Infectious Disease Bacterial Flashcards

Question

Botulism Epidemiology

Answer 1

On a molecular weight basis, botulinum toxins are the most potent toxins known Eight antigenically distinct C botulinum toxins (A through G), Each produce only a single toxin type, A & B most potent Last 20 years, toxin A most common foodborne outbreaks; then toxins B and E 15% of outbreaks, the toxin type is not determined ~154 cases of botulism reported to CDC annually 75% infantile botulism (mean age 3 months old - < 1% mortality) 16% foodborne (5-10% mortality) 2 % wound (15-17% mortality)

Answer 2

> 90% of patients with botulism have 3-5 signs or symptoms: nausea, vomiting, dysphagia, diplopia, dilated/fixed pupils, and an extremely dry mouth unrelieved by drinking fluids GI – prior to paralysis nonspecific findings (nausea, vomiting, abdominal pain, malaise, dizziness, dry mouth, dry throat, sore throat) Neurologic – cranial nerves first (except CN 1 and 2), blurred vision, diplopia, ptosis, EOM weakness or paresis, fixed/dilated pupils, dysarthria, dysphagia, and/or suppressed gag reflex, symmetric descending paralysis; weakness of motor & autonomic nerves Respiratory - muscle weakness may be subtle or progressive, rapid progression to respiratory failure, affected muscles often head/neck, intercostal, diaphragmatic & extremities

Answer 3

Paralytic ileus advancing to severe constipation Gastric dilatation Bladder distention advancing to urinary retention Orthostatic hypotension Reduced salivation Reduced lacrimation

Answer 4

CBC – WNL CSF – WNL Mouse neutralization bioassay (isolates the botulism toxin from serum, stool, vomitus, gastric aspirate, suspected foods) Wound cultures for C botulinum Electromyography (EMG) - reduced amplitude of compound muscle action potentials (nonspecific and non-diagnostic) Edrophonium chloride (Tensilon) - acetylcholinesterase inhibitor used as test for myasthenia gravis may be falsely positive, typically much less dramatically positive than in patients with myasthenia gravis

Answer 5

Supportive care primarily (resolution ~ 30-100 days) Respiratory – hygiene, intubation if vital capacity < 30 % Risk for aspiration pneumonia GI – suction/hyperalimentation for ileus Foley for urinary retention DVT prevention Debridement of contaminated wountds Antibiotics No effect in food born botulism High dose PCN (alternatives clindamycin or chloramphenical) in wound botulsm Botulinum antitoxin, heptavalent (HBAT) - investigational antitoxin for naturally occurring non-infant botulism (equine-derived antitoxin with passive antibody (ie immediate immunity) against C botulinum toxins A, B, C, D, E, F, and G

Answer 6

High-temperature pressure cooking eliminates spores from low-acid fruits & vegetables Boiling for 10 minutes kills bacteria & destroys heat labile botulism toxin, but spores resistant; survive boiling 3-5 hours Food with botulism toxins usually putrefactive odor, but contaminated food may also look & taste normal Recommendations: When preserving food at home, kill C botulinum spores by pressure cooking at 250°F (120°C) for 30 minutes Toxin can be destroyed by boiling for 10 minutes or cooking at 175°F (80°C) for 30 minutes Do not eat or taste food from bulging cans Discard food that smells bad Cessation of intravenous drug use prevents wound botulism (remember just say ‘no’)

Answer 7

Chlamydophila pneumoniae - mild pneumonia or bronchitis in adolescents & young adults, more severe in older adults Chlamydophila psittaci - psittacosis or ornithosis (preferred term) after exposure to infected birds, clinical spectrum: asymptomatic to fulminant toxic syndrome, present with pneumonia or FUO C trachomatis - STDs (trachoma, PID, cervicitis) & pneumonia (primarily in infants, young children, immunocompromised adults & lab workers)

Answer 8

Small, gram-negative, obligate intracellular organisms 15 immunotypes A-C cause trachoma (chronic conjunctivitis endemic in Africa and Asia) D-K, genital tract infections L1-L3, lymphogranuloma venereum (associated with genital ulcer disease in tropical countries) Chlamydia - most commonly reported bacterial STD in US & a leading cause of infertility in women

Answer 9

300,000 cases per year in US 10-20% of community-acquired pneumonia (CAP) cases among adults 4-year incidence cycle for C pneumoniae pneumonia (although occurs annually) Highest incidence in 7-40 year olds More common in males (60-90%) than in females (possibly due to cigarette smoking) High reinfection among elderly persons 50% of young adults; 75% of elderly persons have serologic evidence of a previous infection

Answer 10

Incubation period ~ 3-4 weeks Usually gradual onset that may be biphasic Most infected persons are asymptomatic or mild respiratory illness Bronchitis or pneumonia may follow URI symptoms (rhinitis, laryngitis, pharyngitis, sinusitis) in 1-4 weeks Sputum is usually scant, cough is prominent Prolonged symptoms (cough and malaise) for weeks to months despite antibiotics Hoarseness is more common in C pneumoniae infection than in mycoplasmal infection or other pneumonias Headache (58%) – non-classic pneumonia finding Fever often present first few days, but absent by the time of clinical examination Pharyngeal erythema without exudate seen in atypical pneumonias; sinus percussion tenderness is more common with C pneumoniae pneumonia Rhonchi & rales present even in mild disease

Answer 11

Anyone exposed to infected birds at risk for infection with C psittaci (found worldwide & year-round, most cases sporadic) Ornithosis in the US declined after Introduction of antibiotic-laced bird feed Quarantine period of 30 days for imported birds 1988-1998, 813 CDC reported cases of psittacosis (70% exposure to pet birds), often not correctly diagnosed or reported Incubation period 5-14 days or longer Abrupt onset of constitutional symptoms is common Severity ranges from asymptomatic to severe pneumonia with systemic illness

Answer 12

Nonproductive cough has been observed in 50-80%, but often absent initially Chest pain is common, but pleuritic pain is rare Ausculatory findings sparse; may underestimate the extent of pneumonia Fever most common symptom (103-105°F or 39.4-40.5°C), defervescence is usually slow May present with culture-negative endocarditis or fever of unknown origin < 50% have photophobia, epistaxis, tinnitus, deafness, gastrointestinal (GI) symptoms & arthralgia

Answer 13

Pulse-temperature dissociation (fever without elevated pulse - also seen in Q fever, typhoid fever, & Legionnaires disease) Somnolence Splenomegaly Erythematous, blanching, maculopapular rash (e.g. Horder spots) in the presence of pneumonia (similar to rose spots in typhoid fever) Meningitis or encephalitis, including focal neurologic deficits and seizures, hepatitis, hemolytic anemia, DIC, reactive arthritis or cutaneous findings (Horder spots (rare), splinter hemorrhages, superficial venous thromboses, acrocyanosis, erythema nodosum)

