Wandering spleen

　　Wandering spleen is caused by congenital abnormalities during the development of the spleen, and certain secondary factors also play an important role in the occurrence of the disease. The specific etiology and pathophysiological manifestations are described as follows.

　　1、The etiology of wandering spleen

　　It is generally believed that this is caused by congenital abnormalities during the development of the spleen. Some scholars also believe that there are secondary factors involved in the occurrence of wandering spleen. The normal spleen is maintained in a certain anatomical location due to the support of the gastro-splenic ligament, splenic colonic ligament, splenic renal ligament, and splenic diaphragmatic ligament, as well as the abdominal intra-abdominal pressure generated by the tension of the abdominal muscles. If there is a defect in the development of the dorsal gastric mesentery during the embryonic period, causing the spleen pedicle to become longer, and the aforementioned ligaments to develop abnormally and become loose, the supporting ability is greatly weakened, causing the spleen to displace within the abdominal cavity. Secondary factors such as the elongation of the ligaments due to large spleen, abdominal trauma, or endocrine changes in the abdominal wall muscles during pregnancy in women, as well as postpartum muscle weakness in multiparous women, are all predisposing factors for wandering spleen.

　　2、Wandering spleenPathophysiology

　　The wandering spleen is larger than the normal spleen, which may be due to pre-existing spleen diseases (such as chronic malaria) or the result of torsion and congestion of the spleen pedicle due to prolapse. The wandering spleen often has a large degree of mobility in the early stage, but can become more fixed due to adhesions with surrounding tissues in the late stage. About 20% of wandering spleens can lead to torsion of the spleen pedicle, and the causes of torsion are various. The superior pole of the spleen is larger, and when it moves downward, it is prone to tilt towards the midline, often the beginning of torsion; while the contraction of the abdominal muscles, the peristalsis of the intestinal loops, changes in body position, and external force can all be factors contributing to torsion. The speed and degree of torsion can vary greatly, and the resulting lesions are also diverse: mild torsion or those with only half a circle (180°) torsion often result in congestion and enlargement of the spleen, with more severe cases possibly leading to effusion and hemorrhage; torsion to 2-3 circles can cause complete obstruction of blood supply to the spleen pedicle, leading to complete necrosis of the spleen. The surrounding tissues can also become inflamed due to the stimulation of exudate, leading to localized or diffuse peritonitis, or form chronic perisplenitic adhesions. If only arterial obstruction occurs, it can cause atrophy and fibrosis of the spleen.

　　Wandering spleen can cause varicose veins of the gastric fundus when it is accompanied by chronic splenic torsion and splenic vein congestion. Intermittent torsion can lead to splenic congestion, followed by splenic enlargement, splenic hyperfunction, and various complications such as acute intraperitoneal hemorrhage, acute peritonitis, local abscesses, etc., when the spleen develops effusion, hemorrhage, necrosis, or infection. Wandering spleen can also cause splenic rupture due to trauma or increased intra-abdominal pressure during pregnancy. Some cases may be accompanied by other visceral prolapse.

　　The symptoms of wandering spleen can vary greatly due to different pathological changes, but they mainly depend on whether there is torsion of the spleen pedicle and the degree of torsion. Patients may not have obvious symptoms, or they may experience symptoms such as traction of adjacent organs or compression of surrounding organs where the prolapse occurs. If the wandering spleen itself twists, it can produce different manifestations.

　　When there is no adhesion around the spleen and the spleen has a large degree of mobility, patients may not have obvious symptoms, but they may detect a movable mass in the abdomen. In severe cases, there may be discomfort or pain in the upper left abdomen, which disappears when lying down and worsens when standing. The symptoms of traction mainly involve the stomach, which may include nausea, vomiting, bloating, and belching. The symptoms of compression vary depending on the affected organs: compression of the intestines can cause acute or chronic mechanical obstruction symptoms; compression of the pelvic cavity can cause urgency, poor defecation, or constipation; compression of the bladder or uterus can cause difficulties in urination or menstrual irregularities.

　　The speed and degree of splenic pedicle torsion have a significant impact on symptoms: acute torsion often occurs due to sudden changes in body position, trauma, late pregnancy, etc., which can cause severe abdominal pain accompanied by nausea, vomiting, and other gastrointestinal symptoms, and even lead to shock. However, chronic incomplete torsion may not have any自觉 symptoms, or only mild abdominal pain.

　　The wandering spleen is mainly caused by an elongated and relaxed spleen pedicle. Active treatment of primary diseases such as malaria is required to prevent secondary lesions. Enlarged spleen can also lead to this disease, so it is necessary to develop good living habits to prevent spleen lesions and trigger the disease. In addition, early treatment should be sought for injuries that cause damage to the spleen and spleen pedicle, to prevent long-term delayed healing and the occurrence of concurrent lesions leading to wandering spleen.

　　Before the wandering spleen is asymptomatic, it is often an accidental discovery during physical examination or imaging examination, or because of abdominal mass. When prolapsed, a mass similar to the spleen with a notch can be palpated in other parts of the abdomen, and the dullness area of the normal spleen location disappears, while the mass can return to the spleen fossa when the patient lies flat. Most patients seek medical attention because the prolapsed spleen has twisted, the peritoneum is stimulated by the exudate, and the abdominal muscles are in a rigid state, making it difficult to palpate the shape of the spleen, and the diagnosis is more difficult.

Auxiliary Examination:

　　1. B-ultrasound:The normal spleen under the left diaphragm disappears, and a splenic reflection appears at the abdominal mass.

　　2. Radioisotope scanning:For example, 51Cr labeled examination can detect the accumulation of isotopes in the abdominal mass, and a clear outline of the abdominal mass can be seen.

　　3. Selective abdominal aortic angiography:The blood supply of the mass can be seen to come from the splenic artery.

　　4. CT scan.

　　Patients with wandering spleen should eat light foods first, such as celery, chive, leek, winter melon, black plum, persimmon cake, sesame, lotus seeds, and sea cucumber; avoid spicy foods; and pay attention to eating small meals frequently.

　　After the diagnosis of wandering spleen is clear, different treatments can be given according to different situations. Patients with no symptoms should be informed of the possibility of pedicle torsion and splenic infarction, and an attempt should be made to manually reduce the dislocation. After the displaced spleen is returned to the left upper abdominal splenic fossa, it should be externally fixed with a little pressure from an abdominal band. This method can be temporarily effective for people with a thin body type, but it is prone to recurrence. The longer the spleen prolapses, the worse the effect. Abdominal bands cannot fix the abdomen in overweight individuals. For patients with mild symptoms, moderately large spleen, and not severe splenic dysfunction or slow progression, in order to preserve a normally functioning spleen as much as possible, splenic fixation surgery can be attempted. This means that during the operation, the spleen should be stripped as much as possible from the site of discovery, and it should be relocated to the left upper abdominal splenic fossa or other sites on the left side of the abdomen without affecting the blood supply of the splenic pedicle. The nearby tissues should be used for suturing and fixation. There is no long-term follow-up report on the efficacy of this method, and it is worth further discussion. Women of childbearing age should actively undergo splenectomy to prevent the enlargement of the uterus from causing splenic rupture or increasing the risk of splenic pedicle torsion. Wandering spleen in the pelvic area should also be removed to reduce the possibility of complications. All patients with acute splenic pedicle torsion should undergo splenectomy.