| Ch 16 | Page 4 / 16 | |
| Cancer emergency |
Sudden death | |
Sudden death can be defined as death occurring without any warning within one or two hours. Since cerebral hypoxia leads to irreversible disorders in around 5 minutes, it is of utmost importance that the decision to resuscitate the patient or not be taken as quickly as possible.
Cancer is often the reason for sudden death and the patient, once resuscitated, may enjoy prolonged survival for a few months or even be cured. Certain statistics show that the median survival after cardio-respiratory resuscitation is around 6 months, which is higher than the survival observed after sudden deaths accompanying complicated liver cirrhosis or major cardiac insufficiency. On the other hand, in autopsy studies, unknown cancer is rarely responsible for sudden death.
Many cancers have the same aetiological factors (tobacco, high animal fat consumption, sedentary life, obesity, alcohol) as other diseases due to coronary arteriosclerosis, arteritis or cerebral vascular disease. Thus, ventricular fibrillation or massive cardiac infarction may often be the cause of sudden death syndrome. If the patient is in clinical remission and/or has a good possibility of being cured or relieved for a long period of time, he/she should receive the same cardiological resuscitation as a non-cancer patient.
Direct cardiac involvement is not rare with tumour endocarditis (marantic endocarditis) and even direct invasion of the myocardium by bronchial tumours.
Iatrogenic myocardial complications (i.e. induced by therapy) are frequent: exceptionally due to irradiation (the myocardium is a muscle which is resistant to radiotherapy except in the case of major vascular disease), direct myocardic cell involvement by chemotherapy agents such as anthracyclins (in relation to cumulative dosage), coronary endothelial cell involvement induced by cyclophosphamide, coronary spasm during 5-FU infusion, more rarely direct myocardium involvement due to cisplatin and taxans).
Lastly, some therapies may induce a congestive cardiac failure (Interleukin, Interferon, Taxotere).
Malignant pericardial effusion is the main cause of pericardial tamponade during cancer. It is generally due to metastatic lesions: lung cancer, breast cancer, oesophageal cancer, lymphoma, leukaemia, melanoma or secondary mesothelioma.
Fluid accumulation is provoked by the inflammatory reaction which is in turn related to the localised haemorrhage induced by the tumour implant. Generally, diagnosis can be made by echocardiography or chest radiography before any clinical symptoms appear.
Few clinical symptoms are initially observed: slight dyspnoea, imprecise thoracic pain, coughing, lower limb oedema. Then major symptoms appear with massive pain, right cardiac insufficiency, jugular distension, liver pain, and widening of the cardiac image on radiography.
Evolution may accelerate towards terminal diastolic cardiac insufficiency.
Emergency treatment involves the decompression of the pericardium by pericardiocentesis or surgical pericardectomy or derivation.
Aetiological treatment (i.e. chemotherapy) should then be rapidly instituted.
Such life-saving treatment is most useful among patients with chemosensitive tumours (lymphoma, leukaemia) for whom complete remission is possible after such an acute complication.
Massive pulmonary embolism is an under-recognised cause of sudden death. Cancer patients have two to three times more thrombosis and embolism than non-cancer patients. Most pulmonary emboli are multiple, originating from deep veins from lower limbs, pelvis or central venous catheters.
Pulmonary embolisms are most often massive obstructing more than 50% of the vascular pulmonary bed and result in acute right cardiac insufficiency, with pulmonary hypo-perfusion followed by pulmonary shock. Previous multiple small embolisms may also very quickly produce such symptomatology.
Diagnosis is established by clinical examination, arterial hypoxemia, electrocardiogram (the classical but rare S1-Q3 syndrome), ventilation-perfusion radio-nuclide lung scan (xenon, technetium). Pulmonary angiogram is often too aggressive; new CT scan might be useful.
Treatment includes all the resuscitation procedures, anticoagulant treatment. If the patient’s cancer prognosis is good, a thrombolytic treatment (streptokinase, urokinase) may also be proposed.
In patients with heavy risk of multiple embolism, cava vena umbrellas or filters may be inserted percutaneously under local anaesthesia.
Massive haemorrhage (exteriorised or not) frequently occurs for head and neck cancer, lung cancer, oesophageal or gastric cancer.
Patients with brain tumours may bleed into the brain or have a massive oedema and cerebral hernia resulting in sudden death.
Patients with long lasting leucopoenia may suffer from sudden septic shock. Thus a patient with a febrile neutropoenia, whose fever does not quickly retrocede with antibiotics, should be hospitalised.
Other causes of sudden death may come from undetected metabolic disorders: major hypercalcaemia, severe hyponatraemia with major dehydration, hyperkaliaemia in relation to renal insufficiency or hypokaliaemia due to massive water loss).
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