Chapter 17: Overview of Infectious Diseases PDF

Chapter 17: OVERVIEW OF INFECTIOUS DISEASES FIRST SEMESTER I ACADEMIC YEAR 2024-2025 I PROF. JOHN LEONARD CHAN ○​ Infections: Overview of Disease Categories ​ Otitis Media: Middle ear...

Chapter 17: OVERVIEW OF INFECTIOUS DISEASES FIRST SEMESTER I ACADEMIC YEAR 2024-2025 I PROF. JOHN LEONARD CHAN ○​ Infections: Overview of Disease Categories ​ Otitis Media: Middle ear infection. ​ Infectious Diseases: ​ Otitis Externa: Outer ear Caused by microbes. canal infection. ​ Pathogens cause two general ​ Eyes categories: ○​ Anatomy: Involves conjunctiva, ○​ Microbial Intoxications: sclera, cornea, iris, and lens. Ingestion of toxins produced ○​ Infections: outside the body (in vitro) by a ​ Conjunctivitis: pathogen. Inflammation of the ○​ Infectious Diseases (Infections): conjunctiva. Caused by colonization of a ​ Keratitis: Inflammation body site by a pathogen. of the cornea. Infectious Diseases by Anatomical Site ​ Keratoconjunctivitis: ​ Skin: Physical barrier; prevents most Involves both cornea pathogens. and conjunctiva. Key Terms: ​ Respiratory System 1.​ Epidermis: Superficial layer of the skin. ○​ Divisions: 2.​ Dermis: Inner layer with blood vessels, ​ Upper Respiratory glands, and follicles. Tract (URT): Paranasal 3.​ Dermatitis: Skin inflammation. sinuses, nasopharynx, 4.​ Sebaceous Glands: Produce oily oropharynx, epiglottis, sebum. larynx. Common skin infections: ​ Lower Respiratory ​ Folliculitis: Inflammation of hair Tract (LRT): Trachea, follicles. bronchial tubes, alveoli. ​ Sty: Inflammation of sebaceous ○​ Infections: glands in eyelashes. ​ Epiglottitis: ​ Furuncle: Localized Inflammation of the pus-producing infection (boil). epiglottis (e.g., caused ​ Carbuncle: Deep-seated by Haemophilus infection from multiple furuncles. influenzae type b). ​ Surface Lesions: ​ Laryngitis: ○​ Macule: Flat lesion Inflammation of the (e.g., measles). larynx. ○​ Papule: Firm, raised ​ Pharyngitis: Sore lesion (e.g., throat; commonly chickenpox). caused by viruses ○​ Vesicle: Fluid-filled (Streptococcus blister (e.g., shingles). pyogenes in "strep ○​ Pustule: Pus-filled throat"). lesion. ​ Pneumonia: ​ Ears Inflammation of lungs; ○​ Anatomy: Pathogens enter via: caused by bacteria, ​ Eustachian tube (from viruses, fungi, or throat/nasopharynx). protozoa. ​ External ear canal. ​ Blood or lymph.  Chapter 17: OVERVIEW OF INFECTIOUS DISEASES FIRST SEMESTER I ACADEMIC YEAR 2024-2025 I PROF. JOHN LEONARD CHAN ​ Sinusitis: Inflammation ​ Colitis: Inflammation of of paranasal sinuses; the colon. common causes: ​ Diarrhea: Frequent ​ Streptococcus discharge of semi-solid pneumoniae. or liquid stool, often due ​ Haemophilus to infection. influenzae. ​ Dysentery: Severe ​ Oral Region diarrhea with blood or ○​ Oral Microflora: Includes about mucus. 300 identified species of ​ Enteritis: Inflammation bacteria (aerobes and of the small intestine. anaerobes) and additional ​ Gastritis: Stomach unclassified species. Some lining inflammation. bacteria are beneficial, ​ Gastroenteritis: producing antagonistic Involves both the secretions, while others stomach and intestines. contribute to diseases. ​ Hepatitis: Liver inflammation, often viral ○​ Common Oral Diseases: in origin ​ Dental Caries: Caused ○​ Pathogens: Can include primarily by viruses, bacteria, protozoa, or Streptococcus mutans, helminths. leading to tooth enamel erosion due to lactic ​ Genitourinary (GU) System acid production. ○​ Urinary Tract Infections (UTIs): ​ Gingivitis: ​ Divided into upper UTIs Inflammation of the (e.g., nephritis, gums. pyelonephritis) and ​ Periodontitis: lower UTIs (e.g., Advanced gum