Septic arthritis: introduction
As analyzed in the previous discussion, septic arthritis is a painful infection of the joints, the cause of which resides more often in bacterial insults and, more rarely, in viral and fungal attacks. Septic arthritis gives rise to extremely painful symptoms associated with redness, swelling and a burning sensation; After analyzing the symptoms of septic arthritis in more detail, we will analyze the diagnostic strategies and therapies available for treating the disease.
Symptoms
Normally, septic arthritis does not go unnoticed, since it often begins with a painful symptomatology at the level of the joint involved. In addition to the omnipresent joint pain, which tends to increase with movement, the patient often complains of high fever (even 40 ° C), joint swelling, acute synovitis, vasculitis and a particular burning sensation at the site involved. In children in particular, septic arthritis can also cause mood alteration (irritability), general malaise, loss of appetite and tachycardia.
Some patients develop septic arthritis at the level of joints such as the sternoclavicular, the acromioclavicular (clavicle and scapula) and the sternum costal: in these cases, the pain can spread and also involve the chest. When septic arthritis affects the sacroiliac area, it is very likely that the patient perceives acute pain in the buttocks, hips or in the front of the thigh.
Infant septic arthritis tends to manifest itself, more often, at the level of the hips, while in the adult the joints of legs and arms (therefore also knee, elbow, wrist and ankle) are the most affected; also head, neck and other joints may be affected.
When the infection is not blocked and eradicated in time, the damages could also be permanent (functional impotence) and, in some cases, so serious as to induce the death of the patient who is affected.
Diagnosis
To ascertain the diagnosis of a clinical case of septic arthritis, the presence of pus in the joint and the rapid destruction of the cartilage must be observed.
A patient already being treated for arthritis, which therefore takes specific drugs, may not perceive the typical pain that accompanies septic arthritis: the medicines, in fact, mask the alarming symptoms that septic arthritis normally sends.
The most commonly used diagnostic tests include aspiration of the joint fluid for cell counts (analysis of a sample of synovial fluid taken with a needle directly into the joint), Gram staining, blood tests, and blood culture and radiography ( imaging test).
By examining necrotic tissues taken from a patient with septic arthritis in the laboratory, it is possible to observe some interested ransoms:
- Inflammatory infiltrate consisting mainly of polymorphonuclear neutrophils
- Exudate with a serous, clear / cloudy or purulent appearance
- Thickening of the joint capsule and production of intra-articular fibrous elements (responsible for impaired mobility)
- Neutrophil leukocytosis:> 7500 leukocytes / mm3, of which over 85% are neutrophils
- Very high ESR (erythrocyte sedimentation rate, with reference to the erythrocyte sedimentation rate): the high ESR value indicates a current inflammation
- Very high reactive C protein
Among the molecular investigations, the PCR ( Polymerase Chain Reaction ) should not be forgotten, essential to ascertain the presence of bacterial DNA in the synovial fluid and in the joint tissue: this diagnostic technique is useful for identifying pathogens that are difficult to grow.
From the radiological examination, on the other hand, not much information is obtained, given that only the increase in volume of the para-articular soft tissues and the opacity of the same can possibly be observed.
Through the examination of CT ( computed tomography ) and MRI (magnetic resonance) it is possible to obtain a more accurate morphological evaluation of the pathology: the CT, in fact, better defines the complex joints, revealing a very useful test that acts as a guide for the needle aspiration . The MRI test, being very sensitive, allows to obtain a fast diagnosis and is much more specific than conventional radiology.
In the event that it is not possible to isolate any pathogen, it is recommended to evaluate the amount of neutrophils in synovial fluid: when the count of these cells is greater than 20, 000-30, 000 units / mm3, the diagnosis of septic arthritis is very likely.
Useful data to ascertain the septic arthritis from a sample of synovial fluid : chemical-physical examination Appearance → opaque Color → greenish-yellow White blood cells →> 100, 000 units per mm3 Glucose → friable Mucina → positive (80%) Neutrophils →> 75% Viscosity → variable Volume →> 3.5 |
Prognosis
The course of the infection is heavily conditioned by many factors:
- Virulence of the pathogen
- Early onset of therapy
- Guest response
- Efficiency of the host's immune system
- Age of the patient
- Localization of the pathogen (number of affected joints)
It is believed that 5-10% of aseptic arthritis from gram negative cocci and from S. aureus gives poor prognosis, despite adequate and prompt therapy; Septic arthritis is highly debilitating (leaves permanent injuries) in 25-50% of cases.
Care
Even if there is suspicion of septic arthritis, it is recommended to proceed as soon as possible with an aggressive treatment in a hospital environment, in order to subject the patient to rapid tests to start treatment immediately. During the therapy, even if the immobilization of the limb is not always necessary, it is recommended to avoid the weight load.
Drug therapy is subject to the type of etiopathological agent involved, identified only after the culture of the aspirated synovial fluid or blood culture.
In general, the therapy consists of the administration of antibiotics (in the case of bacterial septic arthritis) to be taken intravenously for three weeks; after this first treatment, it is advisable to proceed with an oral therapy, for another 2 weeks.
In addition to antibiotic therapy, the patient suffering from septic arthritis is generally also subjected to the drainage of the joint, often performed with a spasm; drainage can also be surgical but, in this case, it is preferable to submit to this operation only patients who have a clear involvement of the axial joints (such as shoulder, hip and sternoclavicular joint) and in case of failure to respond to a therapy antibiotic. Drainage gives the patient immediate relief and decreases joint pressure.
We remind you that timely therapy for the treatment of septic arthritis can often prevent the onset of irreversible damage.
