Infectious Disease Flashcards
What is a person or animal that harbors an infectious agent/disease and can transmit it to others but does not demonstrate signs of the disease?
carrier
What is the exposure to a source of an infection?
contact
- contact does imply infection it implies the possibility of infection
What is the capability of being transmitted from person to person by contact or proximity?
Does not need or utilize a vector?
Contagious
What is an organisim that harbors a parasitic, mutualistic, or commensalism guest?
host
What is an organism that lives on or in host organism and gets food from or at the exposure of its host?
parasite
What are the 3 main classes of human parasite?
- protozoa
- helminths
- ectoparasites
What is an infectious agent or organism that can produce disease?
pathogen
What is the invasion of the body tissue of a host by an infectious agent, regardless if it is a disease or not?
infection
What is the pathway into the host that gives an agent access to tissue that will allow it to multiply or act?
portal of entry
What is a population of organisms or the specific environment in which an infectious pathogen naturally lives and reproduces; usually living host of a certain species?
reservior
What is an increase, often sudden, in the number of cases of a disease above what is normally expected in the population and area?
epidemic
What is a pathogen that is transmissible from non-human (typically vertebrates) animals to human?
zoonosis
What carries the same definition of epidemic but is often used for a more limited geographic are?
outbreak
What is the constant presence of an agent or health condition within a given geographic are or population?
endemic
What is an epidemic occurring over a widespread area (multiple countries or continents) and usually affecting a substantial proportion of the population?
pandemic
What is any group of viruses that are transmitted between hosts by mosquitoes, ticks, and arthropods?
arbovirus (arthropod-borne virus)
What is resistance developed in response to an antigen (pathogen or vaccines) characterized by the presence of antibody produced by the host?
active immunity
What kind of immunity occurs when a majority of a group is resistant/immune to a pathogen? This confers confers protection to unvaccinated or susceptible individual/group by reducing the likelihood of infection or spread?
herd immunity
What is the transfer of active humoral immunity of ready-made antibodies produced by another host or synthesized?
passive immunity
What is used when there is a high risk of infection and insufficient time for the body to develop its own immune response?
passive immunization
- SHORT TERM!
What describes an illness, impairment, degradation of health, chronic, or age-related disease?
morbidity
- increased morbidity = decreased lifespan and increased mortality
What is the time interval from a person being infected to the onset of symptoms of an infectious disease?
incubation period
What is the tie interval from a person being infected to the time of infectiousness of and infectious disease?
latency period
What is an infection that is nearly or completely asymptomatic.
subclinical infection
What is an asymptomatic carrier of an infection?
subclinically infected person
What is a combination of symptoms, characteristics of a disease, or health condition; somtimes refers to a health condition without a clear cause?
syndrome
- Greek for “concurrence”
What is the measure of death defined population during a specified time interval, from an defined scale?
mortality rate
What transmission occurs between an infected person and a susceptible person via physical contact with blood or body fluids?
direct contact
What transmission occurs when there is no direct human-to-human contact?
indirect contact
What are the two forms of indirect contacts?
- vehicle borne
- vector borne
What is the person to contaminated surface/object to person contact?
vehicle borne
What is the person to vector (mosquitoes, flies, mites, fleas, ticks, rodents, dogs) to person contact?
vector borne
What is the onset of a disease before more diagnostically specific signs and symptoms develop?
prodrome
- prodromal symptoms
What is a one-celled organism that is free-living or harbor on a host?
protozoa - parasite
What class of parasites are capable of multiplying in humans, contributing to its survival and permitting further infections to develop?
protozoa
What are the 4 further classifications of protozoa based of mode of movement?
- sarcodina
- mastigophora
- ciliophora
- sporozoa
What is ameba group of protozoa?
sarcodina
What is the flagellates class of protozoa?
mastigophora
What is the cilates class of protozoa?
ciliophora
What is the non motile adult stage organism class of protozoa?
sporozoa
What is the leading cause of water borne disease in the US?
cryptosporidium (sporozoa protozoa parasite)
What class of parasite is a large multicellular organism visible to the naked eye in adult stage, that are free-living or harbors on a host?
helminths
What parasites invade the GI tract, but are unable to multiply in humans?
helminths
What class of parasite’s name is derived from the Greek word for worms and categorized into three main groups of soil transmitted human parasite infections?
helminths
What are the 3 main groups of soil-transmitted helminths human parasite infection?
