Untitled Quiz

Environmental Pathology

• Many diseases are influenced by the environment.
• Environmental diseases include chemical or physical agent exposure in the ambient, workplace, and personal environments.
• Nutritional disorders, such as obesity and undernutrition, are also considered environmental diseases.
• Age, genetics, and allergies can also contribute to disease development.

Health Effects of Climate Change

• Climate change can lead to various health effects.

Physical and Chemical Injury

• Severe environmental events, such as the Minamata Bay mercury contamination in Japan (1960s), the Bhopal gas leak in India (1984), the Chernobyl nuclear accident (1986), the Fukushima nuclear meltdown (2011), and the Flint water crisis (2016), have caused significant health problems.

Radiation Injury

• Radiation exposure can result in various health problems.

Temperature Injury

• Heat stroke occurs due to high temperatures, causing excessive sweating, vasodilation, sodium and water loss, hyperkalemia, hypotension, dehydration, and hypoxia.
• Frostbite occurs due to exposure to severe cold, leading to vasoconstriction, capillary thrombi, and gangrene of extremities.

Electric Injury

• Electric injury can lead to various health problems, including skin burns, bone fractures, organ and vessel rupture, cardiac or respiratory disturbances, and sudden death.

Physical Carcinogens

• Physical carcinogens, like UV radiation from the sun, can cause skin cancer.

Chemical Injury

• Chemical injury can lead to various health issues.

Carbon Monoxide

• Carbon monoxide poisoning can cause central nervous system (CNS) depression.

Insecticides

• Insecticides can lead to CNS disorders, arrhythmias, impotence, and infertility.

Lead Poisoning

• Lead poisoning (plumbism) can cause neurological symptoms and anemia.

Methyl Alcohol

• Methyl alcohol is toxic to the retina and brain.

Chemical Carcinogens

• Chemical carcinogens can cause cancer.

Air Pollution & Effects

• Sources of air pollution include gases, fumes, fibers, dust, and bacteria.
• Air pollution can cause inflammation, such as conjunctivitis, bronchitis, and dermatitis.
• It can also contribute to immunological disorders and allergies, such as bronchial asthma, allergic rhinitis, and hay fever.

Nutritional Disorders

• Kwashiorkor (apathetic)

  • Generalized edema, increased subcutaneous fat, moon face, fatty liver (hepatomegaly), and low serum albumin.

• Marasmus (non-apathetic)

  • Severe wasting, including subcutaneous fat, stunted growth, premature aging, no edema or hepatic enlargement.

Selected Trace Elements & Deficiency Syndromes

• Zinc

  • Deficiency can lead to a rash around the eyes, mouth, nose, and anus (acrodermatitis enteropathica), anorexia, diarrhea, growth retardation, depressed mental function, impaired wound healing, impaired immune response, impaired night vision, and infertility.

• Iron

  • Deficiency can result in hypochromic, microcytic anemia.

• Iodine

  • Deficiency can lead to goiter and hypothyroidism.

• Copper

  • Deficiency can cause muscle weakness, neurologic defects, and abnormal collagen crosslinking.

• Fluoride

  • Deficiency can contribute to dental caries.

• Selenium

  • Deficiency can lead to myopathy and cardiomyopathy (Keshan disease).

Vitamin D Deficiency

• In children, Vitamin D deficiency can lead to rickets, a disease characterized by bone softening and abnormalities of bone growth.
• Rickets is characterized by a thick epiphyseal cartilage plate due to cartilage growth without significant degeneration, caused by defective calcification.
• In adults, Vitamin D deficiency can lead to osteomalacia, a disease characterized by bone softening.
• Osteomalacia is caused by disturbed bone turnover, where normal bone resorption is replaced by poorly calcified osteoid tissue.

Rickets & Osteomalacia Manifestations

• Bone deformities: Bowing of legs, pathological fractures.
• Pelvis: Narrow contracted trefoil pelvis.
• Pathological fractures.
• Infections: Due to low immunity.
• Labor problems in females: Due to narrow pelvis.

