Child - D1 - L3

College of Medicine and HIE

  • Presentation by Dr. Hidhab Jawad on Hypoxic Ischemic Encephalopathy (HIE)

Aim & Claim

  • Understand assessment and care for normal birth.

  • Familiarity with:

    • Pathogenesis of birth asphyxia.

    • Apgar score and ABCDE resuscitation.

    • Complications of severe asphyxia.

    • Severity levels of HIE.

    • Management of HIE.

Definition of HIE

  • Hypoxic ischemic encephalopathy (HIE) is a brain injury occurring due to reduced or stopped blood flow or oxygen to the brain around birth.

  • Possible outcomes vary from no long-term consequences to severe disabilities or death.

  • Severity factors include:

    • Duration of oxygen deprivation.

    • Extent of brain affected.

    • Brain's self-repair ability.

Pathophysiology of HIE

  • Inadequate blood oxygen levels lead to:

    • Compensatory increase in blood flow (ischemia).

    • Shift to anaerobic metabolism in brain cells (sustainable only for a few minutes).

Initial Responses

  • Increased pulmonary vascular resistance to prioritize brain, heart, and adrenal perfusion.

  • Cells revert to aerobic metabolism if oxygen is restored promptly.

  • Prolonged deprivation leads to cell death and potential secondary damage (reperfusion injury).

Redistribution Responses to HIE

  • Changes in blood flow and potential brain ischemic injury due to prolonged hypoxemia.

Cellular Damage from HIE

Reversible Damage

  • Early-stage hypoxia may reduce ATP production, impairing cell functions.

  • Reversible if the hypoxic state is brief.

Irreversible Damage

  • Prolonged hypoxia results in irreversible cellular damage, leading to complications.

Etiology of HIE

  • Factors interfering with maternal-fetal blood circulation lead to perinatal asphyxia:

    • Maternal, delivery, and fetal factors.

High-Risk Factors

  • Preeclampsia, umbilical cord issues, maternal infections.

  • Anemia, internal bleeding, labor complications, physical trauma, poor positioning during delivery.

Clinical Presentation of HIE

  • Symptoms may affect multiple organ systems, including:

    • Low heart rate.

    • Respiratory issues.

    • Acidosis and seizures.

    • Stained meconium, low muscle tone, blue/very pale skin, low reflexes.

Insult and Therapeutic Intervention Timeline

  • Primary energy failure occurs immediately.

  • Secondary phases (hours to days) lead to delayed mitochondrial dysfunction and neuronal death. Interventions need to occur within 6 hours of the insult.

Apgar Score

  • Evaluate newborn status:

    • Appearance (skin color).

    • Pulse (heart rate).

    • Grimace (reaction to stimuli).

    • Activity (muscle tone).

    • Respiration.

Apgar Scoring

Criteria

0

1

2

Heart rate

None

<100

>100

Respiration

None

Irregular

Regular

Muscle tone

Limp

Reduced

Normal

Response

None

Grimaced

Cough

Color

White/blue

Pink

Degree of Asphyxia (Apgar Score)

  • 8-10: No asphyxia.

  • 4-8: Mild/cyanotic asphyxia.

  • 0-3: Severe/pale asphyxia.

Clinical Features of HIE

  • Symptoms reflect two types of consciousness:

    • Excitation: hyperactivity, irritability, seizure activity.

    • Depression: coma, hypotonia, bradycardia.

HIE Stages and Symptoms

  • Stage 1: Hyperalert, seizures.

  • Stage 2: Lethargic, some responsiveness.

  • Stage 3: Stuporous, coma, poor prognosis.

Classification of HIE on CT

  • Stage I: Normal.

  • Stage II: Mild hypodensity.

  • Stage III: Moderate hypodensity in multiple areas.

  • Stage IV: Severe, generalized hypodensity with hemorrhage.

Complications of HIE

  • Multiorgan involvement is common:

    • CNS: Increased risk of intracranial hemorrhage (ICH).

    • Respiratory: Severe pulmonary conditions.

    • Cardiovascular: Reduction in myocardial contractility.

    • Renal: Failure leading to electrolyte imbalances.

    • Gastrointestinal: Necrotizing enterocolitis.

Diagnosis of HIE

  • Guidelines require:

    • Profound acidemia (pH < 7).

    • Apgar score of 0-3 for > 5 mins.

    • Neurologic sequelae (seizures, coma).

    • Multiple organ involvement.

Laboratory Studies

  • Serum electrolytes, metabolic studies, coagulation profile, arterial blood gas.

  • Imaging: MRI, cranial ultrasonography, echocardiography.

Management of HIE

ABCDE Resuscitation Steps

  • Airway Management: Positioning and suctioning.

  • Breathing: Oxygen support for appropriate ventilation.

  • Circulation: CPR if heart rate < 60 bpm.

  • Drugs: Administer medications as needed (adrenaline, fluids).

  • Evaluation: Assess resuscitation effectiveness and transfer if needed.

Seizure Control

  • Medications: Phenobarbital, Diazepam, Chloralhydrate.

Control of Cerebral Edema

  • Treatments: Furosemide, Mannitol, therapeutic hypothermia (33-33.5°C for 72h).

Prognosis of HIE

  • Dependent on severity and treatment; mild cases may resolve, severe cases may lead to high mortality or significant disabilities.

Prevention of HIE

  • Emphasis on prenatal care and preventing asphyxia.

Summary

  • Neonatal asphyxia, alongside its complications (HIE and ICH), represents a serious clinical concern with high mortality risk and poor neurological outcomes.