Other
thoracic disorders
The
lungs
Lung
cysts
Developmental. These may develop from the primitive lung buds near the
trachea or main bronchi. There are no communications with the bronchi even
though they are lined with respiratory epithelium and have a tendency to become
infected. Removal is advised for this very reason.
Acquired.
Lung cysts may contain air or fluid and may be single or multiple. The most
common cause of multiple lung cysts is pulmonary hydatid disease, although this
is unusual except in endemic areas. Air cysts (bullae) may be spontaneous but
may be secondary to emphysematous degeneration (Fig.
47.31). In either case the
cysts may become infected or compress functioning lung tissue and therefore some
form of treatment is required.
Pulmonary
sequestration
This describes a section of lung supplied by the aorta and draining into
the systemic circulation. There is no communication with the remainder of the
lung and the segment becomes multicystic and infected, therefore compromising
the surrounding healthy lung tissue. An interlobar sequestration occurs within
the lung substance and commonly presents in younger patients.
Many
cases are discovered on routine chest radiography but others may present with
recurrent chest infections and
Bronchiectasis
This is defined as chronic irreversible dilatation of the medium-sized
bronchi. There are several causes but there are two basic mechanisms that
account for this dilatation:
1. a weakening of the bronchial walls;
2. outward tension on the lung substance.
These
may occur following a suppurative pneumonia or bronchial obstruction. The
process often starts in childhood following a respiratory infection and slowly
progresses during adult life. It is rarely confined to one lobe or even one
lung, which precludes surgery in many cases. The incidence of severe
bronchiectasis is falling thanks to the reduction in cases of whooping cough,
measles and tuberculosis, and the improved management of infantile bronchiolitis.
Inhalation of foreign bodies remains a potential cause of bronchiectasis and
this possibility should be borne in mind.
Presentation.
Some patients remain asymptomatic and the problem is discovered by chance on
chest radiograph or postmortem. Usually there is a history of frequent
chest infections from infancy with the production of copious volumes of sputum.
In advanced cases foul-smelling sputum is produced with pain over the affected
area, and there is weight loss and cachexia. Physical examination may be normal
but often there is finger clubbing (in advanced disease), wheezing and
consolidation over the affected lobe. Chronic nasal sinusitis may be a
presentation and, in severe cases, amyloidosis may occur.
Investigation.
A good posteroanterior chest radiograph will often show crowding of the lung
markings on the
Bronchography.
This is rarely necessary to define
which lobe(s) are affected; most surgeons would be satisfied with a CT scan.
This investigation may need to be preceded by intensive physiotherapy and
postural drainage to obtain adequate images.
Treatment.
Removal of the bronchiectatic part of the lung is indicated when the disease is
localised, and the respiratory function is adequate to cope, with a reduced lung
volume. Conservative surgery to preserve functioning lung tissue should be
employed at all times.
Tuberculosis
This infection remains a major health problem in less developed
countries but is increasing in frequency in Western countries as a result of
immigration and immunosuppression [human immunodeficiency virus (HIV) and
chemotherapy]. It commonly presents in the lungs and, if untreated or
inadequately treated, can lead to serious complications. There is commonly a
chronic cough with haemoptysis, weight loss and night sweats. The diagnosis
should be firmly established by Ziehl—Neelsen staining of bacteria in the
sputum or culture in Lowenstein—Jensen medium before starring antituberculous
chemotherapy. Characteristic chest radiographic changes in symptomatic patients
may be diagnostic if cultures are persistently negative; as a very last resort
chemotherapy may be tried for 2 weeks. An improvement in symptoms indicates that
tuberculosis is the problem.
The
mainstay of treatment is antituberculous chemotherapy for the individual and
bacille Calmette—Guérin (BCG) immunisation for contacts, attention to hygiene
and housing in the community. Combination chemotherapy is usually successful
in treating the infection. Inadequate treatment or noncompliance leads to the
development of resistant organisms. The course of treatment is often over 6
months and in some less developed countries this can result in noncompliance.
Surgery is rarely indicated for tuberculosis in developed countries but, when it
is, it must be combined with adequate antitubercular chemotherapy or the benefit
of surgery will be lost.
