Haematology and Oncology Flashcards
What is the most common type of anaemia?
Iron deficiency anaemia (IDA)
List some risk factors for IDA
Pregnancy:
- Preterm
- LBW infants
- Multiple births
Nutrition:
- After exclusive breast feeding for >6mnths
- Delayed introduction of iron-containing solids
- Children fed mostly cows milk (low in iron)
Adolescent females:
- Growth spurt
- Menstruation
Low iron in diet:
- Poverty
- Veganism
Malabsorption:
- Coeliac disuse
- IBD
Blood loss (rare): (NB 1ml blood loss = 0.5mg iron) - Mickel's diverticulum - Oesophagitis - Cysts - Tumours - NSAIDs
Intestinal parasites:
- Hookworms
What is pica?
Associated with IDA
A disorder characterised by appetite for non-nutritive substances eg ice, hair, paper, stones, soil etc
How should IDA be prevented in the newborn?
Newborns have approx 4 months of iron stores
From 4 months exogenous iron should be given of 1mg/kg/day (if exclusively breastfed)
From 6 months should be started on iron containing foods
Avoid non-modified cows milk
Supplemented formula milk given to 24 months in high risk groups
How may IDA present in a child?
Most cases are subclinical. Symptoms only develop in severe IDA
1) Fatigue
2) Irritability
3) Failure to thrive
4) Exertional dyspnoea
5) Anaemic signs eg pallor, koilonychia
6) Jaundice (if haemolysis)
7) Reduced cognitive and psychomotor performance
8) Pica (rare)
What investigations can be done for IDA and what do they show?
1) FBC:
- Hb <11g/dL
- Decreased MCV
- Increased platelets
2) Blood film
- Hypochromic, microcytic RBCs
3) Serum ferritin
- Decreased = 99% positive predictive value
4) Serum iron
- Low in IDA
- Normal in thalassaemia
What are some ddx for hypochromic, microcytic anaemia? (5)
Microcytic anaemia = MCV <80fL
From insufficient haemoglobin production
Defective haem synthesis:
1) Iron deficiency anaemia (most common)
2) Lead poisoning
3) Anaemia of chronic disease (late phase)
4) Sideroblastic anaemia
Defective globin chain:
5) Thalassemia
What can cause normocytic anaemia? (7)
Normocytic anaemia = MCV 80-100 fL
Decreased volume and/or decreased erythropoiesis
Haemoglobinopathies:
1) Sickle cell anaemia
2) Haemoglobin C disease
Enzyme deficiencies:
3) Pyruvate kinase deficiency
4) G6PD deficiency
5) Blood loss
6) Aplastic anaemia
7) Anaemia of CKD
What can cause macrocytic anaemia?
Macrocytic anaemia = MCV >100fL
Insufficient cell production and / or maturation
Megaloblastic:
1) Vit B12 def
2) Folate def
3) Medications:
- Phenytoin
- Sulfa drugs
- Trimethoprim
- Hydroxyurea
- Methotrexate
Non-megaloblastic:
4) Liver disease
5) Alcohol use
6) Myelodysplastic syndrome
7) Hypothyroidism
8) Multiple myeloma
What is the treatment of IDA in children?
Diet correction: 2mg/kg/day oral ferrous salt, continue until 3 months after normal Hb
NB failure to respond to iron supplements = malabsorption
What is the most common site for solid tumours in childhood?
Brain
What structures may be involved in brain tumours?
Intracranial tumour affecting brain, meninges, pituitary gland, pineal gland and/or cranial nerves
Where are brain tumours in children most commonly?
Most (70-80%) = infratentorial
Tentorium separates the cerebrum (above) from the cerebellum (below)
ie most are in the cerebellum
eg Glial tumours or medulloblastomas
Also midline = germ cell tumours, craniopharyngiomas
(unlike adults where most are secondary and supratentorial)
What proportion of childhood cancers are brain and CNS?
One quarter
How are brain tumours classified?
Low-grade (1 and 2)
High-grade (3 and 4)
What does low-grade mean?