Answer 14

~ 12,000 cases of pneumonia in infants annually ~ 5-22% pregnant women have C trachomatis infection cervical infection 30-50% of neonates exposed at birth become culture positive 15-25% present with clinical conjunctivitis and/or nasopharyngitis, then develop neonatal pneumonitis ~ 11-20% of infants born to infected mothers develop symptomatic pneumonia before 8 wo

Answer 15

Nasal obstruction & discharge, staccato cough, tachypnea (lasting often 3 weeks or more before presentation) Most afebrile, only moderately ill Scattered crackles with good breath sounds without wheezing Conjunctivitis and abnormal middle ear exam in ½ of infants with pneumonia Adult cases only in immunocompromised

Answer 16

IgM titer > 1:16 or 4-fold increase in IgG titer by microimmunofluorescence Absence of antibodies does not exclude diagnosis (IgM may take 6 weeks, IgG 8 weeks w/ primary infection PCR - pharyngeal swab, bronchoalveolar lavage, sputum, or tissue used in some labs (less sensitive than IgM) Cell culture oropharyngeal swabs - best test but only in research labs CBC usually not elevated Alkaline phosphate may be elevated Typically a single subsegmental infiltrate in the lower lobes, consolidation rare, pleural effusions 20-25%, residual changes observed even after 3 months

Answer 17

Paired acute/convalescent sera advised, 3rd sample may be needed Serologic tests are preferred, culture is difficult & hazardous CDC case definition Isolation of organism by culture Compatible clinical illness with a 4-fold rise in complement fixation (CF) or microimmunofluorecsence (MIF) antibodies against C psittaci (to a reciprocal titer of 32 or greater by paired sera at least 2 wk apart) Detection of an IgM titer of 16 or greater against C psittaci by MIF CF test can cross-react with C pneumoniae & C trachomatis MIF & PCR assays can be used to distinguish C psittaci from other chlamydial species Single lower lobe infiltrate most common finding, also patchy reticular infiltrates, diffuse ground-glass or miliary pattern, small pleural effusions in 50%

Answer 18

Clinical findings consistent Confirmation by chlamydial inclusions or elementary bodies on Giemsa-stained smears of the conjunctivae or nasopharynx Testing of the infants may show findings of elevated antichlamydial IgM titer CBC with peripheral eosinophilia Elevated serum immunoglobulin levels characteristic Should screen the parents for chlamydia & other sexually transmitted diseases Bilateral interstitial infiltrates with hyperinflation

Answer 19

Tetracyclines and macrolides drugs of choice: Tetracyclines bacteriostatic; inhibit protein synthesis Macrolides inhibit bacterial growth , possibly blocks dissociation of peptidyl t-RNA from ribosomes, stops protein synthesis

Answer 20

Empiric treatment, lack of rapid testing, in 60% mixed infections present (e.g. pneumococci, mycoplasma, legionellae) Doxycycline preferred, continue 10-14 days after defervescence Alternatives - erythromycin/azithromycin/clarithromycin effective; fluoroquinolones less effective

Answer 21

Tetracycline/doxycycline preferred, treatment 10-21 days | Azithromycin/erythromycin may be less efficacious

Answer 22

Erythromycin preferred, amoxicillin less effective (TCN not option) Mother and sexual partner need screening for chlamydia

Answer 23

Chlamydia infects columnar epithelial cells, adolescent female at more risk, squamocolumnar junction on the ectocervix until early adulthood Epithelial cells response is neutrophilic infiltration, followed by lymphocytes, macrophages, plasma cells, and eosinophilic invasion Cytokine and interferon released by epithelial cells induce inflammation C trachomatis often spread through sexual activity Infected male - 25% chance per sexual encounter of transmitting the infection to uninfected female Infected mother – transmission rate to newborn 50-60%, causing conjunctivitis (in most cases) or pneumonia (in 10-20% cases)

Answer 24

~ 50% infected males and 80% infected females are asymptomatic Symptomatic infection may cause mucopurulent cervicitis in females & urethritis in males Ascending infection causes PID in women & most common cause of epididymitis in men < 35 yo 5-10% women with PID develop perihepatitis (Fitz-Hugh-Curtis syndrome) 40 % of women and 20% of men with chlamydial infection are co-infected with gonorrhea

Answer 25

Nonwhite race Multiple sexual partners or a new sexual partner Age 15-24 years (especially age younger than 19 years) Poor socioeconomic conditions (e.g. homelessness) Exchange of sex for drugs or money Single marital status Intercourse without a barrier contraceptive History of a previous STD or current coinfection with another STD Certain cytokine polymorphisms – associated with severe disease and risk of tubal infertility Certain variants in Toll-like receptor 1 and 4 genes –predispose to infection Having been a foster child (males only)

Answer 26

Women are more likely to be asymptomatic than men (remember 80% vs 50%) Women also more likely to develop long-term complications (e.g. PID & infertility) Chlamydia has been isolated in approximately 40-60% of males presenting with nongonococcal urethritis Epidemiologic studies indicate a high prevalence of asymptomatic men acting as a reservoir for chlamydial infection Findings for all patients with chlamydial infection: Possible history of sexually transmitted diseases (STDs) Dysuria Yellow mucopurulent discharge from the urethra

Answer 27

Vaginal discharge Abnormal vaginal bleeding (postcoital or unrelated to menses) Dyspareunia History of sexual activity without condoms or condom failure Proctitis, rectal discharge, or both in cases of receptive anal intercourse Slow onset and progression of lower abdominal pain Fever (in pelvic inflammatory disease [PID]) No symptoms (in 80%)

Answer 28

Urethral discharge History of sexual activity without condoms or condom failure Proctitis, rectal discharge, or both in cases of receptive anal intercourse Unilateral pain and swelling of the scrotum Fever No symptoms (in 50%)

Answer 29

Symptoms of pneumonia (if present), beginning at 1-3 months Symptoms of conjunctivitis (if present), developing at 1-2 weeks In pneumonia, cough and fever (though classic description is afebrile) In conjunctivitis, eye discharge, eye swelling, or both

Answer 30

Cervical friability (easy bleeding on manipulation) Intermenstrual bleeding Mucopurulent cervical or vaginal discharge Urethral discharge (usually thin & mucoid) Mucopurulent rectal discharge (from anal intercourse) Cervical motion tenderness Dysuria Adnexal fullness or tenderness, associated with progression to PID Lower abdomen tender to palpation Upper right quadrant abdominal tenderness (Fitz-Hugh-Curtis syndrome)

