The incidence of acute hematogenous osteomyelitis has decreased significantly in recent years, and there is an increasing trend of patients presenting with subacute symptoms from the onset. The disease develops in the form of.
1, hematogenous infection.
2, contagion from adjacent septic lesions.
3, direct infection caused by bacterial invasion of bone in open fractures. The knowledge of the pathology of acute hematogenous osteomyelitis is indispensable in diagnosis and treatment.
Prevalent age and gender.
However, the prevalence is certainly the same in young children and pediatrics. One third of the author’s cases occurred in adults, and this point may be related to the higher incidence of hematogenous osteomyelitis in our country. However, in general, it is higher in males.
Prevalent sites.
Anatomically, almost all of the long diaphyses and short tubular bones in children occur in the epiphysis, while in adults, more occur in the diaphysis. From the upper and lower extremities, the lower extremities account for the majority of cases, and the incidence of lower extremities is 2-6 times higher than that of upper extremities. It is especially common above and below the knee.
Causes, causative factors and causative agents.
Upper respiratory tract infection, otitis media, and boils are sources of infection; trauma is often the causative agent. Rivero 27.5%, Inoue 17.5%, and about half of Rivero had previous septic infection of other parts of the body. The author believes that 70% of the cases have a history of trauma and mosquito bites before the onset of the disease, which are minor traumas that do not reach the level of fracture. Drug-resistant bacteria are increasing, other, white staphylococcus, streptococcus, pneumococcus, Gram-negative bacilli such as Pseudomonas aeruginosa, Escherichia coli, Salmonella, etc. can occur, there are also reports of infection caused by viruses.
Pathology.
The primary focus of acute hematogenous osteomyelitis occurring in pediatric long tubular bones is overwhelmingly in the epiphysis of the bone. The majority of septic arthritis, represented by breast and hip arthritis, is secondary to osteomyelitis. The spread to the joint is determined by whether the epiphysis is intra- or extra-articular, and the epiphyseal plate of the bone cartilage has a strong barrier to infection; direct spread of infection through the epiphysis to the epiphysis or joint is almost impossible.
The pathological changes of acute osteomyelitis are shown in the following diagram.
1. proliferation of bacteria and formation of abscesses in the bone marrow usually within 48 hours.
2. increase, enlargement and spread of the abscess through Havers’ canal and Volkmann’s canal to reach outside the bone cortex, subperiosteal stripping of the bone cortex, collection of pus under the periosteum and formation of a subperiosteal abscess; this stripping can be large and long, even the entire stem of the long canal bone is stripped
3. the cortical bone enclosed in the abscess is necrotic due to the loss of blood supply from the periosteum and the embolization of the intra-medullary vessels due to inflammation, so the cortex is necrotic due to the severance of blood flow, or even the whole section is necrotic
4. Bone shell is formed under the periosteum, and the shell is wrapped with dead bone, and the dead bone is filled with sarcomeres, and sarcomeres and bacteria are the source of infection. Sometimes, due to the high virulence of bacteria, not only necrosis occurs in the bone cortex, but also in the periosteum, and the diseased bone loses the ability to produce bone by membranization, forming a large segment of defective pseudo-joint.
Relationship between age and symptoms.
Diagnosis.
The prognosis of acute hematogenous osteomyelitis is determined by early diagnosis and the most appropriate treatment. The so-called early stage is the date when bacterial proliferation begins. The intensity, location, extent, and age of the initial symptoms of infection vary greatly, and are broadly divided into systemic and local symptoms.
Systemic symptoms.
The most typical systemic symptoms are: malignant chills, high fever, vomiting, and septic-like episodes. Newborns and lactating children are easily excited, refuse to breastfeed, cry during diaper changes and often consult the pediatrician when they have fever and vomiting. Recently, although there has been a significant decrease in patients presenting with acute attacks, they can still be seen, even in the international city of Beijing. Be alert for this disease!!! Early cast with a large number of sensitive antimicrobials and herbs. Patients lacking this systemic symptom are less common.
Local symptoms.
Different images of the disease are manifested according to the site, extent and age of the infection.
The first is pain, bacteria multiplying in the bone marrow of the bone cadre, local inflammatory congestion, spontaneous pain due to increased intraosseous pressure caused by inflammatory exudates, newborns and suckling children because they can not speak, pain manifested as immobility of the affected limb, crying during diaper changing is also a manifestation of pain. The pressure pain confined to the epiphysis is the most important and is the earliest local manifestation. Fever and redness are typical manifestations of acute inflammation. Swelling of the joint and retention of joint fluid due to reactive inflammation is aseptic, and symptoms appear later as the disease progresses. The pus sores in the bone marrow are discharged out of the bone, and the pain is relieved by a decrease in the internal pressure in the bone marrow cavity, but the swelling, redness, and fever persist. In the subacute stage, when the bone shell has not yet formed, there can be periosteal proliferation from time to time, the presence of dead bone, and even complete necrosis of large segments of bone, pathological fractures, deformities, and pseudoarthrosis; multiple sinus tracts are formed. The proximal and distal femoral epiphysis and proximal humerus are included in the intra-articular pus that directly affects the joint to form septic arthritis. Septic arthritis can also spread directly to the epiphysis, causing osteomyelitis of the epiphysis and metaphysis. This is particularly important in the pediatric population.
Clinical examination.
