4 Bacterial Infection Flashcards
a superficial skin infection with Stapylococcus aureus alone or in combination with Streptococcus pyogenes
impetigo
two subtypes of impetigo
non-bullous (70%) and bullous
occurs most often in school-aged children
impetigo
time of the year impetigo peaks
summer or early fall (especially in warm, humid climates)
Impetigo is (common/uncommon).
common
very contagious, spreads easily, intact epidermis is usually protective
impetigo
Most cases of impetigo arise how?
damaged skin—cuts and abrasions, insect bites, preexisting dermatitis
affects extremities (legs especially) and face (facial lesions develop around the nose or mouth
non-bullous impetigo
lesions are pruritic (itchy), scratching causes the lesions to spread
non-bullous impetigo
disease course of non-bullous impetigo
red macules or papules that subsequently develop into fragile vesicles —> vesicles rupture and become covered by a thick, honey-colored crust
dx of impetigo
clinical presentation
tx of impetigo (localized/mild cases vs extensive/severe involvement)
Localized/mild cases
• topical mupirocin (Bactroban)
• remove crusts with a cloth soaked in warm, soapy water before applying medication
Extensive/severe involvement
• refer to pediatrician or dermatologist
• systemic antibiotics
• lesions are superficial and typically heal without scarring
Most cases of pharyngitis are caused by ________.
viruses
Tonsillitis and pharyngitis:
organism that causes 15-30% of cases in children and 5-15% of cases in adults
streptococcal bacteria (Group A, beta-hemolytic streptococci)
How is streptococcal tonsillitis and pharyngitis spread?
infectious respiratory droplets or saliva
most common age range of streptococcal tonsillitis and pharyngitis
5-15 yo
Clinical features:
• sudden onset of sore throat and dysphasia
• fever 101-104*F
• enlarged tonsils with a yellowish exudate
• erythema of the oropharynx
• cervical lymphadenopathy
• swollen uvula
streptococcal tonsillitis and pharyngitis
Young children with streptococcal tonsillitis and pharyngitis may develop:
- headache
- malaise and anorexia
- abdominal pain and vomiting
NOT COMMON with streptococcal tonsillitis and pharyngitis
runny nose, cough, hoarseness (suggests viral infection)
dx of streptococcal tonsillitis and pharyngitis
- rapid antigen detection—quick results, sensitive and specific
- throat culture
Tx of streptococcal tonsillitis and pharyngitis is usually recommended to reduce severity and prevent complications:
- peritonsillar abscess
- acute rheumatic fever
- acute post-streptococcal glomerulonephritis
infection usually resolves spontaneously in 3-4 days (with no tx)
streptococcal tonsillitis and pharyngitis
tx of streptococcal tonsillitis and pharyngitis
systemic antibiotics—penicillin or amoxicillin (erythromycin or azithromycin for penicillin allergy)
*pts are considered non-contagious 24 hours after initiating antibiotic therapy
Don’t confuse streptococcal tonsillitis and pharyngitis with:
- normal, large tonsils
* tonsillar concretions
Tonsillar concretions may calcify to form ______, which may show up as calcifications superimposed on the ramus in panoramic images.
tonsilloliths
a systemic infection that begins as a streptococcal tonsillitis/pharyngitis
scarlet fever
organism that causes scarlet fever
group A, beta-hemolytic streptococci
How does group A, beta-hemolytic streptococci cause scarlet fever?
produces a toxin that attacks blood vessels and causes the characteristic skin rash
occurs in susceptible pts who don’t have antibodies to the toxin
scarlet fever
most common in children ages 3-12
scarlet fever
Clinical features:
• fever
• skin rash that looks like a “sunburn with goosebumps”
scarlet fever
Describe the rash characteristic of scarlet fever:
- appearance?
- time frame in which it develops?
- texture?
- more intense in areas?
- uncommon where?
