Pathology of osteomyelitis

2021-01-30 12:00 AM

Osteomyelitis may be natural, but trauma plays a role of blockage localization of an infected organ

Outline

Osteomyelitis is an infection of the bone that is caused by the mechanism of the blood or from the exogenous tract.

Clinical forms

Osteomyelitis in the bloodstream

Define

It is a secondary bone-marrow infection from the first site of infection, the bacteria spread through the bloodstream to localized bones and cause osteomyelitis.

Common in children than adults (70-90%), the age of the developing bones. Boys are 2-3 times higher than girls.

The common cause is staphylococcus (90% of cases), streptococcus, gram-negative bacteria may be encountered.

Location: Common in the head of bones in children, bone body in older children, any bone can be found but usually near the elbow knee.

Osteomyelitis may be natural, but trauma plays a role of blockage localization of an infected organ.

Pathogenesis

According to the thromboembolism theory, it is thought that after a certain purulent infection, the pus that reaches the bone's head is a bacterial embolism. In the onions and skeletons, in addition to the main feeding artery, there are many nourishing small vessels, because this small vessel system slows the circulation, making it easy for bacteria to stagnate and infect bacteria.

However, osteitis can be found at other sites. Therefore, later it was added to the theory of osteomyelitis due to the pre-induction of the body, when the bacteria returned, this susceptibility increased, increasing the number of bacteria rapidly and Increased pathogenicity of bacteria.

Pathological anatomy

Acute inflammation begins in the bone marrow, spread infection produces a total osteomyelitis, initially manifested by hematoma and oedema of the bone marrow causing increased pressure in the endothelium compressing the endothelial arteries.

Inflammation will turn to pus in the marrow, accompanied by a reaction of soft tissue around the bone. On 4-5 days, the pus spread along the Havers' tubes and along the Volkmann tube of the wall of the bone harden out of the bone, filling under the periosteal. The infection clogs the blood vessels, causing an entire portion of the hard bone submerged in nourished pus (partly due to the flaking of the bone) to necrosis.

Pus can destroy the periosteum to spread to soft tissue, rupture the skin and cause osteomyelitis fistula.

Parallel to the destruction process, there is a recovery process, creating new bones from healthy bones, periosteal. The first is the formation of granulation tissue and fibrous tissue between the dead and healed bone, which later forms new bone. Because young bones are in the developing stage, new bone formation will increase dramatically, making the bones thick and dense, which can cause bone deformation. The progression of osteomyelitis may spread to the joint or stop at the synaptic cartilage area.

Symptom

Acute osteomyelitis:

The disease has a very strong initial onset due to a strong systemic reaction, due to the maximum allergic increase in a susceptible body. Usually manifests itself with the following condition:

High fever of 39-40 0 C, prolonged fever, chills, small rapid pulse, maybe 120-140 times / minute, lethargy may have convulsions.

Natural pain in the area near the joint gradually increases, intense pain is diagonal, penetrating and increases with strong pressure.

Reduced or lost muscle function of the inflamed limb (note it is easy to mistake a fracture)

Swelling of all inflamed limbs, pale skin or reddish-purple skin, prominent subcutaneous veins, at first the skin is soft and possibly bland.

Joint swelling is due to a sympathetic reaction, but in infants, the inflammation can spread to the actual joint and cause a purulent arthritis.

Subclinical:

Leukocytes increased; VS increased.

Blood cultures may reveal bacteria (diagnostic value).

Bone puncture to measure endothelial pressure is a relatively valuable sign of the acute stage.

Sparkling radiation isotopes and X-rays.

X-ray: After 2 weeks, it is valid but must be taken to compare the next time with images of osteoporosis, periosteal ossification reaction. If there is a obtuse (later) bone, an area of ​​contrast bone is seen between a light area without bones.

Chronic osteomyelitis:

About 15-25% of acute myelitis turns to chronic due to late diagnosis, improper treatment. Clinical manifestations are dull in place, there is a period of pain relief, then relapse, soft swelling, a slight pain. In the area of ​​the inflamed bone, enlarged, rough, greyish skin, with a few funnel-shaped holes close to the bone, the exacerbations may recur. X-rays: typical with signs: bone solidification, periosteal reaction, obtuse bone, bone deformity.

Treatment

In the acute phase: As an emergency treatment, antibiotics must be used very early, strongly, continuously, for a long time, preventing the progression to purulent. While waiting for the results of the antibiotic mapping, specific antibiotics should be used with gram (+), intravenous antibiotics should be used at least 4 weeks after the blood sedimentation rate returns to normal.

Some authors recommend injecting antibiotics directly with effective intensity.

Motionless: To prevent the infection from spreading and to help relieve pain. The powder should be used to immobilize and immobilize continuously until it is gone

When there is an abscess or soft periosteal drainage required.

Improve fitness.

Several types of atypical osteomyelitis

Brodie's abscess

Prolonged progression, due to good body resistance to fast inflammatory focal local limit, progresses chronic from the beginning.

Clinical manifestations: Dull pain in place, soft swelling, little pain.

X-ray: There is a circular bone destruction area where the head of the bone is usually not confined and does not cause detection.

Treatment: Inflammatory ostomy, pus removal, muscle or spongy bone infestation, immobilization after surgery and high dose antibiotics.

Osteomyelitis dense

Found in long bones, the canal is completely thickened.

Clinical: Similar to Brodie abscess.

X-ray: Whole bone, cannot clearly see the canal.

Treatment: Should open and open the marrow, if any.