Presentation on theme: "Essentials of Pathophysiology"— Presentation transcript:
1 Essentials of Pathophysiology Chapter 22 Respiratory Tract Infections, Neoplasia, and Childhood Disorders
2 Pre lecture quizTrue/FalseFBacteria are the most frequent cause of respiratory tract infections.Influenza is a viral infection that can affect the upper and lower respiratory tracts and is transmitted by aerosol or direct contact.Primary tuberculosis represents either reinfection from inhaled droplet nuclei or reactivation of a previously healed primary lesion.Typical pneumonias result from infection by bacteria.Acute bronchiolitis is a viral infection that has a peak incidence at 3 to 6 months of age and is most commonly caused by the respiratory syncytial virus (RSV). TFTT
3 Pre lecture quizepiglottitisMycobacteriumLungrapidupperThe common cold is a viral infection of the __________ respiratory tract.One distinguishing feature of influenza is __________ onset.Tuberculosis is an infectious disease caused by __________ tuberculosis, a rod-shaped aerobic bacterium that is resistant to destruction and can persist in necrotic and calcified lesions for prolonged periods and remain capable of reinstating growth.__________ cancer is the leading cause of cancer deaths among men and women in the United States.Acute __________ is a dramatic, potentially fatal condition characterized by inflammatory edema of the supraglottic area, including the epiglottis and pharyngeal structures, that comes on suddenly and carries the risk of complete obstruction.
4 Upper Respiratory Viruses in Adults Common coldRhinosinusitisInfluenza
5 The Common Cold Rhinoviruses Parainfluenza viruses Catarrh- Excessive mucus secretion: any of a family (Adenoviridae) ofDNA viruses shaped like a 20-sided polyhedron, causing respiratory diseases (as catarrh), and including some capable of inducing malignant tumors:any of various single-stranded, RNA-containing viruses that cause respiratory infection in humans and resemble a crown when viewed under an electron microscope because of their petal-shaped projections.The Common ColdRhinovirusesOccur in early fall and late spring in persons between ages 5 and 40Parainfluenza virusesOccur in children younger than 3Respiratory syncytial virusOccurs in winter and spring in children younger than 3Coronaviruses and adenovirusesOccur in winter and spring
6 Rhinosinusitis (Sinusitis) Infection or allergy obstructs sinus drainageAcute: facial pain, headache, purulent nasal discharge, decreased sense of smell, feverChronic: nasal obstruction, fullness in the ears, postnasal drip, hoarseness, chronic cough, loss of taste and smell, unpleasant breath, headache
7 Transmission is by aerosol (three or more particles) or direct contact InfluenzaIn the United States, approximately 36,000 persons die each year of influenza-related illnessTransmission is by aerosol (three or more particles) or direct contactUpper respiratory infection (rhinotracheitis)Like a common cold with profound malaiseViral pneumoniaFever, tachypnea, tachycardia, cyanosis, hypotensionRespiratory viral infection followed by a bacterial infection
9 QuestionFor which viruses is a 2-year-old most at risk?RhinovirusesParainfluenza virusesRespiratory syncytial virus (RSV)All of the aboveb and c
10 Answerb and cRationale: Slightly older children (> 5 y) are at risk for rhinoviral infections. Children under the age of 3 are at risk of infection from both parainfluenza viruses and RSV.
11 Mechanism of Viral Infection and Treatment amantadine, rimantadinezanamivir, oseltamivir
12 Pneumonia—Inflammation of Alveoli and Bronchioles Typical: bacteria in the alveoliLobar: affect an entire lobe of the lungBronchopneumonia: patchy distribution over more than one lobeAtypicalViral and mycoplasma infections of alveolar septum or interstitium
13 Typical Pneumonia inhaled and cultured particles in the alveoli Atypical when virons invade and colonize in the alveolar septumType of pneumonia is further identified by lung or bronchial location.Author: Please add title.
14 Infection Inflammation Congestion, productive Serous exudate cough Onset of PneumoniaSigns of systemic inflammationMalaiseChills and feverInfectionInflammationCongestion,Serous exudateproductivecough
15 Hepatinization – Tissue that takes on the appearance of Liver Blood-tinged sputumPleuritic painserous exudatefibrous exudate:REDconsolidationHEPATINIZATIONHepatinization – Tissue that takes on the appearance of LiverWBCs denaturehemoglobin:GRAYHEPATINIZATION
16 If WBCs Overcome the Infection WBCs denaturehemoglobin:GRAYHEPATINIZATIONWBCs destroy fibrousproteins and liquefyresolutionexudate: it is reabsorbedinto the circulation
17 QuestionTell whether the following statement is true or false. In the progression of pneumonia, serous exudate develops before fibrous exudate.
