Shock: Signs, Causes, And Types

Shock: Signs, Causes, And Types

Write a short note on shock.
Or
Defie shock. What are the types of shock?
Answer:

Shock is defied as a clinical state of cardiovascular col-collapse characterized by an acute reduction of effective circulatory blood volume and inadequate perfusion of cells and tissues.

Classification and Etiology of Shock

1. Hypovolemic Shock

• Acute hemorrhage
• Dehydration from vomiting, diarrhea
• Burns
• Excessive use of diuretics
• Acute pancreatitis

Types of shock

2. Cardiogenic Shock

• Deficient emptying, For Example.
  • Myocardial infarction
  • Cardiomyopathies
  • Rupture of the heart, ventricle, or papillary muscle
  • Cardiac arrhythmias
• Deficient filing, For Example.
  • Cardiac tamponade from hemopericardium
• Obstruction to the outflow, For Example.
  • Pulmonary embolism
  • Ball valve thrombus
  • Tension pneumothorax
  • Dissecting aortic aneurysm

3. Septic Shock

• Gram-negative septicemia (endotoxic shock), For Example. infection with E. coli, Proteus, Klebsiella, Pseudomonas, and Bacteroides
• Gram-positive septicemia (exotoxic shock), For Example. infection with streptococci, and pneumococci.

4. Other types

• Traumatic shock
  • Severe injuries
  • Surgery with marked blood loss
  • Obstetrical trauma
• Neurogenic shock
  • High cervical spinal cord injury
  • Accidental high spinal anesthesia
  • Severe head injury
• Hypoadrenal shock
  • Administration of high doses of glucocorticoids
  • Secondary adrenal insufficiency (For Example. in tuberculosis, metastatic disease, bilateral adrenal hemorrhage, idiopathic adrenal atrophy)

Shock Pathogenesis

Clinical Features of Shock

• Hypotension
• Cold clammy skin
• Rapid, thready pulse
• Shallow and sighing respiration
• Pale face, sunken eyes and weakness
• Uncontrolled sepsis-warm skin due to vasodilatation
• Urinary output less than 30 ml/hour

Septic shock causes and treatment

Stages of Shock

• An initial nonprogressive phase during which reflex compensatory mechanisms are activated and perfusion of vital organs is maintained
• A progressive stage characterized by tissue hypoperfusion and on the set of worsening circulatory and metabolic imbalances including acidosis
• An irreversible stage that sets in after the body has incurred cellular and tissue injury so severe that even if the hemodynamic defects are corrected, survival is not possible.

Morphologic Changes of Shock

The morphogenic changes in shock are due to hypoxia resulting in degeneration and necrosis.

• Hypoxic encephalopathy: Cerebral ischemia in compensated shock may produce an altered state of consciousness. In prolonged shock and cardiac arrest, the brain suffers from severe ischemic damage with loss of cortical function, comma, and a vegetative state. Dead and dying nerve cells are replaced by gliosis.
• Heart in shock: There are two important morphogenic changes in the heart in all types of shock
  • Hemorrhage and necrosis: There may be small and large ischemic areas or infarcts particularly located in the subpericardial and subendocardial regions.
  • Zonal lesion: There are opaque transverse contraction bands in myocytes near the intercalated disc.
• Shock lung: Due to dual blood supply lung are not affected by hypovolemic shock but is affected by septic shock.
  • Lungs become heavy and wet.
  • Changes of adult respiratory distress syndrome are seen.
  • The changes include congestion, interstitial and alveolar edema, lymphocyte infiltration, and fibrin and platelet thrombi in the microvasculature.
• Shock kidney:
  • Irreversible renal injury.
  • The end result is generally anuria and death.
  • Tubular lesions are seen referred to as acute tubular necrosis.
• Adrenal shock:
  • Adrenal shows stress syndrome.
  • This includes the release of aldosterone, glucocorticoid, and catecholamines like adrenaline. In severe shock, adrenal hemorrhage can occur.
• Liver in shock:
  • Due to hypoxia vasodepressor material is released which causes vasodilatation.
  • Focal necrosis, fatty liver, and impaired liver functions.
  • Hemorrhagic gastroentropathy: Hyper fusion of alimentary tract.

Septic shock causes and treatment

Shock Complications

Life-threatening complications in shock are due to hypoxic cell injury which results in immune-inflammatory responses and activation of various cascades. Various complications of shockare:

• Acute respiratory distress syndrome
• Disseminated intravascular coagulation
• Acute renal failure
• Multiple organ dysfunction syndrome

With the progression of the condition, the patient can develop a stupor, coma, and finally death.