NSG 533 - Exam 4 questions and answers

Anemia can contribute to: coronary ischemia Composition of blood 5.5L total. 50-55% = plasma; 90% water Erythropoesis is stimulated by... erythropoetin Hemoglobin A the majority of adult hemoglobin. 97% of circulating hemoglobin. 2 alpha and 2 beta chains. HbA2 minor adult hemoglobin. 2-3% of circulating hemoglobin. 2 alpha and 2 delta chains. Hemoglobin F Fetal hemoglobin. 2 alpha and 2 gamma chains. Has a greater affinity for and more regularly binds O2. Anemia a decrease in circulating red blood cells in the body, as reflected by a reduction in hemoglobin, hematocrit, and/or RBCs. Less than 14 in men and less than 12 in women. Normal RBC 4.5-6 Normal Hemoglobin >13 in men, >12 in women. Normal HCT 40-50in men; 35-45 in women. usually 3x the hemoglobin count. Reticulocyte count Low (<0.5%) High (>2%) if high, bone marrow is trying to compensate for loss in hgb or red cells. problem exists outside of the bome marrow MCV (mean corpuscular volume) description of the volume of an RBC. NOT DIAGNOSTIC RDW (red cell distribution width) 11.5-15 %; index of variation in RBC size and shape. Indicates evolving macro/microcytic anemia. MCH (mean corpuscular hemoglobin) commonly used: 27 - 31 pg/ cell Amount of hemoglobin per RBC Microcytic anemia Iron deficiency, thalassemia, inflammation. low MCV <80. Low reticulocyte count. Underproduction. macrocytic anemia Underproduction. B12 deficiency, Folic Acid Deficiency, Antimetabolite drugs. MCV > 100; low reticulocyte count Normocytic Anemia MCV 80-100; low reticulocyte count; ex: dilutional/iatrogenic secondary to phlebotomy. Folate Deficiency Anemia Macrocytic anemia; poor intake; low retic, elevate MCV/MCH, thrombocytopenia ad neutropenia, elevated homocysteine; low RBC folate. Eat orange fruits! Never treat folate deficiency without testing for B12 deficiency - can worsen neurological symptoms specific to B12 deficiency Vitamin B12 Deficiency Macrocytic; malabsorption; occurs when B12 is not released from food proteins due to impaired digestion; Elevated MCV/Macrocytic; Pernicious Anemia lack of mature erythrocytes caused by inability to absorb vitamin B12 into the bloodstream Destruction (Hemolytic anemia) anemia with elevated reticulocytes; intrinsic and extrinsic intrinsic hemolytic anemia (hereditary) - Abnormal hemoglobin - Enzyme deficiencies (pyruvate kinase, G6PD) - RBC membrane abnormalities: sickle cell anemia, thalassemia extrinsic hemolytic anemia (acquired) (+) Coomb's DIC: abnormal coags (prolonged PT/PTT) TTP HUS paroxysmal nocturnal hemoglobinuria: dark urine worse in AM hypersplenism Traumatic 2/2 prosthetic valve; elevated LDH, low haptoglobin; elevated indirect bilirubin Sickle Cell Anemia Hemolytic/hereditary. Identified at birth - 6 months when HbSS replaces fetal hemoglobin. hereditary disorder of abnormal hemoglobin producing sickle-shaped erythrocytes and hemolysis Thalassemia Major Hemolytic/microcytic; defective production of either alpha or beta globin. leads to damage of the RBC membrane, resulting in ineffective erythropoesis and hemolysis Alpha Thalassemia 4 genes determine synthesis of alpha chain. Silent carrier = 1 abnormal allele; 2 abnormal alleles = alpha thalassemia minor; 3 abnormal alleles = Alpha Thalassemia Intermedia: chronic anemia; 4 abnormal alleles not compatible with life, Hydrops Fetalis Beta Thalassemia mutations of the beta-globulin gene; no production of beta chain, absent HgBA; common in mediterranean, african, indian, and asian ancestry. Beta Thalassemia Major: Cooly's Anemia Beta Thalassemia Major; symptomatic at 6 months; deficient beta chains = excess alpha chains; ineffective erythropoesis; erythroid hyperplasia; extramedullary hematopoesis. Low Hgb/HCT; low MCV, normal/elevated retic; increased RBC; need vit C/folate supplementation; avoid excess iron. bone marrow transplant Monroe-Kellie Doctrine when one content in the skull increases, another