Inherited Condictions Flashcards
What’s the most common hereditary haemolytic anaemia in Europeans?
Hereditary spherocytosis
What’s the diagnostic test for hereditary spherocytosis?
Osmotic fragility test
Site of extra vascular haemolysis
The spleen eg in hereditary spherocytosis and sickle cell disease
Inheritance pattern of hereditary spherocytosis?
Autosomal dominant (defect in cell cytoskeleton and destroyed by the spleen)
Heinz bodies are associated with which blood disorder?
GP6D deficency (Mediterranean descent, male, x-linked, fava beans, intravascular haemolysis)
How do you diagnose G6PD deficiency?
Measure enzyme activity of G6PD
What can cause haemolysis in someone with G6PD def?
Drugs: anti-malarials (primaquine), ciprofloxacin, sulph-group (sulphonamides, sulphasalizine, sulfonylureas)
Fava beans
Infections
When should you admit someone to hospital with sickle cell?
Any children
Anyone with fever over 38
Anyone with ‘chest’ symptoms
What are the features of wiskott Aldrich syndrome
X linked ressive disease, combined t and B cell dysfunction
Thrombocytopenia
Recurrent infections
Eczema
Bloody stool
Low IgM levels, high IgE
What infection does HbS protect from?
Falciparum malaria.
What are the triggers for Vaso-occulusive crisis in SCD? And what are the features?
Cold, dehydration, infection, hypoxia.
Severe pain.
<3years dactylitis hands and feet.
Mesentric ishemia, CNS infarct, avascular necrosis, let ulcers, priapism
Long bone pain in adults
What is aplastic crisis in SCD?
Due to parvovirus b19, causes BM failure low RBC, low reticulocytes.
Self limiting in about 2 weeks.
What is sequestration crisis in SCD?
Often in children, Organomegaly (either spleen or liver) due to trapping of RBCs, and causes infarction. (And functional aspleenism)
Severe anaemia and shock - emergency
Rx- urgent transfusion
What is the diagnostic test for SCD?
HB electrophoresis - shows 85-90% Hb SS and absent Hb A.
Diagnosis at birth using cord blood. Or heel prick test
What’s seen on the blood film and blood tests in SCD?
Low Hb (60-90), 10-20% reticulocytes, high bilirubin.
Film: sickle cells and target cells
When to give blood transfusions in Sickle cell?
Try to avoid them But given in: CNS event (stroke or TIA), acute chest syndrome, splenic sequestration crisis, aplastic crisis, before elective op or during pregnancy. Or multi organ failure
What are the feature of acute chest syndrome in SCD?
Tachypnoea, wheeze, pain, fever, cough w/ prodrome for 2 days.
Causes: fat embolism, chlamydia mycoplasma/viral
(Usually take penicillin 500mg each day to reduce bacterial infections)
Treatment in a sickle cell crisis
1) IV opiates
2) bloods - CRoss match, FBC, recticulocytes, blood culture (MSU and CXR in high temp/ chest signs)
3) rehydrate and keep warm
4) o2 if sats <95% or hypoxia
5) cephalosporin of ?infection
6) transfusion if Hb or reticulocytes fall sharply
What’s the chronic management of scd?
Folic acid and daily penicillin. Hydroxycarbamide for crisis prevention
Pneumococcal vaccine
Bone marrow transplant is curative.
Complications of SCD?
Splenic infarct (loss of function leads to infections), stroke, gallstones (due to excessive bilirubin production), priapism and infarction of penis, osteomyelitis (1’ salmonella, 2’ staph A), Chronic kidney disease (acute papillary necrosis and nephropathy), eye/retinal disease, pulmonary hypertension(lung damage and right heart strain/failure), leg ulcers.
What is the life span of a sickle cell?
10-20 days
Presence of which haemogloblin can reduce the number of painful crisis?
Hb F, in which hydroxyurea can be used to stimulate the production of Hb F.
When should hydroxyurea be stopped in Sickle patients?
In crisis related to infection, as it can cause neutropenia
