Anemia, Fever and Temp regulation Flashcards Preview

Virology, Parasitology, Mycology > Anemia, Fever and Temp regulation > Flashcards

Flashcards in Anemia, Fever and Temp regulation Deck (85):

What is hemoglobin a measure of?

gm/dl; blood HB concentration


What is MCV?

average volume of red cells, mean corpuscular volume, volume of blood x HCT / #RBC


What is MCHC?

mean corpuscular hemoglobin concentration, HB/HCT,


What is reticulocyte count?

number of reticulocytes/total RBC;


What is hematocrit?

MCV x RBC, volume percent of RBC


What is mean corpuscular hemoglobin?

MCH, HB/RBC, concentration of hemoglobin packed in RBC


What is RDW?

red cell distribution width, measure variation in cell size, increased in sickle cell and nutritional deficiencies


What is anisocytosis?

RBC unequal size


What is poikilocytosis?

abnormally shaped


What is polychromasia?

abnormal increase in # of RBC premature in blood


what is hypochromia? How is this determined?

hypopigmentation; pale area more than 1/3 of RBC


What is microcytic? macrocytic? What cell is used for size comparison?

small RBC; large RBC; compare size to WBC


What is microcytic anemia?

Hb is decreased below normal and the MCV less than 80fl, MCHC may or may not be decreased if so hypochromic


What are the three general causes of microcytic anemia?

abnormality in iron metabolism, globin metabolism, and porphyrin metabolism


What are the causes of iron metabolism?

inadequate iron intake, chronic blood loss, and anemia of chronic disease


What are the causes of inadequate iron intake in microcytic anemia?

pediatric age, pregnant moms (iron uptake by fetus, suboptimal stores before pregnancy), otherwise inadequate iron intake in adults rare cause of microcytic anemia


What are the causes of chronic blood loss in microcytic anemia?

most common is GI; GI- ulcer, colon or gastric carcinoma, hiatal hernia, esophageal varices, ulcerative colitis, crohn disease, leiomyoma, salicylate, meckel diverticulum, hookworm, angiodysplasia; Female gential- dysfunctional uterine bleed, endometrial hyperplasia/carcinoma, excessive menses; Pulmonary- carcinoma, chronic infection; Urinary- bladder cancer, chronic infection


What are the causes of anemia of chronic disease? what amount are microcytic? normocytic?

rheumatoid arthiritis and other autoimmune disorders, cancer, chronic infection, severe tissue injury; 30% micro, 70% normo


What are the reasons for anemia of chronic disease?

impaired Fe flow into RBC- hepcidin triggers degrade. iron exporter (ferroportin) thus limiting egress from enterocytes and macrophages (limits Fe for microorganisms), may lead to anemia- infection, malignancy, and inflammation; decreased RBC survival, insufficient erythropoietin to stimulate RBC production


What are the types of thalassemia's?

inherited, heterogeneous group, alpha and beta chain most common, in minor not anemia but have microcytosis, major= severe anemia


What are the features of Hemeglobin E?

SE Asia, most common globin abnormality, HgbS, beta chain abnormality, homo (marked hypochromia, microcytosis with little or no anemia) and heterozygous


What us serum ferritin? Decreased means? What can falsely increase?

principle storage form of iron; decrease in iron stores; chronic disease, when acute phase reactant increases (surgery, febrile illness, liver cell necrosis), oral or parenteral iron administration


What is iron-binding capacity?

