PCOL 2 - Uyek

• Cough


  An important defensive reflex that enhances clearance of secretions and particulates from the airways and protects from aspiration of foreign materials occurring as a consequence of aspiration or inhalation of particulate matter, pathogens, accumulated secretions, postnasal drip, inflammation, and mediators associated with inflammation
• Cough Reflex Arc Neuropathophysiology

  1. Afferent pathway

  2. Central pathway (Cough center)

  3. Efferent pathway
• Afferent pathway


  • Sensory nerve fibers (branches of the vagus nerve) located in the ciliated epithelium of the upper airways (pulmonary, auricular, pharyngeal, superior laryngeal gastric) and cardiac and esophageal branches from the diaphragm. The afferent impulses go to the medulla diffusely.
• Central pathway (Cough center)


  • A central coordinating region for coughing is located in the upper brain stem and pons.
• Efferent pathway


  • Impulses from the cough center travel via the vagus, phrenic, and spinal motor nerves to diaphragm, abdominal wall and muscles. The nucleus retroambigualis, by phrenic and other spinal motor nerves, sends impulses to the inspiratory and expiratory muscles; and the nucleus ambiguous, by the laryngeal branches of the vagus to the larynx.
• Cough Reflex Arc Mechanical Events

  1. Inspiratory Phase

  2. Compression Phase

  3. Expiratory Phase
• Acute cough


  Short-lasting cough
• Subacute cough


  Cough lasting for a moderate duration
• Chronic or persistent cough


  Cough lasting >8 weeks
• Refractory cough


  Chronic cough that hasn't responded to treatment
• Productive cough


  Cough that brings up phlegm
• Non-productive cough


  Cough that doesn't bring up phlegm
• Pharmacotherapy for cough


  • Antitussives
  • Mucolytics
  • Expectorants
• Centrally-acting antitussives


  They inhibit the cough center in the brain, elevating the threshold for coughing
• Centrally-acting antitussives


  • Codeine
  • Dextromethorphan
• Peripherally-acting antitussives


  They anesthetize the local nerve endings or act as demulcents
• Peripherally-acting antitussives


  • Benzonatate
• Mucolytics


  They reverse the disulfide bonds in mucus, reducing its viscosity
• Mucolytics


  • N-acetylcysteine
  • Carbocisteine
• Expectorants


  They reduce the viscosity of tenacious secretions by irritating the gastric vagal receptors that stimulate respiratory tract fluid, thus increasing the volume but decreasing the viscosity of respiratory tract secretions
• Expectorants


  • Guaifenesin
• Brainstem


  A part of the brain that connects the cerebrum with the spinal cord and plays a crucial role in regulating essential bodily functions such as breathing, heart rate, and blood pressure. Contains the central coordinating region for coughing.
• Hypothalamus


  A small region of the brain located just above the brainstem that plays a vital role in regulating many bodily functions, including temperature, hunger, thirst, and sleep. Involved in regulating the autonomic nervous system, but not directly involved in coughing.
• Benzonatate


  A peripherally-acting antitussive used to relieve a cough caused by a cold or flu. It works by numbing the throat and suppressing the cough reflex.
• Diphenhydramine


  An antihistamine used to treat symptoms of allergies, such as runny nose, sneezing, itching, and watery eyes. It works by blocking the effects of histamine, a substance in the body that causes allergic symptoms.
• Mucolytics


  A type of medication that reduces the viscosity (thickness) of mucus by breaking down disulfide bonds
• Mucus


  A gel-like substance produced by the respiratory and gastrointestinal tracts to protect and lubricate these surfaces
• Disulfide bonds


  Cross-linking bonds in mucus that contribute to its thickness and elasticity
• Viscosity


  The thickness or "gooeyness" of a substance