must decrease to compensate and maintain normal ICP brain = 1300mL; blood = 110mL; CSF = 65mL Brain Compliance ability of cranial content to tolerate changes in volume. Auto-regulation ability of the brain to regulate cerebral blood flow. if blood is being lost, cerebral blood vessels will dilate to allow for more blood flow in. if increased blood volume or hypertensive, cerebral blood vessels will constrict to limit blood flow. Cerebral Perfusion Pressure CPP = MAP - ICP Normal = 50-150. Less than 50 is not adequate for cerebral perfusion. Will be reduced by an increase in ICP. Intracranial hypotension loss of CSF volume. Can result in sagging of brain tissue away from the skull (CSF provides support in ventricles) damage to bridging veins and dura, hemorrhage Intracranial Hypertension ICP > 15-20mmHg. Sustained ICP >20-25mmHg warrants treatment, ICP >40 is severe and life threatening. Cerebral edema swelling of the brain; can be caused by osmotic changes (acute hyponatremia), hypertensive encephalopathy, tumor related, cytotoxic, acute ischemic stroke, hepatic failure Herniation shift in brain tissue from one compartment to another caused by pressure differences between compartments. Subfalcine (cingulate) herniation herniation syndrome lateral displacement of frontal or parietal lobe across the Falx; may see contralateral or ipsilateral leg weakness; may compress anterior cerebral artery Uncal Herniation intracranial hypertension, medial temporal lobe pushes through tentorium cerebelli Central Herniation Movement of the diencephalon, midbrain, and pons inferiorly, caused by a lesion in the cerebrum, exerting pressure on the diencephalon. This movement stretches the branches of the basilar artery, causing brainstem ischemia and edema. If uncorrected will see dilated pupils, loss of brainstem reflexes due to transtentorial herniation Tonsillar Herniation cerebellum thru foramen magnum; kills by resp/cv depression Meningitis inflammation of the meninges covering brain and spinal cord viral meningitis aseptic meningitis; lower mortality rate; 90% enteroviruses: coxsackie virus, echo virus, fecal /oral route, respiratory: peak in summer and fall months Bacterial Meningitis inflammation of the protective membranes covering the brain and spinal cord caused by various types of bacteria. Life threatening neurological emergency; patients can present in septic shock; endotoxin and inflammatory mediators initiate a CSF inflammatory response and edema formation; see increased ICP, reduction in cerebral perfusion and/or brain death encephalitis inflammation of the brain (usually by virus, herpes) mylitis infection/inflammation of the spinal cord ventriculitis inflammation of the ventricles of the brain Neisseria meningitidis bacteria; common cause for meningitis in adults H. influenzae bacteria; common cause for meningitis in neonates Viral CSF normal glucose, normal/high protein, few mononuclear cells Bacterial CSF low glucose, high protein, many mononuclear cells Infectious Signs of Meningitis Fever, tachycardia, chills meningeal irritation signs severe throbbing headache, severe photophobia, nuchal rigidity, positive kernigs/brudzinski signs Neurologic signs of meningitis Focal signs, ↓ in consciousness, CN palsies, seizures seizure sudden, transient disturbances in brain function resulting from an abnormal firing of nerve impulses d/t increased excitatory synaptic neurotransmitters (glutamate++, aspartate); Ionic excitation with inflow of Na, Ca+++ may or may not be associated with convulsion Hippocampal sclerosis temporal lobe epilepsy; loss of neurons in Ammon's horn of the hippocampus; unclear cause possibly related to birth or early childhood trauma or multiple seizures; elevated glutamate causes damage temporal lobe epilepsy seizures begin in the temporal lobe of the brain; refractory to treatment; due to HS, tumor, cortical dysplasia, vascular malformations or unable to determine