Indications
for surgery. Indications are:
• suspicious lesion on chest radiograph in which neoplasia cannot
be excluded;
• chronic tuberculous abscess, resistant to chemotherapy;
• aspergilloma within a tuberculous cavity;
• life-threatening haemoptysis.
Surgery
is indicated for certain situations and is always used in conjunction with
chemotherapy. With effective treatment and earlier diagnosis, the role of
surgery is gradually decreasing in the management of this condition.
Diagnosis.
Surgical procedures may be necessary to establish the diagnosis if the disease
is suspected clinically, but sputum or pus cultures are persistently negative.
Bronchoscopy.
This has a higher diagnostic yield
than expectorated sputum.
Open
lung biopsy. Tissues from intrathoracic lymph nodes, lung and pleura may be found to
contain tuberculous material.
The
formation of a tuberculous empyema can result in fibrosis of the affected lung
and its functional destruction. A tube thoracostomy may suffice in the early
stages of empyema, but once a fibrous rim has formed an exploratory thoracotomy
with decortication, evacuation of pus and effective postoperative suction will
be required. Complications such as aspergilloma in a chronic cavity, haemoptysis
and localised carcinoma arising from a tuberculous scar may require lobectomy.
Operations designed to collapse the lung, such as thoracoplasty, are
occasionally used to collapse cavities.
Pulmonary
vascular disease
A detailed discussion of all the diseases of pulmonary vasculature is
beyond the scope of this book. However, pulmonary embolus is a major cause of
morbidity and mortality and is discussed here, as is lung and heart—lung
transplantation, which is indicated for end-stage pulmonary vascular disease.
Pulmonary
embolus. This occurs following dislodgement of venous thrombi, generally from
the femoral and iliac veins, and their subsequent impaction in the pulmonary
vasculature. More unusual causes are fat embolus from multiple trauma, tumour
embolus (renal carcinoma) and amniotic fluid. Pulmonary embolism accounts for
over 20 000 deaths per year in the UK. Strategies aimed at preventing the
development of thrombi in those at high risk (postsurgical patients,
postmyocardial infarction and those who have previously had pulmonary embolus)
include early mobilisation, low dose subcutaneous heparin and compression
stockings. The presentation can vary according to the size, number and timing of
embolic episodes.
Small
emboli may pass unnoticed, giving rise to minor pleuritic chest pain. Pulmonary
vascular hypertension may develop with repeated episodes. Larger emboli may give
rise to pleurisy and haemoptysis with signs of pleural rub and crackles on
auscultation. Massive emboli lead to haemodynamic collapse if the outflow to
the right ventricle is obstructed. There is severe chest pain and acute
shortness of breath. The clinical signs are of right heart failure with raised
central venous pressure and tachycardia, and theme may be some changes on the
ECG. A chest radiograph is often not helpful in the early stages but a
ventilation—perfusion scan may show a mismatch, thereby confirming the
diagnosis. A contrast-enhanced CT scan is the most accurate diagnostic
technique.
Treatment:
acute minor pulmonary embolus. Small
emboli do not require specific treatment but preventive measures are needed to
prevent further episodes. These rake the form of systemic heparinisation in the
first instance and then oral anticoagulation with warfarin or its derivatives.
Recurrent emboli, even with adequate anticoagulation, may require treatment with
an inferior vena caval filter.
Treatment:
acute massive embolus. This
occurs when a large embolus obstructs the pulmonary vasculature and results in
haemodynamic disturbance. There is often a history of one or more minor emboli
before the current episode. The haemodynamic problems dominate the clinical
picture of acute might heart failure with corresponding low cardiac output and
acute ventilation—perfusion mismatch. Theme is peripheral vasoconstricrion,
tachycardia with a small volume pulse and tachypnoea. Blood gas analysis
‘usually reveals a low Po2 from the ventilation—perfusion
mismatch and a low Pco2 from the associated hyperventilation. The
patient will usually be more comfortable lying flat, in contrast to the patient
with myocardial infarction who prefers to sir upright. Once the diagnosis has
been made, treatment with thrombolytic agents (streptokinase and tissue
plasminogen activator) is started. The emboli are seen as filling defects in the
pulmonary artery (Fig. 47.33). The immediate priority is to resuscitate the
patient by administering intravenous fluids to increase the right ventricular
filling pressure and to avoid venodilators. Oxygen is administered via a face
mask (100 per cent) and intravenous heparin is administered to prevent any
further propagation of thrombi. Thrombolytic agents may be given directly into
the pulmonary artery to ensure high concentrations at the appropriate site.
