Compendium Chemistry Review-Part 2

Front 1

A 25y/o female in late preganancy presents with nausea, RUQ pain, and jaundice. She eventually becomes confused. If acute fatty liver of pregnancy is suspected, what do you expect to see on histologic examination of the liver? What is the treatment of choice?

Back 1

Widespread microvesicular steatosis (especially around Zone 3-pericentrally), with little inflammation or hepatocellular necrosis.

Delivery of the baby

Front 2

What hematologic problem is common in acute fatty liver of pregnancy?

Back 2

DIC

Front 3

A woman in her 3rd trimester of pregnancy presents with jaundice and itching. If cholestasis of pregnancy is suspected, what laboratory findings can you expect? (6 things)

Back 3

Elevated Alk Phos (massively), increased GGT, increased 5'-nucleotidase, direct bilirubinemia (but less than 5mg/dL), normal or mildly elevated transaminases, increased bile acids *** (most characteristic)

Front 4

What are the typical histological findings in cholestasis of pregnancy?

Back 4

dilated canaliculi containing bile plugs, especially in pericentral (zone 3) region

Front 5

Name 4 tests that might be undertaken to evaluate "recurrent pregnancy loss:"

Back 5

Parental or abortus karyotyping, endometrial biopsy, thyroid function, lupus anticoagulant

Front 6

What is luteal phase defect defined as in regards to endometrial biopsy?

Back 6

endometrial histology that is 2 or more days discrepant with dates

Front 7

3 Clinical applications of Toxicology?

Back 7

Drugs of abuse screening, overdose management, therapeutic drug monitoring

Front 8

Define half-life:

Back 8

The time it takes for the drug concentration to reach 1/2 of the starting amount

Front 9

What is first-order kinetics?

Back 9

The rate of loss is exponential during drug elimination

Front 10

What is steady-state, when speaking of drug metabolism? (conceptually)

After how many doses does this usually occur?

Back 10

the amount of drug leaving the body equals the drug entering the body.

Typically reached after 5 doses given at an interval of 1 half-life each.

Front 11

When do the peak and trough of drug dosages occur?

Back 11

Peak: soon after a dose (typically)

Trough: just before a dose

Front 12

What is the most common thing that circulating drugs are bound to?

Back 12

Albumin

Front 13

Which part is the active component of the drug, free or bound?

Back 13

Free

Front 14

Increasing the amount of a protein that binds drugs into the circulation will do what to a drug's availability?

Back 14

Less free drug is available, and thus may have a weaker effect than anticipated for a dose

Front 15

A patient is taking Drug A, a drug with a narrow therapeutic window. He is prescribed a new Drug B. Three days later, he is admitted to the ER with toxicity of Drug A. What could be a mechanism involved in this that includes binding proteins?

Back 15

Likely Drug B displaced Drug A off of a binding protein, increasing the amount of Drug A available

Front 16

Which drugs remain tightly confined in the vascular space, lipophobic (aka-hydrophilic) or lipophilic (hydrophobic)?

Back 16

Lipophobic/hydrophilic

Front 17

The degree to which a drug can distribute into various body tissues (vasculature, adipose tissue, interstitium, etc) is defined as its:

Back 17

Volume of distribution

Front 18

What equation can calculate a drugs volume of distribution?

Back 18

Vd=D/C

where D= dose and C=resulting measured plasma concentration

Front 19

What is the most typical specimen received for drug screening (drugs of abuse)?

Back 19

Urine

Front 20

Urine drug of abuse screens have a low or high sensitivity?

Low or high specificity?

Back 20

High sensitivity

Low specificity

Front 21

What method is most frequently employed in drug of abuse screens?

Back 21

Immunoassay

Front 22

Why does every positive drug of abuse screen require confirmation?

Back 22

False positives due to cross-reactivity can occur

Front 23

What methods are typically used for confirmatory testing for a positive drug of abuse screen?

Back 23

Mass spectrometry and or gas chromatography

Front 24

What is "chain of custody?"

Back 24

A method insuring that a specimen that will have potential consequences is under control of someone or in locked storage at all times.

Front 25

Name 7 different checks that can be performed to evaluate a urine sample for adulteration:

Back 25

Color, Odor, Temperature, pH, Specific gravity, creatinine, nitrite

Front 26

What is the half-life of Cocaine?

Back 26

1 hour

Front 27

How long is cocaine detectable in testing?

Back 27

24-72 hours

Front 28

Key metabolites of cocaine:

Back 28

benzoyl ecgonine methyl ester

Front 29

What is the half-life of heroin?

Back 29

3 minutes

Front 30

How long is heroin detectable in testing?

Back 30

72 hours

Front 31

Key metabolite of heroin:

Back 31

6-acetyl morphine

Front 32

What is the half-life of amphetamine?

Back 32

30 minutes

Front 33

How long are amphetamines detectable in testing?

Back 33

72 hours

Front 34

2 key metabolites of amphetamines:

Back 34

norepinephrine and phenylacetone

Front 35

What is the half-life of PCP?

Back 35

30 minutes

Front 36

How long is PCP detectable in testing?

Back 36

72 hours

Front 37

2 metabolites of PCP:

Back 37

hyroxylated and gluconarated PCP

Front 38

What is the half-life of cannabis?

Back 38

8 hours (wow!)

Front 39

How long is cannabis detectable in testing?

Back 39

Weeks

Front 40

What is the key metabolite of cannabis?

