Abnormal Head Growth in Children (Lec.4) PDF

Abnormal Head Size Macrocephaly & Microcephaly By Dr. Iman Khalifa Assistant Professor of Pediatrics, Helwan University 2024/2025 AGENDA To know abnormal head growth. To diagnose microcephaly, know its causes, and clinical presentati...

Abnormal Head Size Macrocephaly & Microcephaly By Dr. Iman Khalifa Assistant Professor of Pediatrics, Helwan University 2024/2025 AGENDA To know abnormal head growth. To diagnose microcephaly, know its causes, and clinical presentation. To diagnose macrocephaly, and its causes. Diagnose Hydrocephalus, CSF circulation, causes, clinical presentation, and management.  The head grows rapidly in the first 2 years of life then slows down, but continues to grow throughout childhood. In the early years the sutures are open. Measurement of head circumference (HC), or OFC (occipital frontal circumference), is a reflection of head growth and is a useful tool in tracking and monitoring childhood growth and development, because an abnormality of HC can indicate an underlying congenital, genetic, or acquired neurologic problem. A child with a small head Maya is a 9-month-old baby. She was born small for gestational age and her growth has always been borderline, with her weight, length and head circumference now all below 2nd centile. There are no dysmorphic features. Maya has just now achieved sitting with support and she has reasonable head control. She began to reach out for objects at 7 months and has just started transferring from hand to hand. She makes few sounds. 1. Does Maya have microcephaly? 2. What do you need to focus on in your clinical evaluation? 3. Does Maya need to be investigated?  Microcephaly (means a small head) Definition: It is a head circumference below the 2nd percentile for age and gender. In most instances, a small head circumference is a reflection of a small brain. Brain growth is rapid during the perinatal period, and any insult (e.g., infectious, metabolic, toxic, vascular) sustained during this period or during early infancy is likely to impair brain growth and result in microcephaly.  Microcephaly- Etiology 1- PRIMARY (GENETIC) 1- Familial 2- Syndromes Down (trisomy 21) 2- SECONDARY (NON-GENETIC or ACQUIRED) 1- Congenital Infections 2- Other causes Zika virus Radiation (with exposure before 15th Cytomegalovirus (CMV) week of gestation. Rubella Meningitis/encephalitis Toxoplasmosis Hypoxic-ischemic encephalopathy 3- CRANIOSTENOSIS (CRANIOSYNOSTOSIS) Familial microcephaly Clinical evaluation of microcephaly Full medical and family history: 1. Prenatal e.g. history of infection, drug intake or exposure to radiation. 2. Natal e.g. Obstructed delivery. 3. Postnatal e.g. meningitis. 4. Motor and mental development (mental retardation is a common association). 5. Family history may be positive in familial cases. Complete physical exam 1. Measuring the head circumference, to compare with the average head size for age and gender. A small head circumference at birth denotes intrauterine insult, serial measurements are more important. 2. Associated dysmorphic features and congenital anomalies. 3. Detailed neurological examination. 4. Measuring the head circumference of the parents. Investigations 1. X- Ray : Small-sized head Craniostenosis: small malformed cranium with silver beaten appearance. True microcephaly: small cranium. 2. Karyotyping 3. TORCH screening: CMV or toxoplasmosis. 4. MRI to determine the brain atrophy , intracranial calcifications with toxoplasmosis and CMV. 3- CRANIOSTENOSIS (CRANIOSYNOSTOSIS) Definition: Premature closure of one or more skull sutures. The result is always an abnormal skull shape. When it is generalized: Multiple sutures (microcephaly, motor and mental retardation). Types: 1. Primary: due to abnormalities of skull development. The cause is unknown. 2. Secondary: results from failure of brain growth and expansion. 3. Genetic syndromes: as with exophthalmos in Crouzon's syndrome. Crouzon syndrome Craniostenosis (cont.) The shape of the head depends on which of the major sutures has prematurely closed. Clinical manifestation Children born with craniosynostosis may have increased ICP and vision problems. In craniostenosis there is: 1. Palpable ridge in the region of the prematurely closed suture. 2. Papilledema and other manifestations of increased intracranial tension. 3. Skull deformities. 4. Skull X-ray: silver-beaten appearance, shows a band of increased density at the site of the prematurely closed sutures. The large head The nurse measures Ahmed’s head at 8- week check. She notes that the head circumference has crossed upwards centiles since the newborn examination. Ahmed has been developing normally and is smiling and able to lift head in the prone position. His parents describe him as easygoing and have no concerns. His plotted curves are shown. 1. Is this a worrying pattern of head growth? 2. What are the most common cause of macrocephaly? 3. How do you advise the parents and nurse?  Macrocephaly (means a large head) Definition: It is head circumference above the 98th percentile for age and gender. The volumes of the three compartments that fill the skull (brain 80%, cerebrospinal fluid 10%, and blood 10%) determine the size of the skull during infancy. The extra-cerebral spaces (epidural, subdural, and subarachnoid) may expand with blood and significantly affect cranial volume. Common Causes of Macrocephaly 1- Hydrocephalus (an excessive volume of CSF in the skull). Achondroplasia 2- Benign causes: Familial macrocephaly 3- Macrocrania (increased skull thickness): Achondroplasia, Rickets, and chronic, severe anemia. 