Haemoglobinopathies Flashcards
In sickle cell disease, what proportion of hemoglobin? In sickle cell trait?
- Sickle cell disease (HbSS)- 80-95% is HbS
- Sickle cell trait (HbAS) - ~30% HbS
Which vaccinations are recommended for those with sickle cell disease
- Haemophilus influenzae b
- Pneumococcal
- Meningococcal
- Hepatitis B
- Influenza
What causes increased risk of infection from encapsulated organisms in sickle cell disease?
Splenic atrophy due to microthrombi
What is are effective interventions to prevent childhood mortality due to sickle cell disease?
- Neonatal screening programs in order to make early diagnosis and provide appropriate interventions and supports
- Education to avoid factors that precipitate crises e.g. dehydration, hypoxia
- Folic acid supplements
- Vaccinate against pneumococcal, HBV, Hib, meningococcal
- Anti-malarial prophylyaxis lifelong in endemic areas
- Hydroxyurea (expensive and not always available) decreses frequency of crises
Regarding leg ulcers in sickle cell disease, what age group is most affected, what is the treatment?
Leg ulcers in sickle cell disease
* Manifests in adulthood
Treatment
* Bed rest with leg elevation
* Oral zinc
* Antibiotics for sepsis
* Hydroxyurea is controversial
What antibiotics should be given for osteomyelitis in sickle cell disease?
- Ceftriaxone and ciprofloxacin
- Covers S. paratyphi, E. coli, S. aureus
- Salmonella is a common cause of osteomyelitis in those with SCD
What is the management of painful sickling crises?
- Effective pain relief
- Supplemental oxygen if hypoxic
- Hydration (Oral, IV, NG as required)
- Keep patient warm
What antibiotics should be given in sickle cell disease for bacteremia?
Ceftriaxone
- Covers encapsulated organisms e.g. S. pneumonia, Hib, N. meningitidis which are greatest causes of mortality
What antibiotics should be given in sickle cell disease for suspected meningitis?
Ceftriaxone
What are the common causes of acute chest syndrom in sickle cell disease and what is the management?
- Acute chest syndrome - usually triggered by infection
- Treat with Ceftriaxone and erythromycin (covers S. pneumonia, Hib, mycoplasma, C. pneumoniae)
- Bronchodilators
- Exchange transfusion if severe
- Incentive spirometry
Which sex is more affected by G6PD and why?
Males
G6PD is X-linked
What are the most common triggers of hemolytic episodes in those with G6PD?
- Infection
- Drugs
What are some common drugs that precipitate hemoltyic episodes in those with G6PD?
1. Antimalarials - primaquine
2. Sulfonamides - co-trimoxazole, dapsone
3. Misc - fava beans, methylene blue
3. Antibiotics - nitrofurans
4. Analgesics - phenacetin
5. Antihelminths - Nitrodazole
What cells are seen in G6PD on blood film during a crisis?
- Bite and Blister cells
N.b. diagnosing G6PD is often best done >6wks after a crisis since older RBCs with low G6PD activity are eliminated
How is G6PD managed during a crisis?
- Treat any underlying infection
- Withdraw drugs that may have precipitated the crisis
- Maintain high urine output
- Folic acid supplements
- Neonates may have jaundice and require phototherapy +/- exchange transfusion
When does beta thallaseemia major typically present and what is the clinical presentation?
Beta thallasemia major
* Typically presents in first year of life
* Severe anemia
* Jaundice
* Hepatosplenomegaly due to extramedullary haematopoiesis
* Thallasemic facies
* Expansion of skull and maxillary bones