Back 40

delta-9-THC-COOH

Front 41

What is physiologic basis of chest pain in cocaine users?

Back 41

Vasoconstriction with concurrent increased rate and blood pressure

Front 42

What happens to the specificity of myoglobin, CK-MB, and troponin I in cocaine-induced myocardial infarction?

Back 42

CK-MB and myoglobin specificity decrease due to skeletal muscle effects, but Troponin I stays the same

Front 43

Acute intoxication with opiates can lead to: (name 5 symptoms)

Back 43

Sedation, pinpoint pupils, constipation, bradycardia, and hypotension (also respiratory depression)

Front 44

What drug is commonly used to counteract opioid intoxication?

Back 44

Narcan (Naloxone) (also Nalmefene) are synthetic opioid antagonists that counteract the opioid effects

Front 45

Withdrawl from opiates commonly causes the following: (name 7 symptoms)

Back 45

increased lacrimation, rhinorrhea, diaphoresis, dilated pupils, tachycardia, irritability, restlessness

Front 46

What is methadone?

Back 46

A long-acting opioid that can be used to help withdrawl symptoms (less high, more sustained treatment of all withdrawl symptoms)

Front 47

What is clonidine's role in opioid withdrawl?

Back 47

It does not interact with the opiod receptors (like methadone does) but counteracts the symptoms through other mechanisms.

Front 48

Why does propoxyphene cause more symptoms than other opioids?

Back 48

It (and its metabolite) have a interference with calcium channels of the heart, very similar to quinidine.

Can cause cardiac conduction abnormalities and even seizures

Front 49

How do barbituates act on the CNS?

Back 49

They facilitate GABA (a depressant) effect in the CNS, especially in the medulla

Front 50

How do amphetamines (and methamphetamines) act on the CNS?

Back 50

Mediate release of dopamine

Front 51

What are long-term effects of meth and amphetamine use that are related to their mechanism of action?

Back 51

The release of dopamine eventually depletes and destroys the dopamine secreting cells of the substantia nigra and cause Parkinsonian syndrome (it's irreversible!)

Front 52

How does phencyclidine (PCP) act on the CNS?

Back 52

It acts on blocking catecholamine re-uptake

Front 53

What unique symptomatology often occurs with PCP use? (2 things)

Back 53

Its especially known for psychiatric effects. Horizontal nystagmus is very often seen.

Front 54

What other lab testing, besides a drug screen, must be carried out in those individuals suspected of having PCP intoxication?

Back 54

Glucose monitoring: often can cause hypoglycemia
CK and BUN: can cause rhabdomyolysis

Front 55

At what blood alcohol level does coma/death occur?

Back 55

>0.4 % BAC

Front 56

Outline the steps of alcohol metabolism:

In what organ does this occur?

Back 56

Liver

Ethanol metabolized by alcohol dehydrogenase to acetaldehyde.

Acetaldehyde is then converted by aldehyde dehydrogenase to acetic acid

Front 57

What type of tube should whole blood for alcohol testing be submitted in?

Back 57

Sodium fluoride and potassium oxalate will prevent increases (from fermentation) or decreases in the level

Front 58

What methodology is used for analyzing blood for alcohol content?

Back 58

Enzymatic method utilizing alcohol dehydrogenase

Front 59

What is the short-coming is using an alcohol dehydrogenase method for analyzing blood alcohol content?

Back 59

Only measures ethanol, will not pick up methanol

Front 60

What principle is used for analyzing breath alcohol?

Back 60

Since blood alcohol diffuses across alveolar septa and is excreted in expiration, the level can be measured in breath

Front 61

What is the ratio of blood:breath alcohol?

Back 61

2100:1

Front 62

What liver function test is often increased in chronic alcohol users?

When does it increase?

Back 62

GGT (gamma glutamyl transferase)

>4 drinks per day for more than 4 weeks

4 weeks of abstinence to decrease

Front 63

Wat is CDT? What is it being used for evaluating?

Back 63

Carbohydrate deficient transferrin: being investigated as a marker of heavy alcohol consumption. More specific than GGT, at least as sensitive as GGT. Raises sooner than GGT.

Front 64

Which 2 populations may not be as easy to monitor with CDT levels? Why?

Back 64

Women: they have naturally higher CDT, and it doesn't rise as much with alcohol.

Those with chronic liver disease--they have elevated levels of CDT without drinking being involved

Front 65

What RBC parameter measured by a CBC (or peripheral smear review!) is elevated with heavy alcohol consumption?

Back 65

MCV

Front 66

How is anion gap calculated?

Back 66

Sodium - (Chloride + BIcarb) = anion gap

Front 67

When is an increase in anion gap significant?

Back 67

20 mEq/L or higher is significant

Front 68

What is an important cause of decreased anion gap?

Why is this important?

Back 68

Hypoalbuminemia. For every 1gram decrease, there is a 2.5 mEq decrease in anion gap.

Important because this could "mask" an increase in anion gap!

Front 69

An increase in anion gap can lead typically to acidosis or alkalosis?

Back 69

Acidosis

Front 70

Numerous toxins cause anion gap metabolic acidosis: (listed are 12)

Back 70

Acetominophen, Salicylates, ascorbate, hydrogen sulfide, ethylene glycol, methanol, ethanol, formaldehyde, carbon monoxide, nitroprusside, epinephrine, paraldehyde

Front 71

What is a toxidrome?

Back 71

A set of symptoms that can suggest a particular agent or group of agents have been ingested