We use a bronchoscope at the hospital to look down into the lungs of an anaesthetised patient. We can look at the width of the airways, collect samples using tiny little brushes and flush fluid down a tube, retrieve it in order to use samples to look at the cells, and identify any bacteria that may be present. It is very useful for investigating causes of coughing such as bronchitis, and looking at allergic bronchitis or asthma. It can also be used to look for foreign bodies. This is the term we give to any items that might be inhaled and end up lodge in an airway such as seeds, twigs, and bones. Once located, tiny instruments can go down the instrument and be used to grasp the offending item.
Endoscopy is basically the same technology used to look down the oesophagus and into the stomach. It can be carefully navigated into the small intestine. Its uses are mainly to diagnose conditions by obtain small samples of tissue for examination. It avoids the need for a major surgery, although sometimes, surgery is necessary to get samples that are of good enough quality and sufficient size to make a confident diagnosis. It is also incredibly useful for retrieving things from the stomach that dogs often swallow but this does depend upon what it is and whether we have an instrument capable of holding it for removal. For instance a sock may well be retrieved by this method but we rarely would be able to firmly hold and remove a stone.
Case Example: Monty's Cough
When the normally exuberant Monty began coughing intermittently & slowed down on his walks, we were very keen to find out what was bothering him.
Listening to Monty’s chest, we could quickly identify a heart murmur. This is an abnormal noise associated with the beating of the heart and results from the turbulence of blood flow which occurs for a few reasons but most often because it is being pushed in the wrong direction.
However, Monty’s heart had sounded like this for awhile and coughs from heart problems have typical patterns and Monty didn’t quite fit this particular picture.
Next we took a blood sample to look at Monty’s haematology to see whether there were signs of an infection which is revealed by seeing an increase in a type of cell called a neutrophil. Sometimes we may identify parasitic issues or allergies if we get an elevation in cell types such as Eosinophils and this might be especially important if we think the dog might have a lungworm issue such as Angiostrongylus.
Biochemistry is also important to get an idea of general organ function but increasingly compounds are being identified from specific tissues including the heart that can assist us but more often than not we do have to look at patterns to assist us the diagnosis.
In Monty’s case we found that one area of his larynx didn’t move quite as it should do so we had identified one source of his cough.
However his x-rays showed that his heart was actually tremendously enlarged and was reducing the space for his lungs to fill with air and the knock on effect would be that he would get tired more quickly. We also looked at his airways using a bronchoscope, a small tube that can bend and be steered down the windpipe.
Using this we then found that just where the trachea, the main windpipe, splits in to a left and right side, pressure from the base of the heart was squashing the left side and preventing air to flow down it as it should. The nerves within the tissue would intermittently interpret this as being the result of something being stuck in the airway itself and would produce a reflex to try & cough in order to free the obstruction.
So, Monty’s diagnosis was a combination of his heart struggling along with collapsing if one section of his airway. We currently have very few options to correct this although we can suppress his cough providing we are careful.
We do have a whole host of very effective drugs available to help his heart so Monty should have plenty of energy to enjoy his walks once more even if we have to limit his ball chasing activities!