Shock: Types and Treatment Overview

Shock: Types, Causes, and Treatment

• Shock is the acute failure to supply peripheral tissues with adequate blood. A critical nursing diagnosis associated with shock is inadequate peripheral tissue perfusion, along with alterations in cell metabolism.

Compensatory Mechanisms in Shock

• The body attempts to compensate for shock through various mechanisms. A key goal is maintaining cerebral and cardiac perfusion. Vasoconstriction occurs in the splanchnic, musculoskeletal, and kidney vascular systems.
• Increased heart rate (tachycardia) is mediated by β1 receptors. Vasoconstriction is triggered by α-adrenergic receptors. β2 receptors cause vasodilation and bronchodilation.

Types of Shock:

Hypovolemic Shock

• Characterized by significant blood loss (15% or more).
• Causes: hemorrhage, third-space fluid loss (e.g., burns), vomiting, diarrhea, heat stroke, dehydration.
• Signs: tachycardia, cool clammy skin, decreased hematocrit and hemoglobin, low lactate levels. ADH and vasopressin are released by the hypothalamus.
• Treatment: Identify and address the underlying cause, then replace fluids.

Cardiogenic Shock

• The heart's inability to pump effectively.
• Causes: myocardial infarction (MI), heart failure (HF), arrhythmias, congenital defects, valve disorders.
• Signs: cyanosis, tachycardia, hypotension, tissue hypoxia; decreased mean arterial pressure (MAP) and stroke volume (SV), increased central venous pressure (CVP).
• Treatment: Increase cardiac output (CO) and perfusion through mechanical support (e.g., extracorporeal membrane oxygenation – ECMO).

Neurogenic Shock

• Caused by loss of the sympathetic nervous system (SNS) tone.
• Causes: spinal cord injury above T6. Catecholamine release is impaired. Blood pooling occurs.
• Signs: low blood pressure, increased heart rate.
• Treatment: administer norepinephrine (NE) and intravenous fluids.

Anaphylactic Shock

• Triggered by an allergic reaction (e.g., medications, insects, latex).
• Causes: Histamine release.
• Signs: abdominal cramps, decreased blood pressure and weak pulse (circulatory collapse), hives, itching, cough, choking.
• Treatment: steroids, epinephrine, antihistamines, and bronchodilators.

Septic Shock

• Caused by a dangerous bloodstream infection.
• Signs: coagulation imbalances, fever, leukocytosis, metabolic acidosis, thrombocytopenia.
• Treatment: antibiotics.

Distributive Shock

• Characterized by loss of vessel tone and widespread inflammation, leading to an enlarged vascular compartment.

Stages of Shock

• Stage 1 (Compensated shock): Body can compensate for blood loss or lack of perfusion.
• Stage 2 (Decompensated shock): Body can no longer compensate for low blood volume/perfusion; blood pressure decreases.
• Stage 3 (Irreversible shock): Body struggles to maintain perfusion to vital organs. Organ dysfunction may occur even if vital signs temporarily return to normal.

Obstructive Shock

• Caused by the heart's inability to fill properly due to:
  • Cardiac Tamponade: Fluid buildup in the pericardium compresses the heart.
  • Pneumothorax: Increased pressure in the thoracic cavity.
  • Pulmonary Embolism: Blockage in pulmonary vessels.
• Signs: Increased right heart pressure, jugular venous distension.
• Treatment: chest tube placement, pericardiocentesis, thrombolysis/anticoagulants.

Consequences of Untreated Shock

• Acute Respiratory Distress Syndrome (ARDS): Lung stiffness and fibrosis.
• Acute Kidney Injury (AKI): Kidney damage.
• Gastrointestinal (GI) issues: Bowel obstruction or bleeding.
• Disseminated Intravascular Coagulation (DIC): Late-stage shock, severe bleeding from various orifices.
• Multiple Organ Dysfunction Syndrome (MODS): Frequent cause of death.

Cardiac Myxoma

• A benign heart tumor located in the left atrium.
• Triad Symptoms: heart failure, evidence of embolism, systemic illness (malaise, fever, weight loss, fatigue).
• Treatment: Tumor resection.