Answer 31

Mucopurulent urethral discharge (elicited by having the examiner or patient milk the urethra) Mucopurulent rectal discharge (from anal intercourse) Urinary frequency or urgency Dysuria Scrotal pain, tenderness, or swelling (sometimes unilateral) Perineal fullness (related to prostatitis)

Answer 32

One of the leading causes of infertility in women Leading cause of PID Risk of ectopic pregnancy in women who have had PID is 7-10 times greater than without h/o PID 15% of women with h/o PID may have long-term chronic abdominal pain related to ovarian/fallopian tube adhesions Fitz-Hugh-Curtis syndrome (perihepatitis) although rare is 5 times more likely to be caused by Chlamydia than by N gonorrhoeae, it may lack findings typical of PID

Answer 33

Because of risk of multiple sexually transmitted infections, all patients with any sexually transmitted disease (STD) should be tested for chlamydial infection Endocervical, urethral, rectal, or oropharyngeal specimens should be obtained and assayed for C trachomatis infection in both males & females based on sexual practices A voided urine sample, whether midstream or first-void, effectively captures the chlamydial organism for nucleic acid amplification testing (NAAT) Infants with suspected chlamydial pneumonia need nasopharyngeal swab for Chlamydia culture In severe or complicated cases, consider sending bronchoalveolar lavage fluid for chlamydial culture CBC revealing peripheral eosinophilia in the appropriate clinical situation consistent with C tachomatis pneumonia Infants with suspected chlamydial conjunctivitis, antigen/DNA detection test, chlamydial culture, or both, using scrapings from the palpebral conjunctiva If the mother had documented chlamydial infection during pregnancy & and untreated, presumptively treat the infant, even without confirmation of infection CBC performed for suspected pelvic inflammatory disease (PID) HIV testing (coinfection is not uncommon)

Answer 34

In women, a Papanicolaou (Pap) smear (the risk of cervical cancer is increased 6.5-fold) Testing sexual partners for Chlamydia Pregnancy test mandatory for females with suspected chlamydial infection (early diagnosis & treatment guidance--pregnancy a contraindication for doxycycline and ofloxacin, critical to obtain a pregnancy test before beginning treatment with these drugs) Cytology is used mainly for diagnosing infant inclusion conjunctivitis and ocular trachoma through the demonstration of intracytoplasmic C trachomatis inclusions in HeLa cells (i.e. continuously cultured carcinoma cell line used for tissue cultures)

Answer 35

C trachomatis grows only within columnar cells, must obtain specimen containing urethral or cervical cells, collecting pooled secretions ineffective Assays for DFA, ELISA, DNA probes have overall sensitivity of 80-92%; specificity of 99% Direct fluorescent antibody (DFA) - sensitivity of 50-80% and a specificity of 99% specificity, method for confirming other assays (labor intensive and requires skilled personnel) Enzyme-linked immunosorbent assay (ELISA) - sensitivity of 40-60% and specificity of 99% useful because its automatable and cost-effective for ED or OP offices Chlamydial DNA probes allowing detection of C trachomatis & N gonorrhoeae from voided urine specimens (can be used to evaluate possible sexual abuse, becoming increasingly cost effective)

Answer 36

US Preventive Services Task Force recommendations for screening women for chlamydial infection: Screen for chlamydial infection in all sexually active nonpregnant young women aged 24 years or younger and for older nonpregnant women who are at increased risk Screen for chlamydial infection in all pregnant women aged 24 years or younger and in older pregnant women who are at increased risk Do not routinely screen for chlamydial infection in women aged 25 years or older, regardless of whether they are pregnant, if they are not at increased risk

Answer 37

Ultrasonography may be performed to look for tubo-ovarian abscess CT may identify Fitz-Hugh-Curtis syndrome (perihepatitis) CXR – infants with pneumonia

Answer 38

CDC recommends azithromycin and doxycycline as first-line drugs for the treatment of chlamydial infection, 95% effective 2nd line antibiotics (erythromycin, penicillins, and sulfisoxazole) less effective & more adverse effects Lower genital infections – recommended single-dose, directly observed treatment (reduces noncompliance) Upper genital tract disease should be suspected and treated to avoid complications (e.g. infertility, sepsis, chronic pelvic pain) New DNA/antigen detection with urine specimens may presume uncomplicated lower tract infection

Answer 39

for adolescents with PID to improve compliance & monitoring; discharge when clinical improvement; completed antibiotic course Upper genital tract infections often treated with 10-day course that includes treatment of gonorrhea (some on inpatient basis only, usually 10-14 days) Chlamydial conjunctivitis and pneumonia are usually treated for a total of 14 days Sexual partners of the index case should be treated if the last sexual encounter was within 60 days Treatment for chlamydial indicated for patients being treated for gonorrhea

Answer 40

Follow-up culture is not recommended after azithromycin or doxycycline therapy, F/u culture may be considered in pregnancy after erythromycin or amoxicillin therapy (non-culture tests may give false positive results from nonviable organisms) Patients should abstain from sexual intercourse for 7 days after single-dose therapy or until the end of a longer regimen Patients also should refrain from sexual intercourse until all of their sex partners have been cured

Answer 41

Erythromycin base 500 mg orally four times a day for 7 days OR Erythromycin ethylsuccinate 800 mg orally four times a day for 7 days OR Levofloxacin 500 mg orally once daily for 7 days OR Ofloxacin 300 mg orally twice a day for 7 days Recommended Regimens Azithromycin 1 g orally in a single dose OR Doxycycline 100 mg orally twice a day for 7 days

Answer 42

Chronic keratoconjunctivitis (serovars A, B, Ba, and C of C trachomatis) Disease transmission primarily between children and the caregivers, usually women (transmission cycle described as “disease of the creche” (day nursery)) Repeated reinfection Chronic follicular or intense conjunctival inflammation (active trachoma); Tarsal conjunctival scarring which distorts the upper tarsal plate; In some individuals, entropion and trichiasis (cicatricial trachoma) Corneal abrasions; corneal scarring and opacification; ultimately, blindness

Answer 43

US/Europe – once endemic, disappeared during 20th century as living standards improved Trachoma is endemic in parts of Africa, Asia, the Middle East, Latin America, the Pacific Islands, and aboriginal communities in Australia Estimated 84,000,000 people in 55 endemic countries have active trachoma 1,300,000 blind from trachoma

