Dr. Ibrahim Salah El-Deen M.D Mediastinal syndrome By Dr. Ibrahim Salah El-Deen M.D Lecture of Chest Diseases Tanta University

Anatomy of the Mediastinum The mediastinum occupies the middle part of the thoracic cavity it is limited anteriorly by the sternum , posteriorly by the vertebral colum Anterior , Laterally by the pleural reflections and inferiorly by the diaphragm . It is continuous with the neck from above through the supra-sternal notch . It is divided by the heart into :- 1- Superior medisatinum : above the heart . 2- Anterior medisatinum : in front of the heart . 3- Posterior medisatinum: behind the heart .

The Anterior Mediastinum exists only on the left side where the left pleura diverges from the mid-sternal line. It is bounded in front by the sternum, laterally by the pleuræ, and behind by the pericardium. It is narrow, above, but widens out a little below. Its anterior wall is formed by the left Transversus thoracis and the fifth, sixth, and seventh left costal cartilages. It contains a quantity of loose areolar tissue, some lymphatic vessels which ascend from the convex surface of the liver, two or three anterior mediastinal lymph glands, and the small mediastinal branches of the internal mammary artery.

The Middle Mediastinum is the broadest part of the interpleural space The Middle Mediastinum is the broadest part of the interpleural space. It contains the heart enclosed in the pericardium, the ascending aorta, the lower half of the superior vena cava with the azygos vein opening into it, the bifurcation of the trachea and the two bronchi, the pulmonary artery dividing into its two branches, the right and left pulmonary veins, the phrenic nerves, and some bronchial lymph glands.

The Posterior Mediastinum is an irregular triangular space running parallel with the vertebral column; it is bounded in front by the pericardium above, and by the posterior surface of the diaphragm below, behind by the vertebral column from the lower border of the fourth to the twelfth thoracic vertebra, and on either side by the mediastinal pleura. It contains the thoracic part of the descending aorta, the azygos and the two hemiazygos veins, the vagus and splanchnic nerves, the esophagus, the thoracic duct, and some lymph glands.

Mediastinal syndrome: involvement of the mediastinal structures in a pathological process may lead to the mediastinal syndrome Causes : I- inflammatory causes : e.g . Chronic mediastinitis . II- Mediastinal tumors are classified according to their sites of predilection into 1- Anterior mediastinal tumours , which lie in front of the trachea . They lie in : a) Superior mediastinum : e.g . A- Retro sternal thyroid B- thymus C- Dermoid cyst and teratiod tumours

b) Inferior by : e.g. Pericardial cysts : in the right pericardiophrenic angle . 2- Poseterior mediastinal tumours , lying behind the esophagus and heart : e.g . A- Neurogenic tumours e. g. neurofibroma . B- Meningeal tumours e.g . meningioma , protruding in the thoracic cavity . C- Enterogenous cyst which is a congenital anomaly related to the gut . 3- Hilar tumours , which are mostly related to the lymph nodes

III – Vascular Lesion : e.g. aneurysm : The symptoms are more manifest in the aneurysm of the descending aorta and the sings are more manifest in that of the ascending aorta . Manifestations of the Mediastinal Syndrome . The manifestation depend on the causative lesion and its site : 1- involvement of trachea : a) inspiratory stridor b) Brassy cough

b) Atelectasis , if the obstruction is complete and continuous . 2- Pressure on the bronchi leads to : a) Obstructive emphysema , if the obstruction is incomplete and intermittent . b) Atelectasis , if the obstruction is complete and continuous . 3- involvement of oesophagus : a) Dysphagia b) Regurgitation 4- Pressure on the arteries : a) Inequality of the pulse of the upper limbs . b) Ischemic manifestations e.g. pallor and pain and syncope

b) Dilated veins on the chest wall . 5- Obstruction of the veins : a) Venous congestion in the head and neck , and limbs . The congested neck veins are characteriticaly nonpulsating . b) Dilated veins on the chest wall . c) Odema and hydrothorax . d) Local cyanosis . 6 – involvement of the nerves : a) Sympathetic Hornre's syndrome : i – Ptosis ii – Miosis iii- Enophthalmos iv – Unilateral anhydrosis. b) Vagus nerve leading to : i- Cardiac arrhythmias : supraventricular in type . ii – Dyspeptic manifestation

i- Hoareseness of the voice . c) Recurrent laryngeal nerve , is affected only in left side lesions and will lead to : i- Hoareseness of the voice . ii- Abduction paralysis of the vocal cords . iii- Later adduction paralysis as well . d) phrenic nerve may lead to a raised paradoxical diaphragm on one side

