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Fluid Excess – Edema

  • Edema: Excessive fluid in the interstitial compartment, causing tissue swelling or enlargement.

    • Characteristics:

      • Localized or generalized throughout the body.

      • May impair tissue perfusion and trap drugs in interstitial fluid.

Causes of Edema

  • Increased Capillary Hydrostatic Pressure:

    • Caused by higher blood pressure/increased blood volume.

    • Forces more fluid out of capillaries into tissues (e.g., pulmonary edema).

  • Loss of Plasma Proteins (e.g., Albumin):

    • Results in decreased plasma osmotic pressure.

  • Obstruction of Lymphatic Circulation:

    • Causes localized edema due to excessive fluid and protein not returning to the general circulation.

  • Increased Capillary Permeability:

    • Usually localized, may result from inflammatory responses or infections.

    • Histamines and other mediators increase capillary permeability; bacterial toxins/burns can cause widespread edema.

Effects of Edema

  • Swelling:

    • May appear pale or red.

    • Pitting Edema: Molds to pressure, leaving a pit once released.

  • Physiological Impacts:

    • Increase in body weight.

    • Functional impairment (joint movement).

    • Reduced vital capacity.

    • Pain due to pressure on nerves.

    • Ischemia can lead to tissue breakdown.

Lymphatic Filariasis (Elephantiasis)

  • More common in tropics; caused by nematodes from the family Filariodidea (e.g., Wuchereria bancrofti).

  • Majority of infections asymptomatic, damaging lymphatic system.

  • Acute inflammation results from infections where defenses are lost due to lymphatic damage.

  • Chronic conditions lead to complications: lymphoedema, elephantiasis, hydrocele.

Socioeconomic Impacts

  • Body deformities lead to social stigma and financial hardship due to loss of income and increased expenses.

Pathophysiology

  • Infection occurs through mosquito transmission of larvae to lymphatic vessels.

    • Adult worms block lymph drainage.

    • Usually acquired in childhood, visible symptoms develop later.

Diagnosis and Treatment

  • Diagnosed through blood sample examination.

  • Treatment includes anti-worm medications, compression clothing, and surgery.

Fluid Deficit – Dehydration

  • Causes:

    • Insufficient intake or excessive loss, often measured by weight changes.

    • More serious in infants and older adults; can include water and electrolyte loss during diarrhea.

Manifestations

  • Symptoms include decreased skin turgor, dry membranes, sunken eyes, and low blood pressure.

  • Urine analysis shows low volume but high specific gravity.

Compensatory Responses

  • Increasing thirst, heart rate, and constriction of cutaneous blood vessels to concentrate urine.

Fluid Excess

  • Two forms:

    1. Volume Excess: Retain both sodium and water, often from renal failure.

    2. Hypotonic hydration: More water than sodium is retained, leading to cellular swelling.

Sodium Imbalance

  • Hyponatremia:

    • Causes: excessive loss from sweating, vomiting, diuretics, hormonal imbalances.

    • Effects: fatigue, muscle cramps, and confusion.

  • Hypernatremia:

    • Causes: insufficient ADH, water loss, and excessive sodium.

    • Effects: weakness, dry membranes, agitation.

Potassium Imbalance

  • Hypokalemia:

    • Caused by losses through diarrhea or diuretics, affects cardiac rhythm and neuromuscular function.

  • Hyperkalemia:

    • Causes include renal failure, and can lead to muscle weakness and cardiac arrest.

Calcium Imbalance

  • Hypocalcemia:

    • Causes: hypoparathyroidism, malabsorption, renal issues.

    • Effects: muscle twitching, dysrhythmias.

  • Hypercalcemia:

    • Causes: bone malignancies, hyperparathyroidism.

    • Effects: muscle weakness and cardiac changes.

pH Imbalance

  • Acidosis: Increased hydrogen ions decrease pH; caused by respiratory/metabolic issues.

  • Alkalosis: Deficit of hydrogen ions; increases pH; can result from hyperventilation or excessive bicarbonate.

  • Effects: Both conditions can lead to nervous issues and muscle twitching.

Compensation and Decompensation

  • Compensation mechanisms are often short-lived and cannot address root causes; decompensation occurs when problems worsen or additional issues arise.