- flatworms (platyhelminths)
- thorny-headed worms (acanthocephalins)
- round worms (nematodes)
What helminth reside in the GI tract, blood, lymph or subcutaneous tissue?
roundworms
Ticks, fleas, lice, and mites that burrow into the skin and remain there for weeks to months falls under what category of parasite that broadly includes bloodsucking arthropods such as mosquitoes?
ectoparasites
What causes various disease, and more importantly functions as vectors or transmitters of many different pathogens that causes morbidity and mortality?
ectoparasites
What is ordered to find protozoan or hemlinths parasites in patients presenting with GI symptoms indicative of parasite infection?
fecal exam
What is used when stool exam findings are unremarkable, but patients continue to have symptoms indicative of GI parasitic infections?
endoscopy/colonoscopy
What bloods test looks for antibodies or parasites antigens produce by the body’s immune response to a parasitic disease?
serology
What blood test identifies parasitic species in the blood under a microscope?
blood smear
What can help identify parasitic diseases affecting certain organs?
- x ray
- MRI
What is a single stranded RNA virus of the family Flavivirdae?
west nile virus
What is the leading cause of domestically acquired arboviral disease in the US?
west nile virus
How is the west nile virus transmitted?
- culex mosquito
- blood transfusion/organ donation; mother to child
What is the incubation period for west nile virus?
2-6 days but can range from 2-14 days
is west nile virus lethal?
non-neuroinvasive (no)
neuroinvasive (yes)
What are some predisposing factors of west nile virus?
- outdoor activities during spring and summer
- mosquito bites
West nile virus outbreaks tend to occcur when?
between mid- July and early September
- elevated temperature, rainfall, blood transfusion, and organ transmission correlate with increased WNV transmission
What is the most prevalent mosquito borne disease in the US?
WNV
Mosquitos become infected with WNV when they feed on what? Before spreading virus to human and other animals?
infected birds
What are considered dead end host for WNV?
- horses
- humans
What percentage of human WNV infections are subclinical or sysmptomatic?
70-80%
What presents clinically indistinguishable from viral meningitis due to other etiologies and typically presents with fever, HA, and nuchal rigidity?
WNV meningitis
What is a more severe clinical syndrome that usually manifest with fever and altered mental status, seizures, focal neurologic deficits, or movement disorders such as tremor or Parkinson’s?
WNV encephalitis
What often presents as an isolated limb paresis or paralysis and can occur without fever or apparent viral prodrome?
WNV acute flaccid paralysis
- WNV poliomyelitis
What labs are used to diagnose WNV?
IgM in serum or CSF
What is used to detect IgM antibodies?
ELISA
If CNS symptoms are present in regards to WNV what lab should be ordered?
lumbar puncture with CSF analysis
- CBC is not reliable
What is the first line management protocol for WNV?
vigorous supportive measures
- no antiviral treatment available
WNV warrants MEDEVAC when what signs are present?
- encephalitis
- menigitis
- paralysis
What is the protozoan parasite of the genus plasmodium?
malaria
What are the 4 subtypes of subtypes?
- P. falciparum
- P. vivax
- P. ovale
- P. malarae
What are some predisposing factors of malaria?
- mosquito exposure
- operating in endemic area
- lack of PPE
- lack of chemoprophylaxis
- lack of bed nets
How is malaria transmitted?
female anopheles mosquito
- vector borne illness
- no vaccines available
What is the incubation period for malaria?
7 to 30 days
Is malaria lethal?
- P. falciparum (yes)
- P. vivax (maybe)
- P. ovale (maybe)
- P. malaraeb (maybe)
What are the three phases of malaria lifecycle?
- sporogony phase
- exoerythrocytic phase
- erythrocytic phase
What phase of malaria is the sexual cycle in female anopheles mosquitos?
sporogony phase
What phase of malaria is the asexual cycle in human liver?
exoerythrocytic phase
What phase of malaria is the asexual reproduction in RBCs?
erythrocytic phase
The presentation of malaria can be broken down into what 2 broad categories?
- uncomplicated
- severe
What category of malaria is characterized by paroxysmal (cyclical) fever, influenza-like symptoms including chills, HA, myalgias, malaise, jaundice and anemia secondary to hemolysis?
uncomplicate malaria
What category of malaria is characterized by small blood vessels infarction, capillary leakage, organ dysfunction, altered consciousness, hepatic failure, renal failure, acute respiratory distress syndrome, and severe anemia?
severe malaria
What is considered a clinical hallmark of malaria infection?
paroxysmal fever
What are the stages of paroxysmal fevers in regards to malaria?
cold stage - lasts 1 hour
febrile stage - lasts 2-6 hours
diaphretic stage - lasts 2-4 hours, fever drops
- patient then return to normal and cycle repeats itself every 48-72 hours
What is the lifecycle ranges for malaria?
