Notes by dr Claudio Italiano
The mediastinum is a space located inside the rib cage, which is laterally limited by the lungs, anteriorly by the sternum and posteriorly by the vertebral column, containing various anatomical structures such as the heart, the esophagus, the trachea and numerous lymph nodes. If an expansive process affects this structure, it is called "mediastinal syndrome", that is a series of signs that are a function of the compression of the endomediastinal formations, with impaired respiratory functions and discharge of the venous circulation. This happens, for example, in the case of lung cancer and especially in the apical lesions, in fact, where the compression of the recurrent laryngeal nerve causes dysphonia or we also remember the pain in the shoulder and arm and the Ciuffini Pancoast syndrome
Chest X-ray: thymoma
It may depend on vascular causes, that is to say, the picture of the circulatory mediastinal syndrome or neoplastic causes, that is due to masses occupying space in the mediastinum, where there is little space, so the organs involved, if compressed ab extrinseco, they face deficiencies in their function, e.g. if it is nerves, specific syndromes are established. The vascular causes include the syndrome of the superior vena cava, so the compression of this vessel, since the cephalic portion of the body can not be discharged, causes mantle edema and intracranial hypertension.
However, it is possible to establish collateral circles depending on whether the stop is above or below the outlet of the azigos vein. In case it is under the outlet of azigos, for ex. for obstructive pericardial conditions or aneurysms of the aorta the blood always discharges with the azygos veins but with current inversion, through a discharge towards the back, towards the lumbar veins. If the stop is right at the level of the vein of the azigos vein, the discharge provides voluminous collateral circulation through the thoracic veins.
Even in the case of stop at brachiocephalic vein the picture is similar to that of the caval syndrome, so the discharge is possible through collateral veins of the vertebral plexus, so where there is a route of discharge, this is used for the circle. In the compression of the thoracic duct it is possible to have a lack of discharge of the kilo and a pleural effusion. In the case of dangerous compression on the respiratory tract, stenosis of the trachea and of the bronchi may occur with the phenomenon of tirage and cornage and irritative cough.
Adenopathy: Hodgkin's lymphoma, non-Hodgkin's lymphoma, sarcoidosis
Endothoracic goiter
Thymus tumors: thymoma, thymic carcinoma, lymphoma, thymolipoma
Embryonary tumors: embryonic carcinoma, teratoma, malformative cysts
Nervous tumors: neurinoma, ganglioneuroma, neuroblastoma,
phaeochromocytoma
Vascular tumors: lymphangiomas, hemangiomas
Connective tumors: fibroma, fibrosarcoma, lipoma, liposarcoma
False tumors: aneurysms, hematomas and organized abscesses,
meningoceles, parasitic cysts
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Upper anterior mediastinum |
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In case of compression of the trachea and / or of
the main bronchi, cough and dyspnea are interrupted. Compression of the
esophagus, on the other hand, causes difficulty in swallowing solid or liquid
foods (known as dysphagia), whereas the involvement of the nerve structures is
responsible for pain or changes in the tone of the voice, which may become raspy
or typically nasal and of dysphonia. For example, a patient of mine, a great
smoker for reasons of work stress, had accused hemoptysis and dysphonia. Seen
from the tongue, he had advised (sic!) Therapy with cortisone and vitamin B12,
thinking about a laryngitis. Instead, the patient had a vocal cord paralysis for
a compressive apical tumor syndrome (Ciuffini-Pancoast syndrome). Having been
the patient visited in Milan in a well-known private cancer center, the thoracic
oncology surgeon, being still a fresh graduate doctor, had planned the hourglass
to mark the time of the visit: about 5 minutes. At the end of the hourglass, the
primary had shaken hands and made wishes. On leaving the study, the visit had
been measured by an hourglass stroke: 250,000 old lire!
The most common clinical presentation of the Mediastinal Syndrome is the
Syndrome of the Upper Vena Cava, so defined because it derives from the
compression exerted by the space occupying lesion at the mediastinal level on
the superior vena cava, one of the main veins of the organism directed to the
heart. This syndrome is characterized by the appearance of edema with a "cape"
appearance, that is confined to the upper part of the thorax, to the neck and to
the face as a sort of mantle that surrounds these bodily regions.
It is often associated with the appearance of jugular turgor (congestion of the large neck
veins that appear frankly dilated) and superficial venous circles of reticular
appearance confined to the hips or in the same site of the edema. Only in the
most severe forms is the impairment of the cardiac activity with loss of the
normal rhythm of the heartbeat and of the heart pump function. It is then said
that the heart "disappears" because it is no longer able to provide the body
with enough blood to meet its needs. In case of compressions of mediastinal
nerve structures can have the:
- Compression of sympathetic plexus: S. by Claude Bernard Horner with palpebral
ptosis, miosis, enophthalmos
- Compression of n. frenico: paralysis of the ipsilateral hemidiaphragm
- Compression of n. vague and / or of the n. recurrent: paralysis of the
homolateral vocal cord which causes dysphonia
Compressive phenomena are easier to appear for expansive processes at the
level of the upper strait of the mediastinum, given the characteristics of the
region; in other places it is often observed that mediastinal masses can reach
large dimensions without causing compression phenomena, as structures can escape
this effect, thanks to the laxity and elasticity of the mediastinal cell.
Compressive and englobing phenomena, however, appear early when they arise:
- Cellulite processes, ie, adhesive phenomena affecting the lax cellular tissue
that acts as a scaffold to the mediastinum, since fixing the intra-mediastinal
formations facilitates compression and irritation:
- infiltrative processes, for me more than neoplastic.
-flageable inflammatory processes such as:
a) esophageal perforation
b) bronchial perforation
c) spread of infections contiguous to the mediastinum or by blood
a) granulomatous forms such as tuberculosis, histoplasmosis, nocardiosis
b) fibrotic forms, infectious granulomatous processes
Thus, a sclerotic hardening of the mediastinal tissues that surround the right
margin of the heart (pericardial accretio) causes functional disturbances of the
venous circle, which may be more or less showy depending on its extent and
extent. For the tumor processes the rule is generally valid that a small mass
that causes compressive phenomena and generally of a malignant nature, instead
if a large mass is found when the phenomena of compression arise. This is mostly
benign in nature. In truth, we can witness the appearance of a whole
phenomenology of various clinical manifestations (oligo-pauci or
plurisintomatica), depending on the nature and the mediastinal affection.
Approximately 90% of cases of Mediastinal Syndrome can be attributed to tumors,
starting from bronchopulmonary in 75-80% of cases. Among the histotypes of lung
cancer, the one most often responsible for Mediastinal Syndrome is small cell
lung cancer (see lung cancer). Other causes include lymphomas (malignant
hematologic malignancies) and other malignancies of non-pulmonary origin (eg
thyroid or thymus).
It uses the simplest techniques such as the standard chest radiograph that can
document a mediastinal flare. Thus also the chest CT can provide further
information as well as Magnetic Resonance. However, it is still the biopsy
performed by means of mediastinoscopy and the transparietal fibroscopy and
needle biopsy which give more information. In order to arrive at an
histocytological diagnosis, ie by studying the cell types we go back to the
basic lesion. This therapy involves the use of anti-edema drugs, which is able
to reduce edema and with it the degree of compression on the organs of the
mediastinum. The most commonly used drugs, administered orally or intravenously
over a period of a few weeks, are high-dose steroids (prednisone or
dexamethasone) associated with osmotic drugs (mannitol e.v. at 18%) and
diuretics (furosemide).
pneumology index