Sickle cell anemia

Question 1

How do you diagnose Sickle cell anemia?

Answer 1

1. Blood smear shows: Sickle cells, Howell - Jolly bodies, Target cells
2. For newborn screening→Hemoglobin Electrophoresis, which shows: HbS, HbF
3. Prenatal testing for hemoglobin gene mutation by obtaining samples via Chorionic villus sampling or Amniocentesis

Question 2

How do you diagnose Sickle cell trait?

Answer 2

1.For newborn screening→Hemoglobin Electrophoresis, which shows: HbS, HbF, HbA

2.Sickle prep / Sickledex, which is good at detecting the trait but it cant distinguish trait from homozygous disease

Question 3

What is this?

Answer 3

Sickle cells and Target cells

Question 4

What is this?

Answer 4

Howell-Jolly bodies. They are RBCs with basophilic remnants. Its not normally seen because a healthy spleen would remove it

Question 5

What are the symptoms of Sickle cell carriers?

Answer 5

• Asymptomatic unless exposed to high altitudes or dehydrated
• Sickling tends to occur in the renal medulla, since it’s more hypoxic and acidotic → Papillary necrosis → Isosthenuria (i.e., inability to concentrate urine)

Question 6

How do you treat a patient in Sickle cell pain crisis?

Answer 6

For mild, outpatient - Nonopioid analgesics

For severe, hospitalized - Opioids

Question 7

What is the diagnostic criteria for Acute chest syndrome?

Answer 7

One or more of the following:
* Chest pain
* Cough
* Temperature > 38.5°C
* Tachypnea
* Hypoxemia
* signs of increased work of breathing
* Wheezing
* Crackles

PLUS a **new **pulmonary infiltrate on CXR, that involes at least 1 lung segment and is not due to Atelectasis

Remmember to rule out an infection as the the trigger, do 2 sets of blood culture + sputum

Question 8

How do you treat a patient with Acute chest syndrome?

Answer 8

1. If O2 saturation < 94% →Oxygen: 15L/min via Non-rebreather mask OR 2L/min via nasal cannula (if vomiting)
2. IVF (avoid overhydration): - 5% Dextrose in either water, 0.45% NS or 0.22% NS
   - 500 ml (max 1L) 0.9% NS or LR (for urgent volume correction)

3.If patient has a H/O asthma or evidence of brochospasm → Salbutamol (Albuterol) 2.5-5mg NEB PRN q 4-6hrs or 2 puffs with pump

4. Start empiric antibiotics:

Ceftriaxone (Rocephine)
Adults: 1-2g IV q 12 - 24hrs (max 4g/day)

Children: 50 - 75mg/kg IV OR 25-37.5mg/kg q 12hrs (max 2-4g)

                             PLUS 

Azithromycin
Adults: 500mg IV/PO OD
Children: 5-12mg/kg IV/PO OD (max 500 mg on the first day, then 250mg)

Question 9

How do you treat Low-flow priapism?

Answer 9

You have 3 options:

1. Repeat intracavernosal injections of phenylephrine up to an hour.
2. Aspirate the sludged blood from the corpus cavernosum with/without irrigation of NS.
3. Decompress the penis by creating a shunt either between the glans (Winter technique) or corpus spnogiosum (Ebbehoj technique)

treatment should be within 12hrs or else risk penile fibrosis and permanent erectile dysfunction

Question 10

How do you diagnose Low-Flow priapism?

Answer 10

• No signs of pernial trauma
• A completely rigid corpus carvernosum
• Painful erection
• Recurrent priapism (MC cause in a sickler)

Question 11

How do you treat sickle cell anemia?

Answer 11

1. Vaso-occlusive episode (VOE) > 6xs / year:
   * Hydroxyurea (age > 9 months):
   - Loading dose: 20mg/kg OD
   - Maintainance dose: 20-35mg/kg (max 2500mg OD)

                              OR

• L-glutamine (age > 5 years)
  - < 30kg: 5gm BD
  - 30-65kg: 10gm BD
  - > 65kg: 15kg BD

                              OR

• Crizanlizumab (age > 16 years)
  - Loading dose: 5mg/kg IV q 2weeks x 2 doses
  - Maintainance dose: 5mg/kg IV q 4weeks

                             OR

• Voxelotor (age > 4 years)
  - < 40kg: 600 - 900mg OD
  - > 40kg: 1500mg OD

2. If Hb < 7g/dL: Blood transfusion + Deferoxamine SQ
3. Penicillin prophylaxsis
   Indication: for children < age 5 with a spleenectomy or past severe pneumococcal infections:
   - > 3 years: 125mg BD
   - 3 - 5 years 250mg BD

                              OR

Amoxicillin: 20mg/kg OD If penicillin allergy

4. See treatment of Sickle cell pain crisis & acute chest syndrome

Question 12

What are the symptoms of Sickle cell anemia?

Answer 12

Sickled RBCs tend to get stuck within the:
* Bones of hands & feet → Dactylitis

• Bones of hip → Avascular necrosis
• Lungs→ - Acute Chest Syndrome (Chest pain, Cough, SOB)
  - Sickle cell chronic lung disease
• Kidneys →Hematuria, Proteinuria
• Spleen → -Spleenic sequestration
  -Spleenic infarcts →Splenectomy
• Liver → Acute sickle hepatopathy
• Gallbladder→ Acute cholecystitis
• Penis → Priapism (low-flow)
• Cerebral vasculature→ - Stroke
  - Mental status change
  - Moyamoya disease

Question 13

Removing the spleen increases suceptibility to what infections and why?

Answer 13

• Streptococcus.Pneumoniae
• Haemophilus.Influenzae
• Neisseria.Meningitidis

Because the spleen plays an important role in immunity against encapsulated bacteria

Question 14

What is Moyamoya disease?

Answer 14

progressive stenosis and occlusion of the terminal internal carotid arteries with compensatory formation of collateral blood vessels

Question 15

What are the symptoms of Moyamoya disease?

Answer 15

• TIA
• Strokes
• Hemorrhage
• Seizures

Question 16

How to diagnose Moyamoa disease?

Answer 16

1st. CT brain noncontrast to detect hemorrhage (detects ischemia only after 6-24 hrs)

2nd. Diffusion-weighted MRI to detect ischemia (within 3-30mins after onset)

3rd Cerebral angiogram (definitive Dx) reveals a puff of smoke appearance

Question 17

What is acute sickle cell hepatopathy?