48-72 hours
What is the diagnosing testing for malaria?
rapid malaria testing via blood smear
- givers qualitive results
- results must be confirmed with microscopy
Malaria treatment options are based on what?
- species
- severity of infection
- likelihood of drug resistance
- patients age and pregnancy status
What are 2 reliable supply treatment regimens available in the US for malaria?
- atovaquone-proguanil (malarone)
- artemether-lumefantrine (coartem)
What is the treatment of uncomplicated malaria?
- chloroquine phosphate 1g (600mg base) PO
- 0.5 g in 6 hours
- 0.5 g daily for 2 days
What is the treatment of malaria with chloroquine resistance?
malarone (atovaquone 250mg/proguanil 100mg) 4 tabs PO QD for 3 days
What is the treatment of severe malaria?
- Artesuate 2.4mgkg IV at 0, 12, 48 hours
- Doxycycline 100mg BID x 7 days after parenteral therapy
What is the treatment for malaria P. ovale?
- ADD primaquine 52.6mg (30mg base=2 tabs) PO QD x 14 days
- added to regiment for hypnozoites
What is the most important protective measure for of malaria prevention?
proper clothing and awareness
What is the administration of chloroquine and mefloquine for prophylaxis against malaria?
- start 1-2 weeks prior embark
- continued for 4 weeks after leaving endemic area
What is the administration of malarone, primaquine, and doxycycline for prophylactic medications?
- start 2 days prior to embark
- continued 7 days after departing
What is the disposition for malaria?
MEDEVAC
What is a single strand RNA virus of the genus Flavivirus?
dengue fever
Dengue fever has how many subtypes?
4 serotypes
What is the common name for dengue fever?
breakbone fever
What are the predisposing factors of dengue virus?
- urban environment
- outdoor activities during spring and summer
- mosquito bites
How is dengue fever transmitted?
- aedes aegypti mosquito
- blood transfusion/organ donation
- vector borne
What are the 3 phases of dengue fever?
- febrile
- critical
- convalescent
The febrile phase of dengue fever typically last how long?
2-7 days
- biphasic
What are some signs and symptom during the febrile phase of dengue?
- severe HA
- retroorbital pain
- muscle, joint, and bone pain
- transient maculopapular rash
What are the minor hemorrhagic manifestations of the febrile phase of dengue?
- petechia
- ecchymosis
- purpura
- epistaxis
- bleeding gums
- hematuria
- positive tourniquet test
How long does the critical phase of dengue last?
begins at defervescence and typically lasts 24-48 hours
What is a cardinal feature of dengue hemorrhagic fever?
plasma leakage
Patient’s with severe plasma leakage from dengue fever will present with what?
- pleural effusion or ascites
- hypoproteinemia
- hemoconcentration
patient will appear well despite early signs of shock
In regards to the critical phase of dengue fever once hypotension develops, systolic blood pressure rapidly declines, and irreversible shock and death may ensue despite resuscitation efforts. This is known as?
dengue shock syndrome
In regards to the critical phase of dengue fever can develop severe hemorrhagic manifestations such as?
- bloody stool
- melena
- menorrhagia
especially in prolonged shock
What phase of dengue fever can present with a rash that may be desquamate and pruritic?
convalescent phase
What are the two hallmarks of severe dengue?
- capillary permeability
- disordered/diminished blood clotting
What is a relatively accurate way to get a general determination of a patients capillary fragility or hemorrhagic tendency in dengue fever?
tourniquet test
How do you perform tourniquet test?
- obtain baseline BP
- Attach and inflate BP cuff midway between systolic and diastolic
- keep inflated for 5 min
- deflate and wait 2 min
- count petechia below AC fossa
What is a positive tourniquet test?
10 or more petechia per 1 square inch
What are the diagnostics for dengue fever?
