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24 Cards in this Set
- Front
- Back
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bacillus anthracis
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-gram positive
-aerobic -spore forming bacillus -microscopic exam shows long parrallel chains of organisms with boxcar appearance -animal hides, bone, wool, hair can transmit infx |
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anthracis in lab
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-grows on blood agar
-colonies are sticky (+ strand of pearls test) |
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incidence and prevalence
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-soil organism with worldwide distribution
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bioterrorism
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-aerosol would be most likely route of transmission
-Anthrax is easy to cultivate and spores are readily produced |
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weaponized anthrax
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-Spores resistant to physical and chemical agents
-Spores made smaller to reach alveoli (1-2 microns) -Coated with powder so they do not stick together -Spores made more resistant to antibiotics -Spores invisible and odorless |
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pathogenesis
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-after inoculation into skin or mucous membranes, spores germinate in macrophages and produce exotoxin which produces edema and tissue necrosis
-bacilli enter circulation and cause meningitis, systemic toxicity |
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inhalation anthrax
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-spores enter alveoli, are phagocytized by macrophages and are carried in mediastinal LNs
-Germination, growth and toxin formation results in hemorrhagic lymphadenitis -Organism may attack pulmonary endothelium resulting in thrombosis and respiratory failure -Respiratory failure, shock and pulmonary edema may cause death |
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ingestion
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-ingestion of contaminated meat may result in oropharyngeal or GI infx
-swelling of pharynx may cayse tracheal obstruction -Spores in intestinal tract multiply, produce toxin and cause edema, ulcerations, hemorrhage and necrosis |
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cutaneous anthrax
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-1-12 days after direct contact with organism at break in skin, small pruritic papule forms at site
-develops into vesicle filled with organisms -ulceration occurs with necrotic ulcer base -black eschar forms in several wks, separates and leaves scar |
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clinical manifestations of cutaneous anthrax
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-fever
-malaise -myalgias -HAs -bacteremia and meningitis -Extensive edema may lead to hypotension due to loss of intravascular fluid when fluid enters subcutaneous tissue |
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diagnoses of cutaneous anthrax
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-exposure to animals
-gram stain -culture of fluid: if not visible exudate, lift edge of eschar with forceps and collect fluid near edge -if cx - bx for siler stain |
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tx for cutaneous anthrax
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-mild: PCN, if resistant cipro or doxy
-extensive: PCN IV or cipro or doxy IV -continue tx for total of 60 days |
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clinical manifestations of inhalational anthrax
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first phase: flu-like; fever, fatigue, myalgias, malaise, nonproductive cough
-clinical improvement then worsening illness -second phase: dyspnea, fever ,shock, cyanosis, hypoxia, hemoptysis, stridor, CP |
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inhalational anthrax CXR
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-pleural effusions
-mediastinal widening -hemorrhagic pleural effusions -pulmonary infiltrates |
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inhalation anthrax CT
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-hyperdense mediastinal and hilar LNs
-mediastinal edema -pleural effusions |
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dx of inhalation anthrax
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-gram stain and sputum cx
-if bacteremia, blood cx -Blood Cx + in 12-48 hours on standard culture media (blood agar) -cx of pleural fluid, CSF, skin lesions -PCR to identify B. anthracis DNA |
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tx of inhalational
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-cipro IV
-doxy pluse -1 or 2 additional antimicrobials: rifampin, vanco, PCN/amox, chloramphenicol -switch to oral therapy when stable -cont therapy for 60 days -supportive care -report to local or state dept, of health -mortality rate 90% even with tx!! |
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GI anthrax
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-rare, after ingestion of undercooked meat containing anthrax spores
-infx via breaj in GI mucosa -abd pain -hematemesis -melana -rapid onset of ascites -+/- diarrhea -mesenteric lymphadenitis -ulceraltive lesions in terminal ileum and cecum -bacteremia, toxemia, shock, death |
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oropharyngeal anthrax
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-fever
-sore throat -neck swelling -dysphagia -cervical and submandibular LAD -oral and pharyngeal ulcers with pseudomembrane |
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dx of GI.oropharyngeal anthrax
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-cultures: blood, ascitic fluid, throat, stool
-Lesions similar to cutaneous Anthrax may be seen in oral cavity or intestines by endoscopy. |
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tx for GI/oropharyngeal
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-cipro IV
-doxy and 1-2 others: -rifampin -vanco -chloramphenicol |
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postexposure prophylaxis
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-Recommended for persons exposed to B. anthracis spores. Not contacts
-cipro 500 mg PO or doxy 100 mg PO -PCN or amoxiciliin -cont x 60 days -exposed person should be washed with soap and water and personal items decontaminated with 1:10 bleach solution -barrier precautions -Hospital epidemiologist and local and state DOH should be notified with suspected or confirmed cases |
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anthrax vaccine
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-6 SQ dose series
-annual booster -Given to all US military personnel, lab workers, handlers of hides and animal products. -SE: local and injection site rxns |
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infx control precautions
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-Cutaneous anthrax: contact precautions, hand washing
-Inhalational anthrax: Good handwashing. Masks and isolation room not necessary. |