- looks like a “sunburn with goosebumps”
- develops 12-48 hours after onset of fever
- sandpaper texture
- more intense in areas of pressure and skin folds
- uncommon on the face
Oral manifestations:
• oropharynx—red, swollen uvula and tonsils with yellowish exudate
• white strawberry tongue (first few days)
• red strawberry tongue (by day 4 or 5)
scarlet fever
White/red strawberry tongue associated with scarlet fever:
White strawberry tongue
• first few days
• dorsal surface develops a white-coating through which only the fungiform papillae can be seen
Red strawberry tongue
• by day 4 or 5
• white coating desquamates
• dorsal tongue is erythematous with hyperplastic fungiform papillae
dx of scarlet fever
refer to a physician, rapid antigen detection or throat culture
tx of scarlet fever
penicillin V or amoxicillin
Tx of scarlet fever is indicated to prevent potential complications:
peritonsillar abscess, sinusitis, pneumonia
scarlet fever rash lasts how long?
rash resolves in 1 week, skin begins to desquamate which can continue for up to 6 weeks
organism that causes syphilis and shape
Treponema pallidum, a spirochete bacterium
modes of transmission of syphilis
- sexual contact (vaginal, anal, oral)
- mother to fetus
Infection of syphilis classically proceeds through 3 stages:
Which stages are pts highly contagious?
1) primary
2) secondary
* LATENT PHASE*
3) tertiary
Patients are highly contagious during the first two stages.
After penicillin was invented in the 1940s, incidence of this disease in the US declined until being on the verge of elimination in 2000.
syphilis
After penicillin was invented in the 1940s, incidence of syphilis in the US declined until being on the verge of elimination in 2000.
Syphilis since 2000:
Since 2000, the rate of primary and secondary syphilis has increased almost every year.
- 14% increase from 2017-2018
- MSM accounted for 64% of new cases in 2018, high rates of HIV co-infection
characterized by a chancre (painless, deep ulcer) that develops at the site of inoculation
primary syphilis
During a primary syphilis infection, a chancre occurs anytime between _____ days after exposure. What is the average time? Accompanied by? Healing time?
- occurs anytime between 3-90 days after exposure
- average time = 21 days
- accompanied by regional lymphadenopathy
- heals in 3-8 weeks without tx
Common locations of a chancre (primary syphilis infection):
external genitalia (85%)
anus (10%)
oral cavity, especially the lip (4%)
How long does it take for the secondary stage of syphilis to develop? Resolution time?
develops 4-10 weeks after the initial infection (sometimes before chancre has resolved), resolves on its own over several weeks
Clinical features:
- diffuse, widespread maculopapular skin rash (red/brown/purple)
- mucous patches of the oral cavity
- fatigue, headache, muscle aches, fever
secondary syphilis
affects 30% of patients with secondary syphilis
mucous patches of the oral cavity
Mucous patches of the oral cavity (secondary syphilis):
- affects what % of pts with secondary syphilis?
- appearance?
- common locations?
- affects 30% of pts with secondary syphilis
- focal areas of sensitive, whitish mucosa
- tongue, lip, buccal mucosa, palate
After the second stage of syphilis, patients enter an asymptomatic and lesion-free period called ______ syphilis. How long can it last?
latent / 1-30 years
most serious stage of syphilis
tertiary
stage of syphilis that develops in about 30% of untreated patients
tertiary
the vascular and nervous systems are often affected significantly with this stage of syphilis
tertiary
The ______ and ______ systems are often affected significantly with tertiary syphilis.
vascular and nervous systems
Clinical features:
- foci of granulomatous inflammation (“gumma”) –> can affect any tissue type and cause extensive destruction
- cardiovascular –> aortic aneurysm, congestive heart failure
- neurologic –> paralysis, numbness, psychosis, dementia
tertiary syphilis
often affects the palate and causes perforation into the nasal cavity
tertiary syphilis (foci of granulomatous inflammation, or “gumma”)
transplacental infection, about half of all babies infected in utero die before or shortly after birth
congenital syphilis
congenital syphilis in newborns vs children
Newborns- failure to thrive, jaundice, anemia, fever, rash
Children- abnormalities of the bones, teeth, eyes, ears, and brain
rates have increased in parallel with primary and secondary syphilis among women from 2013-2017
congenital syphilis
What is Hutchinson’s triad associated with? What is it?