- clinically if patient was in endemic are within 2 weeks of symptoms onset
- single acute phase serum specimen of viral components obtained early (<7 days after onset)
- IgM against dengue virus can be detected with ELISA later in illness (>4 days after fever onset)
What rugs should be avoided in the treatment of dengue fever?
aspirin, aspirin containing drugs, and NSAIDs because of there anticoagulant properties
What is a gram-negative, intercellular, coccobacillus bacterium?
rocky mountain spotted fever (RMSF)
- vector borne
What is the scientific name for RMSF?
R.rickettsia
Where is RMSF prevalent?
endemic in central and south America. occurs throughout the US
- North Carolina
- Tennessee
- Missouri
- Arkansas
- Oklahoma
What are some predisposing factors of RMSF?
- hiking
- camping
- high tick population
- spring and summer months
- not performing tick checks
- lack of PPE
How is RMSF transmitted?
American dog tick - east of Rockies and pacific coast
Rocky mountain wood tick - rocky mountain region
Brown dog tick - worldwide
What is the incubation period for RMSF?
2-14 days
What is the lethality of RMSF?
not lethal unless untreated
Spotted fever rickettsiosis is reported in all lower 48 states with over 50% of cases reported where?
- North Carolina
- Arizona
- Montana
- Tennessee
- Virginia
When does peak transmission of SFR occur?
may-august
Wht two states are characterized by unusually high incidence and case fatality rates, particularly among children?
- Arizona
- North Mexico
RMSF is a rapidly progressive disease and without early administration of what drug can be fatal within day?
doxycycline
What/When are the early ilness signs and symptoms?
- day 1-4
- fever
- HA
- GI symptoms
- myalgias
- edema around the eyes and back of hands
- rash
When and how does the rash for RMSF present?
- begins with small flat pink macules on wrist, forearms and ankles that spread to the trunk
- can also involve palms of hands and feet
What ID infects endothelial cells that line blood vessels, causing vasculitis and bleeding or clotting in the brain or other organs?
RMSF (late ilness day 5 or later)
Severe RMSF may cause permanent complications from?
- neurological deficets
- damage to internal organs (respiratory compromise, renal failure)
- vascular damage requiring amputation
Is there any evidence that R. rickettsii causes any persistent or chronic disease?
No
What presents as a sign of severe late sign of RMSF?
petechial rash
- presents 5-6 days after illness
What RMSF DDX present with lesions on hands and feet?
- syphilis
- hand, foot and mouth disease (HFMD)
- dyshidrosis treatment
What is the treatment an disposition for suspected RMSF?
- empiric treatment with doxy
- MEDEVAC for further monitoring and lab studies
When should you perform tick checks?
12- hour intervals
- never let you personnel go more that 24 hours without a check
What disease has an organism type of spirochetes belonginging to the borrelia burgdorferi complex?
Lyme disease
What is the scientific name for lyme disease?
B. burgdorfi
What are the three subtypes of Lyme disease?
- B. afzelii
- B. burgdorfi
- B. garinii
Where is Lyme disease prevalent?
- Europe (central and eastern)
- Asia (western Russia, Mongolia, northeastern China, Japan
- United States (northern and north-central)
What are some predisposing factors of Lyme disease?
- hiking
- camping
- high tick population
- spring and summer months
- not performing tick checks
- lack of PPE
How is Lyme disease transmitted?
bite of a Lyme infected Ixodes (blacklegged) ticks
- vector borne, ticks
What is the lethallity of Lyme disease?
typically not lethal
What is the causative bacteria in Lyme disease, transmitted to a host (most often a mammal) via ticks when taking a blood meal?
B. burgdoferi
What is the main reservoir for Lyme disease?
Rodents
- white foot deer mice
- chipmunks
- squirrels
When do most transmissions and infections of Lyme disease occur?
May-August
when ticks and mammals are active
Ticks attach to any part of the host but often prefer where?
- groin
- axilla
- scalp
In most cases, the tick must be attached for how long for b. burgdorferi can be transmitted?
36-48 hours
- however, transmission has occurred in as little as 24 hours
Many people do not know a tick is attached for days due to what?
anesthetic chemical in saliva
What are the early localized stage symptoms of Lyme disease?
flu-like symptoms
- malaise
- HA
- fever
- myalgia
- arthralgia
- lymphadenopathy
What is a red ring-like or homogenous rash expanding that appears about 1 week after initial infection of lime disease, begins as a slightly raised red lesions at the site of the tick bite, and after several days the rash expands out from the central lesion sometimes appearing as a “bulls-eye/target” lesion, but more often as a muddled circular rash?
Erythema migrans (EM)
What are the constitutional symptoms of the acute/early disseminated stage of Lyme disease?
