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Blue Skin and Mucus Membranes in Dogs

Cyanosis in Dogs

 

Cyanosis is a medical condition characterized by blue colored skin and mucous membranes, which occurs as the result of inadequate amounts of oxygenated hemoglobin -- the molecule which carries oxygen to the body tissues -- or due to hemoglobin abnormalities.

 

Unfortunately, dogs that are suffering from cyanosis caused by advanced lung/airway disease and severe heart disease have a poor long-term prognosis.

 

Symptoms and Types

 

  • Heart murmur
  • Crackles heard when listening to the lungs
  • Muffled heart sounds
  • Harsh sounds upon inhalation
  • Honking cough
  • Difficulty breathing
  • Cyanotic, cool, pale, painful, swollen limbs lacking a strong pulse
  • Weakness
  • Posterior (hind limb) paresis or paralysis

 

Causes

 

Originating in the Respiratory System

  • Larynx (voice box): can be due to paralysis (acquired or congenital); collapse; spasm; swelling; trauma; cancer; chronic inflammatory disease
  • Trachea: can be due to collapse; neoplasia; foreign body; trauma; underdevelopment
  • Lower airway: can be due to pneumonia (viral, bacterial, fungal, allergic, mycobacteria, aspiration); chronic swelling of the bronchioles; allergies, asthma; chronic dilation of the bronchioles; cancer; foreign body; parasites; bruising of the lungs; swelling due to inhalation, snake bite, electric shock; near drowning
  • Pleural space: may be due to air in the chest cavity; infectious (bacterial, fungal); pus in the chest cavity; blood in the chest cavity; cancer; trauma
  • Chest wall, or diaphragm: may be related to congenital defects such as hernia around the heart or through the diaphragm (when an organ pushes through the wall, or enclosure that normally contains it); trauma (diaphragmatic hernia, fractured ribs); neuromuscular disease

 

Originating in the Cardiovascular System

  • Congenital defects
  • Acquired disease: may be linked to mitral valve (left side of heart valve between atrium and ventricle) disease; disease of heart muscle
  • Fluid collection around the heart: due to cancer or unknown causes
  • Clogging of lung blood vessels with a clot
  • Pulmonary hypertension: unknown origin (idiopathic); right-to-left cardiac shunts (blood is diverted to another pathway)
  • Peripheral blood vessel disease

 

Originating in the Neuromusculoskeletal System

  • Brain-stem dysfunction: due to brain swelling; trauma; bleeding; cancer; drug-induced depression of the respiratory center
  • Spinal cord dysfunction: may be due to swelling; trauma; vertebral fractures; disk slippage
  • Neuromuscular dysfunction: may be caused by overdose of paralytic drugs; tick paralysis; botulism; coonhound paralysis

 

Methemoglobinemia

  • Methemoglobin (metHb) binds to water molecules rather than oxygen molecules
  • Elevated concentrations of methemoglobin in the red blood cells leads to tissue hypoxia due to reduced oxygen carrying capacity of blood
  • Congenitally acquired NADH-methaemoglobin reductase (NADH-MR) deficiency: deficiency of an intracellular reductive enzyme, which helps keep methemoglobin at levels of less than two percent, preventing cyanosis
  • May be linked to ingestion of oxidant chemicals: acetaminophen, nitrates, nitrites, phenacetin, sulfonamides, benzocaine, aniline dyes, dapsone

 

 



 




 


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