Nursing Info

Topic: Objectives

Objectives:

• Describe the basic concepts of HIV and AIDS.
• Appreciate global and national HIV statistics and epidemiology.
• Explain HIV combination prevention intervention.
• Describe HIV positive living.

Topic One: Definition of Terms

HIV (Human Immunodeficiency Virus):

• Virus causing HIV infection and AIDS.
• Weakens the immune system by destroying disease-fighting cells.
• Preventable and manageable, but not curable.
• Transmitted via body fluids (blood, breast milk, semen, vaginal secretions).
• Not transmitted through kissing, hugging, shaking hands, sharing personal objects, food, or water.
• Invades helper T cells (CD4+ cells) in the body.
• No signs or symptoms in the initial stages, but still infectious.
• Body can’t fight off infections, leading to AIDS.

AIDS (Acquired Immune Deficiency Syndrome):

• Disease caused by a confirmed positive test for HIV.
• Predisposes patients to multiple opportunistic infections, leading to death.

Risk Factors of HIV Infection

• Unprotected sex (anal or vaginal).
• Having STIs (e.g., syphilis, herpes, Chlamydia, gonorrhea, bacterial vaginosis).
• Sharing injecting needles.
• Receiving unsafe injections, tissue transplantation, or medical procedures involving unsterile cutting or piercing.
• Accidental needle stick injuries (healthcare workers).
• Mother-to-child transmission during pregnancy, birth, or breastfeeding.

HIV Prevention Key Approaches

• Biomedical Prevention:
• Condom use promotion and distribution.
• Elimination of mother-to-child transmission (EMTCT).
• Voluntary medical male circumcision (VMMC).
• Methadone replacement therapy.
• STI treatment.
• Blood safety.
• Behavioral Interventions:
• HIV testing.
• Behavior change communication.
• Social/Structural Interventions:
• Social Protection (e.g., Cash Transfers for Orphans and Vulnerable Children – CT-OVC).
• Building resilience of women and girls.
• Girls enrolled in secondary school.

HIV Positive Living

• Antiretroviral (ARV) drugs control the virus and prevent transmission for healthy, long, and productive lives.
• Antiretroviral therapy (ART) should be taken daily and right away to reduce viral load.
• Use condoms correctly every time you have sex.
• Choose less risky sexual behaviors.
• Not sharing needles for drug use.
• Pre-exposure prophylaxis (PrEP).
• Adherence to treatment.
• Get tested and treated for other STIs.
• Encourage partners to get tested for HIV.

Topic Two: Modes of HIV Transmission and Key Risk Factors

Modes of Transmission:

• Heterosexual (male-female) and homosexual (men having sex with men).
• Non-consensual sexual exposures (assault).
• Parenteral: transfusion of infected blood or blood products, exposure to infected blood/body fluids through contaminated sharps, IDU needle sharing or needle stick accidents, donated organs.
• Perinatal/Vertical: transplacental, during labor/delivery, breastfeeding.
• HIV is not transmitted by casual contact, surface contact, or insect bites.

Biological Factors Influencing HIV Transmission:

• Disease status of the source patient (related to immunosuppression and viral load).
• Presence of untreated STIs in the source and person at risk.
• Circumcision status: uncircumcised men are more likely to acquire HIV than circumcised.
• Gender differences: females are more susceptible due to genital anatomy.

Socio-economic Factors Facilitating HIV Transmission:

• Social mobility: partners living apart.
• Stigma and denial.
• People in conflict: war and struggle for power.
• Cultural factors: traditions, beliefs, and practices.
• Gender: acceptance of men having multiple sexual partners, gender inequalities, inability of women to negotiate condom use.
• Poverty: lack of information needed to understand and prevent HIV.
• Drug use and alcohol consumption: impaired judgment, sharing of needles and equipment.

Key Populations (KP):

• Groups at increased risk of HIV due to specific high-risk behaviors.
• Include sex workers, men who have sex with men, people who inject drugs, and transgender people.
• Should receive routine HIV testing every 3 months and retesting at least annually.

Vulnerable Populations:

• Persons at high risk due to situations beyond their control.
• Include widows and widowers, orphans and vulnerable children (OVCs), families and children living on the streets, young women aged 15-24 years, servicemen and women, refugees, displaced persons and migrants, people who abuse alcohol, survivors of sexual and gender-based violence.