Infectious Diseases

• Infectious diseases are a significant health problem worldwide.
• Infectious diseases can be caused by bacteria, viruses, fungi, or parasites.
• Infectious agents can be normal flora in the body, but they can cause disease under certain conditions.

Infectious Agents

• Prions: Protein structures that cause diseases like kuru (cannibalism) and bovine spongiform encephalopathy (mad cow disease).
• Viruses: Intracellular microorganisms that can cause damage by inducing apoptosis, producing toxins, preventing macro-molecule production, and being targeted by cytotoxic T lymphocytes.
• Bacteria: Prokaryotic microorganisms that can cause damage by using virulence factors, adhering to cells/tissues, or producing toxins.
• Fungi: Eukaryotic microorganisms with cell walls made of chitin. Fungi thrive in warm, dark, moist areas.
• Protozoa: Single-celled eukaryotic microorganisms.
• Helminths: Multi-systemic parasites.
• Insects and Arachnids: Ectoparasites.
• Microbiome: Normal flora found in the human body.

Viral Inclusions

• Viral inclusions are distinct structures found within infected cells, providing clues to the type of virus present. - Examples:
  • Cytomegalovirus: Eosinophilic nuclear, basophilic cytoplasmic inclusions.
  • Herpes 2 virus: Nuclear inclusions surrounded by a clear halo.
  • Smallpox and rabies: Cytoplasmic inclusions.
  • Polio virus: No inclusions.

Viral Tropism

• Viral tropism refers to the specific type of cells or tissues a virus can infect.
• Tropism depends on the presence of specific host cell receptors for viruses, the specificity of transcription factors, and tissue factors.

Transmission, Entry and Dissemination of Infections

• Transmission:
  • Skin contact.
  • Inhalation.
  • Fecal-oral route.
  • Sexual transmission.
  • Insect bites or animal bites.
  • Intravenous drug use.
  • Vertical transmission (mother to child).
  • Zoonotic transmission (animal to human).
• Entry:
  • Respiratory tract.
  • Gastrointestinal tract.
  • Skin.
  • Genitourinary tract.
  • Conjunctiva.
• Dissemination:
  • Lymphatic spread.
  • Direct invasion and lysis of tissue.
  • Blood spread.
  • Neural spread.
  • Natural passage.
  • Cell to cell spread.

Immune System Response & Microbial Evasion

• The immune system can enhance damage, especially during a cytokine storm.
• Microorganisms can evade the immune system through various mechanisms, such as capsular polysaccharides, antigenic variation, and intracellular survival.

Techniques for Identifying Infectious Agents

• Microscopy: Direct visualization of microorganisms.
• Culture: Growing microorganisms in a laboratory setting.
• Serology: Detecting antibodies against specific microorganisms.
• Molecular methods: Detecting specific DNA or RNA sequences of microorganisms.

Agents of Bioterrorism

• Bioterrorism is the intentional use of biological agents to cause harm.
• Agents of bioterrorism include:
  • Anthrax (Bacillus anthracis)
  • Plague (Yersinia pestis)
  • Smallpox (Variola virus)
  • Botulism (Clostridium botulinum)
  • Tularemia (Francisella tularensis)
  • Viral hemorrhagic fevers.

Definitions:

• Endemic: Constant presence of a disease or infectious agent within a geographic area.
• Epidemic: Cases of a disease or outbreak exceeding expected levels for the area.
• Pandemic: A widespread outbreak of a disease affecting a large proportion of the population across many geographic areas.

Additional Notes

• Plague: Caused by Yersinia pestis.
• Epidemic Typhus: Caused by Rickettsia prowazekii.
• Bacterial toxins: Can cause damage to cells and tissues.
• Viral Inclusions: Specific structures within infected cells that can help identify the virus.
• Viral Tropism: The specific type of cells or tissues a virus can infect.