypoxia can cause severe systemic and neurologic consequences.

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Pathophysiology

When placental blood flow is interrupted, fetal hypoxia, hypercarbia, and acidosis occur, which is the pathophysiology of asphyxia. There are both circulatory and non circulatory adaptation mechanisms that let the fetus survive suffocation and maintain the function of critical organs. These protective mechanisms stop working in response to severe and/or protracted insults, resulting in hypoxia ischemic damage, which causes cell death by necrosis and apoptosis. The most severe long-term effect of prenatal asphyxia is permanent brain damage. The mechanisms of injury, including their degree and length, as well as the brain's developmental maturity, have an impact on the injury's location and severity.

Signs of Hypoxia at birth include:

With no breathing or breathing very little

Bluish, gray, or lighter-than-normal skin tone

A slow heartbeat

Muscle tone issues

Weak reactions

(Acidosis) Excessive blood acidification

Meconium-stained amniotic fluid (first feces)

Seizures

Diagnostic Criteria for Severe Birth Asphyxia                   

All of the following are required

• Apgar Score: 0-3 for > 5 minutes
• Severe acidosis (cord blood pH < 7.0)
• Presence of any clinical evidence of CNS dysfunction
  • E.g.: Tone abnormalities, seizures, changes in sensorium etc.
• Presence of any evidence of dysfunction of at least 1 organ other than CNS
• Example
  • Renal: Acute Tubular necrosis, renal vein thrombosis
  • Heart: myocardial dysfunction, CCF, arrhythmias
  • Pulm: pulmonary hypertension
  • GIT: NEC
  • Hemat: coagulation abnormalities
  • Metabolic: hypoglycemia, acidosis
  • Subcutaneous fat necrosis

Staging of Perinatal Asphyxia:

• Sarnat and Sarnat
• Levene's staging
• Thompson score-Maximum score = 22.Score of ≥ 15 is suggestive of poor outcome

Parameters	Stage 1 (Mild HIE)	Stage 2 (Moderate HIE)	Stage 3 (Severe HIE)
1. Level of consciousness	Hyper alert/irritable	Normal/depressed (lethargic)	Comatosed
2. Tone	Normal	Mild hypotonia	Severe hypotonia
3. Moro’s reflex	Exaggerated	Normal/depressed	Absent
4. Seizures	Not seen	Present	Not seen
5. Autonomic involvement	Generalized sympathetic overactivity mydriasis Increased heart rate	Generalized parasympathetic overactivity Miosis Bradycardia	Both systems are depressed Pupils mild dilated Variable HR
6. Prognosis	99% normal outcome	80% normal outcome	50% die 50% severe neurological sequelae

Treatment of HIE

1. Supportive Care

• NICU admission
• IVF
• Maintain euglycemia & normothermia
• Monitor the baby
• Tool used for bedside monitoring of neonates with HIE → aEEG (Amplitude Integrated Electroencephalography)

2. Latest Rx Modality for neonates with Moderate to Severe HIE

• Therapeutic Hypothermia
  • Temp. maintained is 33.5° c –34.5° c
  • Preferred in babies > 35 weeks gestation
  • Used in 1 4-6 hours of life
  • Decreases mortality and neuromorbidity
  • Due to some side effects, done at a tertiary care center.

3. Neonatal Seizures treatment

• DOC: phenobarbitone
• 2nd line: levetiracetam
• Mc type: subtle seizures
• Mc cause: hypoxia
• Type with best prognosis: Focal clonic seizures
• Types with worst outcome: myoclonic seizures
• Preferred initial CNS imaging: Transcranial ultrasound (cranio sonogram)

This is everything that you need to know about perinatal asphyxia  for your PEDIATRICS PREPARATION. For more interesting and informative blog posts like this download the PrepLadder App and keep reading our blog!