Mixed Q’s 6 Flashcards
Impaired transport of ornithine - restriction of which nutritional substance helps?
Impaired transport of ornithine is due to ornithine translocase deficiency in hepatic urea cycle.
Restriction of protein helps
Erythrocytosis features causes
HCT >52% in males and >48% females
Absolute high RBC mass
1o due to myeloproliferative disorders PCV
2o due to hypoxia PaO2 <65mmHg
Or epo producing tumour
Relative low RBC mass 2o dehydration/ excessive diuresis
What shifts the HgB O2 dissociation curve to the left
Hgb wants to hang on to the O2 and not release it to tissues
Decreased H+ —> high pH
Decreased 2,3 BPG
Decreased temp —> hypothermia
Carbon monoxide poisoning
Will lead to renal hypoxia, increase EPO production in—> erythrocytosis
What moves HgB O2 dissociation curve to the Rt
I.e less affinity for O2 —> will give it up easily
Increased H+ —-> decreased pH —> anaemia, strenuous exercise
Increased 2,3 BPG —> COPD, HF , chronic high altitude
Hyperthermia
Erythrocytes use of glycolysis
Produces no ATP
Using 2,3 bisphosphoglycerate to by pass the ATP generating step.
Uses when there’s low blood O2 concentrations.
2,3 BPG lowers Hgb’s affinity for O2
Cold agglutinins
Bacteria e.g mycoplasma pneumoniae attaches to I antigen in resp epithelium also found in RBC, body forms cross reacting IgM —> these bind to RBC in cold areas of body , ears ,nose.
Causing haemolytic anaemia, high Retics count, high LDH
IgM level falls 4 weeks after initial infection 2o fading immune response
Hepcidin
Central regulator of iron homeostasis
Produced by hepatic parenchymal cells
Myoglobin and HgB O2 dissociation curve
Myoglobin has one monomeric subunit. If HgB is divided it too will act like myoglobin
Myoglobin found in skeletal tissue has v high affinity for O2.
Tumour lysis syndrome
Occurs after initiation of chemotherapy in pts with high cell turnover haemotologic malignancy (e.g. ALL)
Hyper PO4 —> CaPo4 stones
Hyperuricaemia —> Uric acid stones
Hyper K —-> cardiac arrhythmias
HypoCa
INH haematologic SE
Can lead to sideroblastic anaemia
INH inhibits pyridoxine phosphokinase enz needed to convert B6 (pyridoxine) to PLP. which is a co-factor for ALA synthase. Rate limiting enz in haem synthesis
Causing accumulation of iron in mitochondria around the nucleus
HgB types
HbA:- 2 alpha 2 beta ( starts to get produced last month of gestation onwards)
HbF:- 2 alpha 2 gamma ( gets replaced by HbA postnatally)
HbA2:- 2 alpha 2 delta
Hb gower:- ( first weeks of gestation) 2 zeta 2 epsilon
Aplastic crisis features and causes
Cause:- Parvovirus B19– nonenveloped single stranded DNA virus
Features :- severe anaemia following minor febrile illness. BM unable to repsond —> low Retics count
CKD anaemia
Normocytic anaemia 2o decrease EPO production in peritubular fibroblasts cells in renal cortex.
Therefore decrease in progenitor cell differentiation
Fluorescence in situ hybridisation use
Used to identify specific chromosomal translocations, duplication or deletions
Complication of high volume transfusion
Acute hypocalcaemia
2o citrate used as an anticoag in the blood chelating Ca
G6PD like clinical scenario with another causative enzyme
Glutathione reductase deficiency
Haemolytic anaemia and jaundice 2o oxidative stress due to inability to use NADPH
Underlying biochemical feature of megaloblastic anaemia in the setting of chronic alcohol misuse
Deficiency in B9/B12 —> defect in DNA synthesis
Lack of purine, pyramidine (thymidine) synthesis
HgB C
Caused by missence mutation
Glutamate substituted by lysine in beta globe chain
Features:- asymptomatic, mild haemolytic anaemia, splenomegaly
Carbon monoxide poisoning
Shifts O2 Hgb association curve to the LT
Increase carboxy HgB %
No change in PaO2
No change in methaemoglobin level
VWF features
VWF binds to G1B receptors on plts to mediate plt adhesion
Carrier for factor VIII
Labs:- N plt count , abnormal ristocetin cofactor assay—> Normally plts donor agglutinate in presence of ristocetin
Deficiency symptoms:- mucocutaneous bleeding
Adenomysosis
Abnormal presence of endometrial glands and storms in myometrium
Features:- dysmenorrhea, heavy menses and a uniformly enlarged uterus
Risk factor:- previous uterine surgery, previous pregnancy
Types of population pyramids
Expansive:- young growing population, high birth rates, high rates of mortality shorter life expectancy ( upside down v)
Stationary:- (Empire State building) decline birth rates, low mortatlity, long life expectancy, stable population
Constrictive:- low birth rates, low mortality rate, long life expectancy, shrinking population ( think china
Eosinophil role in parasitic infection
Stimulated by antibodies bound to parasite
Destroy parasite by antibody dependent cell mediated cytotoxicity with enzymes from their cytoplasmic granules
Chains of command of reporting a impaired colleague
Should be done in timely fashion
1. Colleagues supervisor
2. In non emergency - physician health progress
3. If not possible - the state licensing board