Differential Diagnosis I- Mediastinal tumours should be differentiated from each other depending on : 1- The site of the lesion , and its nature . 2- The type of patient . In this respect a lateral X-ray for the chest is very helpful to differentiate anterior , posterior and hilar lesions . Other investigation may be of help e.g . biopsy . Sometimes , the differentiation cannot be made except after thoracotomy . II – Superior Venacaval thrombosis : The manifestation here are mainly due to venous obstruction , Involvement of other structure is lacking except if it is due to extra –vascular compression .

III- Pericardial Effusion : The presence of : 1- An impalpable apex . 2- Dullness outside the apex beat 3- Distant heart sounds 4- Cardiac tamponade 5- Paradoxical pulse . The X-ray is Characteristic and aspiration is diagnostic . IV- Other causes of thoracic inlet syndrome , are to be differentiated from cases of superior mediastinal tumour . a)Gervical rib b)Gervical spondylosis c)Pancoast tumour .

These are easily differentiated because of the presence of manifestation of the original cause . It may be due to intra-mural or mural obstruction e.g. Gancer oesophagus Neurogenic disturbances e.g achalasia are easily differentiated by the use of barium swallow and oesophagoscopy VI- Paralysis of the Nerves : from extra-thoracic , cervical causes e.g. recurrent larygneal . Sympathetic, and phrenic , Is easly differentiated by the presence of the original cause

Investigations for a case of mediastinal syndrome 1- X-ray for the chest Postero-anterior and lateral views are needed to show the tumour and its localization and possible esqulae . CT scan thorax is essential . MRI is recently applied II – Radioscopy (Fluroscope) :- a- To see whether the shadow is pulsatile or not , e.g . An aortic aneurysm , shows pulsations . b- To asses the position and movements of the diaphragm .

III- Barium Swallow : if there its dysphagia . IV- Bronchoscopy, unless aortic aneurysm is suspected then it is contraindicated . V- Blood picture VI- Sternal puncture , in glandular causes . VII- Redio-active iodine uptake in thyroid swellings . VIII- Biopsy e.g. scalene node , or after mediastinoscopy or even thoracotomy .

Management 1- Treatment is essentially directed to the offending cause . 2- A thoracotomy may be resorted to : At thoracotomy the nature of the cause can be assessed and surgical removal can be made , if indicated . 3- Radiotherapy may be resorted to , in the radiosensitive group of tumoues e.g. lymphosarcoma

Mediastinoscopy/Thoracotomy Gold standard Allows direct visualization of LN, mass in anterior and superior mediastinum, including right paratracheal, left paratracheal to level of aortic arch Provides larger specimens for histologic examination Subcarinal and AP lesions require second intercostal space approach

Anterior Mediastinum Thymic neoplasms Germ Cell tumors Lymphoma Thyroid neoplasms Parathyroid neoplasms Mesenchymal tumors (lipoma, fibroma, hemangioma, lymphangioma) Primary carcinoma Angiofollicular lymphoid hyperplasia (Castleman’s)

Thymoma Most common primary tumor of the anterior mediastinum Up to half suffer from MG, hypogammaglobulinemia, or pure red cell aplasia Only 15% of patient with MG have a thymoma- always check Ach receptor antibody levels in diagnosed thymomas

Thymoma Epithelial neoplasms Most are surrounded by fibrous capsule, but may invade vital structures Metastasis is rare Can seed the pleural space but effusion is rare Goal is complete resection, with XRT for incompletely excised tumors and consideration of cisplatin based chemoTx

Thymic Carcinoma with local invasion and mets Frequently associated with pleural and pericardial effusions Cisplatin with etoposide and concurrent XRT 3-yr survival 40 Most commonly SCC (differentiate from lung primary) Aggressive %, 5-year 33%

Germ Cell Tumors Teratomas Seminomas Nonseminomas

Teratomas Most common mediastinal germ cell tumor Consist of tissues from more than one of three germ cell layers : Ectoderm: teeth, skin, hair Mesoderm: cartilage and bone Endoderm: bronchial, intestinal, pancreatic Rarely malignant (“teratocarcinoma”)

