U3 LEC: CARBOHYDRATES (PT. 3) Flashcards
Condition in which levels of blood glucose are decreased
Hypoglycemia
Glucagon is released if blood glucose level is?
65-70 mg/dL
Symptoms of hypoglycemia appear if blood glucose level is?
50-55 mg/dL
Symptoms of Hypoglycemia are related to?
CNS
Hypoglycemia symptoms include:
- shaking
- fast heartbeat
- shivering
- dizziness
- anxiety
- irritable
- headache
This causes brain fuel deprivation
Hypoglycemia
Hypoglycemia results to?
- impaired judgement and behavior
- seizures
- coma
- functional brain failure
- death
This is the imbalance in the rate of glucose appearance and disappearance from the circulation
Hypoglycemia
Hypoglycemia is rare in individuals with?
normal glucose metabolism
In individuals without diabetes, diagnosis of hypoglycemia should be made only in those who demonstrate the?
Whipple Triad
under the Whipple Triad
1.) Hypoglycemic symptoms
2.) Plasma glucose <50 mg/dL
3.) Symptoms are relieved by correction of hypoglycemia when glucose or glucagon is administered
T/F: The Whipple Triad is only observed in persons without diabetes.
True
Hormones that regulate Hypoglycemia
- Glucagon
- Epinephrine
- Norepinephrine
- Cortisol
- Growth Hormone
Classification of Hypoglycemia
due to fasting state
Post-absorptive (fasting)
Classification of Hypoglycemia
after eating
Postprandial (reactive)
Postprandial is observed how many hours after a meal?
4 hours
Level 1 (Glucose Alert Value)
- <70mg/dL
- sufficiently low for treatment with fast acting carbohydrate and dose adjustment of glucose lowering therapy
Level 2 (Clinically significant hypoglycemia)
- <54mg/dL
- sufficiently low to indicate serious hypoglycemia
Level 3 (Severe hypoglycemia)
- no significant threshold
- associated with severe cognitive impairment requiring external assistance for recovery
Symptom observed in Level 3
loss of consciousness
Characterized by a plasma (or serum) glucose concentration low enough to cause symptoms and/or signs including impairment of brain function
Clinical hypoglycemia
An intentional attempt to induce low blood glucose levels
Factitious hypoglycemia
Results from exogenous self-administration of insulin or insulin secretagogues medications
Factitious hypoglycemia
Factitious hypoglycemia is more common in?
women with diabetes, during third and fourth decades of life
Plasma Glucose Values
Glucagon and other glycemic hormones are released into the circulation
65-70 mg/dL
Plasma Glucose Values
Observable symptoms of hypoglycemia appear
50-55 mg/dL
Plasma Glucose Values
Considered low value and abnormal for infants (requires further diagnostic test)
< 50 mg/dL
Plasma Glucose Values
Impairment of cerebral function starts
<50 mg/dL
Result of the deficiency of a specific enzyme that causes an alteration of glycogen metabolism
Glycogen Storage Diseases
Increase in glycogen stored in the liver will result to?
Hepatomegaly
Type I Glycogen Storage Disease, most common
Von Gierke
Von Gierke
Defective enzyme
Glucose-6-phosphatase
Von Gierke
Organ affected
Liver and Kidney
Von Gierke
Genetic pattern
autosomall recessive
Von Gierke
Diagnosis
Liver Biopsy using Glycogen stain
Von Gierke
Clinical features
- Severe hypoglycemia
- Ketosis
- Hyperuricemia
- Hyperlipemia
- Elevated lactate levels
Von Gierke
Treatment
Liver transplantation (Liver cells)
Type II Glycogen Storage Disease, affects all organs
Pompe
Pompe
Defective enzyme
a-1,4-Glucosidase
Other enzyme defects causing hypoglycemia
- Glycogen synthase deficiency
- Fructose 1,6-biphosphate deficiency
- Phosphoenolpyruvate carboxykinase deficiency
- Pyruvate carboxylase deficiency
- Glycogen debrancher enzyme deficiency
This enzyme deficiency causes hepatomegaly but no hypoglycemia due to gluconeogenesis.
Glycogen debrancher enzyme deficiency
Cause of failure to thrive syndrome in infants
Galactosemia
Congenital deficiency of one of three enzymes involved in galactose metabolism leading to?
increased galactose in plasma
Galactosemia
Defective enzyme
Galactose-1-phosphate uridyltransferase (G1PU)
Galactosemia inhibits?
Glycogenolysis
Galactosemia
Symptoms
- hypoglycemia
- hyperbilirubinemia
- mental retardation and cataracts
Galactosemia
Treatment
remove galactose from diet
Fructosuria is also known as?
Fructose-1-phosphate aldolase deficiency (Fructosuria)
Fructosuria
Defective enzyme
Fructose-1-phosphatase aldolase
Fructosuria
can also be a deficiency due to?
