Red Blood Cell Disorders Flashcards
Red Blood Cells
Normal Hemoglobin 33% by volume.
Hb = 2 pairs of globin chains (αβδγ)
Kidney: senses low O2 level and secrete erythropoietin (stimulates bone marrow release of RBC). Anemia in severe renal disease/dialysis
Normal Red Blood Cell count: 4-6 million cells/ul
Anemia = Hb <13 g/dL (M), <12 g/dL (F)
Causes of Anemia
- decreased production (aplastic anemia, renal disease, folate/B12 def)
- increased breakdown (hemolytic anemia: sickle cell, GD6P deficiency)
- blood loss (Fe deficiency)
Iron Deficiency
Most common type of anemia
Causes: blood loss (menstruation, GI bleed), poor Fe intake (developing countries), poor Fe absorp (GI diseases), increase demand (pregnancy)
Mild anemia in men: serious med problem (GI bleed, malignancy
Microcytic anemia: due to lack of Hb, cells are small to preserve a good concentration of Hb
Folate Deficiency Anemia, Pernicious Anemia
RBC production requires folate and B12. Otherwise, abnormally large RBC are produced and cannot leave the bone marrow (Macrocytic anemia)
Folate: fruits, leafy veg.
- Risk factors: poor diet (poor, elderly), alcoholism, malabsorption, pregnancy
Pernicious Anemia: deficiency of intrinsic factor (IF) that is needed for absorption of vitamin B12 (cobalamin). IF is produced by gastric parietal cells
- Cause: autoimmune destruction of parietal cells –> lower intrinsic factor production
- Chronic pernicious anemia >> gastric carcinoma
Hemolytic Anemia
- Glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency)
- Sickle cell anemia
- hemolytic anemia = normocytic anemia
G6PD: enzyme that helps RBC cope with oxidative stress
G6PD deficiency: red blood cells are broken down in response to stressors (#1 drugs, infections, fava beans)
Avoid Aspirin!
Sickle Cell Anemia
Genetic mutation: single amino acid substitution in β chain of Hb
Glutamic acid replaced by valine (valine hydrophobic, collapse of RBC)
Affected Hb = HbS instead of HbA (α2β2).
Autosomal recessive
Sickle cell trait: heterozygous
Sickle cell anemia: homozygous
Sickling occurs when:
- lowered O2 tension
- decreased blood pH
- dehydration
Sickle cell crisis:
- Sickling causes increased viscosity, reduced blood flow, hypoxia
- Rare in sickle cell trait
Problem: chronic anemia, small blood vessel occlusion
Signs/symptoms: jaundice, pallor dactylitis, leg ulcers, organomegaly, cardiac failure, stroke, attacks of abdominal and bone pain
Sickle Cell Dental Management
Occlusion of blood vessles promote:
- asymp pulpal necrosis, osteomyelitis ischemic necrosis of mandible, peripheral neuropathy.
Costa 2013 retro Sickle cell pts 8x more likely to have pulp necrosis in intact tth
Radiographic: marrow expansion due to increased RBC production
- stepladder configuration of trabecular bone, dense lamina dura
- Hair-on-end appearance in skull film
Sickle Cell Dental Management (continued)
SC Trait: not at risk unless severe hypoxia/infection/dehydration
Abx prophy recommended for major surgery
Analgesics:
- use Tylenol/codeine (No strong narcotics - resp depression)
- No high dose NSAIDs (CV and renal tox)
N2O: O2 >50%
EPI: use with caution (use 1:100K in surgery)
Surgery: med consult
Acute infection:
- incision/drainage
- high dose Abx will avoid crisis
- local heat
- avoid dehydration
- Hospitalization if sickling crisis occurs
Pulse Ox: maintain above 95%
Other Oral Manifestations in Anemic Patients
Mucosal pallor
Angular cheilitis, aphthous ulcers
Atrophic tongue, burning tongue (B12, iron defiency)
Jaundice (hemolytic anemia)
Aplastic anemia:
- gingival hyperplasia with mucosal hemorrhage
- ulceration
- necrotizing ginginvostomatitis
Plummer-Vinson syndrome: Fe-deficiency, dysphagia with esophageal stenosis/webbing, greater risk oropharyngeal CA
Aplastic Anemia
Bone marrow unable to produce adequate RBC, WBC, platelets
Common in young adults
Causes: drugs, virus (hepatitis), organic compounds, radiation, etiopathic (majority)
Presentation: anemia, thromobocytopenia, weakness, fatigue, HA, dyspnea, bruising/bleeding.