congenital syphilis
Hutchinson’s triad:
- Hutchinson’s teeth (Hutchinson’s incisors 63%, mulberry molars 65%)
- ocular interstitial keratitis (9%)
- 8th cranial nerve deafness (3%)
*Very few patients exhibit all three pathognomic features
Two variations of Hutchinson’s teeth and descriptions:
Hutchinson’s incisors:
- greatest mesiodistal width occurs in the middle 1/3 of the crown
- notching of incisal edges
- teeth resemble the head of a straight-edged screwdriver
Mulberry molars:
- crown tapers towards the occlusal surface
- abnormal occlusal anatomy with globular projections of enamel
dx of syphilis
- screening tests (one of these two is performed twice during a woman’s pregnancy –> VDRL and RPR)
- specific and sensitive serologic test (positive for life, performed after a positive screening test result, FTA-ABS)
screening tests done during pregnancy for syphilis (2)
VDRL (Venereal Disease Research Lab)
RPR (Rapid plasma reagin)
specific and sensitive serologic test done to dx syphilis, positive for life
FTA-ABS (fluorescent treponemal antibody absorption)
tx for syphilis
penicillin G IV or IM administration depending on stage, doxycycline for penicillin allergy
stages of syphilis that resolve with or without therapy
primary and secondary
neurosyphilis
when syphilis infection gets into the CNS
T or F: The cardiovascular and neurologic effects of tertiary syphilis are reversible.
F (not reversible!!)
organism that causes TB
Mycobacterium tuberculosis
mode of transmission of TB
airborne droplets from a patient with active disease
T or F: Infection with TB means you have an active disease.
False!! 1/4 of the world’s population is infected
1/4 of the world’s population is infected (infection does not mean active disease)
TB
Overall incidence of TB in the US is declining, but disproportionally high rates (70%) are observed among…?
foreign-born persons (Asians = racial/ethnic group with the most cases)
racial/ethnic group with the most cases of TB
Asians
people previously unexposed to M. tuberculosis, inhalation of airborne droplets from someone with TB disease
latent TB infection
asymptomatic form of TB, initiates a chronic inflammatory response that results in a localized, fibrocalcified nodule in the lung
latent TB infection
signs of a latent TB infection
- localized, fibrocalcified nodule in the lung
- viable organisms remain in the nodule and can become reactivated later in life
PPD skin test will be positive, NOT CONTAGIOUS
latent TB infection
develops in about 5-10% of pts infected with TB, usually occurs later in life due to reactivation of organisms
TB disease
TB disease is associated with…
compromised immune status (AIDS, immunosuppressive drugs, diabetes, old age)
leading killer of HIV-infected people
TB disease
Clinical features:
- low grade fever, night sweats
- malaise, anorexia, weight loss
- persistent, productive cough (chest pain, hemoptysis)
- extrapulmonary lesions present in over 50% of AIDS pts with an active infection, can involve any organ system
TB disease
present in over 50% of AIDS patients with an active TB infection
extrapulmonary lesions (can involve any organ system)
____ and ____ involvement can occur with TB disease. Most commonly affected area?
Head and neck / cervical lymph nodes
calcified lymph nodes may be visible on panoramic radiographs
TB disease with head/neck involvement
intraoral lesions are uncommon, but presents as a chronic painless ulcer or granular tissue proliferation (tongue, mandible, gingiva, lip)
TB disease
dx of TB
- PPD skin test will be positive 2-4 weeks after initial exposure (5-10% of US population is +), does not distinguish between latent and active TB disease (follow by chest x-ray if positive)
- culture of infected sputum
- biopsy: granulamatous inflammation (special stains reveal mycobacteria)
tx of latent TB vs TB disease
Latent TB- chemoprophylaxis, various protocols, drugs utilized: isoniazid, rifampin, rifapentine (3-9 months of therapy)
TB disease- multi-agent drug therapy, various protocols, drugs utilized: isoniazid, rifampin, pyrazinamide, ethambutol (6-9 months of therapy)
organism that causes actinomycosis
Actinomyces israelii or Actinomyces viscosus
Actinomyces species are normal components of the oral flora:
tonsillar crypts, periodontal pockets, dental plaque and calculus, carious dentin
55% of cases are diagnosed in the cervicofacial region
actinomycosis
How does an actinomycosis infection start? How does it spread?
