Page 470 - Medicine and Surgery

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466 Chapter 12: Haematology and clinical immunology

of factors VII, V, X or II. It is also prolonged in liver nia and severe immunodeficiency risking bacterial infec-
disease and in patients taking warfarin. tion, bleeding and anaemia. Total body irradiation has a
The activated partial thromboplastin time (APTT) or numberofpotentiallatecomplicationsincludingthyroid

partial thromboplastin time with kaolin (PTTK) is underactivity, gonad underactivity, cataract formation,
initiatedbyaddinganactivatorsuchaskaolinandthus diarrhoea, sun burn and nausea.
measures the intrinsic and final common pathway. It During this pancytopaenic period support includes
is prolonged in deficiencies of factors XII, XI, IX, VIII, the following:
XorV. Blood transfusion, if haemoglobin falls below
If the coagulation times are prolonged, a 50:50 mix of 10.0 g/dL, (CMV negative if patient and donor have

patients and normal plasma is made. If such a mixture not had CMV). Blood is irradiated to prevent graft
does not correct the time then the result is suggestive versus host disease.
of the presence of an inhibitor of coagulation rather Platelet transfusions may be used.
than a factor deficiency. If heparin is suspected as the Patients are maintained in a filtered air environment.
cause of a prolonged TT then reptilase or protamine Prophylactic antibiotics and antivirals can be used.
is added to the sample, which reverses the effects of The pancytopaenia is reversed by haemopoetic progen-
heparin. itor cell transplantation (infusion into a peripheral vein
of haemopoetic progenitors, which finds its own way to
the marrow cavity and regenerates it). Grafts may be al-
Bone marrow sampling
lografts (HLA matched sibling or unrelated donors) or
Bone marrow sampling is often essential in diagnosing autologous (from self) either bone marrow or more re-
haematologicalconditions.Therearetwosamplingtech- cently peripheral blood stem cell transplants and cord
niques available: blood.
Bone marrow aspiration: Sampling normally occurs
Allografts risk the negative effect of graft versus host
from the iliac crest. Following skin preparation local disease (GVHD) where mature T cells in the trans-
anaesthetic is infiltrated into the skin and down to the plant recognise the rest of the body as ‘non-self’ and
periosteum. The aspiration needle is inserted through therefore attempt to reject it. Coupled to this is a posi-
the skin and advanced rotating clockwise and coun- tive phenomenon known as the graft versus leukaemia
terclockwise until the marrow cavity is entered. The effect (GVL) where the donor marrow recognises any
stylet is then removed and 2–3 mL of marrow is aspi- remaining leukaemic cells and mounts an immunolog-
rated using a syringe. The sample is spread onto glass ical attack. Acute GVHD may occur within the first
slides and stained as required. 3monthsandsubsequentlychronicGVHDmaydevelop.
Bone marrow trephine: Following skin preparation, Acute GVHD affects HLA-rich tissue with desquama-

anaesthetic and incision the biopsy needle (e.g. tion of the skin, impairment of liver function and diar-
Jamshidi needle) is inserted and advanced until it rhoea. Lymphocyte-depleted marrow reduces the risk of
makes contact with the bone. The stylet is then re- GVHD, but also eliminates the graft versus leukaemia
moved and the needle advanced using alternating effect and may thus increases the risk of relapse.
clockwise-counterclockwise motion into the bone Chronic GVHD, which occurs after 3 months may be
marrow cavity. The sample is removed from the nee- an extension of acute GVHD or may occur in patients
dle, fixed, decalcified and stained as required. whonever showed clinical evidence of acute GVHD.
Ocular manifestations: Irritation, photophobia, and

SICCA syndrome (see page 369).
Haemopoeitic progenitor
Gastrointestinal system: Abdominal pain dysphagia,
cell transplantation
odynophagia, weight loss, malabsorption and liver
Haemopoetic progenitor cell transplantation is used disease.
in an attempt to cure various haematological and im- Respiratory system: Obstructive lung disease usually
munological conditions. Treatment begins with ablation nonresponsive to bronchodilator therapy.
of the existing diseased marrow using cytotoxic drugs Neuromuscular system: Weakness, neuropathic pain,
and/or total body irradiation. This induces pancytope- muscle cramps.