bacterial infections Flashcards
botulism
neuroparalytic disease (unique from others)
produced by clostridium botulinum (anaerobic, spore-forming bacillus found in soil)
three forms of botulism:
food-borne
infant botulism
wound botulism
mechanism of action of botulinum toxin
toxin blocks release of ACH from vesicles at neurons, preventing use of muscles
botulism: clinical findings
Visual Disturbance (within 36 hours):
-Diplopia
-Loss of accommodation
-Fixed dilated pupils
-Ptosis (eyelid droop)
-Extraocular movement palsy
Dry mouth
Dysphagia/dysphonia (difficulty swallowing, not pain)
Nausea and vomiting
botulism clinical findings cont.
Acute, bilateral cranial nerve neuropathy (unique part):
-Symmetric descending weakness (only thing that will cause symmetric descending weakness)
-Paralysis progressing to respiratory failure and death
The sensory examination is normal (can feel face, just can’t move it)
-MOTOR NEURONS ONLY
note on emphasis:
stroke will knock out everything
botulism: sensory is fine, but paralysis and symmetrical descending weakness
botulism is very serious and can cause death
botulism
diagnostic findings: toxin analysis of serum, stool, vomit, food
Treatment: serum antitoxin
In most cases will make something like this a test question:
do you eat a lot of jarred or self-canned foods? Botulism!!
Campylobacter jejuni infection
One of the most frequently occurring bacterial agents of gastroenteritis
Occurs worldwide (diarrhea in children in underdeveloped countries)
Highest incidence <5 years old, especially in resource-limiting settings
Estimated 1.3 million cases annually in US
Campylobacter jejuni sources of contamination
Poultry
Unpasteurized milk
Contaminated drinking water (Traveler’s Diarrhea)
-(Traveler went (camp)ing in costa rica)
Campylobacter jejuni risk factors
International travel in the week prior to onset
Use of proton pump inhibitors and histamine-2 receptor antagonists (why?)
Campylobacter jejuni symptoms
-Arise 1-3 days after exposure; typical duration 1 week
-Watery diarrhea which may be bloody
-Abdominal pain/cramps
-Nausea
-Occasional vomiting
-Weight loss
Campylobacter jejuni Diagnosis
Gold standard: Stool culture
not usually done in clinical practice
-takes too long, symptoms only last a week
Campylobacter jejuni management
Self-limiting
Supportive therapy: Fluid and electrolyte replacement
Campylobacter jejuni: traveler’s diarrhea
Antibiotics are usually recommended
Either azithromycin, 1 g orally as single dose
Or Ciprofloxacin, 500 mg twice daily orally for 3 days
note: there are reasons why you would choose one over the other (heart issues for ex.)
rare complications of campy jejuni
-Bacteremia
-Guillain-Barre syndrome
-Reactive arthritis
GB syndrome: (“out of the blue stroke kind of” where nerves break down [ex. if they get a cold] but can regenerate back to normal [so severe patient must learn to walk again])
Chlamydia Trachomatis
Sexually transmitted disease caused by Chlamydia trachomatis
-Often asymptomatic
-Common cause of urethritis, cervicitis, and post-gonococcal urethritis.
-Occasionally causes epididymitis, prostatitis, or proctitis
Leading cause of infertility in females in the US
Symptoms causing suspect of Chlamydia
-Vaginal discharge
-Postcoital or intermenstrual bleeding or dysuria in women
-Urethral discharge, dysuria, scrotal pain or swelling in men
-dysuria: painful urination
Chlamydia: Diagnostic findings
-Highly sensitive nucleic acid amplification tests (NAAT)
-In women: Vaginal swab
-In men: Use first-void urine
-Rectal and oropharyngeal swabs may be performed, if necessary
Chlamydia: treatment (meds)
Doxycycline orally 100 mg twice daily for 7 days
-Preferred
-DO NOT USE in pregnancy
A single oral 1-g dose of azithromycin 500 mg
-Preferred for pregnancy or with concern of
adherence
levofloxacin once daily for 7 days.
Chlamydia treatment (without meds)
-Abstinence from sexual intercourse for 1 week after completion of medication
-Retesting is not recommended except in pregnancy
-Screening for reinfection is recommended in all patients 3 months after treatment
-Test and treat sexual partners (within 60 days)
Chlamydia treatment (without meds)
-Abstinence from sexual intercourse for 1 week after completion of medication
-Retesting is not recommended except in pregnancy
-Screening for reinfection is recommended in all patients 3 months after treatment
-Test and treat sexual partners (within 60 days)
Cholera (risk factors)
An acute diarrheal illness caused by Vibrio cholerae
-The disease is toxin-mediated (getting sick off the
toxin, not the bacteria)
Risk factors: Travel endemic area, contact with infected person, crowding, war, famine, refugee camps
Cholera: Clinical Findings
-The toxin produces hypersecretion of water and chloride ion in the small intestine
-Sudden onset of severe, frequent watery diarrhea(!!)
