Fetus & Neonatal Infant: Nervous System & Renal Disorders PDF

# The Fetus and the Neonatal Infant: Nervous System Disorders and Renal Disorders ## Presenter: Dr. Jeannette D. Nacilla-Sulit, FPPS, IBCLC ## General Pediatrics & Occupational Medicine ### CNS Disorders - CNS disorders are important causes of neonatal mortality and short and long-term morbidity...

# The Fetus and the Neonatal Infant: Nervous System Disorders and Renal Disorders ## Presenter: Dr. Jeannette D. Nacilla-Sulit, FPPS, IBCLC ## General Pediatrics & Occupational Medicine ### CNS Disorders - CNS disorders are important causes of neonatal mortality and short and long-term morbidity. #### Insults - Hypoxia - Asphyxia - Hemorrhage - Trauma - Hypoglycemia - Direct cytotoxicity #### Etiologies of CNS damage - Acute perinatal complications - Postnatal hemodynamic instability - Developmental abnormalities (genetic/environmental) #### Predisposing Factors - Maternal illness resulting in uteroplacental dysfunction - Intrauterine infection - Macrosomia/dystocia - Malpresentation - Prematurity - IUGR ### The Cranium | Description | Caput Succedaneum | Cephalhematoma | |---|---|---| | | - Diffuse, sometimes ecchymotic, edematous swelling of the soft tissues of the scalp involving the presenting area - visible at birth | - Subperiosteal hemorrhage - No discoloration of overlying scalp - Swelling is not usually visible for several hours after birth | | Location | - Involves the presenting area - May extend across the midline and across suture lines - Often associated with molding and overriding of the parietal bones | Always limited to the surface of one cranial bone | | Resolution | Resolves within first few weeks of life | Resorb within 2 weeks - 3 months | | Management | No specific treatment | No treatment or occasional phototherapy | - A diagram of the skull is shown. It shows the layers of the skin, galea or epicranial aponeurosis, periosteum, skull, dura caput, cephalhematoma, subgaleal hemorrhage, and extradural hemorrhage. #### Subgaleal Hemorrhage - A collection of blood beneath the aponeurosis that covers the scalp the entire length of the occipitofrontalis muscle. - Bleeding can be extensive and may even dissect into the subcutaneous tissues of the neck. - Often associated with vacuum deliveries. - Mechanism of injury: - Linear fracture - Suture diastasis or fragmentation of the superior margin of the parietal bone - Rupture of the emissary vein - Firm fluctuant mass that increases in size after birth. - Monitored for hypotension and hyperbilirubinemia. #### Fractures of the skull - Result of pressure from forceps or from maternal symphysis pubis, sacral promontory, or ischial spines. - May be asymptomatic unless with intracranial injury. ##### Linear Fractures - Most common and cause no symptoms and require no treatment. ##### Depressed Fractures - Usually indentations of the calvaria similar to dents in a ping pong ball. - Advisable to elevate severe depressions to prevent cortical injury from sustained pressure. ##### Fracture of the occipital bone - Separation of basal and squamous portions almost invariably causes fetal hemorrhage due to disruption of vascular sinuses. #### Subconjunctival and retinal hemorrhages - Sudden increase in intrathoracic pressure. - Rapidly resolve within the first 2 weeks of life. #### Traumatic, Epidural, Subdural, & Subarachnoid Hemorrhage - Likely when the fetal head is large in proportion to the mother's pelvic outlet. - With prolonged labor. - Breech or precipitous deliveries. - Mechanical assistance during delivery. - A diagram is shown of the brain representing subdural hematoma, epidural hematoma, and intracerebral hematoma. - Massive subdural hemorrhage is often associated with tears in the tentorium cerebelli or falx cerebri. - Infants may rapidly deteriorate and die soon after birth. - Subdural and epidural hemorrhage often resolve without intervention, but consultation with a neurosurgeon is recommended. - CT scan and MRI confirm the diagnoses. - Symptomatic subdural hemorrhage is managed by removal of the subdural fluid collection with a needle placed through the lateral margin of the anterior fontanelle. - Child abuse? #### Subarachnoid Hemorrhage - A diagram is shown of the brain representing subarachnoid space, subarachnoid hemorrhage, aneurysm, and a nerve. - Rare and typically clinically silent. - Anastomoses between penetrating leptominingeal arteries or the bridging veins are the most likely