Most common in children and young adults Commonly asymptomatic but expectoration of hair or sebum is pathognomonic of ruptured teratoma Surgical excision

Seminoma White men in third-fourth decades 10% have elevated β-HCG, not AFP Highly sensitive to XRT and chemo Therapy is curative in most patients with survival rates of 60-80%

Nonseminomas Comprised of embryonal cell carcinoma, endodermal sinus tumor, choriocarcinoma or mixed germ cell tumors AFP and HCG levels frequently elevated Metastasize to regional LN, pleura, pericardium and distant sites Chemo with bleomycin, etoposide and cisplatin, followed by surgical excision of residual tumor 2-year survival= 67%, 5-year= 60%

Anterior Mediastinum Lymphomas Thyroid neoplasms and GOITERS (consider airway compromise) Mesenchymal tumors- Lipoma most common, mediastinal lipomatosis- generalized obesity, Cushing’s, steroids

Middle Mediastinum Lymphomas Developmental cysts LN metastases Vascular abnormalities

Foregut Cysts 20% of primary mediastinal masses Bronchogenic cysts represent 50-60%, remainder are esophageal duplication or neurenteric cysts, and pericardial Result from aberrant development of the primitive foregut with abnormal budding

Bronchogenic Cysts Bronchogenic cysts arise close to the trachea, main bronchi and carina Many are discovered incidentally and are asymptomatic Some communicate with bronchial tree and develop recurrent infections, requiring resection

Pericardial Cysts Lie against pericardium, diaphragm, or anterior chest wall Usually asymptomatic, but may enlarge to cause RV outflow obstruction, or rupture with tamponade

Enteric (Enterogenous) Similar in location and appearance to bronchogenic, but have digestive tract epithelium Commonly associated with malformations of vertebral column (neurenteric) Most cysts of all types should be resected because of potential for development of complications

Posterior Mediastinum Neoplasms arising from nerve sheath-Neurofibromas, Neurosarcomas Neoplasms arising from sympathetic ganglia (Neuroblastoma, ganglioneuroma, ganglioneuroblastoma)- children Neoplasms arising from paraganglionic tissue- (pheochromocytoma, paraganglioma)

Neurofibromas/Schwannomas Most common mediastinal neurogenic tumor Benign and slow growing Neurofibromas are homogeneous, non-encapsulated Schwannomas are heterogeneous with cystic degeneration and are encapsulated

Occur in the third-fourth decades of life Frequently asymptomatic, but can cause parasthesias or pain from nerve or spinal cord compression 30-45% of neurofibromas occur as part of neurofibromatosis (malignant transformation) 10% become “dumbbell” lesions extending into the spinal canal

Neurofibroma

Mediastinitis Mediastinitis is inflammation of the tissues in the mid-chest, or mediastinum. It can be either acute or chronic. Acute mediastinitis is usually bacterial and due to rupture of organs in the mediastinum. As the infection can progress rapidly, this is considered a serious condition. Chronic sclerosing (or fibrosing) mediastinitis, while potentially serious, is caused by a long-standing inflammation of the mediastinum, leading to growth of acellular collagen and fibrous tissue within the chest and around the central vessels and airways. It has a different cause, treatment, and prognosis than acute infectious mediastinitis.

Causes and treatment Acute Before the development of modern cardiovascular surgery, cases of acute mediastinitis usually arose from either perforation of the esophagus or from contiguous spread of odontogenic or retropharyngeal infections. However, in modern practice, most cases of acute mediastinitis result from complications of cardiovascular or endoscopic surgical procedures. Treatment usually involves aggressive intravenous antibiotic therapy and hydration. If discrete fluid collections (such as abscesses) have formed, they may have to be surgically drained.

Chronic Chronic medistinitis is usually a radiologic diagnosis manifested by diffuse fibrosis of the soft tissues of the mediastinum. This is sometimes the consequence of prior granulomatous disease, most commonly histoplasmosis. Other identifiable causes include tuberculosis and radiation therapy. Fibrosing mediastinitis most frequently causes problems by constricting blood vessels or airways in the mediastinum. This may result in such complications as superior vena cava syndrome or pulmonary edema from compression of pulmonary veins. Treatment for chronic fibrosing mediastinitis is somewhat controversial, and may include steroids or surgical decompression of affected vessels.