Answer 44

is the presence of 5 or more follicles (each at least 0.5 mm in diameter) on the central part of the upper tarsal conjunctiva

Answer 45

is pronounced inflammatory thickening of the upper tarsal conjunctiva that obscures more than one half the normal deep tarsal vessels

Answer 46

presence of easily visible scars in the tarsal conjunctiva

Answer 47

presence of at least 1 eyelash rubbing on the eyeball or evidence of recent removal of in-turned lashes Easily visible corneal opacity over the pupil; it is so dense that at least part of the pupil margin is blurred when viewed through the opacity

Answer 48

WHO recommends 2 antibiotics: oral azithromycin and tetracycline eye ointment Facial cleanliness Reduced active trachoma risk/severity community-randomized trials; Must be community based to be effective Environmental improvement Improved water supplies and improved household sanitation (particularly fecal disposal) Flies that transmit trachoma preferentially lay their eggs on human feces lying exposed on the soil (pit latrines reduced trachoma but not statistically) General improvements in personal and community hygiene are almost universally associated with a reduction in the prevalence—and eventually the disappearance—of trachoma

Answer 49

Determine the district-level prevalence of follicular trachoma in 1- to 9-year-old children Prevalence > 10% - mass treatment with antibiotic of all people in the district Prevalence < 10% - assess community level in areas of known follicular trachoma Prevalence at community level of follicular trachoma in 1- to 9-year-old > 10 % - conduct mass treatment of all people with antibiotics 5-10 % - targeted treatment considered (families with 1 or more with follicular trachoma) < 5 % - antibiotic distribution may not be necessary, though targeted treatment can be considered

Answer 50

Cholera - intestinal infection caused by Vibrio cholerae Hallmark of disease is profuse secretory diarrhea (symptoms range from asymptomatic to severe diarrhea with death within hours of onset) Cholera can be endemic, epidemic or pandemic Cholera is transmitted by the fecal-oral route With advanced water and sanitation systems-- cholera is not a major threat Definitive diagnosis is not a prerequisite for the treatment; priority is management of any watery diarrhea by replacing the lost fluid and electrolytes Antibiotics are not essential, but may reduce volume/duration for diarrhea by 50 %

Answer 51

V cholerae is a comma-shaped, gram-negative aerobic or facultative anaerobic bacillus Antigenic structure consists of a flagellar H antigen and a somatic O antigen (somatic antigen allows separation into pathogenic and nonpathogenic strains) > 200 serogroups of V cholerae have been identified, V cholerae O1 and V cholerae O139 are the principal epidemic serogroups V cholerae is not acid-resistant, it depends on large inoculum size to withstand gastric acidity Variable infectious clinical dose of V cholerae Ingested with water infectious dose is 103 -106 organisms Ingested with food, fewer organisms (102 -104) required Gastrectomy, H pylori infections, antacids, histamine receptor blockers, and proton pump inhibitors increases the risk and severity of cholera infection due to reduced gastric acidity

Answer 52

24- to 48-hour incubation period Symptoms begin with the sudden onset of painless watery diarrhea that may quickly become voluminous - ‘rice water’ Vomiting also often present initially Afebrile Dehydration 3-5% loss of normal body weight - Excessive thirst 5-8% loss of normal body weight - Postural hypotension, tachycardia, weakness, fatigue, dry mucous membranes or dry mouth >10% loss of normal body weight - Oliguria; glassy or sunken eyes; sunken fontanelles in infants; weak, thready, or absent pulse; wrinkled "washerwoman" skin; somnolence; coma

Answer 53

Hypoglycemia is the most common lethal complication of cholera in children Diminished food intake Exhaustion of glycogen stores Defective gluconeogenesis secondary to insufficient stores of gluconeogenic substrates in fat and muscle Acidosis Bicarbonate loss in stools Accumulation of lactate because of diminished perfusion of peripheral tissues Acidemia results when respiratory compensation is unable to sustain a normal blood pH Hyponatremia with rehydration of hypotonic fluids Hypocalcemia if rehydration therapy with bicarbonate-containing fluids - decreasing ionized serum calcium (Chvostek and Trousseau signs are often present, and spontaneous tetanic contractions can occur) Hypokalemia from potassium loss in the stool With acidosis, patients usu have normal serum potassium despite depletion of potassium Develops only after the acidosis is corrected and intracellular hydrogen ions are exchanged for extracellular potassium Most severe in children with preexisting malnutrition who have diminished body stores of potassium and may be manifested as paralytic ileus

Answer 54

Electrolytes, glucose, calcium Stool Gram stain - gram-negative curved bacillus that is motile by single flagellum Dark field exam - characteristic motility of Vibrio species cannot be identified on a Gram stain, but it is easily seen on direct dark-field examination of the stool Stool culture – selective media Serotyping with specific antisera Positive immobilization test result (ie cessation of motility of the organism) is produced only if the antiserum is specific for the Vibrio type present; the second antiserum serves as a negative control

Answer 55

In endemic cholera areas, cholera cots assess volume of ongoing stool losses A cot covered by a plastic sheet with a central hole allowing stool to collect in calibrated bucket below Use allows minimally trained health workers to calculate fluid losses & replacement (stool volume every 2-4 hours is replaced) Initially, urine losses are small proportionately, the bucket appropriately reflects stool losses With rehydration, urine should be collected separately to avoid increasing urine output being collected & replacement overhydration due to excessive replacement

Answer 56

1990, < 30,000 cases reported to the WHO 10-fold increase with the beginning of the Latin American epidemic in 1991-1993 1994, the number of cases (384,403) and countries (94) reporting cholera was the largest ever registered at the WHO Europe experienced a 30-fold increase in cholera from 1993-1994, with reported cases increasing from 73 to 2,339 and deaths increasing from 2 cases to 47 2005-2008, 178,000-237,000 cases and 4000-6300 deaths were reported annually worldwide Actual global burden is estimated to be 3-5 million cases and 100,000-130,000 deaths per year

Answer 57

C diphtheria is responsible for both endemic and epidemic diseases 1st described in the 5th century BC by Hippocrates Diphtheria manifests as either an upper respiratory tract or cutaneous infection and is caused by the aerobic gram-positive bacteria, C diphtheria Infection usually occurs in the spring or winter months It is communicable for 2-6 weeks without antibiotic treatment Number of carriers corresponds to disease rates in susceptible individuals