IBC is a reflection of transferrin levels, although transferrin can be directly measured


What are causes of normocytic anemia?

chronic disease (most common), acute blood loss, marrow replacement (myeloplastic anemia), aplastic anemia, renal failure, hemolytic anemia


What are the causes of increased reticulocyte count in normocytic anemia? normal or decreased reticulocyte count?

acute blood loss, hemolytic anemia; anemia of chronic disease, renal failure, aplastic anemia, myelophthisic anemia (marrow replacement by infiltrative disease such as cancer and histoplasmosis)


What are the features of folate or B12 deficiency causing megaloblastic anemia?

maturation pattern in bone marrow, nuclear:cytoplasmic dyssynchrony, especially in RBC series, lab assessmentbegins with folate and B12 levels depending on hist and PE, schilling test- abnormal in B12 deficiency


what are the causes of drug-induced perturbed DNA synthesis?

antineoplastics, immunosuppressive, and antiretroviral


What are the causes of non-megaloblastic macrocytic anemia?

liver disease, hypothyroidism, bone marrow regeneration following blood loss or hemolysis with increased reticulocyte counts, myelophthisic anemia, myeloproliferative disease, multiple myeoloma, some causes of sideroblastic anemia


what neural structures are involved in thermoregulation? Which is the "thermostat"?

hypothalamus and limbic -> <- spinal cord and sympathetic ganglia; hypothalamus (esp. preoptic region, thermosensitive neurons)


What are mechanisms of heat production in the body?

mitochondrial oxidative phosphorylation (ADP->ATP, >50%), skeletal muscles during exercise ~25%, shivering in adult humans, and brown adipose tissue


where is brown adipose tissue located? characteristics? physiological role?

esp. near neck and scapulae; brown, profuse vasculature, numerous mitochondria (uncoupling protein 1, UCP1), thermoregulation in newborns and small mammals, possibly energy metabolism in adults (BAT activity inversely related to BMI)


What is the function of UCP1 in brown fat?

leaky inner membrane, energy released as heat, not stored as ATP, regulated by T3 locally


How is brown fat activated?

adrenergic neuron to B3 adrenergic receptor-> cAMP-> nucleus-> increase UCP1 production-> increase in heat


Where is heat lost? percent for each site?

skin 80-90%, 10% from lung


What is the mechanism for fine adjustment of temperature from hypothalamus?

sense absolute and change in temp of blood, autonomic nerves to skin BV, inc. BV diameter-> inc. heat loss -> dec. body temp OR dec. BV diameter-> dec. heat loss-> inc. body temp


What is the mechanism for coarse adjustment of temperature from hypothalamus?

thermal skin receptors relay to hypothalamus which relays signals; autonomic neurons-> sweating-> dec. body temp OR somatic neurons-> shivering-> inc. body temp


What causes hyperthermia? other name and clinical features?

abnormal thermoregulation; heat stroke- warm dry skin, no sweat, inc. temp, delirium, coma, organ failure, cardiac arrhythmia, death


treatment for hyperthermia? risk groups?

rehydration, immersion in cool bath, not antipyretics; s/p CVA, cord injury, low mobility, low sweating (drugs or skin disorder), and diuretics


what is normal body temp? What is the upper limits of normal?

old- 37C and 98.6F; new- 36.8C or 98.2F (men 98.1, women 98.4), 37.7C or 99.9F


What are some things that cause normal body temperature variation? slight elevation?

normal diurnal variation (circadian T rhythm,0.5C -0.9F, high point 4-6p, low point 2-6a); menstruation, 1st trimester, ovulation, giant meal, hard exercise (1-4 deg), ambient temp >85F)


what are the bodies high->low gradients? Regional variants of temp?

core-> epidermis, thrunk-> extremeties, hand-> fingertips, flexor->extensor surface; heart, brain and GI-37, scrotum 32, fingertips 20-25


How does regional body temp effect infections?

mycobacterium leprae grow best at ~31C (affects ears, nose, fingers and toes), sporothrix grows best at 25C (affects extremities, rarely organs, heat to treat), rhinovirus grows best at 33C (temp of nasopharynx


How does regional temp variation effect rash development?

some spread warm to cool (trunk to extremities, i.e. VZV) some spread cool to warm (extremities to trunk, i.e. rickettsia rickettsi)


What are exogenous pyrogens? How do they work?

microbes or their products, ligands for TLR, stimulate cells to make endogenous pyrogens (macrophage, monocyte, PMNs, glial cells, neurons


