PBL #1 Flashcards
1
Q
What factors increase UTI risk?
A
- Poor hygiene
- Sexual activity
- Urinary retention
- Postmenopausal status
- Immunosuppression
- Catheter
- Urinary tract abnormality (short urethra)
- Prostate hypoplasia
2
Q
What is the epidemiology of UTI’s?
A
- UTI is most commonly occurring bacterial infection in outpatient setting in U.S.
- Self-reported annual incidence of UTI in 12% of women
- 50% of women will have UTI by age 32
- 250,000 cases of acute pyelonephritis occur each year in the U.S.
- results in >100,000 hospitalizations
3
Q
What are the clinical signs and symptoms of a lower UTI?
A
- Dysuria
- Caused by bacterial colony irritating the urinary epithelium
- Frequency
- Caused by the stimulation of urinary reflex
- Urgency
- Caused by the stimulation of urinary reflex
- Systemic signs are usually absent!!
4
Q
What are the clinical signs and symptoms of a upper UTI?
A
- Dysuria, frequency, and urgency PLUS below:
- Chills and fever
- Caused by release of cytokines
- Flank pain → CVA tenderness
- Caused by inflammation of renal parenchyma and capsule
- Constitutional symptoms caused by bacterial invasion of the kidney
- Nausea and vomiting
5
Q
What is the sensitivity and specificity of urine dipstick evaluation?
A
- performance of ≥ 2 positive findings for prediction of UTI:
- sensitivity 80.3%
- specificity 53.7%
6
Q
What is the value of a urine culture?
A
- GOLD STANDARD
- Detects and identifies the organism causing UTI
- indicates definitive treatment
7
Q
Tell me about empiric antibiotic therapy for UTI
A
- Nitrofurantoin:
- activated when processed in the kidney
- Not high levels to have an effect on kidney
- Accumulates to therapeutic levels in the bladder
- Doesn’t work in upper UTI
- Bactrim (Trimethoprim/Sulfamethoxazole)
- Do not use Bactrim if it has been used within the last 3 months on a given patient
- Fluoroquinolones
- Ciprofloxacin
- Ceftriaxone or aminoglycoside if resistance of E. coli locally is greater 10%
8
Q
What are risk factors for development of nephrolithiasis?
A
- history of renal stone (50% have single recurrence, 10% have multiple recurrences)
- reduced intake or increased water loss
- low urine volume and increased solute production
- high ion levels (calcium, phosphate, oxalate, sodium, and uric acid)
- low urinary pH
- reduced levels of natural calculus inhibitors
- infections (UTI with urease + organisms)
- genetic defects/diseases (hyperparathyroidism, metabolic syndrome, GI dz, sarcoidosis, lesch-nyhan, CF, cystinuria)
- anatomical abnormalities (medullary sponge kidney (tubular ectasia), ureteropelvic junction obstruction, calyceal diverticulum, calyceal cyst, ureteral stricture, vesico-uretero-renal reflux, horseshoe kidney, ureterocele)
- certain drugs
- gout/high purine intake - meat
- oxalate rich foods - spinach, chocolate, nuts
- insulin resistance
- prolonged immobilization
- obesity
- Vitamin C supplements in Men
9
Q
What are the signs and symptoms associated with nephrolithiasis?
A
- Symptoms/signs:
- severe debilitating pain (flank pain)
- (usually unilateral) w/ radiation to low abdomen, crampy, intermittent)
- gross and microscopic hematuria
- N/V
- dysuria, urgency, frequency
- fever and chills possible
- other complications: UTI may present concurrently
- severe debilitating pain (flank pain)
10
Q
What is the sensitivity and specificity of x-ray, ultrasound, IVP, and CT for identifying nephrolithiasis?
A
- X-ray:
- sensitivity: 45-59%
- specificity: 71-77%
- US:
- sensitivity: 19%
- specificity: 97%
- IVP:
- sensitivity: 64-87%
- specificity: 92-94%
- CT: detect stones as small as 1-2 mm
- sensitivity: 95-100%
- specificity: 94-96%
- ***Noncontrast CT is first line w/ US as alternative
11
Q
What is a urinary tract antiseptic?
A
- Drug that is excreted mainly by way of the urine and performs its antiseptic action in the bladder.
- These drugs may be given before examination of or operation on the urinary tract, and they are sometimes used to treat urinary tract infections.
12
Q
What are the primary mechanisms of action of the urinary tract antiseptics and their major toxicities?
A
- Nitrofurantoin
- reactive intermediates generated that inactivate/alter ribosomal proteins interfering with many cellular processes
- therapeutic doses may not be achieved if patient has Crcl of less than 40
- Side effects:
- hypersensitivity
- hepatotoxicity
- pulmonary fibrosis in the elderly
- hemolytic anemia if G6PD deficient
- Methanamine
- Antibacterial effect of methenamine hippurate or methenamine mandelate depends on conversion of methenamine to formaldehyde in an acid medium (acidic urine)
- formaldehyde is an antibiotic
- nalidixic acid
- oxolinic acid
13
Q
What situations are considered complicated UTIs?
A
- Children
- Males
- Pregnancy
- Neurogenic bladder
- Postmenopausal
- Stones
- Obstruction
- Diabetes Mellitus
- Renal insufficiency
- Immunosuppression
14
Q
E. coli and UTI’s
A
- colonies appear to have a green metallic sheen on EMB agar
- Gram (–) bacilli
- Catalase +
- Oxidase –
- reduces nitrates to nitrites → will see positive nitrites in urine
15
Q
What virulence factors does E.coli use in UTIs?
A
- adherence factors: pili, adhesins
- type 1 pilus (fimbria)
- immune evasion: capsular antigens
- other: flagella