source. - Elevated number of RBC in a lumbar puncture sample. - Some experience seizures (2nd day). - Usually no neuro abnormalities during acute episode or on follow up. ### Intracranial - Intraventricular Hemorrhage & Periventricular Leukomalacia (PVL) - Develops spontaneously. - May be due to trauma/asphyxia, primary hemorrhagic disturbance, or congenital vascular anomaly. - Often involves the ventricles (IVH) of premature infants delivered spontaneously without apparent trauma. - May be associated with DIC, isoimmune thrombocytopenia, neonatal vitamin K deficiency. #### Pathogenesis - Immature blood vessels in the highly vascular region of the developing brain combined with poor tissue vascular support predispose premature infants to hemorrhage. - Germinal matrix involutes as the fetus approaches full-term gestation and the tissue's vascularity improves, therefore IVH is less common in a term infant. - The risk is inversely related to gestational age and birth-weight, with the smallest and most immature infants being at the highest risk. #### Periventricular Hemorrhagic Infarction - Often develops after grade IV IVH owing to venous congestion. ##### Predisposing factors - Prematurity - RDS - HIE/hypotensive injury - Reperfusion injury of damaged vessels - Increased/decreased cerebral blood flow - Reduced vascular integrity - Increased venous pressure - Pneumothorax - Thrombocytopenia - Hypervolemia - Hypertension - A diagram is shown of an infant brain representing periventricular leukomalacia, periventricular gliosis, and lateral ventricles. #### Clinical Manifestations - Acute deterioration on 2nd to 3rd day of life. - Hypotension. - Apnea. - Pallor/cyanosis. - Poor suck. - Decreased muscle tone. - Metabolic acidosis. - Shock. - Decreased hct or failure to increase after BT. - PVL is usually clinically asymptomatic until neuro sequelae of white matter damage become apparent in later infancy as spastic motor deficits. - May be present at birth, but usually occurs later as an early echodense phase (3-10 days of life), followed by the typical echolucent (cystic) phase (14-20 days of life). #### Grades of IVH - Grade 1: bleeding is isolated to subependymal area. - Grade 2: bleeding within the ventricle, but without ventricular dilatation. - Grade 3: IVH with ventricular dilatation. - Grade 4: intraventricular and parenchymal hemorrhage. - Grade 1: bleeding confined to germinal matrix-subependymal region or to <10% of ventricle. - Grade 2: 10-50% filling of the ventricle. - Grade 3: >50% of the ventricle is involved, with dilatation. #### Ventriculomegaly - Mild (0.5-1 cm) - Moderate (1-1.5 cm) - Severe (>1.5 cm) - A diagram of a normal brain and a brain with ventriculomegaly is shown. #### Diagnosis - History, clinical manifestations, and knowledge of birthweight-specific risks for IVH. - <32 weeks AOG - routine sonography. - Ultrasonography is preferred because it is noninvasive, portable, reproducible, and sensitive and specific for IVH detection. - PVL may not be visible for the first 2-4 weeks. #### Prognosis - Neurodevelopmental impairment. #### Prevention - Minimize traumatic brain injury. - Decrease risk of preterm delivery. - Single course of antenatal corticosteroids in 24-34 wks AOG that are at risk for preterm delivery. - Indomethacin to VLBW infants. ### Hypoxic-Ischemic Encephalopathy (HIE) - A diagram of an infant with decreased blood flow to the brain is shown. - Anoxia - consequences of complete lack of oxygen as a result of a number of primary causes. - Hypoxemia - decreased arterial concentration of oxygen. - Ischemia - insufficient blood flow to cells/organs to maintain their normal function. - HIE may result in neonatal death or manifest as cerebral palsy or developmental delay. #### Etiology - Inadequate maternal blood oxygenation from hypoventilation during anesthesia, cyanotic heart disease, respiratory failure, or CO poisoning. - Low maternal BP from acute blood loss, spinal anesthesia, or compression of the vena cava and aorta by the uterus. - Inadequate relaxation of the uterus to permit placental filling. - Premature separation of the placenta. - Impedance to circulation due to cord compression. - Placental insufficiency from toxemia or postmaturity. - Failure of oxygenation from cyanotic CHD or severe pulmo disease. - Severe anemia. - Shock. #### Pathophysiology & Pathology - Hypoxia/ischemia - anaerobic metabolism - lactate and inorganic phosphates. - Excitatory and toxic AA, esp