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Thursday, December 2, 2021

Development and Developmental Disorders of the Hypothalamus

Development and Developmental Disorders of the Hypothalamus

Development and Developmental Disorders of the Hypothalamus

CYTOGENETIC DISEASE: PRADER-WILLI SYNDROME
CYTOGENETIC DISEASE: PRADER-WILLI SYNDROME


The hypothalamus in mammals arises as a part of the ventral diencephalon and the adjacent telencephalon, and its embryologic origins are intimately related to those of the optic chiasm and tracts and to the pituitary gland. Thus disorders that affect the hypothalamus fre- quently manifest with signs and symptoms resulting from dysfunction of neighboring, developmentally related structures. The developing neural tube is divided into three primary regions: forebrain, midbrain, and hindbrain. The forebrain is further subdivided into the telencephalon, which gives rise to the cerebral cortex and basal ganglia, and the diencephalon, from which the thalamus and hypothalamus are derived. The hypothalamus develops from the anterior portion of the diencephalon in a series of steps that involve the activation of suites of transcription factors, which determine the fates of the developing cell populations.

Anatomic Relationships of the Hypothalamus

Anatomic Relationships of the Hypothalamus

Anatomic Relationships of the Hypothalamus

The hypothalamus is a small area, weighing about 4 g of the total 1,400 g of adult brain weight, but it is the only 4 g of brain without which life itself is impossible. The hypothalamus is so critical for life because it contains the integrative circuitry that coordinates autonomic, endocrine, and behavioral responses that are necessary for basic life functions, such as thermoregulation, control of electrolyte and fluid balance, feeding and metabolism, responses to stress, and reproduction.

ANATOMY AND RELATIONS OF THE HYPOTHALAMUS AND PITUITARY GLAND
ANATOMY AND RELATIONS OF THE HYPOTHALAMUS AND PITUITARY GLAND


Perhaps for this reason, the hypothalamus is particularly well protected. It lies at the base of the skull, just above the pituitary gland, to which it is attached by the infundibulum, or pituitary stalk. As a result, trauma that affects the hypothalamus would almost always be lethal. It receives its blood supply directly from the circle of Willis (see Plate 5-3), so it is rarely compromised by stroke, and it is bilaterally reduplicated, with survival of either side being sufficient to sustain normal life.

Child Abuse

Child Abuse

Child Abuse

Child abuse is defined by the Child Abuse Prevention and Treatment Act (CAPTA) as “Any recent act or failure to act on the part of a parent or caretaker that results in death, serious physical or emotional harm, sexual abuse or exploitation; or an act or failure to act that presents an imminent risk of harm.” There are four major types of maltreatment: neglect, physical abuse, psychologic mal-treatment, and sexual abuse. Most states set up their own guidelines indicating the level of evidence to make the distinguishing finding or disposition for the abuse.

FRACTURES IN ABUSED CHILDREN
FRACTURES IN ABUSED CHILDREN


The National Child Abuse and Neglect System (NCANDS) of the Administration of Children, Youth, and Families (ACYF) Annual Report 2009 indicates that there were 9.3 unique abuse victims confirmed per 1,000 children in the United States. Children 1 year and younger had the highest rate of victimization; there was an almost equal distribution of boys and girls; some children experienced multiple abuses. Neglect was most frequent (78.3%), followed by physical abuse (17.8%). Sexual and psychologic maltreatment each occurred in 10% of abused children overall. The 2009 national fatality rate was 2.34 per 100,000 and has been increasing over the past 5 years. Health and mental health-care professionals should maintain the possibility of abuse on their differential every time they see a child.

