Hematology Flashcards
Treatment of ITP??
-Oral prednisolone (80% of patients respond)
-Splenectomy if platelets < 30 after 3 months of steroid therapy
-IV immunoglobulins
-immunosuppressive drugs e.g. cyclophosphamide
A 34-year-old man started on a new medication, his lips and nail-beds are significantly blue. He mentions that he has been feeling short of breath for the past 48 hours and that he has an accompanying headache. His oxygen saturations were 80% on room air. This improved only to 83% on 35% venturi mask. Medicine??
(Acquired methaemoglobinemia)
Antimalarials (chloroquine, atovaquone), Antibiotics (co-trimoxazole, dapsone) Local anaesthetics (benzocaine, lidocaine).
A pt on heparin with worsening pain and swelling in her leg.. PC dropped. AB formed against??
This is HIT.. Ab against complexes of platelet factor 4 and heparin
These antibodies bind to the PF4-heparin complexes on the platelet surface and induce platelet activation by cross-linking FcγIIA receptors..
Does not develop until after 5-10 days of treatment..
Despite being associated with low platelets HIT is actually a prothrombotic condition..
There is a greater than 50% reduction in platelets, thrombosis and skin allergy
Rx: need for ongoing
anticoagulation:
Direct thrombin inhibitor e.g.
-Argatroban
-Danaparoid
Which blood product has more risk of developing reaction as compared to others??
Platelet transfusions have the highest risk of bacterial contamination compared to other types of blood products.
This is because platelets are stored at room temperature between 20-24ºC as too cold temperatures lead to damage to the platelet membranes. These warmer temperatures are much more favorable for bacterial contamination and growth, compared to products stored at colder temperatures.
What is the storage temperatures for various blood products??
Platelets: 20-24 C
RBCs: 2-6 C
FFPs: -30 c
Cryoprecipitate: -30 c
(FFPs and cryoppt are thawed just before use)
Fibrinogen stored in powder form and mixed in sterile water just before use.
What are the thresholds for platelet transfusion?
-For grade 2 bleeds, transfuse if <30 x 10 9
-For severe bleeds/bleeds at CNS site: Tx if < 100 x 10 9
-For surgeries: (Targets are)
> 50×109/L for most patients
50-75×109/L if high risk of bleeding
>100×109/L if surgery at critical site
-If no active bleeds and no CI:
10 x 109
What are the CIs for platelet Tx??
-Chronic bone marrow failure
-Autoimmune thrombocytopenia
-Heparin-induced thrombocytopenia
-Thrombotic thrombocytopenic purpura.
If a pt is having a past history of hypothyroidism and is on levo, now presents with SS of anemia, with LOW MCV (normally in hypothyroid pt, MCV is increased), then what is the next step in investigation of pt??
Hb ELECTROPHORESIS
{Disproportionate microcytic anaemia - think beta-thalassaemia trait: reduced or absent haemoglobin A, increased haemoglobin A2 (>3.5%) and increased haemoglobin F}
LEUKAMOID REACTION??
Presence of immature cells such as myeloblasts, promyelocytes and nucleated red cells in the peripheral blood. This may be due to infiltration of the bone marrow causing the immature cells to be ‘pushed out’ or sudden demand for new cells..
Causes
-severe infection
-severe haemolysis
-massive haemorrhage
-metastatic cancer with bone marrow infiltration
CML vs LEUKAMOID REACTION?
Leukaemoid reaction
1) high leucocyte alkaline phosphatase score
2) toxic granulation (Dohle bodies) in the white cells
3) ‘left shift’ of neutrophils i.e. three or fewer segments of the nucleus
Chronic myeloid leukaemia
-low leucocyte alkaline phosphatase score
AIP??
Increased urinary porphobilinogen between acute attacks. Acute intermittent porphyria (AIP) is a genetic disorder characterized by the deficiency of an enzyme, porphobilinogen deaminase, leading to the accumulation of porphyrins and their precursors in the body. The most reliable biochemical finding in AIP is an increase in urinary excretion of delta-aminolaevulinic acid (ALA) and porphobilinogen (PBG), especially during acute attacks. However, even between attacks, PBG levels remain elevated in most patients with AIP.
How to manage AIP??
Avoiding triggers
For Acute attacks:
-IV haematin/haem arginate
-IV glucose should be used if haematin/haem arginate is not immediately available
A pt with Waldenstrom’s macroglobulinaemia, now develops purpuric rash and new joint pains and rash, esp painful in cold weather, has low C4, diagnosis?
{Raynaud’s - Type I cryoglobulinaemia}
secreted due to an underlying plasma cell dyscrasia or lymphoproliferative disorder
What are the 3 types of Cryoglobulinemia?
Type I (25%):
monoclonal - IgG or IgM
Associations: multiple myeloma, Waldenstrom macroglobulinaemia
Type II (25%)
mixed monoclonal and polyclonal: usually with rheumatoid factor
Associations: hepatitis C, rheumatoid arthritis, Sjogren’s, lymphoma
Type III (50%)
polyclonal: usually with rheumatoid factor
associations: rheumatoid arthritis, Sjogren’s
What are the features of cryoglobulinemia??
-Raynaud’s only seen in type I
-Cutaneous
{Vascular purpura
Distal ulceration
Ulceration}
-Arthralgia
-Renal involvement
(diffuse glomerulonephritis)
What are the investigations for cryoglobulinemia??
-Low complement (esp. C4)
-High ESR
What is the management of crypglobulinemia?
-Rx the underlying cause (Hep C)
-Immunosuppression
-Plasmapheresis
A pt going for elective splenectomy, vaccines before and after?
2 WEEKS BEFORE:
-Pneumococcal (both PCV13 and PPV23)
-Meningococcal ACWY
-Meningococcal B
-Haemophilus influenzae type b
{or ASAP after surgery}
ANNUAL INFLUENZA
5 YEARLY PNEUMOCOCCAL
What is the AB prophylaxis for splenectomy?
Penicillin V
{continued for at least 2 years | at least until the patient is 16 years of age | sometimes for life}
What are the indications for splenectomy??
-Trauma: 1/4 are iatrogenic
-Spontaneous rupture: EBV
-Hypersplenism: hereditary spherocytosis or elliptocytosis etc
-Malignancy: lymphoma or leukaemia
-Splenic cysts, hydatid cysts, splenic abscesses
What are the post-splenectomy complications?
-Haemorrhage (may be early and either from short gastrics or splenic hilar vessels
-Pancreatic fistula (from iatrogenic damage to pancreatic tail)
-Thrombocytosis: prophylactic aspirin
-Encapsulated bacteria infection e.g. Strep. pneumoniae, Haemophilus influenzae and Neisseria meningitidis
What are the post-splenectomy changes?
-Platelets will rise first (therefore in ITP should be given after splenic artery clamped)
-Blood film will change over following weeks, Howell-Jolly bodies will appear
-Other blood film changes include target cells and Pappenheimer bodies
-Increased risk of post-splenectomy sepsis, therefore prophylactic antibiotics and pneumococcal vaccine should be given.
