Haematology and Oncology Flashcards
causes of Fe deficiency anaemia in a child?
inadequate dietary intake e.g. exclusively bottle fed milk
blood loss e.g. cow’s milk colitis-with non IgE mediated cows milk allergy*
malabsorption e.g. coeliac disease
what might immune (prev idiopathic) thrombocytopenic purpura (ITP) occur secondary to?
SLE antiphospholipid syndrome viral infections-CMV, HIV, Hep C, varicella zoster H pylori infection drugs lymphoproliferative disorders
how does ITP occur?
otherwise normal PLTs destroyed most often in response to unknown stimulus
AI disease in which Abs produced against platelet antigens and binding causes platelet destruction
may also be Ab inhibition of PLT production
likely genetic susceptibility as often FH
how can ITP be classified?
primary-PLT count less than 100 in absence of other causes or disorders assoc. with thrombocytopenia, or secondary-assoc. with other disease e.g. SLE
time scale: persistent=lasting 3-12mnths
chronic=lasted more than 1 yr
what does ITP most commonly occur in association with in children?
usually follows a viral infection, or occasionally following immunisation
common features of ITP in children?
follows viral infection
usually self-limiting following benign course with spontaneous recovery after 6-8wks
may be asymptomatic
most common presentation=petechiae (non-blanching) or bruising
may be epistaxis
haematuria and GI bleeds less common
may be menorrhagia in older girls
IC bleeds very rarely, but must be aware of
general measures in treating child with ITP?
if child asymptomatic, or skin petechiae or bleeding only, no matter their PLT count, can be managed by observation alone
further testing of FBC if child’s condition changes
advise to avoid NSAIDs and aspirin
avoid contact sports
educate about symptoms to look out for and report urgently
pharmacological tment of ITP in a child?
use in specialist setting if thought that clinical condition requires increase in PLT count
1st line: prednisolone, IV Ig, IV anti-D Ig-in rhesus +ve children
2nd line (if resistant to 1st line and signifiant bleeding): rituximab, high dose dexamethasone
tranexamic acid for menorrhagia, but CI if haematuria
emergency PLT transfusions
splenectomy
why should a BM aspirate be considered in the presentation of likely ITP?
to exclude leukaemia
what is acute lymphoblastic leukaemia?
a malignant clonal proliferation of lymphoid progenitor cells
most commonly of B cell origin
causes BM infiltration and other organs with leukaemic blast cells
most common Ca of childhood?
ALL-acute lymphoblastic leukaemia
causes of haemolytic anaemias in childhood?
genetic or acquired
genetic: red cell membrane defects-hereditary spherocytosis
red cell enzyme abnormalities-G6PDD, pyruvate kinase deficiency
haemoglobinopathies e.g. sickle cell disease, thalassaemia
acquired: DIC e.g. sepsis hypersplenism AI haemolysis isoimmune hamolysis e.g. haemolytic disease of the newborn, blood transfusion reactions infections-malaria, septicaemia drug and toxin induced
mode of inheritance of thalassaemia?
autosomal recessive
give 5 examples of conditions inherited in an autosomal recessive pattern?
CF CAH thalassaemia sickle cell disease glycogen storage diseases galactosaemia PKU oculocutaenous albinism werdnig-hoffmann disease (SMA I)
epidemiology of thalassaemias?
beta-usually from indian subcontinent, Mediterranean and middle east
alpha-south east asian
what is beta thalassaemia?
a condition inherited in an autosomal recessive pattern in which there is a severe reduction in beta-globin production and reduction in HbA production
types of beta thalassaemias?
major and intermedia
major=most severe form, HbA (alpha2beta2) cannot be produced due to abnormal beta globin gene
intermedia=beta globin gene mutations allow a small amount of HbA and/or a large amount of HbF (alpha2gamma2) to be produced.
clinical features of beta thalassaemias?
severe anaemia-transfusion dependent, from 3-6mnths of age, and JAUNDICE
failure to thrive/growth failure
EM haemopoiesis-in absence of regular blood transfusions develop hepatosplenomegaly and BM expansion; latter causing the classical facies with maxillary overgrowth and skull bossing
how is hepatosplenomegaly in beta thalassaemias prevented?
by regular blood transfusions (monthly lifelong of rbc) to prevent EM haemopoiesis
what treatment is required in addition to regular blood transfusions in the management of beta thalassaemias?
iron chelating agent e.g. SC desferrioxamine, or an oral drug e.g. deferasirox, starting from 2-3 years of age, to stop chronic iron overload that would lead to heart failure, DM, infertility, liver cirrhosis and growth failure.
only cure for beta thalassaemia major?