18 AnswerTrue Rationale: Serous exudate develops (just after inflammation) before fibrous exudate, and is characterized by a congested, productive cough. If the pneumonia does not resolve at this stage, fibrous exudate develops, and the patient will experience pleuritic pain (worse when taking a deep breath or coughing) and may expectorate blood-tinged sputum.
19 TuberculosisWorld’s foremost cause of death from a single infectious agentCauses 26% of avoidable deaths in developing countriesDrug-resistant formsMycobacterium tuberculosis hominisAerobicProtective waxy capsuleCan stay alive in “suspended animation” for years
20 Initial TB Infection Macrophages begin a cell-mediated immune response Takes 3–6 weeks to develop positive TB testResults in a granulomatous lesionor Ghon focus containingMacrophagesT cellsInactive TB bacteria
21 Ghon complex Nodules in lung tissue and lymph nodes Caseous necrosis inside nodulesCalcium may deposit in the fatty area of necrosisVisible on x-rays
25 Discussion If someone in your class has a positive TB test. Question: What does this mean?Are you at risk of infection?
26 Primary TB primary TB usually if immune response is isolated in inadequate, bacteriaGhon focimultiply in the lungsbacterianotprogressive primary TBarecontagiousinactive
27 Miliary TBMiliary TB lesions look like grains of millet in the tissuesMeat inspection was introduced to keep them out of the food supplyPasteurization of milk was introduced to keep TB out of the milk supplyprogressive primary TBbacteria maysigns ofbacteria inerode bloodpneumoniasputum andvessels andexhaledspread throughdropletsthe bodyMILIARYTB
28 Secondary TB Reinfection from inhaled droplet nuclei Reactivation of a previously healed primary lesionImmediate cell-mediated response walls off infection in airwaysBacteria damage tissues in the airways, creating cavitiesSigns of chronic pneumonia: gradual destruction of lung tissue“Consumption”: eventually fatal if untreated
29 QuestionWhich type of TB may be reactivated if the patient becomes immunocompromised?PrimaryLatentMiliarySecondary
30 AnswerSecondaryRationale: Secondary TB, often referred to as reactivation or reinfection TB, may occur if patients are reexposed to TB bacilli (after a primary infection) or if they become immunocompromised (they are unable to contain the infection).
32 Lung Cancer Bronchogenic carcinoma Arises from epithelial cells lining the lungsSmall-cell lung cancerNon–small-cell lung cancerLarge-cell carcinomaSquamous cellAdenocarcinoma
33 Adenocarcinoma of the Lung Large Cell Carcinoma
34 Manifestations of Lung Cancer Changes in organ function (organ damage, inflammation, and failure)Local effects of tumors (e.g., compression of nerves or veins, gastrointestinal obstruction)Ectopic hormones secreted by tumor cells (paraneoplastic disorders)Nonspecific signs of tissue breakdown (e.g., protein wasting, bone breakdown)
35 Respiratory Distress Syndrome Lack of surfactant; infants are not strong enough to inflate their alveoliProtein-rich fluid leaks into the alveoli and further blocks oxygen uptakeTreatment with mechanical ventilation may cause bronchopulmonary dysplasia and chronic respiratory insufficiency
36 Respiratory Distress Syndrome Lack of surfactant; infants are not strong enough to inflate their alveoli
37 QuestionTell whether the following statement is true or false. Premature infants are at greater risk of developing respiratory distress syndrome (RDS) than term infants.
38 AnswerTrue Rationale: RDS occurs due to a lack of surfactant in the alveoli (the surfactant is produced by alveolar cells, and keeps them inflated). Surfactant is typically produced from week 28 (gestational age) through term (40–42 weeks). The more premature the infant/neonate, the greater the likelihood that there will be insufficient surfactant to sustain ventilation.
39 Respiratory Obstruction in Children Increased airway resistanceExtrathoracic airways (upper airways)Prolonged inspiration; inspirational stridorInspiratory retractions as ribs are moved outward and body wall does not expand with rib cageIntrathoracic airways (lower airways)Prolonged expiration with wheezingRib cage retractions as ribs are pulled inward, but air does not leave lungs
41 QuestionTell whether the following statement is true or false. Epiglottitis causes stridor.
42 AnswerTrue Rationale: Epiglottitis affects the upper airway (inflammation causes the lumen of the upper airway to become more narrow). When the child inspires, it is difficult to pass air through the narrowed airway. This causes noisy inspiration/stridor.