Survivors of Sexual and Gender-Based Violence:

• Should receive HIV testing services (HTS) at first contact.
• Immediate referral for clinical evaluation, documentation and treatment, trauma counseling, and post-exposure prophylaxis (PEP).
• Retesting recommended after 4 weeks, and if still negative or in a discordant relationship, retesting at 12 weeks.

Topic Three: Global HIV Statistics

Global HIV Statistics (2016):

• People living with HIV: 36.7 million.
• People accessing antiretroviral therapy: 19.5 million.
• Newly infected with HIV: 1.8 million.
• Deaths from AIDS-related illnesses: 1 million.
• Total people infected since the epidemic began: 76.1 million.
• Total deaths by AIDS: 35 million.

HIV/Tuberculosis (TB) Co-infection:

• Leading cause of death among people living with HIV.
• Around one in three AIDS-related deaths due to TB.
• Global TB cases (2015): 10.4 million; 1.2 million among people living with HIV.
• TB-related deaths among people living with HIV fell by 33% between 2005 and 2015.
• 60% of TB cases among people living with HIV were not diagnosed or treated, resulting in 390,000 TB-related deaths among people living with HIV in 2015.

HIV is not transmitted by:

• Touching/hugging.
• Mutual masturbation, kissing, oral sex.
• Insect bites.
• Water, food, air.
• Sharing toilet seats, tables, door handles, cutlery, towels.

Myths and Misconceptions of HIV and AIDS

• Common myths and misconceptions should be addressed to improve understanding and reduce stigma.

Topic Two: The Immune System

The Immune System:

• A system of special cells (lymphocytes, monocytes), proteins (antibodies), tissues, and organs that defend the body against foreign substances (antigens).

Antigen:

• A foreign substance which stimulates the immune system to respond by producing antibodies.

Antibody:

• A protein produced by lymphocytes, binding to specific antigens.

Immune System Organization:

• The immune system is organized into innate, cellular, and humoral responses.
• Organs involved are categorized into primary (thymus and bone marrow) and secondary (lymph nodes and spleen) lymphoid organs.

Cellular Responses to HIV Infection:

• HIV enters the body, triggering anti-HIV antibody and cytotoxic T cell production.
• Macrophages and dendritic cells present the virus to CD4 cells.
• CD4 T lymphocytes are the main target for HIV attack.
• CD8+ cytotoxic cells lyse HIV-infected cells and secrete cytokines and chemokines to inhibit virus replication.

Humoral Response to HIV:

• Production of specific antibodies in response to HIV infection.
• Non-neutralizing antibodies target HIV structural proteins (P17 and P24).
• Neutralizing antibodies target gp120, CD4 binding sites, chemokine receptors, and gp41.

Combined Cellular and Humoral Response:

• Both responses play important roles in HIV infection.
• Cellular responses are initiated first, followed by antibody responses 4-8 weeks after infection.
• B cells produce antibodies, but mutations in HIV glycoproteins render them ineffective.

Summary

• HIV has become a pandemic since the first cases were identified.
• It is a major cause of morbidity and mortality, especially in sub-Saharan Africa (SSA).
• Multiple factors contribute to HIV transmission in society.
• Effective prevention requires a combination of biomedical, behavioral, and social/structural interventions.

Learning Objectives

At the end of this chapter, students should be able to:

• Discuss bone tissue.
• Explain the general features and surface markings of bones.
• Discuss the skeleton and its function:
• Axial skeleton
• Appendicular skeleton
• Explain joints, types of joints, and their movements.

Selected Key Terms

• Appendicular skeleton
• Myeloid tissue
• Articulation
• Orbits
• Axial skeleton
• Ossicles
• Bone cell
• Ossification
• Cranium
• Perichondrium
• Diaphysis
• Periosteum
• Endosteum
• Skull
• Epiphyseal plate
• Surface marking
• Epiphysis
• Sutures
• Fontanel
• Tendons
• Intervertebral disc
• Thorax
• Metaphysis
• Vertebrae

Overview of the Skeletal System

• The skeletal system includes bones, joints, cartilages, and ligaments.
• It provides support, protection, movement, storage, and blood cell formation.