Fructose-1,6-diphosphatase
Fructosuria
Symptoms
- nausea
- hypoglycemia
- fructose in urine
Fructosuria
Treatment
removal of fructose in diet
Other causes of Hypoglycemia
- Errors in amino acid metabolism
- Long chain fatty acid oxidation
- Alimentary hypoglycemia
- Idiopathic hypoglycemia
Specimen for glucose
- blood (serum/plasma)
- urine
- CSF
Specimen for Glycated /Gycosylated Hemoglobin
Whole blood
Specimen for Insulin testing
Blood (serum/plasma)
Diagnostic test for screening DM suspects
Fasting Blood Sugar (FBS)
FBS
requires how many hours of fasting?
8 hours
FBS
fasting hours should not exceed?
16 hours
FBS
Abnormal indicative value
> 126 mg/dL
FBS
Percentage of Whole Blood Glucose
11%
T/F: Fasting of FBS is not followed if patient’s request include lipid profile analysis.
True
Glucose is increased and decreased in?
increased: morning
decreased: afternoon
Collection of FBS in the afternoon, after fasting in the morning will result to?
false decrease
This refers to simple glucose loading to check insulin secretion
Two hour post prandial (2hr PPBS)
2hr PBBS
Standardized glucose loading is?
75g (taken 2 hours after)
2hr PBBS
DM value after 2 hours
> 200 mg/dL
This is not recommended for routine use under ADA guidelines
Glucose Tolerance Test
OGTT stands for?
Oral Glucose Tolerance Test
2 types of OGTT:
- 3 hours
- 5 hour
5 hour OGTT is done after a?
3 hour blood glucose dip
OGTT
Medications to be avoided
- salicylates
- diuretics
- anti convulsants
- OCPS
- corticosteroid
3 days prior
OGTT
Glucose load for children
1.75 g/kg of weight ng child
OGTT
Glucose load for adult
75g
OGTT
Glucose load for pregnant women
100g
This GTT is done if there is a defect in GI glucose absorption.
Intravenous Glucose Tolerance Test (IGTT)
IGTT
____ is administed via IV
25mg of glucose
IGTT
How many minutes should glucose be administered?
1-2 minutes
IGTT
Blood draw must be done during?
- before infusion
- 1,3,5,10,20,30,40,60 & 120 minutes following infusion
This is an index for long term plasma glucose, indicates compliance and efficacy of tretment.
Glycosylated/Glycated Hemoglobin (HbA1c)
HbA1c
Rate of formation is directly proportional to?
glucose levels
T/F: HbA1c can be used to control glucose levels if patient is diagnosed with DM.
True
HbA1c
2 Methods of measurements
- charge
- structure of glycogroups
HbA1c
Methods under charged differences
- cation-exchange chromatography
- electrophoresis
- isoelectric focusing
- hplc
HbA1c
Methods under structural characteristics of glycogroups
- affinity chromatography
- immunoassay
HbA1c
Most common method for charged differences
High-pressure liquid chromatography (HPLC)
For every 1% increase of A1c, how much Mean Plasma Glucose is increaased?
by 35
4% A1c
65 mg/dL
Testing for Plasma Glucose and HbA1c
patients with stable glycemic control
2 times a year (EVERY 6 MONTHS)
Testing for Plasma Glucose and HbA1c
patients with unstable glycemic control
4 times a year (EVERY QUARTER)
Testing for Plasma Glucose and HbA1c
Two factors
- RBC Life Span
- Average Glucose Concentration
Old red cells, anemia, iron deficiency, pernicious, alcoholism, uremia, illicit and therapeutic drugs, hyperbilirubinemia
False increased HbA1c
Shortened RBC survival, hemolytic anemia, recovery from acute blood loss, abnormal hemoglobin
False decreased HbA1c
Other Laboratory tests for glucose
- Oral Glucose Challenge Test (OGCT)
- Random Blood Sugar (RBS)
- Fructosamine
- 1,5-anhydroglucitol (1,5-AG)
This tolerance test determines fasting hypoglycemia with blood samples drawn at 2 minutes to 2 intervals (6 specimens) to measure glucose and insulin
Tolbutamide tolerance test
Intervals for Tolbutamide tolerance test
2 minutes to 2 hours intervals of 6 specimens
This tolerance test determines reactive hypoglycemia by measuring response of insulin to a cocktail meal
Mixed-meal tolerance test
Mixed-meal tolerance test
Meal with a mixture of carbohydrate, protein, fats
cocktail meal
Mixed-meal tolerance test
Blood sample may be drown at what intervals?
15, 30, 45, 60, 90, 120
Capillary blood glucose is identical to?
arterial blood glucose
CSF glucose concentrations should be approximately?
60-80%
What tube is used for Chemistry in CSF?