Pediatrics: Eating Disorders

Pediatrics: Eating Disorders

Pediatrics: Eating Disorders

Pediatrics: Eating Disorders


Eating disorders occur in adolescents who have intense preoccupation with body weight and shape and impaired eating habits. Patients have distorted thoughts and emotions concerning their appearance as well as abnormal eating behaviors; these lead to alterations in body composition and functioning occur. The etiology of eating disorders is multifactorial and includes a genetic component, sociocultural pressures to be thin, and the promotion of dieting. Performers and athletes, particularly those participating in activities that reward a lean body (e.g., gymnastics, running, wrestling, dance, or modeling) are at particular risk. Girls who feel most negatively about their bodies at puberty are at highest risk for the development of eating difficulties. The prevalence of eating disorders is variably reported, 0.8% to 14%. Their epidemiology has gradually changed concomitantly in the United States and world-wide, with an increasing prevalence in males, younger age groups, minority populations in the United States, and now countries where eating disorders uncommonly occurred. Acculturation to Western values is a risk factor for eating disorders in U.S. immigrants.

Pediatrics: Attention-Deficit/Hyperactivity Disorders

Pediatrics: Attention-Deficit/Hyperactivity Disorders

Pediatrics: Attention-Deficit/Hyperactivity Disorders

Pediatrics: Attention-Deficit/Hyperactivity Disorders


The attention-deficit hyperactivity disorders (ADHD) are a group of childhood, adolescent mental health problems characterized by difficulty controlling attention, motivation, and behavioral impulses. These are common childhood psychiatric conditions, affecting 5% to 12% of children worldwide. More common in boys, there is increasing evidence that the principal cause of ADHD is genetically based. A greater American prevalence may result from varied diagnostic practices and cultural expectations. ADHD is related to differences in prefrontal cerebral cortex structure and function. These are important for controlling organization, planning, attention, and impulses. Maternal drinking or smoking during pregnancy, low birth weight, chemical injuries to the brain (e.g., lead poisoning), and severe child neglect are associated with ADHD.

Pediatrics: Disruptive Behavior Disorders

Pediatrics: Disruptive Behavior Disorders

Pediatrics: Disruptive Behavior Disorders

The disruptive behavior disorders (DBDs) are mental health problems occurring in children and adolescents, more commonly in boys, characterized by out-of-control behavior. Prevalence rates vary from 1% to 16%. A cluster of factors, including the child’s characteristics, parental interactions, and environmental factors contribute to their development.

Pediatrics: Disruptive Behavior Disorders


Ineffective parenting strategies often underlie these disorders. Parents may have insufficient time and emotional energy for the child or may use inconsistent methods of disciplining and limit setting. These ineffective strategies include authoritarian parenting, wherein the parent demonstrates too much anger or is too harsh, and permissive parenting, with the parent giving in to the child’s excessive demands. Authoritative parenting is defined as having high levels of both warmth and firmness and is the most effective parenting strategy.

Pediatrics: Anxiety Disorders

Pediatrics: Anxiety Disorders

Pediatrics: Anxiety Disorders

The anxiety disorders (AD) are mental health problems found in children and adolescents, characterized by disabling scared or worried feelings. These disorders are common, with 10 to 15 of 100 youths estimated to have one of these disorders. These occur more commonly in girls. ADs are caused by a difference in the structure or function of the brain that controls worries and fears. Vulnerability to the development of anxiety disorders can be genetically transmitted. Parents who are overprotective or overcontrolling appear more likely to have anxious children, and children also can learn to be anxious from parents who are anxious. Sometimes environmental events can trigger an anxiety disorder. For example, separation anxiety disorder can be caused by exposure to frightening events, such as domestic violence.

Pediatrics: Anxiety Disorders


Generalized Anxiety Disorder. Generalized anxiety disorder is characterized by excessive worry/angst occurring on more days than not about a variety of areas, such as schoolwork, friendships, family, health/ safety, and world events. The worry is accompanied by feeling tired, tense, restless or irritable; having difficulty focusing; and having trouble falling or staying asleep. Sometimes these youngsters have associated physical symptoms, including muscle aches, stomach cramps, or nausea. The youth finds it difficult to control the worry. To meet the diagnosis, the problems must be present for at least 6 months, and must cause distress and/or impair the youth’s function at home, at school, or with peers.