Grade 1 = doesn’t spread
Grade 2 sometimes spreads slowly and may recur if removed
Sometimes called ‘benign brain tumours’ but misleading as their mass effects mean they can still be harmful
What does high-grade mean?
Malignant tumours which spread to other tissues and tend to recur if removed
How do brain tumours typically present? What % are diagnosed in ED?
Progressive and subacute
60% diagnosed in ED
Give some examples of low-grade brain tumours?
1) Meningioma
2) Pituitary adenoma
3) Acoustic neuroma
4) Craniopharyngioma
What is an acoustic neuroma?
Benign tumour of CN8 (vestibulocochlear) Schwann cells
aka vestibular schwannoma
What are acoustic neuromas associated with?
Neurofibromatosis type 2
How may an acoustic neuroma present?
Gradual onset of unilateral sensorineural deafness and pressure in one ear
Followed by unilateral face numbness and absent corneal reflex (due to CN5 compression), vertigo, n&v
How are acrostic neuromas managed?
Slow growing so can be monitored with annual MRI
Removed with surgery or Gamma knife radiosurgery
What ages does craniopharyngiomas affect?
5-15 and 65-75yrs
Where do craniopharyngiomas arise? Where may they also affect?
Pituitary stalk
May affect hypothalamus and pituitary
How may a craniopharyngioma present?
Signs of raised ICP
Bitemporal hemianopia
Hydrocephalus
Endocrine symptoms
List some examples of high-grade brain tumours?
1) Gliomas
2) Medulloblastomas
3) Primary CNS lymphoma
What is the most common type of glioma?
Astrocytoma
What are types of astrocytoma?
Glioblastoma aka glioblastoma multiforme (GBM)
(most common malignant tumour in adults, life expectancy 1yr)
Pilocytic astrocytoma (PCA) = commonest benign tumours in kids → 5yr survival 95%
Other than astrocystoma, what are other types of gliomas?
Ependymomas
Oligodendrogliomas
What are medulloblastomas?
Tumour of cerebellar neurons
A type of primitive neuroectodermal tumour (PNET)
How common are medulloblastomas?
Most common malignant tumours in children
How may a medulloblastoma present?
What is the 5yr survival?
Hydrocephalus
Cerebellar signs eg abnormal gait and coordination
5yr survival is 70%
What are primary CNS lymphomas most commonly?
Diffuse large B-cell lymphoma
Which population are more likely to have primary CNS lymphomas?
Those with HIV
What are the most common type of brain tumours in children?
Gliomas, either:
1) Astrocytomas (40%)
- very variable prognosis
2) Medulloblastomas (20%)
- most have spinal mets at diagnosis
How may brain tumours present in children?
Mostly cerebellar signs = DANISH
Signs of raised ICP
+/- focal neurological signs depending on site of tumour
- eg squint from 6th nerve palsy, seizures, cerebellar signs, personality changes
What is are cerebellar signs - DANISH?
Dysdiadochokinesia Ataxia Nystagmus Intension tremor Scanning dysarthria Heel-shin test +ve
What are signs of raised ICP?
Papilloedema Altered LOC Headache Vomiting Behavioural changes Bulging fontanelle Raised BP Decreased HR
How should brain tumours in children be investigated?
MRI with contrast
Never perform a LP if raised ICP
Why should a LP never be performed if suspected raised ICP?
High pressure gradient from within cranium can cause herniation of brainstem through foramen magnum
What should you do with a child presenting with persistent back pain?
Always do MRI with contrast
What is the management of brain tumours?
Surgery = first line
Not all operable eg brainstem not
Chemo/radiotherapy
What has the best survival rates of brain tumours?
Astrocytomas
What is haemophilia?
Bleeding disorder caused by a deficiency of clotting factors
No fibrin is formed in blood clots leading to easy clot breakdown
What are the two types of haemophilia?
Haemophilia A = Factor VIII deficiency
Haemophilia B = Factor IX deficiency
A8 B9
What is the mode of inheritance of haemophilia?
X-linked recessive
Affects males born to carrier mothers
How is severity of haemophilia A classified? What ages does each present?