glutamate, accumulate in the damaged tissue. - Intracellular sodium and calcium may result in tissue swelling and cerebral edema. - Increased free radical production and nitric oxide. - Shunting through ductus venosus, ductus arteriosus, and foramen ovale with transient maintenance of perfusion of the brain, heart, adrenals, in preference to the lungs, liver, kidneys, and intestines. A diagram of an infant is shown as well as an illustration of the pathogenesis of HIE. It shows a pathway involving perinatal asphyxia, re-oxygenation, cell death, and survival. - Perinatal asphyxia decreases oxygen saturation, increases anaerobic metabolism, and decreases ATP. Also, increased anaerobic metabolism increases lactate, which causes cell death. - Re-oxygenation increases oxygen saturation, which causes oxidative stress, DNA damage, and PARP-1. PARP-1 activates p50, p65, and IkB to cause cell death, or causes repair and survival. - Early congestion, fluid leak from increased capillary permeability, and endothelial cell swelling - coagulation necrosis and cell death. - Congestion and petechiae in pericardium pleura, thymus, heart, adrenals, meninges. - PVL. - Pulmonary arteriole smooth muscle hyperplasia. - Combination of chronic fetal hypoxia and acute hypoxic ischemic injury - gestational age-specific neuropathology. #### Clinical Manifestations - IUGR. - Variable or late deceleration. - Meconium stained amniotic fluid. - Fall to breathe spontaneously. - Hypotonic or hypotonic to hypertonic, may be normal. - Pallor. - Cyanosis. - Apnea. - Bradycardia. - Unresponsive to stimulation. - Brainstem depression due to cerebral edema. - Selzure may be severe and refractory to usual doses of anticonvulsants. #### Diagnosis - Diffusion-weighted MRI preferred because of its increased sensitivity and specificity early in the process and its ability to outline the topography of the lesion. - CT scans - limited ability to identify injury during the first few days of life. - Ultrasonography - preterm infants. - Amplitude integrated electroencephalography (aEEG) help to determine which infants are at highest risk for long-term brain injury. #### Treatment - Selective cerebral or whole body (systemic) therapeutic hypothermia reduces mortality or major neurodevelopmental impairment. - Decreases rate of apoptosis and suppresses production of mediators known to be neurotoxic. - Downregulation of the secondary mediators of injury resulting from cerebral edema, accumulation of cytokines, and seizures. - Within 6 hours of the event. - Phenobarbital. - Supportive care. #### Prognosis - Complete recovery to death (depending on the severity of the insult and the treatment). - Infants with initial cord or initial blood pH <6.7 have a 90% risk for death or severe neurodevelopmental impairment at 18 mo. old. - Infants with Apgar scores of 0-3 at 5 min, high base deficit (>20-25 mmol/L), decerebrate posture, and lack of spontaneous activity are at increased risk for death/impairment. - Highest risk: likely to die or have severe disability despite aggressive treatment. - Intermediate scores: likely to benfit from treatment. - Severe encephalopathy (flaccid coma, apnea, absence of oculocephalic reflexes and refractory seizures) is associated with a poor prognosis. - Low Apgar score at 20 min, with absent spontaneous respirations and persistence of abnormal neuro signs at 2 wk of age also predict death or severe cognitive and motor deficits. - Normal MRI and EEG associated with good recovery. - Microcephaly and poor head growth during the first year of life correlate to injury to the basal ganglia and white matter and adverse developmental outcome at 12 mo. #### Brain Death - Coma unresponsive to pain, auditory, or visual stimulation. - Apnea with PCO2 rising from 40 to 60 mm Hg without ventilatory support. - Absence of brainstem reflexes (pupillary, oculocephalic, oculovestibular, corneal, gag, sucking). - Persistence of the clinical criteria for 2 days in term infants and 3 days in preterm infants predicts brain death in most asphyxiated infants. ### Spine & Spinal Cord - Separation of vertebrae - strong traction when spine is hyperextended or when direction of pull is lateral, or forceful longitudinal traction on the trunk while the head is firmly engaged in the pelvis. - 4th cervical vertebra. - Lower cervical-upper thoracic in breech presentations. - A diagram of a spine is shown with an arrow pointing to the separation of vertebrae. #### Transection of the cord - Occur with or without vertebral fractures. - Areflexia, loss of sensation, complete paralysis of voluntary motion occur below the level of injury. - If with severe injury: may deteriorate rapidly to death within several hours before any neuro signs are obvious. - If with protracted course: s/sxs appear at birth or later in the 1st wk (immobility, flaccidity, associated brachial plexus injuries). - Constipation may be present. - Apnea on day 1 and poor motor recovery by 3 months are poor prognostic signs. - MRI confirms the diagnosis. - Disability. - A diagram of the spinal cord is shown with an arrow pointing to the complete transection of the cord. ### Peripheral Nerve Injuries #### Brachial Palsy - Paralysis of the upper part of the arm with or without paralysis of the forearm or hand, or more commonly, paralysis of the entire arm. - Macrosomic infants (Lateral traction on head and neck during delivery of the shoulder in a vertex presentation, when the arms are extended over the head in a breech presentation, or when excessive traction is placed on shoulders). - A diagram of a baby inside the womb is shown displaying excessive traction. #### Brachial Plexus Injury - Torn nerve endings at the base of the spinal cord and stretched nerves of the brachial plexus. #### Erb-Duchenne Paralysis - Injury limited to 5th and 6th cervical nerves. - Loses power to abduct the arm from the shoulder, rotate the arm externally, and supinate the forearm. - Characteristic position: adduction and internal rotation of the arm with pronation of the forearm. - Power to extend the forearm is retained, but biceps reflex is absent. - Moro reflex is absent on the affected side. - Power in forearm and hand grasp is preserved unless lower part of plexus is also injured. - A diagram is shown of a man with his arm showing the typical Erb-Duchenne paralysis, demonstrating adduction and internal rotation of the arm. #### Klumpke Paralysis - Rare form. - Injury to 7th and 8th cervical nerves and first thoracic nerve produces a paralyzed hand and ipsilateral ptosis and miosis (Horner syndrome) if the sympathetic fibers of the 1st thoracic root are also injured. - A diagram is shown of a hand displaying Klumpke paralysis. #### Prognosis - Depends on whether nerve was injured or lacerated. #### Treatment - Conservative management. - Monthly follow up. - Surgical intervention by 3 months. - Partial immobilization and appropriate positioning prevent contractures. - Brace/splint in 1-2 wk; intermittent. - Gentle massage and range-of-motion exercises at 7-10 days old. - Active and passive corrective exercises. - Neuroplasty, neurolysis, end-to-end anastomosis, nerve grafting. - Full recovery in most patients. #### Types of Nerve Injuries - **Neuropraxia:** The mildest injury to a peripheral nerve. It is due to edema and heals spontaneously within a few weeks. - **Axonotmesis:** More severe and is due to nerve fiber disruption with an intact myelin sheath. Function usually returns in a few months. - **Neurotmesis:** Total disruption of nerves or root avulsion. This is the most severe, especially if involving C5-T1. Microsurgical repair may be indicated. ### Phrenic Nerve Paralysis - (3rd, 4th, 5th cervical nerves) with diaphragmatic paralysis must be considered when cyanosis and irregular and labored respirations develop. - Associated with ipsilateral upper brachial palsy. - Abdomen does not bulge with inspiration. - Breath sounds are diminished on the affected side.. - Dx is established by ultrasonographic or fluoroscopic exam; reveals elevation of the diaphgram on the paralyzed side and seesaw movements of the 2 sides of the diaphragm during respiration. - No specific Tx (infants placed on the involved side and given 02). - Recovery usually spontaneous at 1-3 months. ### Facial Nerve Palsy - Pressure over the facial nerve in utero, from efforts during labor, or from forceps use during delivery. - Nuclear agenesis. - Flaccid and when complete, involves the entire side of the face, including the forehead. - Movement occurs only on the nonparalyzed side of the face, and mouth is drawn to that side. - Affected side: forehead is smooth, eye cannot be closed, nasolabial fold is absent, corner of mouth droops. - Forehead wrinkles on affected side with central paralysis because only the lower 2/3 of the face is involved. - Improvement within few weeks if nerve was injured by pressure. - A diagram is shown of a man with facial nerve palsy on one side of his face.