This book describes Olecranon Bursitis (Elbow bursitis), Diagnosis and Treatment and Related Diseases

I had a patient who had a protrusion of his left elbow which he mistook for bone and wanted me to do something about it.
He was surprised when I told him that it was just a sac of fluid stuck below his elbow and all he needed was aspiration of the swollen sac of fluid under local anesthesia.
He was more than happy for me to aspirate out the fluid and the compressed the affected part of the elbow with bandaging to prevent a recurrence of the swelling.

Olecranon Bursitis is the inflammation or infection of the bursa at the olecranon which is part of the bones forming the elbow joint.
The superficial site and limited blood flow make the bursa susceptible to direct trauma and infection.
People in certain occupations are mostly susceptible, such as plumbers or heating and air conditioning technicians who have to crawl on their knees in tight spaces and lean on their elbows.
Inflammation may also be because of a systematic inflammatory process, like rheumatoid arthritis, or a crystal deposition disease, like gout and pseudogout.
This disorder may be a side-effect of sunitinib which is used to treat renal cell carcinoma.
Whether it is injury or the introduction of an infectious germ, the inciting episode produces a reactive inflammation in the bursa.
The inflammatory action causes the extra-vasation of protein and synovial type fluid into the bursa.
The result is the obvious round swelling (bursitis) linked with this disorder
The starting symptom of elbow bursitis is often swelling.
There is a hard rubbery swelling at the olecranon
If the disorder has been present for some time, small lumps may be palpated underneath the skin over the olecranon.
Occasionally these lumps sense like something is floating around in the olecranon bursa, and they can be very tender.
These lumps are normally the thickened folds of bursa tissue that have produced in reaction to chronic inflammation.
The bursa sac may become swollen and fill with fluid at times.
Over time the bursa can become very thick, almost like an elbow pad on the olecranon.
Finally the olecranon bursa can also become infected.
There may be a graze or wound on the skin over the bursal swelling, where the germs entered.
Olecranon bursitis causes pain and swelling in the area at the tip of the elbow.
The patient may develop a fever and feel chills.
An abscess, or area of pus, may develop on the elbow.
If the infection is not treated rapidly, the abscess may even start to drain, meaning the pus starts to seep out.
Diagnosi:
Bursal aspiration and analysis are regarded to be the gold standard in diagnosis.
X-rays of the elbow together with ultrasound imaging helps to confirm bursitis and evidence of bone spurs.
Treatment:
Patients who have often olecranon bursitis are advised to use the RICE method of treatment.
Rice represents Rest, Ice, Compression and Elevation.
There are also other physical treatment methods that could be useful for reducing pain and inflammation e.g., phonophoresis, electrical stimulation.
Most patients with olecranon bursitis do not necessary require those methods.
The treatment for bursitis is dependent largely on whether it is infective or non-infective.
Acute non-infective bursitis is self-limiting.
It can be treated conservatively with rest, ice, and the usage of NSAIDs.
Compression with elastic bandage has also been proven to help prevent swelling.
Corticosteroid injection can cause an early decrease in symptoms of olecranon...