Functions of the Skeletal System

1. Support: Forms the internal framework that supports and anchors all soft organs.
2. Protection: Bones protect soft body organs.
3. Movement: Skeletal muscles attached to the bones use them as levers to move the body.
4. Storage: Bones store minerals like calcium and phosphorus and fat in their internal cavities.
5. Blood Cell Formation: Occurs within the marrow cavities of certain bones.

Bone

• Specialized connective tissue that is strong and light.
• Living bone is moist and continually resorbed, reformed, and remodeled.

Types of Bone

1. Long Bones: Longer than they are wide (e.g., arms and legs).
2. Short Bones: Roughly equal in length, width, and thickness (e.g., wrists and ankles).
3. Flat Bones: Thin or curved (e.g., ribs, scapulae, sternum, cranium).
4. Irregular Bones: Do not fit into other categories (e.g., vertebrae, facial bones, hipbones).
5. Sesamoid Bones: Embedded in tendons (e.g., patella, pisiform).
6. Accessory Bones: Often found in the feet and appear as extra bones or broken on X-ray.

Gross Anatomy of a Typical Long Bone

• Diaphysis: Tubular shaft with walls of compact bone tissue.
• Epiphysis: Spherical ends of the bone.
• Metaphysis: Separates diaphysis from epiphysis.
• Medullary Cavity: Contains yellow marrow.
• Spongy Epiphyses: Filled with red bone marrow (myeloid tissue).
• Endosteum: Lines the medullary cavity.
• Periosteum: Covers the outer surface of the bone except at joints.

Bone Tissue

• Composed of cells in a matrix of ground substances and fibers.
• Contains inorganic salts like calcium phosphate and calcium carbonate.
• Compact Bone: Forms the outer sheet, contains osteons with central and perforating canals.
• Spongy (Cancellous) Bone: Open, interlaced pattern with trabeculae.

Bone Cells

1. Osteogenic Cells: Small, spindle-shaped cells found in periosteum and endosteum, can transform into osteoblasts.
2. Osteoblasts: Found in growing bones, synthesize and secrete unmineralized ground substance.
3. Osteocytes: Main cells of fully developed bones, derived from osteoblasts.
4. Osteoclasts: Multinuclear giant cells that resorb bone.
5. Bone-lining Cells: Found on the surface of bones, derived from inactive osteoblasts.

Bone Development and Growth

• Ossification: Process of bone development.
• Intramembranous Ossification: Bone develops directly from mesenchymal tissue (e.g., skull vault, flat bones).
• Endochondral Ossification: Bone tissue replaces hyaline cartilage (e.g., long bones).

Functions of Bone

• Support and protection of internal organs.
• Storage and supply of calcium and phosphate.
• Manufacture of red and white blood cells.

The Skeleton

• Surface markings include bumps, holes, and ridges for muscle, tendon, ligament attachment, and passage of blood and lymph vessels and nerves.

Divisions of the Skeletal System

• Axial Skeleton: Bones around the axis (e.g., skull, vertebral column, rib cage).
• Appendicular Skeleton: Bones of appendages and girdles (e.g., arms, legs, shoulder, pelvic girdles).

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Bone Counts

• Total Axial Bones: 80
• Total Appendicular Bones: 126

Skull

• Total Bones: 22 (skull bones, ossicles of the ears, and hyoid bone)
• Cranial Bones: 8
• Facial Bones: 14

Axial Skeleton

• Skull: Contains 22 bones, composed of cranial and facial bones.

Cranial Bones (Description and Function)

1. Ethmoid (1): Base of cranium, forms roof of nasal cavity and septum, attachment for brain membranes.
2. Frontal (1): Forehead and brow areas, contains frontal sinuses and supraorbital foramen.
3. Occipital (1): Posterior part of cranium, contains foramen magnum and occipital condyles, protects posterior brain.
4. Parietal (2): Sides and roof of cranium, protect top and sides of brain.
5. Sphenoid (1): Base of cranium, houses pituitary gland, contains foramina for cranial nerves.
6. Temporal (2): Sides and base of cranium, contains ear ossicles, mastoid sinuses.