What are endogenous pyrogens? How do they work?

cytokines (IL-1beta, IL6, TNF alpha, IFN gamma), work at hypothalamic level- increase cyclooxygenase which increases PGEs-> reset thermostat higher


what role does PGE2 play in fever?

levels high in hypothal and 3rd ventricle, highest near circumventricular organs (network of large capillaries, pyrogen-> endothelial rxn= 1st step), triggers release cAMP-> induces release of monoamine NT, hypotalmic reset up, causes myalgia, arthralgia in peripheral tissues


What are endogenous cryogens? Examples?

affect firing of thermosensitive neurons (help control upper limit of body T), arginine vasopressin, alpha-MSH, neurochem (epi and NE), glucocorticoids and their inducers (CRF, ACTH)


What are acute phase proteins? What effects change in levels?

rise or fall by 25%, altered due to production by hepatocytes; substantial- infection, trauma, surgery, burns, tissue infarction, inflammatory states; moderate- hard exercise, heatstroke, and childbirth; small- psychological stress and psychiatric illness


What are some examples of acute phase proteins?

C-reactive protein, amyloid A, haptoglobin, fibrinogen, and procalcitonin


What are some other acute phase reactions?

neuroendocrine, hematopoietic, and metabolic


What does CRP bind and do?

binds phosphocholine on B and to pahgocytes, activates complement


What is amyloid A, it binds to and does what?

apolipoproteins that bind lipoproteins, inc. adhesion and chemotaxis of phagocytes, ?inflammation in coronary arteries?, 2ndary amyloidosis if chronic


What is haptoglobin? What does it do?

anti-inflammatory antioxidant, aids wound healing


What is fibrinogen? What does it do?

coagulation component, affects rate of RBC fall in plasma (erythrocyte sedmentation rate, ESR, or sed rate)


What is procalcitonin? What does it do?

prohormone (thyroid C cell response to hypercalcemia), inc. w/ B infection (IL1-beta), rises faster than ESR or CRP, falls quick if infection responds to Rx, no increase if viral (PCT sytnh. inhibited by IFN-gamma), biomarker for respiratory infection


What occurs in the neuroendocrine acute phase response?

inc. CRH, ACTH and corticol; inc. adrenal secretion of catecholamines


What occurs in the hematopoietic acute phase response?

anemia of chronic disease, leukocytosis, thrombocytosis


What occurs in the metabolic acute phase response?

dec. muscle and negative nitrogen balance, dec. gluconeogenesis


what are the benefits of fever?

preserved thru evolution (all vertebrates and some invertebrate), prevent fever (inc. death in animals), high temps inihibit B growth (Rx syphilis and gonorrhea), associated cytokines can aid host defense


What are some harmful effects of fever?

seizures (103F or 40C, infants and young kids, prob rate of rise, high fever any age ~105), increased metabolic demands (dec. LV stroke volume and work), loss of brain function (>106F or 41C any age)


What is the host perspective on fever? species perspective?

effect either good or bad; mediates speedy recovery from mild-moderate infection and hastens death of hopelessly infected who pose epidemiologic threat


When and with what do you treat fever?

controversial- probly ok; high fever in very young (prevent seizures or metabolis demands too great; ASA (avoid under 21-Reye's), acetaminophen, NSAIDS- inhibit COX-> dec. PGE2, 4-6hrs round the clock; steroids- inhibit CO and mRNA for cytokine synthesis


What is the cause and treatment of intermittent fever?

pyogenic abcess, prn ASA; 2 daily spikes- military TB, GC endocarditis, salmonellosis, malaria, visceral leishmaniasis (Kala azar)


What are some causes of recurrent fever (cycle of fever and afebrile) days? weeks?

malaria, meningiococemia, cholangitis, dengue f., yellow f., Colorado tick f., relapsing f. (borrelia) and influenza; Hodgkins disease (pel-ebstein fever), brucellosis, relapsing F. (Borrelia), ocassionally TB


What are some general features of drug fever?