Answer 58

C diphtheria adheres to mucosal epithelial cells endosomes release exotoxin causing a localized inflammatory reaction; tissue destruction and necrosis The toxin is made of two joined proteins The B fragment binds to a receptor on the surface of the susceptible host cell, which proteolytically cleaves the membrane lipid layer enabling segment A to enter Fragment A inhibits an amino acid transfer from RNA translocase to the ribosomal amino acid chain inhibiting protein synthesis required for normal host cell functioning Local tissue destruction enables the toxin to be carried lymphatically and hematologically to other parts of the body (e.g. myocardium, kidneys, and nervous system)

Answer 59

Incubation period 2-5 days (range, 1-10 days) Symptoms initially are general and nonspecific, resembling a URI Respiratory involvement typically begins with sore throat and mild pharyngeal inflammation Development of a localized or coalescing pseudomembrane can occur in any portion of the respiratory tract – dense, gray layer of necrotic tissue and inflammatory cells Cervical adenopathy and swollen mucosa yields a "bull's neck" Most frequent cause of death is airway obstruction or suffocation following aspiration of the pseudomembrane Cutaneous diphtheria -indolent, nonhealing ulcers covered with gray membrane Ulcers are often co-infected with Staphylococcus aureus and group A streptococci Cutaneous diphtheria is seen with increasingly in poor inner-city dwellers & alcoholics

Answer 60

Low-grade fever (rarely >103°F) (50-85%) and chills Malaise, weakness, prostration Sore throat (85-90%) Headache Cervical lymphadenopathy and respiratory tract pseudomembrane formation (about 50%) Serosanguineous or seropurulent nasal discharge, white nasal membrane Hoarseness, dysphagia (26-40%) Dyspnea, respiratory stridor, wheezing, cough

Answer 61

Diagnosis - both isolation of C diphtheriae on culture media & identify the presence of toxin production Bacteriologic testing Gram stain shows club-shaped, nonencapsulated, nonmotile bacilli found in clusters Immunofluorescent staining of 4-hour cultures or methylene blue–stained specimen may sometimes allow for a speedy identification Cultures Inoculation (tellurite or Loeffler media) with swabs taken from the nose, pseudomembrane, tonsillar crypts, any ulcerations, or discolorations. Any diphtheria bacilli isolated must be tested for toxin production Obtain throat and pharyngeal swabs from all close contacts

Answer 62

Elek test - immunoprecipitin band on a filter paper impregnated with antitoxin and then is laid over an agar culture of the organism being tested Polymerase chain reaction (PCR) assays for detection of DNA sequence encoding the A subunit of tox+ strain are both rapid and sensitive If diphtheria infection detected CDC should be contacted for further testing

Answer 63

CBC may show moderate leukocytosis Urinalysis (UA) may demonstrate transient proteinuria Serum antibodies to diphtheria toxin prior to administration of antitoxin: Low levels cannot exclude the possibility of the disease; high levels may protect against severe illness (concentrations of 0.1 to 0.01 IU are thought to confer protection) Serum troponin I levels seem to correlate with the severity of myocarditis ECG – evaluated for heart block

Answer 64

Patients with active disease & all close contacts should be treated with antibiotics Treatment is most effective in the early stages of disease; decreases transmissibility; improves the course of diphtheria Close contacts, such as family members, household contacts, and potential carriers, must receive chemoprophylaxis regardless of immunization status or age

Answer 65

Treatment with erythromycin or penicillin for 14 days; post treatment cultures to confirm eradication Macrolides, eg erythromycin first-line agents for patients > 6 mo (macrolide therapy has been associated with an increase in pyloric stenosis in children younger than 6 months, especially treatment with erythromycin) Intramuscular penicillin is recommended for noncompliant or intolerant of erythromycin Horse serum antitioxin – most efficacious early Given to anyone suspected to have diphtheria Administered without confirmation from cultures, as most efficacious early

Answer 66

Cardiac involvement is associated with a very a poor prognosis, particularly AV and left bundle-branch blocks (mortality rate 60-90%) Bacteremic disease - mortality rate of 30-40% High mortality rate is seen with invasive disease High mortality rates are seen in individuals younger than 5 years and in those older than 40 years

Answer 67

2nd most common notifiable disease in US Purulent infection of mucous membrane surfaces caused by the gram-negative diplococcus Neisseria gonorrhoeae Most frequently spread during sexual contact Also causes ophthalmia neonatorum & systemic neonatal infection, transmitted from mother's genital tract to the newborn during birth In women, the cervix is the most common site of gonorrhea infection, resulting in endocervicitis and urethritis, which can be complicated by pelvic inflammatory disease (PID) In men, gonorrhea causes anterior urethritis

Answer 68

Presence of N gonorrhoeae in the bloodstream, which can lead to the development of disseminated gonococcal infection (DGI) Gonococcemia occurs in about 0.5-3% of patients with gonorrhea Clinical manifestations of this process are biphasic Early bacteremic phase consisting of tenosynovitis, arthralgias, and dermatitis Localized phase consisting of localized septic arthritis (most common cause of acute septic arthritis in sexually active adults) Other clinical complications include osteomyelitis, meningitis, endocarditis, adult respiratory distress syndrome (ARDS), fatal septic shock, polymyositis (rare)

Answer 69

Patients who are pregnant or menstruating may be particularly prone to gonococcemia (change in vaginal pH) Populations at risk of infection Adolescent females - ectopy of the squamocolumnar junction onto the ectocervix Complement deficiencies (13% of patients with DGI) HIV disease Systemic lupus erythematosus (SLE) – endocarditis affecting aortic valve

Answer 70

Risk of transmission of N gonorrhoeae from an infected woman to the urethra of her male partner is approximately 20% per episode of vaginal intercourse and rises to 60-80% after 4 or more exposures In contrast, the risk of male-to-female transmission approximates 50-70% per contact, with little evidence of increased risk with more sexual exposures Persons who have unprotected intercourse with new partners frequently enough to sustain the infection in a community are defined as ‘core transmitters’

Answer 71

Sexual exposure to an infected partner without barrier protection (eg, no condom/condom failure) Multiple sex partners Male homosexuality Low socioeconomic status Minority status - Blacks, Hispanics, and Native Americans have the highest rates in the US History of concurrent or past STDs Exchange of sex for drugs or money Use of crack cocaine Early age of onset of sexual activity Pelvic inflammatory disease (PID) - Use of an intrauterine device (IUD)

Answer 72

Long-term sequelae of PID, tubal factor infertility, ectopic pregnancy & chronic pain in up to 25% of affected patients Epididymitis or epididymo-orchitis may occur in men after gonococcal urethritis Risk factor for other concurrent other sexually transmitted diseases (STDs), including HIV Conjunctivitis can occur in adults, as well as children, following direct inoculation (usually result of hand-eye inoculation in adults); can lead to blindness Incidence of involuntary infertility ~ 15% after one attack of PID & ~ 50%-80% after 3 attacks. (remember, infertility may be more common after chlamydial PID than after gonococcal PID) Incidence of ectopic pregnancy is increased from 7-fold to 10-fold in women with previous salpingitis