Sutures

• Coronal Suture: Between frontal and parietal bones.
• Sagittal Suture: Between parietal bones.
• Lambdoidal Suture: Between parietal and occipital bones.
• Squamosal Suture: Between parietal and temporal bones.

Fontanels (Infant Skull)

1. Anterior Fontanel: Diamond-shaped, closes 18-24 months after birth.
2. Posterior Fontanel: Diamond-shaped, closes 2 months after birth.
3. Antrolateral Fontanels: Paired, irregular, close at 3rd month.
4. Postrolateral Fontanels: Paired, irregular, begin closing at 1-2 months, completed by 12 months.

Facial Bones (Description and Function)

1. Inferior Nasal Conchae (2): Lateral walls of nasal cavities, thin and curved.
2. Lacrimal (2): Medial wall of orbit, contains tear duct depression.
3. Mandible (1): Lower jaw, strongest facial bone, part of temporomandibular joint.
4. Maxillae (2): Upper jaw and part of hard palate, contains maxillary sinuses.
5. Nasal (2): Supports bridge of nose.
6. Palatine (2): Posterior part of hard palate, floor of nasal cavity.
7. Vomer (1): Forms part of nasal septum.
8. Zygomatic (2): Cheekbones, part of eye sockets.
9. Hyoid (1): Suspended from temporal bone, attachment for muscles used in speaking and swallowing.
10. Ossicles of Ear (6): Tiny bones in the ear (malleus, incus, stapes) that convey sound vibrations.

Orbits

• Roof: Frontal and sphenoid bones.
• Lateral Wall: Zygomatic and sphenoid bones.
• Floor: Maxilla, zygomatic, and palatine bones.
• Medial Wall: Maxilla, lacrimal, ethmoid, and sphenoid bones.

Vertebral Column

• Composition: 26 vertebrae in adults (previously 33).
• Functions: Supports head, protects spinal cord, attachment for ribs and back muscles.

Intervertebral Discs

• Composition: Annulus fibrosus (outer fibrous ring) and nucleus pulposus (inner soft core).
• Function: Absorb shock, permit movement.

Normal Curves

• Concave Curves: Thoracic and sacral (primary curves).
• Convex Curves: Cervical and lumbar (secondary curves).

Typical Vertebra

• Parts: Body, vertebral arch, transverse processes, spinous processes.
• Function: Protect spinal cord, support body weight, attachment for muscles.

Vertebral Column Bones

1. Cervical Vertebrae (7): Atlas (C1), Axis (C2), support head movement.
2. Thoracic Vertebrae (12): Articulate with ribs, allow limited movement.
3. Lumbar Vertebrae (5): Support back muscles, allow bending.
4. Sacrum: Fused vertebrae, supports pelvis.

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Coccyx:

• Description: Triangular tailbone.
• Attachment: United with the sacrum by intervertebral (3 to 5 fused bones) disk.
• Embryonic Vestige: Represents a vestige of an embryonic tail.
• Vertebrae Count: In children, there are 33 separate vertebrae. The 9 in the sacrum and coccyx are not yet fused.

The Thorax:

• Definition: Refers to the chest.
• Components: Bony cage formed by the sternum (breast bone), costal cartilage, ribs, and bodies of the thoracic vertebrae.
• Sternum (Breast Bone):
• Location: Flat, narrow bone located in the median line of the anterior thoracic wall.
• Dimensions: Approximately 15 cm (6 inches) long.
• Portions:
  • Manubrium: Superior portion; has a jugular (supra sternal) notch.
  • Body: Middle and largest portion; articulates with 2nd to 10th ribs.
  • Xiphoid Process: Inferior and smallest portion; consists of hyaline cartilage in infancy and childhood, ossifying by age 40.
• Junctions:
  • Manubrium: Articulates with the 1st and 2nd ribs.
  • Clavicular Notch: On each side of the jugular notch, articulates with the medial end of the clavicle.

Ribs:

• Total: 12 pairs.
• Length: Increase from 1st through 7th and decrease from 8th through 12th.
• Attachment:
• True Ribs (1st-7th): Directly attached to sternum by costal cartilage.
• False Ribs (8th-10th): Vertebrochondral ribs; cartilage attaches to cartilage of the 7th rib.
• Floating Ribs (11th-12th): Do not attach anteriorly to the sternum.
• Typical Rib Structure:
• Head: Projection at the posterior end; articulates with vertebrae.
• Neck: Constricted portion just lateral to the head.
• Tubercle: Knob-like structure that articulates with the transverse process of the vertebra and attaches to trunk muscles.
• Body (Shaft): Main part of the rib.
• Costal Angle: Site where the rib changes direction; contains the costal groove for protection of thoracic nerves and blood vessels.

