If a small malignant nodule is found within the lung, it can sometimes be excised and the prognosis is excellent. Unfortunately, many patients present with a tumor mass that has invaded structures in the mediastinum or the pleurae or has metastasized. The tumor may then be inoperable and is treated with radiotherapy and chemotherapy.
Spread of the tumor is by lymphatics to lymph nodes within the hila, mediastinum, and root of the neck.
A key factor affecting the prognosis and ability to cure the disease is the distant spread of metastases. Imaging methods to assess spread include plain radiography (Fig. 3.54A), computed tomography (CT; Fig. 3.54B,C), and magnetic resonance imaging (MRI). Increasingly, radionuclide studies using fluorodeoxyglucose positron emission tomography (FDG PET; Fig. 3.54D) are being used.
In FDG PET a gamma radiation emitter is attached to a glucose molecule. In areas of high metabolic activity (i.e., the tumor), excessive uptake occurs and is recorded by a gamma camera.
In the clinic
Pericarditis is an inflammatory condition of the pericardium. Common causes are viral and bacterial infections, systemic illnesses (e.g., chronic renal failure), and after myocardial infarction.
Pericarditis must be distinguished from myocardial infarction because the treatment and prognosis are quite different. As in patients with myocardial infarction, patients with pericarditis complain of continuous central chest pain that may radiate to one or both arms. Unlike myocardial infarction, however, the pain from pericarditis may be relieved by sitting forward. An electrocardiogram (ECG) is used to help differentiate between the two conditions. It usually shows diffuse ST elevation. Echocardiography can also be performed if there is clinical or radiographic suspicion of pericardial effusion.
In the clinic
Normally, only a tiny amount of fluid is present between the visceral and parietal layers of the serous pericardium. In certain situations, this space can be filled with excess fluid (pericardial effusion) (Fig. 3.62).
Because the fibrous pericardium is a “relatively fixed” structure that cannot expand easily, a rapid accumulation of excess fluid within the pericardial sac compresses the heart (cardiac tamponade), resulting in biventricular failure. Removing the fluid with a needle inserted into the pericardial sac can relieve the symptoms.
In the clinic
Abnormal thickening of the pericardial sac (constrictive pericarditis), which usually involves only the parietal pericardium, but can also less frequently involve the visceral layer, can compress the heart, impairing heart function and resulting in heart failure. It can present acutely but often results in a chronic condition when thickened pericardium with fibrin deposits causes pericardial inflammation, leading to chronic scarring and pericardial calcification. As a result, normal filling during the diastolic phase of the cardiac cycle is severely restricted. The diagnosis is made by inspecting the jugular venous pulse in the neck. In normal individuals, the jugular venous pulse drops on inspiration. In patients with constrictive pericarditis, the reverse happens and this is called Kussmaul’s sign. Treatment often involves surgical opening of the pericardial sac.
In the clinic
Valve problems consist of two basic types: incompetence (insufficiency), which results from poorly functioning valves; and stenosis, a narrowing of the orifice, caused by the valve’s inability to open fully.