Occasionally pulmonary embolectomy may be required. This may be done without
cardiopulmonary bypass using caval inflow occlusion and extracting the embolus
through a pulmonary arteriotomy. Better results are likely if the patient is fit enough for
cardiopulmonary bypass to be established.
Lung
transplantation. Lung transplantation is becoming an established therapy for
those with end-stage parenchymal or pulmonary vascular disease. The indications
for lung transplantation are varied and may involve the use of one donor lung,
two donor lungs or the heart—lung block. Cystic fibrosis and irreversible
pulmonary hypertension with right ventricular failure are the main indications
for heart—lung transplantation but there is now a trend towards single and
sequential bilateral lung transplantation, leaving the native heart in situ. This
reduces the risk of airway dehiscence which is common with a tracheal
anastomosis. Pulmonary fibrosis and obstructive airway disease in young people
are indications for single lung transplantation. Donor selection is much the
same as for cardiac transplantation except that there must be good respiratory
function and no evidence of pulmonary oedema, contusion or infection at the time
of harvesting. Matching of donor and recipient and cytomegaloviral (CMV) status
is more important than in heart transplantation in trying to avoid the
development of CMV pneumonitis.
The
recipient operation depends on the nature of the transplant. Heart—lung
transplantation requires a median sternotomy and cardiopulmonary bypass. The
recipient heart (in the absence of right heart failure) may be suitable for
transplantation into another recipient. Single lung transplantation is
performed through a thoracotomy with cardiopulmonary bypass if required.
Vigorous physiotherapy and judicious antibiotic use are important in the early
postoperative period. Opportunist infections may develop secondary to the
immunosuppressive drugs and carry a high mortality unless treated aggressively.
One-year survival following heart—lung, double lung and single lung transplantations
stands at between 60 and 70 per cent.
There
is a current shortage of suitable donors for organ transplantation, therefore
alternative treatments for end-stage disease are being explored. One recent
development in the field of thoracic surgery is lung volume reduction. This
involves excising areas of lung in emphysematous patients with often surprising
degrees of subjective and objective improvement. It is unsure whether this
procedure restores the mechanics of breathing by altering the chest wall
dimensions or improves respiratory function by minimising
ventilation—perfusion mismatching.
The
diaphragm
The diaphragm is the fibromuscular structure separating the thorax from
the abdomen (Fig. 47.34). There are two well-recognised congenital sites where
abdominal viscera can herniate into the chest. Traumatic rupture of the
diaphragm may also lead to herniation. Congenital hernia tend to be apparent
shortly after birth, with over 80 per cent presenting on the left side (Fig.
47.35).
There is respiratory distress, apparent dextrocardia, a scaphoid abdomen and
radiological appearances of bowel in the hemithorax. Treatment involves urgent
nasogastric suction (to prevent distension of the bowel
Repair
is advised and is undertaken through a left upper transverse abdominal approach
or by thoracotomy through the seventh intercostal space with nonabsorbable
sutures to repair the defect once the hernia has been reduced.
Oesophageal
hiatus hernia is a common problem and is dealt with in Chapter 50.
Hernia
through the foramen of Morgagni
This is an anteriorly placed hernia with the defect between the sternal
and costal attachments of the diaphragm. The most commonly involved viscus is
the transverse colon.
This is really the persistence of the pleuroperitoneal canal and the
opening is in the dome of the diaphragm posteriorly. It is the most common
diaphragmatic hernia in children and presents with severe respiratory distress.
There is a classic triad of respiratory distress, apparent dextrocardia and a
scaphoid abdomen.
Eventration
of the diaphragm
This is an abnormally elevated position of one or both hemidiaphragms
from paralysis or atrophy of the muscle fibres. There may be some spontaneous
improvement if the condition occurs in the perinatal period but long-standing
cases with paradoxical respiration may benefit from operation.
The aim of surgery is to fix the diaphragm in inspiration so that
paradoxical movement and mediastinal shift are minimised. This is achieved by
plication of the redundant diaphragm, raking care not to damage the branches of
the phrenic nerve.