Appendicular Skeleton:

• Upper Extremities:
• Bones Count: 64 bones.
• Support: Connected and supported by the axial skeleton through the shoulder joint and muscles from the vertebral column, ribs, and sternum to the shoulder girdle.
• Clavicle (2): Collarbone; holds shoulder joint and arm away from thorax.
• Scapula (2): Shoulder blade; site of muscle attachment.
• Humerus (2): Longest, largest bone of the upper limb; forms ball-and-socket joint with the scapula.
• Radius (2): Larger forearm bone; forms hinge joint at elbow.
• Carpals (16): Short bones in wrist; allow slight gliding movement.
• Metacarpals (10): Long bones in hand; aid in thumb opposition and hand cupping.
• Phalanges (28): Miniature long bones in fingers; allow stable grips.
• Lower Extremities:
• Bones Count: 62 bones.
• Support: Connected to the axial skeleton via the hip girdle.
• Hipbone (Coxal) (2): Formed by fusion of ilium, ischium, and pubis; forms socket for ball-and-socket joint with the femur.
• Femur (2): Longest, strongest bone; supports body and forms ball-and-socket joint with pelvic bones.
• Patella (2): Kneecap; increases leverage for quadriceps muscle.
• Fibula (2): Smaller lower leg bone; provides strength to the ankle joint.
• Tibia (2): Larger lower leg bone; supports body weight and transmits it from femur to talus.
• Tarsals (14): Short bones in the ankle; form arches of the foot and bear body weight.
• Metatarsals (10): Long bones in foot; form the sole and arches of the feet.
• Phalanges (28): Miniature long bones in toes; provide stability during locomotion.

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The Body Fluids and Kidneys

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Fluid Balance

• Maintenance of constant volume and stable composition is crucial for homeostasis.
• Abnormalities in control systems cause many clinical symptoms.
• Continuous exchange of fluids and solutes occurs with the external environment and different body compartments.
• Fluid intake varies and must be balanced by equal output to prevent changes in body volumes.

Water Intake

• Ingestion: about 2000 ml/day
• End product of carbohydrate oxidation: 200 ml/day
• Total intake: about 2200 ml/day

Water Loss

• Evaporation through respiration and diffusion: about 700 ml/day (insensible water loss)
• Sweat: variable, about 100 ml/day
• Feces: about 100 ml/day
• Kidneys: most important regulator, loss varies from 0.5 l to 10 l daily.

Body Fluid Compartments

• Two compartments: extracellular (plasma and interstitial fluid) and intracellular.
• An adult human has about 42 liters of fluids, varying with age.

Intracellular Fluid

• Fluid inside cells, about 28 liters.
• Consistent concentrations of constituents across cells.

Blood Volume

• Contains both extracellular (plasma) and intracellular fluids (inside red cells).
• Average blood volume: 7% of body weight (~5 l), with 60% plasma and 40% cellular components.

Composition of Extracellular and Intracellular Fluids

• Ionic composition of plasma and interstitial fluid is similar, except for protein concentration.
• Major ions in extracellular fluid: sodium, calcium, chloride, bicarbonate.
• Major ions in intracellular fluid: potassium, magnesium, phosphates, proteins.

Movement of Body Fluids and Electrolytes

• Continuous intake and output within the body and between compartments.
• Stable composition and volume maintain dynamic equilibrium (homeostasis).

Movement of Solutes Between Body Fluid Compartments

1. Membrane permeability.
2. Concentration and electric gradients.
3. Pressure gradients and active transport systems (e.g., sodium-potassium pump).

Movement of Water Between Body Fluid Compartments

• Controlled by hydrostatic pressure and osmotic pressure.
• Osmosis: water moves from low solute concentration to high solute concentration.
• Edema: excess fluid in interstitial spaces due to imbalances.