4- Masses: cysts, subdural fluid collections/hematoma, Chronic hemolytic anemia arteriovenous malformations and Neoplasm 5- Megalencephaly (enlargement of the brain). RICKETS  Hydrocephalus o Definition: Increase in ventricular size due to an imbalance between the production of CSF and its drainage by the arachnoid villi. o It is the main cause of macrocephaly at birth in which intracranial pressure is increased. o Etiology: 1) Increased production, 2) Decreased absorption, or 3) CSF flow obstruction. To be rplaced  Types: 1- Non-communicating (obstructive) 2- Communicating (non-obstructive) hydrocephalus hydrocephalus (extra-ventricular obstruction) Caused by a block before the CSF flows to the subarachnoid Impairment of CSF flow within the subarachnoid space or space, usually within the fourth ventricle or at the level of impairment of absorption, where there is actually extra- the aqueduct. ventricular obstruction of CSF flow. 1. Congenital 1. Hypoplasia of the arachnoid villi a. Aqueduct of Sylvius (cerebral aqueduct) 2. Extensive cerebral sinovenous thrombosis obstruction/stenosis (the most common congenital cause). 3. Post-infectious or post-hemorrhagic destruction of b. Dandy-Walker malformation arachnoid villi or subarachnoid fibrosis Incomplete formation of the cerebellar vermis with 4. Neoplastic: Hydrocephalus caused by overproduction of obstruction of foramina of Magendie and Luschka: Cystic CSF without true obstruction is seen in choroid plexus expansion of the 4th ventricle with bulging occiput. papillomas, which account for 2–4% of childhood c. Vein of Galen malformation. intracranial tumors. 2. Acquired (the most common site of obstruction is at the aqueduct of Sylvius) a. Post-hemorrhagic b. Post-infectious or post-inflammatory. c. Neoplastic: posterior fossa tumors e.g. cerebellar medulloblastoma. Parasellar mass (craniopharyngioma, germinoma, pituitary tumor), Midbrain or pineal region tumor. REMEMBER ü Most common cause of congenital hydrocephalus = aqueductal stenosis. ü Most common cause of non-obstructive or communicating hydrocephalus = subarachnoid hemorrhage, which is usually a result of intraventricular hemorrhage in a premature infant. ü Common cause of acquired hydrocephalus, is post- inflammatory obstruction. Bacterial and tuberculous meningitis have a propensity to produce thick tenacious exudate that obstructs the basal cisterns. Clinical Manifestations of Hydrocephalus Variable. Depends on: (1) age of onset, (2) nature of the lesion causing obstruction, a (3) the duration and rate of increase of the intracranial pressure. Include irritability, Sleepiness, poor appetite, and vomiting. In infants (before closure of fontanelle and sutures) üHead examination: 1. Accelerated rate of head enlargement. 2. Wide bulging anterior fontanel. 3. The sutures are separated. 4. The scalp veins are dilated. 5. The forehead is broad. 6. The eyes deviated down giving the ‘setting sun’ eye sign. Clinical Manifestations of Hydrocephalus Long-tract signs, including brisk tendon reflexes,spasticity, clonus (particularly in the lower extremities), and Babinski sign. üBack examination: For any swellings: meningocele or meningomyelocele in Chiari malformation In older children, the signs are subtle with headache and a deterioration in school performance. Diplopia and sixth nerve palsy. Investigations ØCT scans and MRI scans are often used in combination to confirm a diagnosis of hydrocephalusà dilatation of the ventricular system. - Obstructive hydrocephalus: dilatation only proximal to the site of obstruction. - Communicating hydrocephalus: all ventricles are dilated Axial (A) and sagittal (B) T1-weighted MRI revealing a communicating hydrocephalus Dandy-Walker malformation A 2 year-old girl presented with an enlarging head and a delay in motor milestones. Non-communicating Hydrocephalus - Aqueductal Stenosis Hydrocephalus Treatment A. The two main types of surgery include: 1. Ventriculoperitoneal (VP) shunt: A VP shunt is a tube that diverts CSF from the brain to the abdomen, where it is absorbed. A surgeon inserts the tube into a ventricle and threads the tube under the skin to the abdominal area. A valve placed on the tube helps manage the flow of fluid. A VP shunt is the most common treatment for hydrocephalus. Hydrocephalus Treatment A. The two main types of surgery include: 2. Endoscopic third ventriculostomy (ETV): This is a minimally invasive procedure that eliminates the need for a shunt. The surgeon uses a thin tube (endoscope) and tiny instruments to create a small hole at the bottom of one of the ventricles. The opening allows fluid to drain and relieves pressure. ETV is an option for non-communicating hydrocephalus. B. Acetazolamide: decrease secretion of CSF at the level of the choroid plexus. In non-progressive cases. The major complications of shunting 1. Occlusion (characterized by headache, papilledema, emesis, mental status changes) 2. Bacterial infection (fever, headache, meningismus), usually caused by Staphylococcus epidermidis.