Answer 73

Incubation period – 2-7 days following exposure If symptomatic usually within 10 days of infection Most common infections involve endocervix (80%-90%), followed by the urethra (80%), rectum (40%), and pharynx (10%-20%) PID symptoms (although silent in 10-20%) Lower abdominal pain (most consistent symptom of PID) Increased vaginal discharge or mucopurulent urethral discharge Dysuria (usually without urgency or frequency) Cervical motion tenderness Adnexal tenderness (usually bilateral) or adnexal mass Intermenstrual bleeding Fever, chills, nausea, and vomiting (less common) Acute perihepatitis (Fitz-Hugh-Curtis syndrome), esp with chlamydia

Answer 74

Urethritis – ‘drip’, ‘clap’ Acute epididymitis – especially < 35 years, in conjunction with urethral exudate, usually unilateral pain and swelling posteriorly in scrotum Ophthalmia neonatorum Eye pain, redness, and purulent discharge Neonates may also acquire pharyngeal, respiratory, or rectal infection or disseminated gonococcal infection (DGI)

Answer 75

``` Classic presentation of DGI is arthritis dermatitis syndrome Joint or tendon pain most common presenting complaint 25% have pain in a single joint Many patients describe migratory polyarthralgia (esp knees, elbows, other distal joints) Tenosynovitis affecting flexor tendon sheaths of the wrist or the Achilles tendon ("lovers' heels") Skin rash (5-40 peripheral maculopapular to hemorrhagic pustular lesions) 1st complaint in 25% (most with DGI have a rash below the neck or palms and soles) 2nd stage of DGI usually septic arthritis, most often knee (rash has disappeared and BC typically negative) Rare complications of DGI include gonococcal meningitis, pericarditis, and endocarditis ```

Answer 76

Culture Thayer-Martin plates that must be stored refrigerated but warmed to room temperature before obtaining a sample Plate is then incubated in a carbon dioxide atmosphere Poor technique drastically reduces test sensitivity Serologic tests Latex agglutination, ELISA, immunoprecipitation, and complement fixation tests Lower sensitivity and specificity (especially in populations with a low prevalence of disease), therefore are not routinely used for diagnosis Testing for other STDs with GC suspected Syphilis infection C trachomatis (high rate of asymptomatic carriage) HIV (with counseling) Hepatitis B virus (administer hep B vaccine unless documented full series) Herpes simplex virus

Answer 77

Prevention of neonatal disease (ophthalmia neonatorium) - silver nitrate 1% eye drops or 1% tetracycline or 0.5% erythromycin ophthalmic ointment within 1 hour of birth Uncomplicated gonococcal infection of the urethra, cervix, or rectum Ceftriaxone 250 mg intramuscular (IM) single dose OR, IF NOT AN OPTION Cefixime 400 mg oral (PO) single dose OR Single-dose injectable cephalosporin regimens PLUS Azithromycin 1 g PO single dose OR Doxycycline 100 mg PO twice a day for 7 days Fluoroquinolones NOT RECOMMENDED (4/2007 CDC -GC in heterosexual men 6.7% fluoroquinolone-resistant (QRNG, 11-fold increase from 0.6% in 2001 Tetracycline NOT RECOMMENDED, TCN resistance 5-15%

Answer 78

Gonococcal arthritis, pharyngitis, epididymitis, disseminated gonococcal infection (DGI), meningitis, endocarditis or conjunctivitis - ceftriaxone preferred (also azithromycin or doxycycline for conjunctivitis) Pelvic inflammatory disease (PID) Outpatient Cefoxitin (Mefoxin) at 2 g IM plus probenecid at 1g orally as a single dose or ceftriaxone at 250 mg IM 14-day oral regimen of doxycycline at 100 mg twice daily Each of the above regimens may be accompanied by metronidazole 500 mg orally twice daily for 14 days Inpatient Cefoxitin at 2 g parenterally every 6 hours or cefotetan (Cefotan) at 2 g IV every 12 hours plus doxycycline Alternative regimens for penicillin-allergic patients include clindamycin 900 mg IV every 8 hours with gentamicin of loading dose 2 mg/kg of body weight followed by 1.5 mg/kg of body weight every 8 hour Evaluation and treatment of sexual partners

Answer 79

Salmonellae - gram-negative motile bacilli Genus Salmonella, belongs to the family Enterobacteriaceae (named after Daniel E. Salmon, American veterinarian who first isolated Salmonella choleraesuis from pigs with hog cholera in 1884 2500 serovars of S enterica, current nomenclature of S typhi is S enterica serovar Typhi Closely related bacterium Escherichia coli Clinical diseases Potential enteric pathogens, a leading cause of bacterial foodborne illness Enteric or typhoid fever (primarily Salmonella typhi and Salmonella paratyphi) Bacteremia Endovascular infections Focal infections (eg, osteomyelitis) Enterocolitis (typically Salmonella typhimurium, Salmonella enteritidis, and Salmonella heidelberg)

Answer 80

Transmission of salmonellae usually via consumption of contaminated foods, most common sources of salmonellae include beef, poultry, and eggs Egg shell fragments (S enteritidis) ~182,060 cases of enteritis in the United States (2000) Jalapeno and serrano peppers (S enterica serotype Saintpau) - 1442 across 43 states (2008) Peanut butter (S enterica serotype Tennessee) - > 600 cases in 2007, 2008-2009 Powdered infant formula (S enterica serotype Agona) among infants in France Amphibian and reptile exposures associated with ~ 74,000 Salmonella infections annually in US Large inoculum (~ 106 bacteria) required to overcome stomach acidity & compete with normal intestinal flora, high inocula result in higher rates of illness & shorter incubation periods Low stomach acidity (elderly, antacids) may only require 103 organisms Postvaccine ~ 109 bacteria required

Answer 81

Organism selectively attaches to specialized epithelial cells (M cells) of the Peyer patches Bacteria are then internalized by receptor-mediated endocytosis and transported within phagosomes to the lamina propria, where they are released Salmonellae induce an influx of macrophages (typhoidal strains) or neutrophils (nontyphoidal strains) Risk factors were found to be corticosteroid use, malignancy, diabetes, HIV infection, prior antimicrobial therapy, immunosuppressive therapy, sickle cell disease, malaria, schistosomiasis, bartonellosis, and pernicious anemia

Answer 82

Mortality rate for S enteritidis infection outbreaks in the United States from 1985-1991 was 0.4% Case-fatality rates were 70 times higher in nursing homes and hospitals Mortality rates associated with typhoid fever are similarly low in the United States (< 1%), but mortality rates of 10-30% some Asian and African countries Bacteremia had 18% mortality rate at Mass General in the 1990s (total 45 fatal outcomes) 50% of CNS infections are fatal

Answer 83

Nontyphoidal enterocolitis Nontyphoidal focal disease Typhoid Fever

Answer 84

Focal disease is due to transient or persistent bacteremia, almost any organ can be affected, most vulnerable sites may have preexisting structural abnormalities

Answer 85

Enterocolitis similar to other bacterial enteric pathogens Incubation period depends on inoculum ~ 6-72 hours Stools are typically loose and bloodless, rarely large-volume cholera-like diarrhea with tenesmus, resolves within 3-7 days Fever (resolves in 48 hours), abdominal cramping, chills, headache, and myalgia are common

Answer 86

Variable clinical course ranging from isolated fever to multisystem toxemia, 10-15% of patients develop severe disease, nonspecific features Incubation period of 10-14 days (usually prolonged low-grade fever, dull frontal headache, malaise, myalgia, dry cough, anorexia, and nausea) Stepwise fever progression common, persistent and high grade by end of 2nd week, lasting up to 4 weeks if untreated Relative bradycardia at fever peak (dissociation) is an indicator of typhoid fever (well, not so universal) Coated tongue, alteration of bowel habits (varying from constipation in adults to diarrhea in children), tender abdomen, and hepatosplenomegaly common Malaise and lethargy can continue for a couple of months - apathetic-lethargic state (tuphos in ancient Greeks) Rose spots develop on the back, arms, and legs ( < 25% at the end of the 1st febrile week)

Answer 87

Blood cultures - 80%-100% accurate in detecting bacteremia (as disease progresses, sensitivity of blood cultures decreases, while sensitivity of stool isolation increases) Freshly passed stool is the preferred specimen for isolation of nontyphoidal Salmonella species Stool carriage of S typhi may be prolonged, interpretation of positive results merits caution - diagnosis should be established only when accompanied by clinical findings that are typical of infection Grouping of Salmonella isolates is usually performed with polyvalent antisera specific for O and Vi antigen. S typhimurium belongs to group B; S enteritidis and S typhi belong to group D Salmonellosis is a reportable disease in the United States.

Answer 88

