Micro 8 - UTI

Question 1

What do we see in the urine lab in cystitis?

Answer 1

WBC and often RBCs. Casts won’t be seen because they are only seen when the kidneys are affected.

Question 2

Who are more predisposed to UTIs?

Answer 2

Women, males with congenital defects (hypospadias and epispadias), enlarged prostate, static urine in the bladder, diabetics, pregnant women, vesicoureteral reflux.

Question 3

What are the symptoms of pyelonephritis?

Answer 3

Fever, chills, flank pain, hematuria, WBC casts.

Question 4

What is the Nitrite test?

Answer 4

Test that checks for the presence of Enterobacteriaceae. It will not detect other types of bacteria causing the UTI.

Question 5

What does the Leukocyte esterase test indicate?

Answer 5

A positive LE indicates inflammation in the urinary tract. It can also be positive when there is a gonorrhea infection.

Question 6

What are the 4 most common causes of UTI?

Answer 6

E.coli (80%), Staph saprophyticus, Klebsiella pneumoniae, Proteus.

Question 7

What is interesting about UTIs caused Proteus mirabilis and Proteus vulgarus?

Answer 7

They are motile and have urease, which can cause ammonium-magnesium renal stones (Staghorn calculi).

Question 8

What is the treatment for UTIs?

Answer 8

Has to cover G(-) organisms. Use sulfonamides w/ trimethoprim, aminopenicillins, fluoroquinolones, nitrofurantoin.

Question 9

What sulfonamides are used in UTIs?

Answer 9

Sulfamethoxazole (SMX) y sulfadiazine.

Question 10

What is the mechanism of action of sulfonamides?

Answer 10

They are folic acid inhibitors: bacteria can produce it while humans have to absorb it from the environment. Sulfonamides are competitive inhibitors of dihydropteroate synthetase.

Question 11

What are the uses of sulfonamides?

Answer 11

They cover some G(+) and G(-). They are used in UTIs, skin infections. It is always combined with trimethoprim (TMP-SMX).

Question 12

What are the side effects of sulfonamides?

Answer 12

Hypersensitivity reactions, hemolysis (especially to G6PD patients), Nephrotoxicity, Kernicterus (to fetus), displace other drugs from albumin (eg. Warfarin), Steven-Johnson syndrome, and photosensitivity.

Question 13

What drugs have photosensitivity reactions?

Answer 13

[SAT for a photo]

Sulfonamides, Amiodarone, Tetracycline.

Question 14

What would be three factors that can lead to resistance of sulfonamides?

Answer 14

Altered dihydropteroate synthetase, decreased drug uptake, and increased PABA synthesis.

Question 15

What are the drugs that can cause a sulfa allergy?

Answer 15

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Sulfasalazine, Probenecid, Furosemide, Celecoxib, Thiazides/TMP-SMX, Acetazolamide, Sulfonylureas.

Question 16

What are the three major categories of drugs and one outlier that can cause Steven-Johnson syndrome?

Answer 16

Penicillin, sulfa, and seizure drugs. The outlier is allopurinol.

Question 17

What are 5 seizure drugs that can cause Steven-Johnson syndrome?

Answer 17

Ethosuximide, lamotrigine, carbamazepine, phenobarbital, phenytoin.

Question 18

What is the mechanism of action of Trimethoprim?

Answer 18

It inhibits Dihydrofolate reductase

Question 19

What is the mechanism of action of Methotrexate?

Answer 19

Inhibit Dihydrofolate reductase.

Question 20

What is Cystitis and what are it’s symptoms?

Answer 20

Infection of the bladder, a lower urinary infection. Causes painful urination, frequency, urgency and suprapubic pain.

Question 21

What is the mechanism of Nitrofurantoin?

Answer 21

Bacteriocidal. Reduced by bacterial proteins to a reactive intermediate that inactivates bacterial ribosomes.

Question 22

When do we use nitrofurantoin?

Answer 22

Mild UTIs and cystitis (not pyelonephritis) by E.coli or S.saprophyticus (not Proteus). Safe in pregnancy.

Question 23

What are 3 flouroquinolones used in UTIs?

Answer 23

Levofloxacin, ciprofloxacin, Norfloxacin.

Question 24

What is the mechanism of action of fluoroquinolones?

Answer 24

It inhibits DNA gyrase (topoisomerase II).

Question 25

What is contraindicated when taking flouroquinolones?

Answer 25

Antiacids and supplements (that includes Ca, Fe, or Mg).

Question 26

To whom is flouroquinolones contraindicated and why? What is the one special occasion?

Answer 26

Contraindicated in pregnancy and children because it damages cartilage. It can cause tendonitis and tendon rupture in adults. Can be used in children with cystic fibrosis because they are predisposed to lung infections, especially to pseudomonas infections.

Question 27

What is the mechanism for metronidazole?

Answer 27

It gets absorbed by the microorganism and forms toxic free radicals that damage the organism’s DNA.

Question 28

Which organisms are susceptible to Metronidazole?

Answer 28

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Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobic bacteria, h.Pylori.

Question 29

What is a special side effect of metronidazole?

Answer 29

Has a disulfram-like reaction when combined with alcohol.

Question 30

What does disulfiram do?

Answer 30

It inhibits aldehyde dehydrogenase, leading to accumulation of aldehyde causing: flushing, sweating, nausea, headache, hypotension.

Question 31

What infections is klebsiella pneumonia known for causing?

Answer 31

Aspiration pneumonia, lung abscesses, UTIs (nosocomial).

Question 32

What is the function of the enzyme urease?

Answer 32

Splits urea into NH3 and CO2.

Question 33

RFF: Most common medication used for UTI prophylaxis.

Answer 33

TMP-SMX.

Question 34

RFF: Most common bacterial in a patient with struvite kidney stones.

Answer 34

Proteus, then Staph.