semana 9 - medi

Introduction to Internal Medicine and Congenital Malformations

Overview of the Course Structure

• The course is in its eighth week, focusing on theoretical aspects after seven weeks of introductory classes in internal medicine.

• Emphasis on integrating semiological knowledge for comprehensive patient evaluation through clinical history, anamnesis, and clinical examination.

Importance of Complementary Exams

• Complementary exams are crucial for assessing a patient's general health, especially before surgical interventions. Common tests include hemograms and biochemical analyses.

• Understanding these tests helps identify potential risks related to anesthesia or surgery, aiding in evaluating morbidity and mortality risks.

Clinical Case Presentation Requirement

• Students must present a clinical case by the seventh week, focusing on congenital malformations or hereditary disorders observed in patients. This includes developing a small monograph on the chosen condition.

• Examples provided include cases like cleft lip/palate where students will document patient history and relevant information about the condition's etiology and treatment options.

Understanding Genetic Disorders

Definitions: Congenital vs Hereditary Disorders

• Genetic disorders can be classified as congenital (present at birth) or hereditary (passed down from parents). Not all congenital issues are hereditary; some arise spontaneously during development.

• The distinction is made clear: congenital conditions manifest at birth while hereditary conditions may not show symptoms until later in life.

Types of Malformations

• Congenital malformations can result from genetic factors (25% of cases), teratogenic influences (15%), or multifactorial interactions between genetics and environment.

• Classification based on developmental processes includes malformations, disruptions, deformations, and dysplasias—each with specific characteristics affecting organ formation during gestation.

Clinical Implications of Anomalies

Major vs Minor Anomalies

• Major anomalies significantly impact biological function or survival (e.g., anencephaly), often requiring complex surgeries or therapies due to their severity.

• Minor anomalies typically have cosmetic implications without serious health consequences (e.g., extra digits) but still require monitoring for potential complications over time.

Syndromes and Sequences

• Syndromes consist of multiple anomalies stemming from a single known cause (e.g., Down syndrome), while sequences involve cascading defects resulting from an initial anomaly (e.g., Pierre Robin sequence).

• Associations refer to groups of anomalies that occur together but lack a clear etiological link; examples include VACTERL association involving vertebral, anal, cardiac, tracheal, esophageal, renal limb defects.

Etiology of Congenital Malformations

Genetic Factors

• Malformations can arise from chromosomal abnormalities—either numerical or structural—and mutations affecting one or multiple genes leading to various syndromic presentations such as Turner syndrome or Marfan syndrome.

Environmental Influences

• Teratogens are external factors that disrupt normal embryonic development; they can be biological agents like viruses or environmental toxins impacting fetal growth during pregnancy stages such as the first trimester when critical organ systems develop most rapidly.

Understanding Congenital Malformations and Their Causes

Overview of Congenital Infections

• The term "torch" refers to a group of infections including toxoplasmosis, syphilis, rubella, cytomegalovirus, and herpes that can affect pregnant women.

• These infections can lead to severe fetal complications such as brain damage, blindness, microcephaly, congenital heart defects, hearing loss, and psychomotor delays.

Types of Congenital Malformations

• Congenital malformations can be structural or functional; the latter may not be evident at birth but manifest later during growth.

• External factors like medications and chemicals ingested by the mother during pregnancy can also contribute to these malformations.

Teratogenic Effects of Medications

• Certain drugs (e.g., valproic acid for seizures and isotretinoin for acne) have been linked to fetal malformations; thalidomide was previously used as an anti-inflammatory but caused limb deformities.

• Social drugs such as alcohol and tobacco are also implicated in fetal growth issues and malformation risks.

Physical Agents Impacting Fetal Development

• Exposure to X-rays during pregnancy is discouraged due to potential harm; protective measures should be taken if imaging is necessary.

• High fever or prolonged exposure to high temperatures can disrupt neural tube formation in embryos.

Nutritional Factors Affecting Embryonic Development

• Maternal health conditions like uncontrolled diabetes or nutritional deficiencies (e.g., anemia lacking folic acid) are associated with increased risks of conditions like spina bifida.

Genetic vs. Environmental Influences on Malformations

• Both genetic predispositions and environmental interactions play roles in the development of congenital malformations; most defects arise from a combination rather than a single cause.

Etiology of Congenital Defects

• The etiology includes both genetic factors (dominant/recessive inheritance patterns or mutations) and non-genetic factors such as infections or hormonal imbalances affecting fetal development.

Non-genetic Triggers for Malformation

• Environmental triggers include maternal drug use (e.g., antibiotics), nutritional deficiencies, dehydration during pregnancy, hypoxia due to oxygen deprivation, etc.

Mechanisms Leading to Facial Malformations

• Traumas during pregnancy or abnormal embryonic conditions (like amniotic band syndrome or oligohydramnios leading to pressure effects on developing structures).

Soft Tissue Disorders: Focus on Cleft Lip and Palate

Introduction to Cleft Conditions

• The discussion shifts towards soft tissue disorders focusing on congenital anomalies like cleft lip/palate which occur due to developmental disruptions.

Prevalence of Cleft Lip/Palate

• Cleft lip/palate occurs in approximately 1 out of every 800–1000 live births; one-third present only with cleft lip while two-thirds have both cleft lip and palate issues.

Developmental Timeline for Oral Structures

• Formation begins between the sixth and tenth weeks gestation; disruption in this timeline often leads to combined cleft conditions due to interrelated developmental processes.

Gender Differences in Cleft Occurrence

• Isolated palatine clefts are more common in females compared with males; left-sided occurrences are more frequent than right without clear reasons identified yet.

Genetic Considerations in Cleft Formation

• Less than half of patients with clefts have hereditary backgrounds indicating that many cases arise from new mutations rather than inherited traits.

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