Salmonella gastroenteritis is usually a self-limiting disease Fluid and electrolyte replacement may be indicated in severe cases Antibiotics do not shorten the duration of symptoms and may prolong duration of convalescent carriage - not routinely used to treat uncomplicated nontyphoidal Salmonella gastroenteritis Current recommendations - antibiotics be reserved for patients with severe disease or patients at a high risk for invasive disease Quinolone, macrolide, and third-generation cephalosporin antibiotics are preferred for empiric therapy pending sensitivities Sensitivity to quinolones has been steadily declining - no longer fool-proof agents for typhoid fever Increasing resistance reported of nontyphoidal salmonella to nalidixic acid and ceftriaxone Salmonella bacteremia - single bactericidal drug for 10-14 days Life-threatening infections should be treated with both a third-generation cephalosporin and a fluoroquinolone until sensitiviities known

Answer 89

Typhoid fever is occasionally complicated by intestinal perforation or hemorrhage, cholecystitis, endocarditis, arteritis, osteomyelitis, or soft-tissue abscess formation, necessitating surgical intervention Long-term S typhi carriage (usually with the gallbladder as the reservoir) may necessitate cholecystectomy Splenectomy may be required for splenic abscesses Surgical care dramatically improves the likelihood of survival in patients with endarteritis, especially involving abdominal aorta

Answer 90

Fecal-oral transmission predominant Ingestion of contaminated food or water (untreated wading pools, interactive water fountain Contact with a contaminated inanimate object Certain mode of sexual contact Vectors like the housefly can spread the disease by physically transporting infected feces Infectivity dose (ID) is extremely low (10 S dysenteriae bacilli causes clinical disease, whereas 100-200 bacilli are needed for S sonnei or S flexneri infection) Virulent Shigellae can withstand the low pH of gastric juice (most isolates survive acid pH 2.5 for at least 2 hours) Incubation 2-4 days (12 hours to 7 days), depending on ID Communicable while infected person excretes the organism in the stool (bacterial shedding ceases within 4 weeks of onset)

Answer 91

Virulence in Shigella species involves both chromosomal-coded and plasmid-coded genes Plasmid DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA Virulence trait is encoded on a large (220 kb) plasmid responsible for synthesis of polypeptides that cause cytotoxicity Shigellae that lose the virulence plasmid are no longer pathogenic Escherichia coli (E coli O157:H7) that harbor this plasmid clinically behave as Shigella bacteria

Answer 92

Shigella bacteria invade the intestinal epithelium through M cells and proceed to spread from cell to cell, causing death and sloughing of contiguously invaded epithelial cells and inducing a potent inflammatory response resulting in the characteristic dysentery syndrome. Only S dysenteriae type 1 Shiga toxin that inhibits protein synthesis in eukaryotic cells May lead to extraintestinal complications, including hemolytic-uremic syndrome and death Initial event may be the invasion of M cells, the specialized cells that cover the lymphoid follicles of the mucosa, overlying Peyer patches

Answer 93

Highest incidence of shigellosis among children younger than 5 years > 95% of Shigella infections may be asymptomatic (estimated 450,000 total annual cases of shigellosis in the United States) High-risk for shigellosis include: Children in daycare centers (< 5 y) and their caregivers Persons in custodial institutions International travelers Homosexual men People living in crowded conditions with poor sanitary facilities and inadequate clean water supply (e.g. refugee camps, shelters for displaced people) People with human immunodeficiency virus (HIV) infection

Answer 94

Sudden onset of severe abdominal cramping, high-grade fever, emesis, anorexia, and large-volume watery diarrhea Seizures may be an early manifestation Abdominal pain, tenesmus, urgency, fecal incontinence, and small-volume mucoid diarrhea with frank blood (fractional stools)

Answer 95

Elevated temperatures (as high as 106 º F) in 1/3, generally toxic appearance Tachycardia and tachypnea may occur secondary to fever and dehydration. Dehydration manifest as dry mucous membranes, hypotension, prolonged capillary refill time, poor skin turgor Abdominal tenderness is usually central and lower, may be generalized CNS symptoms include severe headache, lethargy, meningismus, delirium, and convulsions lasting less than 15 minutes, especially with S dysenteriae Microangiopathic hemolytic anemia, thrombocytopenia, and renal failure (HUS) occurs wiith S dysenteriae because of vasculopathy mediated by Stx

Answer 96

CBC, leukemoid or leukopenia occasionally, anemia and thrombocytopenia c/w HUS Blood culture in toxic children Stool examination - ~ 70% of patients with shigellosis, fecal blood or leukocytes present in stool (confirming colitis) Stool culture – greatest yield early in the course of disease, falsely in 20% Enzyme immunoassay for Stx is used to detect S dysenteriae type 1 in the stool Gene probes or polymerase chain reaction (PCR) primers detect virulence genes (invasion plasmid locus) Fluorescent antibody test and enzyme-linked DNA probes in research settings

Answer 97

Fluid and electrolyte resuscitation Antipyretics Vitamin A (200,000 IU) may hasten clinical resolution in malnourished children Zinc supplementation (20 mg elemental zinc for 14 d) Reduce duration of diarrhea Improve weight gain during recovery Improve immune response to the Shigella Decreased incidence of diarrheal illness in the subsequent 6 months in malnourished children

Answer 98

Beta-lactams: Ampicillin, amoxicillin, third-generation cephalosporins (ceﬁxime, ceftriaxone), and pivmecillinam (not available in the United States) Quinolones: Nalidixic acid, ciproﬂoxacin, norﬂoxacin, and oﬂoxacin Macrolides: Azithromycin Others: sulfonamides, tetracycline, cotrimoxazole, and furazolidone

Answer 99

Escherichia coli is one of the most frequent causes of many common bacterial infections Cholecystitis/cholangitis Bacteremia Urinary tract infection (UTI) - 90% of all uncomplicated UTIs Traveler's diarrhea Antimicrobials known to be useful in cases of traveler's diarrhea include doxycycline, trimethoprim/sulfamethoxazole (TMP/SMZ), fluoroquinolones, and rifaximin Shorten the duration of diarrhea by 24-36 h Antibiotics are not useful in enterohemorrhagic E coli (EHEC) infection and may predispose to development of HUS Antimotility agents are contraindicated in children and in persons with enteroinvasive E coli (EIEC) infection Neonatal meningitis – 28% of neonatal cases Neonatal pneumonia – microaspiration of respiratory secretions

Answer 100

Major cause of infant mortality in underdeveloped countries Infection results from umbilical cord contamination during unsanitary delivery, coupled with a lack of maternal immunization End of the first week of life, infected infants become irritable, feed poorly, and develop rigidity with spasms Neonatal tetanus has a very poor prognosis

Answer 101

Cephalic tetanus Uncommon and usually occurs following head trauma or otitis media Present with cranial nerve palsies, may be localized or may become generalized Local tetanus Persistent rigidity in the muscle group close to the injury site Muscular rigidity results from dysfunction in the interneurons that inhibit the alpha motor neurons of the affected muscles No further CNS involvement occur; very low mortality rates

Answer 102

~ 50-75% of patients with generalized tetanus present with trismus ("lockjaw"), nuchal rigidity, dysphagia, risor sardonicus, Progressive generalized muscle rigidity with intermittent reflex spasms in response to stimuli (e.g. noise, touch) Tonic contractions cause opisthotonus (ie, flexion and adduction of the arms, clenching of the fists, extension of the lower extremities) During these episodes, patients have intact sensorium and feel severe pain Spasms can cause fractures, tendon ruptures, and acute respiratory failure

Answer 103

C tetani, a mobile, spore-forming, anaerobic, gram-positive bacillus. This bacillus is found in or on soil, manure, dust, clothing, skin, and 10-25% of human GI tracts. The spores need tissue with the proper anaerobic conditions to germinate; the ideal media are wounds with tissue necrosis In anaerobic conditions, the spores of C tetani germinate and produce 2 toxins: tetanolysin (a hemolysin with no recognized pathologic activity) and tetanospasmin, which is responsible for the clinical manifestations of tetanus Toxin travels by retrograde axonal transport from the contaminated site to the spinal cord in 2-14 days When the toxin reaches the spinal cord, it enters central inhibitory neurons with loss of inhibitory action on motor and autonomic neurons

Answer 104

Symptoms usually begin 8 days after the infection (range from 3 days to 3 weeks) Patients may report a sore throat with dysphagia (early sign) Localized tetanus causes muscle rigidity at the site of spore inoculation The initial manifestation may be local tetanus, in which the rigidity affects only 1 limb or area of the body where the clostridium-containing wound is located Severe tetanus results in opisthotonos, flexion of the arms, extension of the legs, periods of apnea resulting from spasm of the intercostal muscles and diaphragm, and rigidity of the abdominal wall Late in the disease, autonomic dysfunction develops, with hypertension and tachycardia alternating with hypotension and bradycardia

Answer 105

