Multiple Myeloma and Related Conditions

This heterogeneous group of conditions is associated with monoclonal immunoglobulin in serum or urine, and is characterized by disordered proliferation of monoclonal lymphocytes or plasma cells. The clinical phenotypes of these conditions are determined by the rate of accumulation, site and biological properties of both the ab- normal cells and the monoclonal protein.

Read more »

The Myelodysplastic Syndromes

Introduction

• The myelodysplastic syndromes (MDS) are a group of clonal haemopoietic disorders. They are characterized by:

• Ineffective haemopoiesis resulting in peripheral blood cytope- nias of all three lineages, but especially anaemia

• Increased risk (30%) of transformation to acute myeloid leukaemia

• MDS is mainly a disease of the elderly, with a median age at diag- nosis of 60–75 years. It does, however, affect younger adults also. MDS is rare in children, and is associated with genetic disorders such as Fanconi’s anaemia.

Read more »

Quality assurance in the laboratory

Quality assurance in the laboratory includes all aspects of the analytical work, from correct identification and preparation of the patient to ensuring that the laboratory result goes back to the doctor.

The prime objective of quality assurance is to ensure that the laboratory provides results that are correct and relevant to the clinical situation of the patient.

Read more »

Safety in the laboratory

● Each laboratory should have a written manual of safe laboratory practices which should be followed at all times.

● The laboratory should have a first-aid box (see section 3.8.2) and at least one staff member trained in first aid.

● The laboratory should be a work area only; visitors should be restricted.

● No food or drink should be consumed in the laboratory.

● Wear protective clothing and remove it before leaving the laboratory.

● Always consider any laboratory specimen as potentially infectious and handle it carefully; wear protective gloves.

Read more »

Intravenous fluid therapy

Does this patient need IV fluids?

The easiest and best way to give fluids is orally. The use of oral glucose and salt solutions may be life-saving in infective diarrhoea. However, patients may be unable to take fluids orally. Often the reason for this is self-evident, e.g. because the patient is comatose, or has undergone major surgery, or is vomiting. Sometimes the decision is taken to give fluids intra-venously even if the patient is able to tolerate oral fluids. This can be because there is clinical evidence of fluid depletion, or biochemical evidence of electrolyte disturbance, that is felt to be severe enough to require rapid correction (more rapid than could easily be achieved orally)

Read more »

Hypokalaemia

The factors affecting potassium balance have been described previously (p. 22). Hypokalaemia may be due to reduced potassium intake, but much more frequently results from increased losses or from redistribution of potassium into cells. As with hyperkalaemia, the clinical effects of hypokalaemia are seen in ‘excitable’ tissues like nerve and muscle. Symptoms include muscle weakness, hyporeflexia and cardiac arrhythmias. Figure 12.1 shows the changes that may be found on ECG in hypokalaemia.

Diagnosis 

The cause of hypokalaemia can usually be determined from the history. Common causes include vomiting and diarrhoea, and diuretics. Where the cause is not immediately obvious, urine potassium measurement may help to guide investigations. Increased urinary potassium excretion in the face of potas- sium depletion suggests urinary loss rather than redistribution or gut loss. Equally, low or undetectable urinary potassium in this context indicates the opposite.

Reduced intake

This is a rare cause of hypokalaemia. Renal retention of potassium in response to reduced intake ensures that hypokalaemia occurs only when intake is severely restricted. Since potassium is

Fig 12.1 Typical ECG changes associated with hypokalaemia. (a) Normal ECG (lead II). (b)
Patient with hypokalaemia: note flattened T-wave. U-waves are prominent in all leads.

Read more »

Spirochetes and Bacteria without a Cell Wall

Spirochetes and bacteria without a cell wall do not quite fit in with the classic con- cepts of bacteria that have been discussed so far. It is also a fact that there is no similarity between the members of the two groups; they are very different from each other. They are discussed here in one chapter only for the sake of brevity.

SPIROCHETES

Spirochetes are spiral, Gram-negative bacteria with a unique mode of motility that is quite different from those of other bacteria (they lack external flagella). All bacteria classified as spirochetes generally have a helical protoplasmic cylinder made of a thin layer of peptidoglycan and a multilayered outer membrane. Spirochetes differ considerably from each other with respect to habitats and physiological characteristics. Three genera are associated with serious diseases in humans. These are Treponema, Borrelia, and Leptospira.

Read more »