disease cystitis, urethritis). that can result in tooth ​ Common causes loss. include E. coli, ​ Prevention: Emphasis Chlamydia trachomatis, on oral hygiene, diet and other bacteria or management, fluoride fungi. treatments, and ​ Prevention involves professional dental good hygiene and care. maintaining the urinary tract's natural defenses. ​ Gastrointestinal (GI) Tract ○​ Genital Infections: ○​ The GI tract is designed for food ​ Indigenous microflora of digestion, nutrient absorption, the genital area can and waste elimination. lead to infections if ○​ Most ingested microorganisms disrupted (e.g., Candida are destroyed by stomach acid albicans causing yeast (pH ~1.5) or expelled via vaginitis). defecation. ○​ Diseases and Terms:  Chapter 17: OVERVIEW OF INFECTIOUS DISEASES FIRST SEMESTER I ACADEMIC YEAR 2024-2025 I PROF. JOHN LEONARD CHAN ​ Common Conditions: ​ Myocarditis: ​ Bartholinitis: Inflammation of the Bartholin’s heart's muscular walls. gland ​ Pericarditis: inflammation. Inflammation of the ​ Cervicitis: pericardium. Cervix ○​ Bloodstream Infections: inflammation. ​ Bacteremia: Presence ​ Pelvic of bacteria in the blood, Inflammatory often transient (e.g., Disease (PID): from dental Inflammation of procedures). fallopian tubes, ​ Septicemia: A serious often due to systemic infection with sexually bacteria/toxins in the transmitted bloodstream, leading to pathogens. chills, fever, and ​ Vaginitis: exhaustion. Caused by ○​ Blood Donation Screening: yeast (C. Routine testing for pathogens albicans), like HIV, hepatitis, and syphilis protozoans in donor blood. (Trichomonas ○​ Lymphatic System: Includes vaginalis), or lymph vessels, nodes, tonsils, bacteria (as in thymus, and spleen. bacterial ​ Common conditions vaginosis). include: ○​ Sexually Transmitted ​ Lymphadenitis: Inflamed Diseases (STDs): lymph nodes. ​ Include infections ​ Lymphangitis: Inflamed transmitted via sexual lymph vessels. contact, such as ​ Central Nervous System (CNS) HIV/AIDS, gonorrhea, ○​ CNS (brain, spinal cord, chlamydia, and syphilis. meninges) is protected by the ​ STDs can affect various blood-brain barrier. systems, not just the ○​ Peripheral nerves branch from genital tract. the CNS. ​ Circulatory System Common CNS Infections: ○​ Cardiovascular System: ​ Meningitis: Inflammation of the Composed of the heart, arteries, meninges, caused by various capillaries, veins, and blood. pathogens, drugs, or toxins. ○​ Viral Meningitis: Often Infections include: referred to as "aseptic ​ Endocarditis: meningitis" and less Inflammation of the severe than bacterial endocardium. meningitis. ○​ Bacterial Meningitis: Caused by H.  Chapter 17: OVERVIEW OF INFECTIOUS DISEASES FIRST SEMESTER I ACADEMIC YEAR 2024-2025 I PROF. JOHN LEONARD CHAN influenzae, Neisseria meningitidis, S. pneumoniae, among others. ○​ Parasitic Causes: Protozoa (Naegleria, Acanthamoeba) and fungal pathogens (Cryptococcus neoformans) ​ Toxins: Bacterial neurotoxins (e.g., botulinum toxin) and fungal toxins (e.g., ergot). ​ Opportunistic Infections (OIs) ○​ Affect immunosuppressed individuals more severely. ○​ Examples include: ​ Aspergillosis, Candidiasis, Cytomegalovirus, and Herpes Simplex Virus. ​ Pneumocystis pneumonia, Toxoplasmosis, and Tuberculosis. ​ Emerging and Reemerging Infectious Diseases ○​ Emerging Causes: ​ Changes in demographics, climate change, international travel, and misuse of antibiotics. ​ Examples: Avian influenza, SARS, Lyme disease, Ebola, and West Nile virus. ○​ Reemerging Causes: ​ Pathogen mutations, acquired drug resistance, and reduced vaccination compliance. ​ Examples: Cholera, malaria, TB, yellow fever, and MRSA infections.