Overview: Diaphragmatic bulge is an abnormal elevation in the position of the diaphragm caused by the weakness of the diaphragm due to incomplete muscularization, non-muscularization or atrophy of the thoraco-peritoneum caused by paralysis, hypoplasia or atrophy of the diaphragm. Etiologically, there are two major categories: (1) congenital or non-paralytic; and (2) acquired or paralytic. Congenital diaphragmatic bulges can also be divided into 3 categories: complete, partial, and bilateral, depending on the degree. Epidemiology: Diaphragmatic bulges can be found in all age groups, but routine fluoroscopic findings in adults account for about 1/10,000, and can be partial or total, with the left side being more common. Etiology: congenital diaphragmatic bulge is just a dysplasia of the diaphragmatic fibers, which is thin and weak, and in severe cases it looks like a semipermeable membrane, with no lesion of the phrenic nerve. Acquired diaphragmatic bulge is caused by injury or lesion of the phrenic nerve. In infants, birth injuries, injuries during surgery for congenital heart disease or mediastinal tumors are the most common causes; in adults, invasion by malignant tumors (e.g., lung cancer, thymoma, malignant germ cell tumors, non-Hodgkin’s disease), the effect of ice shavings cooling the surface of the heart during direct cardiac surgery, surgical injuries (e.g., mediastinotomy, resection of intrathoracic or cervical masses, subclavian or jugular vein catheter and electrode placement) and High cervical spinal cord trauma can cause phrenic nerve palsy and diaphragmatic bulge. Idiopathic phrenic nerve palsy and diaphragmatic bulge in adults may be the result of subclinical viral infection. Pathogenesis: Congenital hypoplasia of the muscle fibers of the diaphragm or injury to the phrenic nerve at birth causes paralysis of the diaphragm and atrophy of the muscle fibers, resulting in a membrane shape of one lobe of the diaphragm and a significant elevation of the top of the diaphragm. This condition is called diaphragmatic bulge. In most cases, diaphragmatic bulge occurs on one side only. It is more common in adults in the left lobe and in infants and children in the right lobe. The clinical symptoms of diaphragmatic bulge vary in severity. In infants and children, the elevated position of the diaphragm, the atrophy of the lower lobe of the lung and the elevated position of the intra-abdominal organs can cause acute respiratory distress and feeding difficulties. Clinical manifestations: Bilateral diaphragmatic bulges are rare and are mostly seen on the left side, while partial diaphragmatic bulges are mostly seen on the right side. The symptoms of diaphragmatic bulge are different in adults and children. In adults, the symptoms of diaphragmatic bulge tend to be dysphagia, epigastric pulling sensation or epigastric distension, epigastric burning sensation and belching. Gastrointestinal symptoms are worse when lying down, or after a full stomach, and can be relieved when changing to a lateral position. Respiratory symptoms include dyspnea, shortness of breath, coughing, and wheezing during activity. Some children may have chest pain and intestinal symptoms, such as poor appetite or intermittent intestinal obstruction. In severe cases, the mediastinum may be displaced to the opposite side, and when the diaphragm is fully expanded and elevated, there may be hyperextension of the lower chest on the affected side during deep inspiration, which is called Horner’s sign. The abdomen is flattened and the liver and spleen are often not easily palpable. Complications: complications of bronchitis and pulmonary infections. Laboratory tests: Blood leukocytes may be increased in case of pulmonary infection. Other ancillary tests: on a standard chest radiograph, the diaphragm is abnormally elevated on the side of the lesion, and sometimes a basal segment of atelectasis is seen. On fluoroscopy, the patient is made to perform a sudden inspiratory maneuver, and the paradoxical movement of the diaphragm on the side of the lesion can be clearly seen, especially in the case of acquired diaphragmatic bulge. Diagnosis: According to clinical manifestations, auxiliary examinations such as X-ray examination can show elevation of the affected side of the diaphragm, which can rise to the height of the third and fourth anterior intercostal space, with the diaphragm immediately below the gastric vesicle and a marked thinning of the diaphragm thickness, and chest X-ray can show restricted or absent diaphragmatic activity on the affected side, sometimes with paradoxical movements, especially in cases of acquired diaphragmatic bulge. Differential diagnosis: 1. Diaphragmatic hernia is formed by congenital or acquired causes of intra-abdominal organs entering the thoracic cavity through the diaphragmatic defect. A localized elevation of the diaphragm can also be seen on chest radiography, but the elevated part of the diaphragm can be seen as a cavity of the gastric sac or intestinal cavity, and a pneumoperitoneum technique can be used to examine the patient in the upright position with gas rising into the thoracic cavity, i.e., in the hernia sac on the diaphragm, while a diaphragmatic bulge can be seen with gas under the diaphragm. 2. Fundic fluid Patients with fundic fluid are often seen to have an “elevated diaphragm” on x-ray, which can usually be distinguished after changing position on chest X-ray or ultrasound. 3.Diaphragmatic tumor is very rare, mostly without specific symptoms, but X-ray examination shows smooth round or oval dense shadow on top of the diaphragm, which can move up and down with the movement of diaphragm, its shape and size do not change with breathing, and diagnostic pneumoperitoneum helps to diagnose. Treatment: Asymptomatic individuals do not require any treatment. Symptomatic patients can be treated symptomatically. If severe gastrointestinal symptoms are caused by gastric torsion, surgical treatment is feasible; in elderly patients with repeated combined respiratory symptoms and compromised lung function, surgery can be considered to unite the weak diaphragm with partial overlap; in neonates and infants with severe respiratory distress due to diaphragmatic bulge, emergency surgery should also be performed. Prognosis: The prognosis for satisfactory surgical treatment is good.