Regulation of Fluid Exchange and Osmotic Equilibrium

• Balance between plasma and interstitial fluid is determined by hydrostatic and colloid osmotic pressure.
• Balance between extracellular and intracellular fluid is by osmotic pressure of solutes.

Osmosis and Osmotic Pressure

• Movement of water from high water (low solute) concentration to low water (high solute) concentration.
• Osmotic pressure depends on the number of solute particles.

Edema

• Presence of excess fluids in body tissues, mostly extracellular.
• Causes: increased capillary pressure, decreased plasma proteins, increased capillary permeability, blockage of lymph return.

Renal Functions

• Excretion of metabolic waste products and foreign chemicals.
• Regulation of water and electrolyte balances.
• Regulation of body fluid osmolality and electrolyte concentrations.
• Regulation of arterial pressure.
• Regulation of acid-base balance.
• Secretion, metabolism, and excretion of hormones.
• Gluconeogenesis.

Excretion

• Kidneys eliminate metabolic waste products, toxins, and foreign substances.

Regulation of Water and Electrolyte Balances

• Kidneys adjust excretion rates to match intake for homeostasis.

Regulation of Arterial Pressure

• Long-term regulation through sodium and water excretion.
• Short-term regulation by secreting vasoactive substances.

Regulation of Acid-Base Balance

• Kidneys excrete acids and regulate body fluid buffer stores.

Regulation of Erythrocyte Production

• Kidneys secrete erythropoietin, stimulating red blood cell production in response to hypoxia.

Regulation of Vitamin D Production

• Kidneys produce active vitamin D (calcitriol), essential for calcium metabolism.

Glucose Synthesis

• Kidneys perform gluconeogenesis during prolonged fasting.

Urinary System Structure

• Components: kidneys, ureters, bladder, urethra.
• Kidneys divided into cortex and medulla, with nephrons as functional units.

Renal Blood Supply

• Blood flow to kidneys is about 22% of cardiac output.
• Renal artery branches into arterioles and capillaries, regulating hydrostatic pressure.

Nephron Structure

• Nephrons consist of glomerular capillaries and a long tubule.
• Types: cortical (short loops of Henle) and juxtamedullary (long loops of Henle).

Juxtaglomerular Apparatus

• Regulates blood pressure through renin secretion and response to NaCl content.

Glomerular Filtration

• Passive process driven by hydrostatic pressures.
• Efficient filtration due to large surface area and high pressure.
• Filtration membrane includes endothelium, basement membrane, and podocytes.

Filtration Forces

• Blood hydrostatic pressure, colloid osmotic pressure, and capsular hydrostatic pressure determine filtration rate.
• Glomerular filtration rate (GFR) of 125 ml/min (180 L/day).

Pathophysiology of Edema

• Causes include increased capillary pressure, decreased plasma proteins, increased capillary permeability, and lymphatic blockage.

The Organisation of the Human Body, Dysfunctions, and Management

Introduction

• Internal environment of the human body: refers to cells and their organization.
• Importance: understanding cell functions and processes affecting them.

Objectives

• Describe the cell and its functions.
• Explain cell multiplication.
• Detail the transfer of substances across cell membranes.
• Define tissues and their functions.
• Discuss body fluids and electrolytes.

Structure and Function of Cells, Tissues, Organs, and Systems

The Cell Structure and Its Functions

• Cells: Basic units of tissues, organs, and systems.
• Cell Membrane: Boundary of the cell.
• Protoplasm: Divided into cytoplasm (gel-like substance) and nucleus (coordinates cell activities, contains DNA/RNA).
• Nucleic Acids: RNA (in nucleus and cytoplasm), DNA (in chromosomes).

Key Cell Structures

• Mitochondria: Energy production.
• Golgi Body: Protein and carbohydrate processing.
• Endoplasmic Reticulum: Enzyme production.
• Lysosomes: Cellular digestion.

Cell Multiplication

• Mitosis: Division into two identical diploid daughter cells.
• Meiosis: Division into four haploid daughter cells with different characteristics (occurs in spermatozoa and ova production).

Substance Transfer Across Cell Membranes

• Diffusion: Movement of dissolved substances following a concentration gradient.
• Osmosis: Movement of solute materials through a semi-permeable membrane.
• Active Transport: Energy-utilized movement of substances.