The most basic and important thing is that once the disease is suspected, blood cultures are performed before antimicrobial agents are applied. In fact, it is common to come to the orthopedic department only after poor antimicrobial treatment at an outside hospital. Even if the blood culture is made, it is not always positive. There is no special test for osteomyelitis, increased white blood cells, leftward nuclear shift, increased sedimentation, and C-reactive protein (+). When the disease is suspected, a bone marrow aspiration, smear, and largely identifying the causative organism should be performed. Bone puncture should be performed with saline, bone marrow should be extracted, and when pus is formed under the periosteum, the puncture should be performed in layers, which is extremely successful, when it has already entered the middle stage.
X-ray examination.
In the early stage, always keep in mind that the X-ray is completely devoid of bone changes; the earliest appearances are soft tissue swelling and abnormal shadows in the deep muscular layer, from 2-4 days after the onset of the disease, and such findings are determined by the conditions of the film. The earliest changes in bone are determined by the conditions of the radiograph. The earliest changes in bone appear from 4-5 days after the onset to around 10 days before the onset of the disease and are caused by exudate in the bone marrow causing marrow blurring, the photographic conditions must be good and contrasted with the contralateral side. Next, local congestion and necrosis cause resorption of bone trabeculae. As the lesion progresses, new bone formation is seen in the bone cortex, and it is at this point that the diagnosis of osteomyelitis is made on X-ray, as described in the “Pathology” section, when the disease has progressed from the early to the mid-stage. The disease progresses to necrotic bone formation, bone shell formation and chronic phase. The changes on these X-rays are not limited to the epiphysis but to the entire medullary cavity and the bone stem; in severe cases, the entire bone stem is invaded. These are the stereotypical x-ray changes. Sometimes, depending on the initial site and the availability of treatment, the X-rays may be amorphous. When there is no change in the initial X-ray, a good turnaround is obtained due to the application of a large amount of effective antimicrobial agents, and sometimes no change in the final X-ray occurs, which is the cure of the primary lesion of osteomyelitis.
Bone scan.
It is commonly recognized that the preferred positive rate of bone scan is fast and sensitive compared to simple x-ray. As a radioisotope, mostly 99mTC is used. calcium and white blood cells are combined and clustered at the site of acute inflammation, and the combination of the two is characteristic. In young children, the epiphysis would have been the site of very high absorption of RI.
CT.
My experience is mainly that after entering the middle stage or primary osteomyelitis, not really early osteomyelitis, CT shows vague cortical resorption thinning of the bone marrow and other simple X-rays when it is still unclear, enabling a detailed depiction of the extent of the lesion in all periods of osteomyelitis compared to the usual tomographic X-rays, which correctly depict the destruction of the bone cortex and marrow. Changes in the bone cortex are clearer on CT than on MRI.
MRI.
MRI is an imaging and diagnostic method that has recently gained rapid popularity. I believe that MRI has a very definite value as a special imaging diagnosis over X-rays and bone scans for the diagnosis of infectious diseases of the bone and joint, and because of inflammatory exudates and ischemic allergic reactions, MRI can accurately grasp the extent of the lesion, especially in the inflammatory phase of congestion, when there is no bone destruction, and when there are intervertebral discs and intravertebral canal infections. Before the appearance of x-ray changes, CT diagnosis cannot be timed, and MRI can accurately depict them. MRI can show clear changes even when X-rays and CT do not change within 48 hours of onset.
Treatment.
Sepsis-like morbidity, physical examination, and systemic management are very important.
I. Local quiet.
Splint or and plaster immobilization, local quiet, close observation and intravenous application of large amounts of antimicrobials. And must be admitted to the hospital for treatment.
Second, the application of antimicrobial agents.
Do not wait to determine the diagnosis, as long as the disease is suspected, should be a large number of intravenous antimicrobial application, the use of blood culture before. When the causative agent is unknown, how to choose the antimicrobial agent has become a problem, because 75% of the Staphylococcus aureus, so this bacteria effective antimicrobial agent is preferred. Recently, the increase of MRSA should be noted.
Third, the principles of drug use.
1, bactericidal antimicrobials.
2, a large number.
3.Starting with static drip, and can be taken orally after the condition is stabilized.
Input amount: the antimicrobial agent entering the bone is only 1/10 of the intravenous. highly sensitive agents, Staphylococcus aureus 1.56 μg/ml, Gram-negative bacilli 6.25 μg/ml of the minimum inhibitory concentration. Considering the concentration line of the agent in the blood, the maximum amount of the commonly used amount for highly sensitive, and the upper and lower amount of the commonly used amount for gram-negative bacteria. Within 48 hours after the onset of the disease if the antimicrobial agent is fully effective, the systemic and local symptoms improve rapidly, the clinical examination value also improves rapidly, and the X-ray film may not show changes.
The antimicrobial agent should be discontinued only when the body temperature, white blood cell and sedimentation values are normal after at least 3 weeks of administration; continue to observe for several weeks. Continue for at least 3 weeks after clinical and examination findings show disappearance of active osteomyelitis and normal body temperature and blood sedimentation before continuing for 2 weeks. Even if the symptoms disappear, do not discontinue, and continue for 2 weeks after the ESR value is normal, if it is a pediatric patient. Symptoms improve, ESR 20mm/h or less should continue to apply antimicrobials for 2-3 weeks and then discontinue, the author agrees with the above opinion, after the cessation of antimicrobials Chinese herbal medicine continues to treat. The condition for the real effective use of antimicrobials is that the blood circulation in the epiphysis exists, and if the disease develops further due to the occlusion of capillaries in dead bone and the formation of bone encapsulation, the agent cannot reach the lesion and has become necessary with surgical treatment, in other words, if there is a clear change in the X-ray, it is designated as necessary for surgical treatment.
Fourth, surgical treatment.
Surgical treatment is based on medical treatment, giving thorough debridement, removing dead bone, opening up the dead cavity, and adequate drainage.