8(f) White Blood Cells, Platelets, DVT
Low white blood cell counts
Treatments which impact on bone marrow (radiotherapy to some extent, chemotherapy more seriously) may reduce white blood cell count, by reducing the production of white blood cells. White blood cells are central to the immune system. If there are not enough white blood cells, there is a risk of the body not being able to control bacterial infection. Bacteria are always present in the body. The majority are beneficial, essential to life. Bacteria which threaten life can grow in numbers rapidly in the absence of white blood cells and especially in a person who is weak. A sedentary or bedridden person can, with insufficient white blood cells, succumb swiftly to pneumonia.
Low platelets
A Full Blood Count will also indicate platelet numbers. Platelets are also produced in bone marrow. They are tiny pieces of 'fibrin' which last only two or three days in the blood stream. Their purpose is to physically block weaknesses, imperfections, holes in blood vessels, and thus to prevent haemorrhage (blood leaking from blood vessels). A person with low platelets will bruise swiftly and badly; if you have a blood sample taken while platelet numbers are low, it is likely to be immediately evident with substantial bruising around the site of where the needle entered the vein.
Consequences of these low blood counts
When you are taking Temodal (or other chemotherapy, but the following details relate to Temodal) regularly, five days then 23 off (i.e. 5/28), you have a blood test regularly. The low point in white blood cell and platelet counts is normally 21 to 28 days after the first Temodal dose. So you need a blood test before the next round. If your bone marrow production of these things has not recovered, you cannot proceed. The pathology report indicates normal ranges. If the numbers are low, treatment may need to be deferred or dosage reduced. It's a hard choice — deferring or reducing treatment may advantage the tumour, but persisting with treatment which is damaging bone marrow risks swiftly killing the patient.
Signs and symptoms
Bruising is a sign of low platelets. High temperature suggests infection and perhaps low white blood count. If the temperature is high, take the temperature and ring the triage nurse. If the nurse tells you to go to the hospital, then GO.
Deep vein thrombosis
A substantial proportion of bran tumour patients will develop deep vein thrombosis [DVT] — the same thing as happens to some long distance travellers, the 'Economy Class Syndrome" that comes from sitting in one place far too long.
In brain tumour patients, as well as risks from being bedridden after an operation, there may also be risks arising from the quality of circulation, all cancer patients appear to be at elevated risk of DVT.
Before an operation and for some days after, until mobile, a hospital patient wears 'TEDs': constant non-graduated compression hosiery. T.E.D stands for Thrombo Embolism Deterrent. Everyone in hospital for a major operation will get these pretty white stockings.
Some hospitals use TEDs which are full length, and which are a great struggle to get into. Some use knee-high TEDs. Research at Royal North Shore Hospital in Sydney indicated that results are equal for the two lengths, the shorter stockings are easier keep clean and are more likely to continue to be worn than the longer and more difficult to manage stockings.
The purpose of the stocking is to prevent pooling of blood in the legs, which can cause blood to form clots (deep vein thromboses - DVT) there. DVT may cause local pain symptoms, but the real risk to health is not in the legs but in the prospect that bits of clots may break away and travel elsewhere to block fine blood vessels and the places where this is most critically a risk are the brain and the lung. In the brain, interruption of blood supply is a cause of stroke, in the lung, pulmonary embolism.
A DVT is identified using a specific type of ultrasound device, with which the length and extent of a DVT can be measured. A DVT may extend a considerable distance, say from below the knee to above the groin . And it becomes more serious if it is bilateral - in veins in both legs, joining in the abdomen.
The medical management of DVT requires medication to prevent further clotting. These medications do not dissolve the clot itself, that is left to bodily mechanisms.
The need is to give patients enough medication for quick protection against further clotting, without overdose. There has been some traditional use of Warfarin, a drug you may be familiar with in rat poisons (give the rat or mouse enough and a bump on the furniture may cause prompt haemorrhage). Warfarin dosage needs careful monitoring and where a patient is in bed or otherwise easily given a daily injection patients may be given Clexane which does not require monitoring.
Clinical trials in the United States in 1998 tried giving patients medication before brain operations to try to prevent DVT afterwards; alas the trials were stopped because in reducing clotting they increased the incidence of brain haemorrhaging. So we end this section reminding readers that not all clinical trials are worth joining.