Tissues

• Made up of large numbers of cells.
• Four key types:
• Epithelial: Covers and protects body parts, produces secretions.
• Connective: Supports body structures.
• Muscle: Capable of stretching and contracting.
• Nerve: Conducts impulses.

Organs and Systems

• Organs: Made up of tissues, perform multiple functions.
• Systems: Groupings of organs performing related functions (e.g., respiratory, cardiovascular, digestive).

Homeostasis

• Maintaining equilibrium in the body.
• Feedback Mechanism: Senses changes in the internal environment and makes adjustments.

Body Fluids and Electrolytes

Water

• Essential for life, makes up 60% of body weight.
• Functions: temperature regulation, intracellular pressure, medium of excretion, etc.
• Types: Intracellular Fluid (ICF) and Extracellular Fluid (ECF).

Electrolytes and Ions

• Electrolytes: Conduct electricity in dissolved form (e.g., sodium, potassium, magnesium).
• Ions: Charged particles (e.g., Na+, K+).

Important Electrolytes

• Sodium: Abundant in extracellular compartment, involved in nerve conduction and muscle contraction.
• Potassium: Abundant in intracellular compartment, affects nerve conduction and muscle strength.
• Calcium: Involved in bone formation, nerve/muscle function, blood clotting.
• Magnesium: Involved in energy metabolism, found in bones.

Acids and Bases

• Acids: Produce hydrogen ions when dissolved, neutralize bases.
• Bases: React with acids to form salt and water.
• Balance: Must be maintained for optimal body processes.

Body Defence Mechanisms

Immune Response

• Antibodies: Produced to fight microbes.
• Immunization: Prepares the body to fight diseases.

Types of Acquired Immunity

• Active Natural Immunity: Produced by encountering an antigen.
• Active Artificial Immunity: Produced by vaccines.
• Passive Natural Immunity: Antibodies received from mother.
• Artificial Passive Immunity: Antibodies injected from serum.

Homeostatic Dysfunction

Fluid and Electrolyte Imbalance

• Common in major illnesses.
• Fluid Volume Deficit: Occurs when fluid loss exceeds intake.
• Fluid Volume Excess: Caused by high sodium and water intake.

Management of Adults with Sodium and Fluid Imbalances

• Assessment: Personal history, physical assessment.
• Monitoring: Intake and output, weight, skin assessment.
• Treatment: Fluid replacement for deficit, fluid restriction for excess, managing sodium levels.

Potassium Imbalances

• Hypokalaemia: Low potassium, managed with supplements and dietary intake.
• Hyperkalaemia: High potassium, managed with dietary adjustments and medical interventions.

Calcium and Magnesium Imbalances

• Hypocalcaemia: Treated with supplements.
• Hypercalcaemia: Managed with loop diuretics and fluid intake.
• Hypomagnesaemia: Treated with supplements and dietary intake.
• Hypermagnesaemia: Managed with IV calcium, promoting urinary excretion, and dialysis if necessary.

Plasma Protein Imbalance

• Plasma Proteins: Maintain oncotic pressure, include albumin, antibodies, and lipoproteins.

Infections

Human beings are constantly interacting with microorganisms, some of which are commensals, while others are pathogens that cause disease. Our bodies employ various defense mechanisms to minimize the danger posed by these harmful agents. The primary infectious agents include viruses, bacteria, rickettsiae, chlamydia, fungi, and parasites. Let’s delve into each of these agents, starting with viruses.

Viruses

Viruses are small intracellular organisms classified as either DNA or RNA viruses based on the nucleic material they contain. Each virus contains only one type of nucleic material and cannot replicate outside a living cell. Viruses may be enveloped in lipoprotein envelopes derived from the host cell membrane. To multiply, viruses must enter a host cell and utilize its mechanisms, making it challenging for the host cell to recognize and combat them. Viruses are grouped according to their characteristics and the diseases they cause. Examples include the herpes virus group (herpes zoster, chickenpox, and cytomegalovirus) and the retrovirus group (Human Immunodeficiency Virus – HIV).

Viruses are classified according to:

• Type of viral genome
• Mechanism of replication
• Mode of transmission
• Type of disease produced

A prominent example is HIV, a retrovirus capable of producing DNA from RNA. This unit covers infections affecting various body functions.

