1. Department of Medicine Manipal College of Medical Sciences
MEDIASTINAL DISEASES
ALOK SINHA
Department of Medicine
Manipal College of Medical Sciences
Pokhara, Nepal

2. What is mediastinum ?
Mediastinum is the space in the middle of the chest between the two pleurae
Extends from the sternum to the spine
Contains
ALL the viscera in the thorax except the lungs

3. Divisions of Mediastinum
Posterior
Superior
Anterior
Middle

4. Subdivision of mediastinum as seen on cross section .
Subdivision of mediastinum as seen on cross section
anterior mediastinum (1)
middle mediastinum (2)
posterior mediastinum (3)

6. Superior mediastinum Boundary
Inferiorly: by the transverse thoracic plane – oblique plane passing posteriorly from sternal angle of Louis to the junction of the 4th and 5th thoracic vertebra
Superiorly: line from sternum
to T1
Laterally: by the pleurae

7. Contents Arteries Muscles AORTIC ARCH & its bracnches
Brachiocephalic artery
Thoracic portions of the left common carotid and the left subclavian veins
Innominate veins and
Upper half of the superior vena cava
Left highest intercostal vein
Muscles
origins of the Sternohyoid and Sternothyreoid

8. Nerves Trachea Esophagus Thoracic duct Remains of the thymus
phrenic nerve
left recurrent laryngeal nerve
vagus nerve
cardiac nerve
superficial and deep cardiac plexuses
Trachea
Esophagus
Thoracic duct
Remains of the thymus
Some lymph glands

9. Anterior mediastinum-in front of the heart
Bounded
in front by the sternum
behind by the pericardium
at the sides by the pleurae
It contains
remains of thymus gland
origins of the sterno-hyoid, sterno-thyroid, and the triangularis sterni muscles
internal mammary glands of the left side
lymphatic vessels, and loose areolar tissue

10. Middle Mediastinum: Contains Heart & pericardium Ascending aorta
Lower half superior vena cava with vena azygos opening into it
Bifurcation of trachea and two bronchi
Pulmonary arteries and veins
Phrenic nerves
Some lymphatic glands

11. Posterior Mediastinum:
Bounded
In front by pericardium and roots of lungs
Behind by vertebral column
At the sides by the pleurae
Contains
Descending aorta
Oesophagus
Azygos veins
Vagus
Splanchnic nerves
Thoracic duct
Some lymphatic glands

12. Mediastinal diseases 1. Mediastinitis 2. Pneumomediastinum
Infection or inflammation in the mediastinum
acute
Chronic
2. Pneumomediastinum
Air in the mediastinum

13. 3. Mediastinal mass Commonly caused by Tumor Cyst Vascular anomaly
Lymph nodes

14. SOME CAUSES OF A MEDIASTINAL MASS
Superior mediastinum
Retrosternal goitre
Thymic tumour
Dermoid cyst
Lymphoma
Aortic aneurysm
Anterior mediastinum
Pericardial cyst
Hiatus hernia through the diaphragmatic foramen of Morgagni

15. Posterior mediastinum
Neurogenic tumour
Paravertebral abscess
Oesophageal lesion
Aortic aneurysm
Foregut duplication
Middle mediastinum
Bronchial carcinoma
Lymphoma
Sarcoidosis
Bronchogenic cyst
Hiatus hernia

16. Trachea and main bronchi
SYMPTOMS AND SIGNS - MALIGNANT INVASION OF THE STRUCTURES OF THE MEDIASTINUM
Trachea and main bronchi
Stridor
Breathlessness
Cough
Pulmonary collapse
Oesophagus
Dysphagia
Phrenic nerve
Diaphragmatic paralysis
Left recurrent laryngeal nerve
Paralysis of left vocal cord giving rise to hoarseness and 'bovine' cough
Body_ID: B019082

17. Sympathetic trunk Superior vena cava Pericardium
Horner's syndrome
Ptosis
Meiosis
enopthalmos
anhydrosis
Superior vena cava
Non-pulsatile distension of neck veins
Subconjunctival oedema
Oedema and cyanosis of head, neck, hands & arms
Dilated anastomotic veins on chest wall
Pericardium
Pericarditis and/or pericardial effusion