% of FVIII activity
1) Mild
- >5% FVIII activity
- Presents >2yrs of age
2) Moderate
- 1-5% FVIII activity
- Presents <2yrs
3) Severe (most)
- <1% FVIII activity
- Presents in infancy
What mutation causes haemophilia A?
Usually FH (2/3rd) But sporadic cases can occur due to novel mutations (1/3rd)
What is more common haemophilia A or B?
A is 5x more common than B
How may severe haemophilia A present?
1) Neonatal bleeding (1/3rd) eg following circumcision
2) Neonatal haemorrhage
3) Haematoma
4) Prolonged bleeding from cord or umbilical area
5) Hx of spontaneous bleeding into joints esp knees, ankles and elbows, without hx of significant trauma
6) IM haemorrhage
7) GI / mucosal haemorrhage - but more often haemophilia B/von Willibrand’s disease
8) Haematuria
How may moderate haemophilia A present?
Bleeding after venepuncture
How may mild haemophilia A present?
Bleeding after major trauma
What may untreated cases of severe haemophilia A lead to? (4)
1) Athropothy and joint deformity
- May require replacement of affected joints
2) Soft tissue haemorrhages
- Can lead to compartment syndrome and neurological damage
3) Extensive retroperitoneal bleeds
- Can cause haemodynamic compromise
4) Haematoma formation
- May require fasciotomy
List some ddx for haemophilia A (7)
1) Haemophilia B
2) Von Willebrand’s disease
3) Vit K deficiency / antagonism with antiogoagulants
4) Haemophilia C (factor XI deficiency)
5) Disorders of fibrinogen or fibrinolytic production
6) Platelet disorders
7) Blood vessel disorders
What investigations are performed for haemophilia A?
FBC
- Low haematocrit and reduced Hb if recent bleeding
PT, bleeding time, fibrinogen levels and VWF
- Normal
APTT
- Usually prolonged but can be normal if mild
- Mixed pt plasma 1:1 with donor plasma should normalise
Factor VIII:C
- Reduced
- % activity shows severity of disease
Imagine arthtopathies with MRI or US
CT head if haemorrhage
What is the prophylactic management of haemophilia A?
Infusions of factor VIII minimum once weekly
What is a complication of haemophilia A?
Degenerative joint disease due to recurrent haemarthrosis
What tends to be more severe - haemophilia A or B?
A = more severe
What does the activated partial thromboplastin time (aPTT) measure?
The intrinsic and common pathways
What is the intrinsic pathway?
HMWK (high molecular weight kininogen) activates:
FXII - XIIa
XIIa activates:
FXI to FXIa
FXIa activates:
FIX to FIXa
12 + 11 + 9
FVIIIa (8 = Haemophilia A) then with FIXa activates FX
What does prothrombin time (PT) measure?
Extrinsic and common pathways
What is the extrinsic pathway?
Tissue factor activates factor FVII - FVIIa
7 = heaven = extrinsic
What is the common pathway?
Factor X is activated by FIXa (intrinsic) and FVIIa (extrinsic)
Xa AND Va then activate:
Prothrombin (FII) to thrombin (FIIa)
Thrombin activates:
Fibrinogen (FI) to Fibrin (FIa)
10 + 5 + thrombin + fibrin
What is protein C?
= autoprothrombin IIa
A proenzyme that inactivates FVa and VIIIa
Too little = clot too much
What % of haemophilia B are mild, moderate and severe?
Severe - 50%
Moderate - 3%
Mild - 20%
In general, deficiencies in what cause:
a) Petechial haemorrhages and ecchymoses (bruising)
b) Haematomas and haemarthroses
a) Petechial haemorrhages and ecchymoses (bruising)
- platelet deficiency
b) Haematomas and haemarthroses
- Clotting factor deficiency
What did haemophilia B used to be known as?
Christmas disease
What are signs/symptoms of haemophilia B?
Same as A
May be slower to bleed
What investigations are done for haemophilia B?
aPTT - elevated
% activity of FIX = reduced
What is the management of haemophilia B?
Recombinant FIX usually twice a week
