Pain in the foot

Introduction Foot pain is the pain of the sole of the foot. It is aggravated by walking or standing for a long time. It is common in ankylosing spondylitis. Common symptoms of ankylosing spondylitis include heel pain, foot pain, intercostal muscle pain. The etiology of AS has not yet been fully elucidated, and most of them are related to genetics, infection, and immune environmental factors. Ankylosing spondylitis is a chronic disease in which the spine is the main lesion, involving the ankle joint, causing spinal rigidity and fibrosis, causing different degrees of eye, lung, muscle and bone lesions, and is an autoimmune disease.

Cause

The etiology of AS has not yet been fully elucidated, and most of them are related to genetics, infection, and immune environmental factors.

Genetic

Genetic factors play an important role in the pathogenesis of AS. According to the epidemiological survey, the positive rate of HLA-B27 in AS patients is as high as 90% to 96%, while the positive rate of HLA-B27 in the general population is only 4% to 9%, and the incidence of AS in HLA-B27 positive patients is about 10% to 20%. The incidence of the general population is 12, which is about 100 times.

However, on the one hand, not all HLA-B27-positive patients have spondyloarthropathy. On the other hand, about 5% to 20% of patients with spondyloarthropathy have negative HLA-B27, suggesting that in addition to genetic factors, there are other factors affecting AS. The onset of HLA-B27 is an important genetic factor in AS expression, but it is not the only factor affecting the disease.

Most HLA-B27 molecules also have M2 epitopes. HLA-B27M2 negative molecules appear to be more strongly associated with AS than other HLA-B27 subtypes, especially in Asians, and HLA-B27M2 positive subtypes may have increased susceptibility to Reiter's syndrome. It has been demonstrated that HLA-B27M1 and M2 antigenic determinants and the joint-causing factors of S. cerevisiae, Shigella and Nasrogen can cross-react. Those with low response appear to be mostly AS, and those with increased response develop into reactive arthritis or Reiter syndrome.

2. Infection

Recent studies suggest that the incidence of AS may be associated with infection. Ebrimger et al found that the detection rate of Klebsiella pneumoniae in stools of AS patients was 79%, while that in the control group <30%; the carrier rate of Klebsiella pneumoniae in the active phase of AS and the IgA type antibodies against the bacteria in serum The titer was higher than that of the control group and was positively correlated with the disease activity.

3. Autoimmune

It has been found that 60% of AS patients have elevated serum complement, most cases have IgA type wet factors, serum C4 and IgA levels are significantly increased, and circulating immune complexes (CIC) are present in the serum, but the antigenic properties are not determined. The above phenomenon suggests that the immune mechanism is involved in the pathogenesis of this disease.

4. Other

Trauma, endocrine, metabolic disorders and allergies are also suspected to be pathogenic factors. In short, the cause of this disease is currently unknown, and there is no single theory that can fully explain the full performance of AS. It is likely to be caused by various factors such as environmental factors (including infection) on the basis of genetic factors.

an examination

Related inspection

Bone palpation general film examination

1. Computerized tomography (CT)

For clinical suspicion and X-ray can not be diagnosed, CT examination can be performed, which can clearly show the ankle joint gap, and is unique for measuring whether the joint space is widened, narrowed, straight or partially strong.

2. Magnetic resonance (MRI) and single photon emission computed tomography (SPECT)

The researchers believe that MRI and SPECT scintigraphy of the ankle joint film is very helpful for very early diagnosis and treatment. From this point of view, it is obviously superior to ordinary X-ray, but it is expensive and is not recommended as a routine examination.

3. Laboratory inspection

The white blood cell count is normal or elevated, the proportion of lymphocytes is slightly increased, a few patients have mild anemia (positive cells with low pigmentation), erythrocyte sedimentation rate can be increased, but the correlation with disease activity is small, while C-reactive protein is more meaningful. . Serum albumin decreased, 1 and gamma globulin increased, serum immunoglobulins IgG, IgA and IgM increased, and serum complements C3 and C4 increased frequently. About 50% of patients have elevated alkaline phosphatase and serum creatine phosphokinase is also elevated. Serum rheumatoid factor was negative. Although 90% to 95% of AS patients are HLA-B27 positive, generally do not rely on HLA-B27 to diagnose AS, HLA-B27 is not routinely examined.

4. X-ray inspection

The diagnosis of AS is of great significance. 98% to 100% of cases have X-ray changes of the ankle in the early stage, which is an important basis for the diagnosis of this disease. The early X-ray showed ankle arthritis, and the lesion usually began in the middle and lower part of the ankle joint and was bilateral. At the beginning, more violations of the humeral side, and in violation of the humeral side. It can be seen as a spot or block, and the humerus side is obvious. In turn, the entire joint can be invaded, the edges are serrated, the bones under the cartilage are hardened, the bones proliferate, and the joint space is narrowed. Finally, the joint space disappears and bony rigidity occurs. The X-ray diagnostic criteria for sacroiliitis are divided into 5 stages: grade 0 is normal ankle joint, stage I is suspicious ankle arthritis, stage II is ankle joint edge blur, slightly hardening and micro-invasive lesions, joint space is not Change, stage III is moderate or progressive ankle arthritis with one (or more) changes: near joint area sclerosis, joint space narrowing / widening, bone destruction or partial rigidity, stage IV is complete fusion of the joint Or with or without hardening.

X-ray findings of spinal lesions, early general osteoporosis, vertebral facet joints and vertebral trabecular trabeculae (decalcification), vertebral body as "square vertebrae", the normal curvature of the lumbar spine disappeared and straightened, can cause One or more vertebral compression fractures. The lesion progresses to the thoracic and cervical intervertebral facet joints, calcification occurs in the intervertebral disc space, the anterior longitudinal ligament calcification, ossification, and ligament callus formation, so that the adjacent vertebral bodies are commissure, forming a vertebral body bone bridge, showing the most A characteristic "bamboo-like spine". Primary AS and secondary spondylitis associated with inflammatory bowel disease, Reiter syndrome, and psoriatic arthritis have similar X-ray findings, but the latter is asymmetrical. Bone erosion and periostitis can occur at the attachment of ligaments, tendons, and bursa, most commonly in calcaneus, ischial tuberosity, and humerus. Similar X-ray changes can occur in other surrounding joints.

Differential diagnosis

Identification with heel pain:

Heel pain is a common disease in the elderly. Although it is neither red nor swollen on the surface, it feels pain when standing or walking, causing great inconvenience to walking. The cause of pain is mostly due to phlegm. After the injury of the membrane, local traumatic inflammation is caused. A small number of heel spurs caused by calcaneal spurs are tenderness of the foot. When walking, the heel does not dare to force, there is a feeling of stone sputum, acupuncture, and the symptoms are relieved after the activity is opened.

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