Lymphadenitis in Cats

An inflamed lymph node will appear as a localized swelling underneath the skin’s surface. Depending on the location of the lymph inflammation, the cat could display an array of symptoms that coincide with the infection and enlarged lymph. For example; an inflamed lymph node in the neck may cause the feline to have difficulties swallowing, cough or drool, whereas an inflamed lymph node in the leg may cause the cat to have an abnormal gait. Lymphadenitis can easily be mistaken for lymphadenopathy, which is often caused by cancer, so you must seek veterinary professional consultation for proper diagnosis. 

Lymph node inflammation in cats is termed lymphadenitis in the veterinary world and is characterized by inflammation in one or more lymph nodes. Lymphadenitis is noncancerous, commonly caused by an infection of fungi, viruses, or bacteria. 

Lymph node inflammation, lymphadenitis, in cats displays a clinical sign of lymph enlargement. However, lymphadenitis does not often cause the lymph node to reach a size large enough for a pet owner to visualize and is usually only detected through palpation. Lymph nodes can be found throughout the body including the limbs, groin, pelvis, mesentery, chest, armpits and throat. A cat owner may detect a lump on the cat’s skin when they pet the feline or if the feline begins walking strangely, as inflamed lymph nodes near the limbs can cause an abnormal gait. Inflamed lymph nodes are often painful, especially when they are touched, so a feline may vocalize or bite a pet owner under palpation. Other symptoms of lymphadenitis a feline may display depend on the area of infection and the infectious agent (virus, bacteria or fungus). Possible clinical signs of lymphadenitis paired with this condition include: 

• Decreased appetite
• Decreased water intake
• Inability to swallow
• Drooling
• Coughing 
• Irregular breathing 
• Runny nose 
• Sneezing
• Constipation 
• Low urine output 
• Exercise intolerance 
• Abnormal gait 
• Depression
• Restlessness 
• Fever

Lymphadenitis in cats is caused by an infection of bacterial, fungal or viral origin. The lymphatic system is a series of tube-like structures composed of lymphatic ducts that pick up excess fluids that have leaked from the blood capillaries and return said fluid to the bloodstream. As this action occurs, the fluid passes back through the bean-shaped organs known as the lymph nodes, where infectious material are picked up and destroyed by lymphocytes (a type of white blood cell). This processes of destroying infectious materials causes the lymph node to become inflamed and therefore the area adjacent to the lymph will pinpoint the location of infection. Specific infectious microorganisms that are known to infect the lymph nodes of cats include the following: 

Bacteria 

• Bartonella spp 
• Francisella tubarensis 
• Yersinia pestis
• Fusobacterium spp
  
• Bacteroides
• Pasteurella 

Fungi

• Sporothrix 
• Coccidiodes 
• Histoplasma 
• Cryptococcus 
• Blastomyces 

Viruses 

• Feline Infectious Peritonitis (FIP) or Coronavirus 

Diagnosis of lymphadenitis will begin with a physical examination including a palpation to locate the inflamed lymph node. If the lymph inflammation is located on the chest or pelvis region, radiographs may be required to view any internal organs that may be affected. Lymphadenitis can easily be mistaken for cancerous lymphadenopathy, therefore further testing to evaluate the nature of the mass is required. A review of your cat’s blood work and a urinalysis will be required to detect for signs of infection. An infection will cause the feline’s white blood cells to increase, as lymphocytes are produced by the bone marrow to trap and destroy infectious microorganisms. To pinpoint the exact cause behind the lymph node inflammation, a sample if lymph fluid will be taken from the lymph node for evaluation. The biopsy type used to aspirate fluid is called fine needle aspiration, which may require sedation of the feline. 

The underlying cause of lymph node inflammation in cats must be determined before treatment begins. Microscopic bacterial infections are treated with antibiotic drugs, whereas fungal infections are treated with antifungals. Bacteria and fungus cannot be treated with the same drugs, as these drugs are designed to fight different types of infection. Viral infections are often treated with intravenous therapy infused with anti-viral medication.

True lymphadenitis in cats is not a serious condition if treated properly. Once the underlying cause is identified and treatment is received, the affected lymph node will return to normal size. If you have completed the feline’s prescribed medication and the lymph node remains the same, contact your veterinarian promptly.