20. Which one is “invasion” and which is “compression” ?

21. Benign tumours and cysts:
Frequently diagnosed on unrelated X ray of the chest
Do not invade vital structures
May cause symptoms by compressing
Trachea
Superior vena cava

22. Malignant mediastinal tumours: Can be due to
invade as well as compress bronchi & lungs
Can be due to
Mediastinal lymph node metastases
Lymphomas & leukaemia
Malignant thymic tumours
Aortic and innominate aneurysms
have destructive features resembling those of malignant mediastinal tumours

23. INVESTIGATIONS !

24. 1. Radiological examination
Benign mediastinal tumour
sharply circumscribed opacity situated mainly in mediastinum
often encroaching on one or both lung fields
Malignant mediastinal tumour
no clearly defined margin
general broadening of the mediastinal shadow
CT (or MRI) is the investigation of choice for mediastinal tumours

25. Liposarcoma

28. 2. Endoscopic investigation:
Bronchoscopy
may reveal a primary bronchial carcinoma causing mediastinal tumour by secondary lymphatic spread

29. Posterior mediastinum can be imaged by
3. Ultrasonography
Posterior mediastinum can be imaged by
Transoesophageal ultrasound
Needle biopsies of lymph node masses may be obtained under USG through endoscope

30. 4. Surgical exploration
1. Mediastinoscopy: tissue from enlarged lymph nodes in ant. mediastinum can be removed for histological examination
2. surgical exploration of the chest with removal of part or all of the tumour
often required to obtain a histological diagnosis

31. Management Benign mediastinal tumours removed surgically because
Most produce symptom sooner or later
Cysts may become infected
Neural tumours may undergo malignant transformation
Low operative mortality in absence of
Coexisting cardiovascular disease
COPD
Extreme age

32. MEDIASTINAL INFECTIONS

33. Acute Mediastinitis Most cases are due to: 1. Oesophageal perforation
spontaneously (Mallory weiss syndrome)
complication of esophagoscopy
Acutely ill with chest pain and dyspnea
Treatment is surgical
exploration of the mediastinum with primary repair of the esophageal tear and drainage of the pleural space and the mediastinum

34. 2. After median sternotomy for cardiac surgery
Presentations with
sepsis or
widened mediastinum
Treatment includes
immediate drainage & debridement
parenteral antibiotic therapy
mortality still exceeds 20%.

35. Chronic Mediastinitis
Ranges from
Granulomatous inflammation of lymph nodes to
Fibrosing mediastinitis
Due to TB
Histoplasmosis & other fungal infections
Sarcoidosis
Silicosis

36. Patients with fibrosing mediastinitis usually have compression of
superior vena cava
large airways
phrenic or recurrent laryngeal nerve paralysis
pulmonary artery or proximal pulmonary veins
Other than antituberculous therapy for tuberculous mediastinitis, no medical or surgical therapy has been demonstrated to be effective for mediastinal fibrosis

37. Pneumomediastinum

38. Gas in the interstices of the mediastinum Causes are:
(1) alveolar rupture with dissection of air into the mediastinum
(2) perforation or rupture of the esophagus, trachea, or main bronchi
(3) dissection of air from the neck or the abdomen into the mediastinum

39. Excessive coughing
Repeated bearing down to increase abdominal pressure (such as pushing during childbirth or a bowel movement)
Sneezing
Vomiting
Rapid rises in altitude, SCUBA diving
Tearing of the esophagus
Tracheal tear
Use of vevtilator
Using inhaled recreational drugs such as crack cocaine

40. Symptom Severe substernal chest pain
With radiation into the neck and arms
Pain may worsen on breathing or swallowing
With which disease it is likely to be confused ?

41. Physical examination reveals
Subcutaneous emphysema in suprasternal notch
small bubbles of air is felt under the skin of the chest, arms, or neck
Hamman's sign (crunching or clicking noise synchronous with the heartbeat and best heard in the left lateral decubitus position)
Diagnosis is confirmed with chest X ray

42. Pneumomediastinum

44. A previously healthy 18 year old male had chest pain of sudden onset.
Heart sounds were normal but crunching and clicking sounds were heard over the left sternal border
An ECG was normal

48. Usually no treatment is required
Mediastinal air will be absorbed faster if the patient inspires high concentrations of oxygen
Compression can be relieved with needle aspiration
Surgery for tracheal or esophageal tear