organism infects tissue through an area of prior trauma (injury, extraction socket, perio pocket, etc) –> infection spreads by direct extension through soft and hard tissue (not the usual lymphatic and vascular spread)
most common location of actinomycosis infection
soft tissue overlying the angle of the mandible
Clinical features:
- slow progression and minimal pain
- begins as a “wooden” indurated area, eventually forms a soft abscess
- may discharge yellowish flecks called sulfur granules (colonies of the bacteria)
actinomycosis
Dx:
- characteristic colonies can be seen in biopsy specimens
- culture has low sensitivity (positive in less than 50% of cases)
- clincian’s surgical findings and description can be helpful (sulfur granules)
actinomycosis
may discharge yellowish flecks called SULFUR GRANULES
actinomycosis
tx of actinomycosis
- surgical drainage of abscess
- 5-6 week course of high-dose penicillin or amoxicillin
- pts with a deep-seated infection may require longer duration of therapy
- fibrotic nature of lesion makes it difficult for antibiotics to penetrate
organism that causes cat-scratch disease
Bartonella henselae
spread of cat-scratch disease
- begins in the skin –> characteristically spreads to adjacent lymph nodes
- no person-to-person transmission
- arises after contact with a cat
the most common cause of regional lymphadenopathy in children, majority of cases (80%) occur in patients under 21 yo
cat-scratch disease
Clinical features:
- a papule or pustule develops in 3-14 days within the area of the scratch/exposure, resolves in 1-3 weeks
- lymphadenopathy takes 3 weeks to develop, may be accompanied by fever and malaise
- evidence of the primary trauma may have completely resolved by this time
cat-scratch disease
a single lymph node is involved in about half of all cases (head and neck, axillary, groin)
cat-scratch disease
Cat-scratch disease: scratches on the face usually lead to ________ lymphadenopathy
submandibular
this dx should always be suspected in cases of unexplained lymphadenopathy
cat-scratch disease
tx of cat-scratch disease
- analgesics
- lymph node aspiration
- self-limiting, resolves within 4 months
- antibiotics are used only for severe cases or immunocompromised pts
one of the most common health complaints in the US
sinusitis
Usually the result of a disruption in the normal balance/function of the paranasal sinuses:
- patency of ostial openings (through which the contents of sinus cavities drain into the nose)
- function of the cilia
- quality of nasal secretions
sinusitis
most sinus disease begins due to…
blockage of the sinus ostia, which prevents normal drainage
bacteria are inherently present in the sinuses, so even a light thickening of the lining can lead to blockage and infection
sinusitis
Organisms often responsible for acute cases of sinusitis (4):
- viruses
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
Most common predisposing factors of sinusitis:
- recent upper respiratory viral infection
- allergic rhinitis
up to 30% of cases of ______ sinusitis are the result of an odontogenic problem
maxillary (infection of maxillary teeth, extractions of maxillary teeth, placement of implants)
Clinical features:
- headache
- fever
- facial pain in the area involved
- anterior nasal or posterior pharyngeal discharge (can be thick, thin, clear, mucoid, purulent)
acute sinusitis
REMEMBER: this can present as a toothache
acute maxillary sinusitis
- recurring episodes of acute sinusitis or symptomatic sinus disease lasting > 3 months
- facial pressure, headache, obstructed sensation
- less diagnostic than the acute form (involved sinus shows cloudy increased density on panoramic films, endoscopy, CT)
chronic sinusitis
tx of acute vs chronic sinusitis
Acute- the infection is self-limiting, but antibiotics are usually prescribed (amoxicillin)
Chronic- rule out odontogenic infection, refer to ENT specialist, often corrected with endoscopic sinus surgery (enlarges ostial openings and corrects blockages)