1st tube
Normal value of Glucose
Conventional Unit
70-99 mg/dL
Normal value of Glucose
SI unit
3.9-5.5 mmol/L
Normal value of Glucose
Conversion factor
0.055
This enzymatic method targets the consumption of H20.
Glucose Oxidase
Glucose Oxidase
What is used alongside peroxidase to oxidize H202
Reduced chromogen
Glucose Oxidase
This enzyme converts alpha D glucose to beta D glucose
Mutarotase
Glucose Oxidase
Glucose that GOD can measure
beta D glucose
Glucose Oxidase
Monitoring
- consuming H202 in a side reaction
- rate of disappearance of oxygen
Glucose Oxidase
Colorimetric Method
Saifer Gernstenfield Method
Glucose Oxidase
Coupling peroxidase reaction
Trinder reaction
Glucose Oxidase
Chromogen
3-methyl-2-benzothiazolinone hydrazone or N,N-dimethylaniline
Glucose Oxidase
Source of errors
False decreased: BUA, bilirubin,
ascorbic acid
False elevated: strong oxidizing agents, bleach
Glucose Oxidase
Oxygen consumption is also referred to as?
Polarographic GOD
Glucose Oxidase
Catalase utilizes?
ethanol to acetaldehyde
Glucose Oxidase
Molybdate utilizes?
Iodine
This enzymatic method is most accurate
Hexokinase Method
This is used for the REFERENCE METHOD FOR GLUCOSE DETERMINATION
Hexokinase Method
Hexokinase Method
False decrease
- gross hemolysis
- high bilirubin
Hexokinase Method
Product of G6PD
NADPH
This methods are done under clinical microscopy to monitor glucose levels in urine, or other body fluids.
Non-enzymatic Methods
Nelson Somogyi is also known as a?
Copper Reduction Method
Nelson Somogyi measures?
true glucose
Nelson Somogyi
What does it use to remove non-glucose?
Barium Sulfate
Nelson Somogyi
Reagent
arsenomolybdic acid
Nelson Somogyi
Product
arsenomolybdenum blue
si nelson smurf
This is known as the ferric reduction method.
Hagedorn Jensen
Hagedorn Jensen
Principle
Inverse colorimetry
Hagedorn Jensen
Reagent
Ferricyanide (yellow)
Hagedorn Jensen
Product
Ferrocyanide (colorless)
This non-enzymatic method utilizes condensation with aromatic amines.
Ortho-toluidine
Ortho-toluidine
Reagent
O-toluidine in glacial acetic acid
Ortho-toluidine
Product
Schiff’s base (green)
Ortho-toluidine
Disadvantage
corrosiveness and toxicity of reagent
T/F: Ortho-toluidine is the most specific non-enzymatic method.
True
Benedict’s and Fehling’s test is also known as what method?
copper reduction
Benedict’s and Fehling’s test
Stabilizer
citrate or tartrate
Benedict’s and Fehling’s test
Result
deep blue solution to red ppt
This is produced by the liver through fatty acid metabolism as energy source when carbohydrates are low.
Ketones
T/F: Ketones are normally low in the body.
True
Types of Ketones in body
- Acetone (20%)
- Acetoacetic acid (20%)
- 3-B-hydroxybutyric acid (78%)
High ketones is observed/will result to?
- DM
- starvation/fasting
- high-fat diets
- prolonged vomiting
- glycogen storage disease
Used to detect acetoacetic acid
Nitroprusside
Used to detect acetone
Nitroprusside with glycerin
Result in Nitroprusside
purple color
This refers to a DM complication in which glucose passes through the glomerula.
DM nephropathy
DM nephropathy can lead to?
increased urinary albumin
Microalbumin is also known as?
Albuminuria
Persistent albuminuria
Urinary albumin to creatinine ratio
30-299 mg/g
Normal creatinine ratio
<25mg
Persistent albuminuria
Urine collections
3 collections over 3-6 month period
2 of which ay dapat nasa mataas na ratio
Albuminuria is an early indicator of?
diabetic kidney disease
Factors increasing albumin excretion:
- exercise within 24 hours
- infection
- fever
- congestive heart failure
- marked hyperglycemia
- marked hypertension
This is a characteristic of Type 1 DM
Islet autoantibody
Islet autoantibody
Method
Direct ELISA
Islet autoantibody
under direct ELISA
- sample with IgG against islet cells
- ICA-IgG enzyme conjugate
- Substrate
Islet autoantibody
IFA produces?
Apple green fluorescence
This is used for hypoglycemic state testing
Insulin
Insulin
Method
HTRF Sandwich
This peptide is produced with Insulin
C-peptide
under C-peptide ELISA
C-peptide/creatinine ratio and antibody screening
C-peptide
used for diagnosis of?
- MODY
- LADA
- Uncertainty about type 1 versus type 2 diagnosis