Pediatrics: Depressive Disorders

Pediatrics: Depressive Disorders

Pediatrics: Depressive Disorders

The depressive disorders are a group of mental health problems in children and adolescents characterized by a sad or irritable mood. In simple terms, these disorders are caused by a difference in the structure and function of the part of the brain that controls the intensity of sad and irritable moods. Vulnerability to the development of depressive disorders can be genetically determined. Concomitantly, there is often something in the youth’s environment that triggers the sad or irritable feelings, such as poor relationship(s) with peers or with a parent or loss of loved ones. It is estimated that 4 to 5 of 100 youths have depressive disorders.

Pediatrics: Depressive Disorders


The most severe of these disorders, major depressive disorder, is characterized by a distinct period of at least 2 weeks during which the child/adolescent experiences a depressed or irritable mood that is present most of the day nearly every day and/or is associated with loss of interest or pleasure in nearly all activities. There are often severe problems with eating, sleeping, energy, concentration, feelings of worthlessness or extreme guilt, and loss of the desire to live. These symptoms may manifest as the youth being cranky, having loss of interest in hanging out with friends, refusal to get out of bed for school in the morning, or preoccupation with song lyrics that suggest life is meaningless. To meet the diagnosis, the problems must cause distress and/or impair the youth’s function at home, at school, or with peers. After puberty, major depressive disorder is more common in girls than boys.

Insomnia

Insomnia

Insomnia

Most people experience occasional insomnia sometime in their lives. However, a diagnosis of insomnia disorder, which is present in 10% to 15% of adults, requires a symptom, that is, difficulty with sleep onset, sleep maintenance, or nonrestorative sleep; a frequency and duration present on most nights over a period of at least 4 weeks; and a consequence, associated distress, or social occupational dysfunction. Insomnia disorder is most commonly comorbid (75%), in which the insomnia occurs in the context of a medical, psychiatric, or sleep disorder that initiated or maintained the sleep disturbance, or primary insomnia, with no comorbid disorders.

Insomnia


Insomnia disorder is more common with increasing age, female gender, poor physical health, and increased social and familial stress. Often, this is a chronic condition, with 50% of insomnia disorder patients continuing to meet criteria after 3 years, particularly with more severe symptoms. However, specific insomnia symptoms (initial insomnia, nocturnal awakenings) are often dynamic, shifting over the course of the disorder. In comorbid insomnia, sleep disturbance is a marker of greater medical, neurologic, and psychiatric illness severity. Insomnia disorder is an independent risk factor for incident major depressive episodes. It is not established whether comorbid insomnia treatment improves outcomes in such disorders. Insomnia sufferers have an increased risk of hypertension and diabetes.

Delirium and Acute Personality Changes

Delirium and Acute Personality Changes

Delirium and Acute Personality Changes

Delirium is an acute confusional state commonly seen in patients with medical illness, especially among the geriatric population. Delirium encompasses four key clinical features, including (1) a disturbance of consciousness with impaired attention and concentration, (2) the disturbance develops over a short period of time (hours to days) and often fluctuates in severity. (3) a perceptual disturbance that is not related to a pre-existing condition such as dementia, and (4) an underlying medical condition, intoxication, or medication side effect is evident. Approximately 30% of older patients experience delirium in the course of hospitalization, with higher rates among more frail patients and those under-going complex surgery. In the intensive care unit (ICU), the prevalence of delirium is about 70% as measured by standardized screening and diagnostic tools.

Delirium and Acute Personality Changes


There are multiple pathophysiologic mechanisms that may cause delirium; there is no final common pathway allowing a simple approach to diagnosis or treatment. The neurobiologic basis of delirium is, therefore, poorly understood, and diagnosis relies on a comprehensive clinical assessment with judicious use of ancillary studies. In general, areas of the brain that govern arousal, attention, insight, and judgment are affected. These include the subcortical ascending reticular activating system (ARAS) and integrated cortical regions. The ARAS predominantly serves arousal mechanisms, whereas integrated cortical function is necessary for proper orientation to person, place, and time, as well as higher cognitive functions.

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