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Case 11: Anaemia > Sickle cell anaemia > Flashcards

Flashcards in Sickle cell anaemia Deck (15)
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1

What is sickle cell anaemia?

A disease of RBCs caused by an autosomal recessive single gene defect in the beta chain of haemoglobin (HbA) which results in sickle cell haemoglobin (HbS)

2

Aetiology of sickle cell anaemia

Inherited condition.
Sickling occurs when RBCs containing sickle Hb become rigid and distorted into a crescent shape.

3

Pathophysiology of sickle cell anaemia

The polymerisation of sickle Hb in RBCs can be triggered by hypoxia and acidosis.
This causes cells to become rigid and deform into a crescent shape.
These deformed cells may cause vaso-occlusion in the small vessels or they can adhere to vascular endothelium, resulting in intimal hyperplasia in larger vessels and slowing blood flow.
These deformed cells are also prone to haemolysis, which contributes to anaemia.

4

What are the precipitants of sickle cell anaemia crises?

Acidosis
Dehydration
Cold temperature
Extreme exercise
Stress
Infections

5

Signs and symptoms of sickle cell anaemia

Persistent pain in the skeleton, chest and/or abdomen.
Dactylitis- swollen dorsal of hands and feet.
High temp with cough, watery stools, tender abdomen, malaise, chest pain, diarrhoea is suggestive of infection.
Bone pain.
Pneumonia-like syndrome.
Visual floaters
Tachypnoea
Failure to thrive: infants
Pallor
Jaundice
Lethargy

6

Risk factors of sickle cell anaemia

Parents diagnosed with sickle cell anaemia or they have the sickle cell trait.

7

Investigations of sickle cell anaemia

DNA-based assays
Haemoglobin isoelectric focusing
Electrophoresis
Peripheral blood smear
FBC and reticulocyte count
Iron studies

8

Differentials of sickle cell anaemia

Gout
Septic arthritis
Connective tissue diseases
Avascular necrosis
Perthes' disease
Acute abdomen
Osteomyelitis
Trauma

9

Management of sickle cell anaemia in young children

The main treatment goal is to improve survival by reducing the threat of infections.
This can be achieved through:
-Early diagnosis
-Pneumococcal immunisation
-Antibiotic prophylaxis with penicillin
-Nutritional counselling

10

Management of sickle cell anaemia in adults

The main treatment goals are symptom control and management of disease complications.
This can be achieved through:
-Pain management (chronic and acute)
-Pharmacological amelioration of disease severity with the use of hydroxycarbamide.
-Prophylaxis and prompt treatment of infections.
-Prevention and management of acute complications (acute chest syndrome)
-Prevention of stroke
-Prevention and treatment of chronic organ damage (kidney, renal, pulmonary)
-Genetic counselling

11

Prophylactic treatment in sickle cell anaemia

Hydroxycarbamide- prevents life-threatening neurological events in patients at risk of stroke and reduce the frequency of dactylitis in infants.
L-glutamine- In people who are intolerant to hydroxycarbamide or who continue to have painful events while on hydroxycarbamide
Blood transfusion- Repeated simple transfusion is repeated to maintain HbS below 30%

12

When should bone marrow transplant be suggested for patients with sickle cell anaemia?

Kids with severe complications of sickle cell anaemia (stroke, recurrent acute chest syndrome) who are unresponsive to first-line therapies

13

Complications of sickle cell anaemia

Stroke- offer regular blood transfusion
Splenic infarct before 2 years of age
Poor growth
Chronic renal failure
Gallstones
Retinal disease
Iron overload
Lung damage: hypoxia- fibrosis- pulmonary HTN

14

Management of crises in sickle cell anaemia

Prompt generous analgesia e.g. IV opiates
Oxygen by mask if sats < 95%
Fluid resuscitation to lower haematocrit
Start antibiotics if there are signs of sepsis
Exchange transfusion reserved for those with rapid worsening.

15

Why is surgery a problem for patients with sickle cell disease?

Propensity to Hypoxia:
Pre-existing anaemia
Pre-op dehydration
Anaesthesia
Operative blood loss

Stress of the Surgery predisposes to Sickle Crises:
Fever
Post-op hypoxia
Post-op Infection

These pre-dispose to development of:
Painful Crises
Acute Chest Syndrome