common cause, only sign of drug rxn in 3-5%, increased risk w/ more drugs taken (esp. elderly), increased risk w/ HIV


What are the mechanisms of drug fever?

hypersensitivity, altered thermoregulatory mechanisms, directly related to administration, related to pharmacologic effect, idiosyncratic reactions


What are the features of drug fever due to hypersensitivity?

most common, Ag-Ab complex formation, T-cell response, usually in 3 days, but up to years, may see: rash, uticaria, mucosal ulcers, liver, kidney, lung, bone marrow dysfunction


What are the features of drug fever due to altered thermoregulation?

exogenous thyroid hormone (inc. metabolic rate-> inc heat production), anticholinergics (dec. sweating-> dec. heat loss), and sympathomimetics (inc. vasoconstriction-> dec. heat loss; amphetamine and cocaine)


What are the features of drug fever due to drug administration?

IV fluid contaminated with endotoxin, chemical phlebitis, local inflammation at injection site, low-grade fever after vaccines, intrinsic pyrogenic prop. (amphotericin B, bleomycin)


What are the features of drug fever due to pharmacologic effect?

chemotherapy (dying cells pyrogens-> cytokine release; Jarish-Herxheimer rxn (Antibiotic rxn-> dead bugs-> induce cytokines), may see rash, symptoms worse (syphilis, brucellosis, enteric fever)


What are the idiosyncratic rxns that cause drug fever?

malignant hyperthermia, neuroleptic malignant syndrome (NMS), serotonin syndrome, glucose-6-phosphate dehydrogenase deficiency


What are the features of malignant hyperthermia?

(rare), T >40C, muscle rigidity, metabolic acidosis, and BP instability, occurs during anesthesia (halothalene, succinylcholine), autosomal dominant in 50%, mutation in ryanodine receptor (Ca channel in skeletal muscle SR)


What are the features of NMS?

high fever, muscle rigidity, altered mental state and dysautonomia (BP up and down), >25 drugs (all deplete CNS dopamine), major tranqs (haloperidol), significant mortality, RX: DC drug, dantrolene, bromocriptine


what are the features of serotonin syndrome?

agitation, hyperthermia, diaphoresis, tachycardia, rigidity (similar to NMS), inc. stimulation of 5HT1A receptors (SSRI meds, inc. risk if given with linezolid), also LSD, lithium, L-dopa, and MAO-inhibitors


What are the features of drug fever with G-6-PD deficiency?

fever with: primaquine, quinine sulfate and sulfonamides, hemolytic anemia is more worrisome


What is fever of unknown origin? setting?

>38C (101F) every day or repeatedly, 3wk duration (eliminates self-limited cause), no Dx after > 2 visits or 3d in hospital; community, clinic, or hospital


What are the leading causes of fever of unknown origin?

infection (30-40%), Neoplasm (20-30%), collagen or vascular (10-15%), granulomatous (5-10%), Misc (10-20%), and unknown (10-15%)- SQ fecal injection to induce, etc


What infections are a leading cause of FUO?

occult abscesses, TB, endocarditis, CMV


What neoplasms are a leading cause of FUO?

leukemia, lymphoma, myeloma, hyerpnephroma, and hepatoma


What collagen or vascular conditions are a leading cause of FUO?

SLE, RA, rheumatic fever, arteritis


What granulomatous diseases are a leading cause of FUO?

sarcoidosis, granulomatous hepatitis, IBD


What are the miscellaneous leading causes of FUO?

drug, PE, thermoregulatory disorder, endocrine disorder (hyperthyroid, Addison's, pheochromocytoma), factitious/fraudulent


What are the common causes of nosocomial FUO?

hospital acquired infections, post-op complications, and drug fever


What are the common causes of FUO in cancer or transplant patient?

majority infection!, cause documented in only 50%


What are the common causes of FUO in HIV or AIDS patient?

HIV primary infection, mycobacterial (TB or NTM esp MAI), CMV- toxoplasmosis, lymphoma