Bacteria

Bacteria are autonomously replicating unicellular organisms containing both DNA and RNA. The structure and synthesis of their cell walls determine their shape: spherical (cocci), helical (spiral), or elongated (bacilli). Bacteria are further classified based on their growth requirements (aerobes, anaerobes, facultative anaerobes) and staining properties (gram-positive or gram-negative).

• Spirochaetes: Gram-negative rods moving in a corkscrew fashion, sub-classified into Leptospira, Borrelia, and Treponema.
• Mycoplasma: Capable of independent replication, smaller than bacteria, and lacking a typical cell wall.
• Rickettsiae and Chlamydia: Intra-cellular organisms with both DNA and RNA characteristics, causing diseases like epidemic typhus (Rickettsiae) and chlamydia trachomatis (Chlamydia).

Fungi

Fungi are free-living saprophytes, some of which are part of the normal flora on the human body. Despite being normal flora, some fungi can cause serious illnesses. They are classified into yeasts (single-celled, reproducing by budding) and moulds (producing long hollow branching filaments). Fungi can reproduce both sexually and asexually, with asexual spores being highly resistant.

Parasites

Parasites refer to microorganisms from the animal kingdom that cause diseases in other animals. This group includes protozoa (e.g., Plasmodium causing malaria), helminths, and arthropods. Helminths are mobile parasites, while arthropods (e.g., ticks) can act as disease vectors. Ectoparasites, such as lice and mites causing scabies, live on the outer body surface of their host.

Malaria

Malaria, caused by the Plasmodium parasite, is a significant health challenge, especially in Kenya. Plasmodium falciparum is the most common species, transmitted through the bite of a female Anopheles mosquito. Symptoms include fever, joint pains, chills, mental confusion, abdominal pain, diarrhoea, nausea, and vomiting. Malaria can present as uncomplicated or severe, with severe malaria causing prostration, unconsciousness, and respiratory distress.

Treatment of uncomplicated malaria involves artemisinin-based drugs like Coartem (artemether and lumefantrine). Supportive management for anemia, fever, nausea, and diarrhoea is also essential. In Kenya, areas like Kitui, Taita Taveta, and Tana River districts are endemic, while regions like Kisii and Kericho experience epidemic outbreaks.

Care of Adults with Infections

Developing countries experience high morbidity and mortality due to infectious diseases. The nursing process involves assessing, planning, and administering care based on nursing diagnoses. Acute intervention includes monitoring vital signs (fever, pulse, respiration, blood pressure) and using antipyretic medications like acetylsalicylic acid and acetaminophen to control fever. Antimicrobial drugs (antibiotics, anti-protozoa, antiviral, and antifungal drugs) are crucial for infection control.

Patient comfort, nutrition, fluid and electrolyte balance, and symptom management are vital. Evaluating the care administered ensures objectives are met.

Infection Prevention and Control

Aseptic procedures and infection prevention precautions are crucial in minimizing infections. These precautions include hand washing, instrument decontamination, high-level disinfection, and sterilization. Barrier nursing, isolation, and reverse barrier nursing are also important to prevent the spread of infections.

Care of an Adult with an Immune Deficiency

When the immune system is compromised, an immune deficiency state exists. Management of such states varies, but AIDS (Acquired Immunodeficiency Syndrome) is a significant concern in sub-Saharan Africa, including Kenya. The management of HIV-infected patients involves monitoring disease progression, initiating antiretroviral therapy, treating opportunistic infections, managing symptoms, and preventing complications.

HIV and AIDS

Prevention of HIV/AIDS starts with knowing one’s HIV status, maintaining faithfulness to one’s sexual partner, and using condoms. Patient education on HIV transmission, prevention, and living with HIV is essential. Antiretroviral drugs, though expensive, slow down virus multiplication. Opportunistic infections and other manifestations of HIV respond well to treatment, including antibiotics for pneumonia, rehydration and drugs for diarrhoea, antifungal agents for oropharyngeal candidiasis, and anti-tuberculous drugs for tuberculosis.

HIV testing and Voluntary Counselling and Testing (VCT) services are important aspects of managing and preventing AIDS. Education on HIV transmission, prevention, and healthy living with HIV infection is crucial for patient care.