BM transplantation
generally reserved for children with a HLA-identical sibling
features of beta thalassaemia trait?
(heterozygotes) usually asymptomatic hypochromic and microcytic red cells anaemia mild or absent with disproportionate reduction in MCH and MCV, rcc usually increased raised HbA2 (2alpha2delta)
how can beta thalassaemia trait be distinguished from Fe deficiency anaemia on blood results?
measuring serum ferritin-low in Fe deficiency
what is alpha thalassaemia major?
also known as Hb Barts hydrops fetalis:
most severe alpha thalassaemia resulting from deletion of all 4 alpha globin genes so no HbA produced
presents in mid-trimester with fetal hydrops-oedema and ascites, from fetal anaemia which is always fatal in utero or within hrs of delivery
LT survivors exist who received monthly IU transfusions until delivery followed by mnthly lifelong transfusions post birth
diagnosed with Hb electrophoresis or Hb high performance liquid chromatography (Hb HPLC)
how does alpha thalassaemia present if less than all 4 alpha globin genes are deleted?
if 3 (HbH disease), then mild to moderate anaemia, some transfusion dependent. 1 or 2 (alpha thalassaemia trait), usually asymptomatic and anaemia mild or absent, may be microcytic and hypochromic red cells. usually african or far eastern origin.
why is inadequate Fe intake common in infants?
additional Fe required for increase in blood volume accompanying growth and to build up child’s iron stores.
why is a diet containing a large amount of cow’s milk a cause of Fe deficiency?
insufficient iron rich foods in diet as cows milk has a low Fe content and the Fe contained is poorly absorbed
Fe absorption could be increased if eaten with food rich in Vit C e.g. fruit and vege-also likely to be low intake
also if pt has a non-IgE mediated cows milk protein allergy then may have chronic GI blood loss.
how is a blood film of use in investigation of a child with anaemia?
Fe deficiency-hypochromic microcytic red cells-also see in thalassaemia-but here ferritin is normal
hereditary spherocytosis-spherocytes
sickle cell-sickle cells and target cells
management of Fe deficiency anaemia in children?
dietary advice, avoid unmodified cows milk
supplement with oral Fe-Sytron (sodium iron edetate) or Niferax (polysaccharide iron complex)-and these both do not stain the teeth, must continue until Hb normal and for at least 3 mnths after this to replenish iron stores, Hb should rise by about 1g/dl per wk.
complications of Fe deficiency anaemia in children?
associated with intellectual and behavioural deficiencies
‘pica’-inappropriate eating of non food materials
tiring easily
amino acid substitution in sickle cell disease?
valine replaces glutamic acid
result of mutation of A to T in codon 6 of beta globin gene
what is the concern if a pt with known sickle cell disease presents with chest pain?
they have acute sickle chest syndrome: most serious type of painful vaso-occlusive crisis
this can cause severe hypoxia and the need for mechanical ventilation and emergency exchange transfusion.
epidemiology of ALL?
incidence peaks between 2 and 4 yrs of age, much smaller peak apparent in adults over 50yrs
much rarer disease of adulthood
RFs associated with ALL?
genetic and environmental
genetic: trisomy 21-note also transient leukemoid reaction, and other disorders assoc. with excessive chromsome fragility e.g. Fanconi’s anaemia and ataxia with telangiectasia
prenatal chromsomal translocations-production of chimeric fusion genes
enivronmental:
?exposure to cigarette smoking, alcohol, hydrocarbons
infection:
?lack of exposure to common infections in early life may increase risk
symptoms of ALL?