-Massive diarrhea of up to 15 L/day.
-Liquid stool is gray; turbid; and without fecal odor, blood, or pus (“rice water stool”).
-Severe dehydration may lead to hypotension and shock within hours
-Fever is rare
-Can kill you
Cholera: Diagnostic findings and treatment
Diagnostic Findings:
-Stool cultures are positive, and agglutination of vibrios with specific sera can be demonstrated
Treatment:
-Replacement of fluids
-Supportive management
Cholera: Antimicrobial treatment
Antimicrobial therapy will shorten the course of illness
Several antimicrobials are active against V cholerae, including:
Tetracycline
Ampicillin
Chloramphenicol
Fluoroquinolones
Azithromycin
Trimethoprim-sulfamethoxazole
Diphtheria
-Acute infection caused byCorynebacterium diphtheriae
-An acute infection with a toxin-producing strain of Corynebacterium diphtheriae
-Usually attacks the respiratory tract but may involve any mucous membrane or skin wound
-The organism is spread primarily by respiratory secretions
-Exotoxin produced by the organism is responsible for myocarditis and neuropathy
Diphtheria: Clinical findings (3 forms)
Three forms of diphtheria:
Nasal infection
-Nasal infection produces few symptoms other than a nasal discharge
Laryngeal infection
-Laryngeal infection may lead to upper airway and bronchial obstruction
Pharyngeal diphtheria
-In pharyngeal diphtheria, the most common form, a tenacious gray membrane covers the tonsils and pharynx
Diphtheria: Treatment
Removal of membrane (from throat)
Antitoxin
Antibiotics: Penicillin or Erythromycin
Diphtheria: Treatment
Vaccine: Booster dose of diphtheria toxoid
-Plus, active immunization if not previously immunized,
-Antitoxin prepared from horse serum
-As well as a course of penicillin or erythromycin
-Azithromycin, clarithromycin or erythromycin for
carrier state (all -mycin)
Diphtheria: Prevention
Isolation from potentially sick person
Prophylaxis for close contacts:
-Booster dose of diphtheria toxoid
-Course of penicillin or erythromycin
Women should receive Tdap with each pregnancy, preferably between 27 and 36 weeks
Diphtheria: Complications
Exotoxin produced by the organism is responsible for myocarditis and neuropathy
Gonorrhea
-Sexually transmitted infection
-Caused byNeisseria gonorrhoeae, a gram-negative
diplococcus
-Greatest incidence in the 15- to 29-year-old age group.
-The incubation period is usually 2–8 days.
-Can infect any mucocutaneous surface
-Oral, urethral, vaginal, anal
Gonorrhea: clinical findings in men
Men:
-Burning on urination and a serous or milky discharge(!)
-One to 3 days later, the urethral pain is more pronounced and the discharge becomes yellow, creamy, and profuse, sometimes blood-tinged.
-Chronic infection leads to prostatitis and urethral strictures (can also increase risk of prostate cancer)
-Rectal infection is common in men who have sex with men
-Atypical sites of primary infection (eg, the pharynx) must always be considered
-MAY PRESENT ASYMPTOMATIC
Gonorrhea: clinical findings in women
Women:
-Becomes symptomatic during menses
-Women may have dysuria, urinary frequency, and urgency, with a purulent urethral discharge
-Vaginitis and cervicitis with inflammation of Bartholin glands are common
-It can progress to involve the uterus and tubes with acute and chronic salpingitis, with scarring of tubes and sterility
-Can lead to Pelvic Inflammatory disease (PID)
-Rectal infection may result from spread of the organism from the genital tract or from anal coitus
Gonorrhea: clinical findings
Disseminated Disease: systemic complications follow the dissemination into bloodstream
Two distinct clinical syndromes:
-Either purulent arthritis or
-(possible pearl): The triad of rash, tenosynovitis (inflamed tendons), and arthralgias (join pain)
-are commonly observed in patients with
disseminated gonococcal infection, although overlap
can be seen.
Gonorrhea: Clinical findings
Conjunctivitis (eyes!)
-The most common form of eye involvement is direct inoculation of gonococci into the conjunctival sac
-In adults, this occurs by autoinoculation of a person with genital infection
-The purulent conjunctivitis may lead to loss of the eye unless treated promptly
Gonorrhea: Diagnostic Findings
-Historically gram stain & culture of discharge was performed –uncommon now
-Nucleic acid amplification testing (NAAT) of discharge or urine for men & women
-Looks for gonorrhea & chlamydia concurrently
-Excellent sensitivity & specificity
-Doesn’t preclude doing a pelvic exam!
test Q?
GC-CHL
(check gonorrhea and chlamydia together, they’re best buds)
Gonorrhea: treatment
Ceftriaxone 500mg IM X1
Conjunctivitis
A single 1-g dose ofceftriaxoneis effective
Gonorrhea: Treatment of pelvic inflammatory disease
Ceftriaxone
AND
Probenecid
AND
Doxycycline
with or withoutmetronidazole