Pedia

• Prothrombin time (PT)


  Measures the action of prothrombin; reveals deficiencies in prothrombin, factors V, VII, and X
• Normal PT value

  11-13 s or 2.0-3.0 international normalized ratio (INR)
• Partial thromboplastin time (PTT)


  Measures activity of thromboplastin; reveals deficiencies in thromboplastin, factors VIII to XIII
• Normal PTT value

  30 - 45 s
• Bleeding time


  Measures the time required for bleeding at a stab wound on the earlobe to stop; reveals deficiencies in platelet formation and vasoconstrictive ability
• Normal bleeding time

  3 - 10 min
• Clot retraction


  Measures platelet function; interval from placement of blood in a tube to the point the clot shrinks and expels serum
• Normal clot retraction

  Retraction at side of test tube should be present by 1 hr; complete in 24 hr
• Tourniquet test


  Measures capillary fragility and platelet function; response of tissue to application of tourniquet to forearm for 5-10 min
• Normal tourniquet test

  0 - 2 petechiae per 2cm area
• Prothrombin consumption time


  Evaluates thromboplastin function, if clot formation used a great deal of prothrombin (as it should), serum prothrombin time will be brief; prolongation denotes defects in thromboplastin function
• Normal prothrombin consumption time

  Approximately 20s
• Thromboplastin generation time


  Tests basic ability to form thromboplastin; distinguishes factor VIII from factor IX disorders
• Normal thromboplastin generation time

  12 s or less
• Plasma fibrinogen


  Measures stage 4 clotting process or level of fibrinogen in blood
• Normal plasma fibrinogen

  200 - 400 mg/100 ml plasma
• Venous clotting time (Lee-White clotting time)


  Measures factor deficits in stage 2 and 4
• Normal venous clotting time

  9 -12 min

  
• Sickle cell anemia


  Autosomal recessive inherited disorder carried on the beta chain of hemoglobin, where the amino acid valine takes the place of the normally appearing glutamic acid
• Sickle cell anemia


  • Diagnosed prenatally or at birth, the form of hemoglobin is designated hemoglobin SS (homozygous involvement), both parents are carriers (heterozygous) of the sickle cell trait
• Sickle cell crisis


  Sudden, severe onset of sickling, tissue hypoxia beyond the blockage, can be triggered by various factors
• Sickle cell crisis symptoms include sudden, severe, and painful onset, low hemoglobin level, sickled cells on peripheral blood smear, increased bilirubin and reticulocyte levels, elevated white blood cell count, and potential complications like aseptic necrosis, cerebrovascular accident, coma, seizures, or death
• Other types of sickle cell crisis include

  SEQUESTRATION CRISIS: splenic sequestration of RBCs or severe anemia . The spleen is enlarged and tender

  
  

  HYPERHEMOLYTIC CRISIS: increased destruction of RBCs

  
  

  MEGALOBLASTIC CRISIS: folic acid or vitamin B deficiency

  
  

  APLASTIC CRISIS: (temporary cessation of RBC production)
• Assessment of sickle cell anemia


  • Stasis of blood and infarction, swelling of hands and feet, enlarged spleen and liver, susceptibility to Streptococcus pneumonia and meningococcus, acute chest syndrome, cirrhosis of the liver, decreased kidney function, yellowing of sclera, and priapism
• Therapeutic management of sickle cell crisis

  Three primary needs:

  1. Pain relief
  2. Adequate hydration
  3. Oxygenation to prevent further sickling and halt the crisis
• Hyperbilirubinemia


  Elevated bilirubin levels in newborns, leading to jaundice
• Hyperbilirubinemia occurs as fetal red blood cells are destroyed and heme is broken down into indirect bilirubin, which cannot be excreted by immature liver
• Kernicterus


  Permanent neurological effects including cognitive impairment, caused by very high levels of indirect bilirubin interfering with brain cell synthesis
• Management of hyperbilirubinemia

  -Early feeding

  -phototherapy to initiate liver enzyme maturation
• Phototherapy involves exposing the infant to specialized light to break down bilirubin, with the infant's eyes covered
• A newer innovation is the phototherapy blanket, a fiberoptic blanket wrapped around the baby
• PRIAPISM a persistent painful erection, is a clinical manifestation of sickle cell cause by vasoocclusion in the penis
• Excessive potassium levels can lead to cardiac arrhythmias
• Hydroxyurea, an anti Neoplastic agent increase the strength and oxygenation capacity of sickled cells

  
  

  Given orally, a side effect is anorexia
• EXCHANGE TRANSFUSION - remove most of the sickled cells and replace them with normal cells
• HEMATOPOIETIC STEM CELL TRANSPLANTATION is a permanent solution to the disorder
• ASSESSMENT FINDING:

  infant’s skin and sclera of the eyes appear yellow
• DIAGNOSTIC TEST

  Serum bilirubin is obtained by heel puncture
• Globin is a protein component that is reused by the body and is not a factor in the developing jaundice
• Heme is further broken down into iron (which is also reused and therefore not involved in the jaundice) and protoporphyrin

  
  

  Protoporphyrin is further broken down into indirect bilirubin.