often vague symptoms of fatigue and malaise
complications of BM infiltration:
infection-may present with fever without obvious infection source, may be recurrent and severe infections e.g. throat, oral, skin, perianal,
thrombocytopenia-bruising, petechiae (non blanching), epistaxis
severe and unusual bone and joint pain
dyspnoea-mediastinal mass in large T cell tumours, or anaemia
early satiety due to splenomegaly
headaches, dizziness, palpitations, irritability and neck stiffness-CNS involvement
signs of ALL?
pallor
nonspecific signs of infection
tachycardia and flow murmur
petechiae
abdo distension due to hepatomegaly and splenomegaly
lymphadenopathy
testicular enlargement
gum hypertrophy
leukaemia cutis-firm papules and nodules, erythroderma
cranial nerve palsy-III, IV, VI, VIII in mature B cell disease
blood tests results in ALL?
FBC: anaemia is usual, WCC may be high (due to large number of blast cells), normal or low, but usually a neutropenia, thromobocytopenia also usual, note FBC will not always be abnormal if pt does not yet have marrow suppression.
LDH-usually raised with rapid cell turnover, as is uric acid
US and Es and LFTs-check before chemo
clotting studies-may be DIC-elevated PTT, decrease fibrinogen, and presence of FDPs
may be infection on blood culture-must manage appropriately
blood film-anaemia, blast cells-may be absent if confined to BM.
investigations other than blood tests to be done in investigating for ALL?
CXR-mediastinal mass characterisitic of T cell disease, may be asymptomatic but cause of airway compromise during BM aspiration when child given GA, may be lytic bone lesions, pneumonia
testicular US if testes enlarged on examination-infiltrated with leukaemic blast cells
ECG, ECHO and/or MUGA scan (multiple-gated acquisition) before use of anthracycline chemotherapy-cardiotoxic.
BM aspiration and biopsy, immunophenotyping, BM sample cytogentics-translocations
what is necessary to find on investigation to diagnose ALL?
20% or more blast cells in BM and/or the peripheral blood
-ve myeloperoxidase stain helps
general 3 stages to ALL treatment?
remission induction
intensification/consolidation
maintenance/continuation therapy
which body system must be considered in terms of requiring prophylaxis during ALL treatment as common site of disease recurrence?
CNS:
intrathecal MTX
intrathecal triple therapy-MTX, steroids, cytarabine
sytemic high dose MTX
overview of ALL treatment?
disease tment and prophylaxis/supportive tment-infection-ABx, antifungals, disease recurrence in CNS, includes blood cell replacement, GCSF, allopurinol-control uric acid levels during induction, insertion of central line for frequent treatments.
tment: 6-8mnths intensive OP based therapy, then 2-3 yrs immunosuppressive tment.
induction: pre phase therapy for 5-7 days-corticosteroids poss. comb with chemotherapy, then anthracycline, vincristine, corticosteroids.
maintenance: once normal haematopoiesis achieved.
presentation of wilm’s tumour (nephroblastoma)?
- usually in children under age of 5
- painless abdo mass
most common presentation - painless haematuria
- loin pain
- anorexia
- fever
- nausea
- SOB+cough if lung mets
RFs for wilm’s tumour?
-female
-genetic conditions-WAGR syndrome-iris partially or totally missing, urogenital abnormalities, learning disability
-beckwith-wiedemann syndrome-larger than normal internal organs, large tongue, 1 arm or leg bigger than the other
-edward’s syndrome
FH
1/3 of cases assoc. with loss of function mutation of WT1 gene on chromosome 11
management of wilm’s tumour?
nephrectomy
chemo
radiotherapy if advanced disease
80% cure rate
what infection are we part. concerned about in children with ALL receiving chemotherapy?
pneumocystis jiroveci pneumonia=fungal infection
therefore, should be given prophylactic co-trimoxazole
px: dyspnoea, dry cough, fever, very few chest signs
ix: silver stain bronchoalveolar lavage