``` US Centers for Disease Control and Prevention (CDC) statistics from 1982-84: Infected lacerations or puncture wounds (69%) Infected chronic wounds and abscesses (20%) Exposure via intravenous drug abuse (3%) Neonates (1%) Other or no identifiable cause (7%) Otitis media Burns Intranasal foreign bodies Corneal abrasions Foreign bodies Dental or surgical procedures ```

Answer 106

Passive immunization - human tetanus immune globulin (TIG) shortens the course of tetanus and may lessen its severity ICU admission and supportive therapy may include ventilatory support, high-calorie nutritional support, and pharmacologic agents that treat reflex muscle spasms, rigidity, tetanic seizures and infections Benzodiazepines have emerged as the mainstay of symptomatic therapy for tetanus. To prevent spasms that last longer than 5-10 seconds, administer diazepam intravenously, typically 10-40 mg every 1-8 hours Vecuronium (by continuous infusion) or pancuronium (by intermittent injection) are adequate alternatives Magnesium sulfate used to help control muscle spasms and tetanus-associated autonomic dysfunction

Answer 107

Thoroughly clean wounds and remove dead or devitalized tissue If the patient has not had a tetanus toxoid booster in the previous 10 years, administer a single booster injection on the day of injury Severe wounds, consider administering a booster if more than 5 years have elapsed since the last dose Consider administering TIG, antitoxin, or antibiotics if the patient has not been previously immunized with a series of at least 3 doses of toxoid 70% of a random sample of US residents aged 6 years or older have protective levels of tetanus antibodies Age 60-69 years, the prevalence of protective antibodies is less than 50% Age 70 years, the prevalence is approximately 30%