- multiple secondary annular rashes
- flu-like symptoms
- lymphadenopathy
What are the cardiac manifestations of the acute/early disseminated stage of Lyme disease?
- conduction abnormalities (atrioventricular node block)
- myocarditis
- pericarditis
What are the neurologic manifestations of the acute/early disseminated stage of Lyme disease?
- bell’s palsy
- meningitis
- encephalitis
What are the manifestations of the late disseminated stage of Lyme disease?
Rheumatologic manifestations
- transient, migratory arthritis and effusion in multiple joints
- migratory pain in tendons, bursae, muscle, and bones
In regard to Lyme disease when should you NOT perform serologic testing?
- asymptomatic patients in endemic areas
- asymptomatic patient after an ixodes tick bite
- patients with non-specific symptoms (subacute myalgias, arthralgias, or fatigue)
What is used for the acute/early phase of Lyme disease?
2 ELIZA tests
What is used for late disseminated stage of Lyme disease?
@ ELIZA test or 1 western blot
What test can show specific antigens of B. burgdorferi are reacting with serum antibodies?
western blot
For patients with Lyme disease illness duration of more than 1 month what test should be used?
IgG or combined IgG/IgM testing can detect the disease
What is the treatment for ALL stages of Lyme disease? As well as post exposure prophylaxis
doxycycline
What can be used for chemoprophylaxis to reduce risk of acquiring Lyme disease after the bite of a high-risk tick?
single dose of 200mg of doxycycline
What is the disposition for suspected Lyme disease?
MED ADVICE
A vast majority of patients treated with ABx in early stage of Lyme disease recover rapidly and completely without complications. However a small percentage of cases have lingering fatigue, myalgia, and arthritis that can persist for months to years, this is known as?
post-treatment Lyme disease syndrome (PTLDS), or chronic Lyme disease
What ID is an obligate intracellular protozoan parasite?
leishmaniasis
What is the scientific name for leishmaniasis?
leishmania (species) AKA L. tropica
What are the subtypes of leishmaniasis?
- old world leishmaniasis (eastern hemisphere)
- new world leishmaniasis (western hemisphere)
What is the prevelance of leishmaniasis?
700,000 to 1.2 millions cases each year
- on every continent except Australia and Antarctica
What are the predisposing factors for leishmaniasis?
- chronic san fly exposure
- poverty
- proximity to dogs/cats/rodents
How is leishmaniasis transmitted?
- sand fly
- sand flea
vector borne
What is the incubation time for leishmaniasis?
2 weeks to several months and in some cases up to 3 years; some >20 years
What is the lethality of leishmaniasis?
- cutaneous leishmaniasis (maybe)
- mucocutaneous leishmaniasis (yes)
- visceral leishmaniasis (yes)
What is the most common manifestation of leishmaniasis?
cutaneous leishmaniasis
What is the primary vector for the protozoa of leishmaniasis?
sand flies
Where do the lifecycle for the leishmaniasis protozoa take place?
one stage in the sand fly and, one stage in the mammalian host
What is a normal sand fly bite reaction?
pruritic but do not enlarge and resolve after several weeks
How does infection form CL differ from normal sand fly bites?
- begin as pink colored papule that enlarges to a nodule or plaqu-like lesion
- lesion ulcerates with indurate border and may have thick white-yellow fibrous material
- lesion are often painless
- multiple lesions may be present
- lesions gradually heal over months to years with noticeable scarring at site
Clinicians should maintain a high suspicion for CL in any patients with what?
- chronic non healing skin lesions
- endemic area
- sand fly bites
CL is diagnosis through lab confirmation by what means?
- microscopic examination for leishmaniasis parasite or DNA of tissue.
- culture techniques
- molecular methods
CL is diagnosis through lab confirmation by what means?
- microscopic examination for leishmaniasis parasite or DNA of tissue.
- culture techniques
- molecular methods
Tissue collected from the base and margins of CL ulcers should be submitted for what tests?
- histology
- cuture
- PCR
What is the treatment for visceral leishmaniasis?
Amphotericin B deoxycholate
What is the treatment for CL?
- oral azoles
- topical formulations of paromomycin
What is the most commonly used drug to treat leishmaniasis?
pentavalent antimonials
What is the FDA approved treatment for CL, MCL and VL caused by leishmaniasis species?
miltefosine
What is the foundation of leishmaniasis prevention?
avoidance by sand flies in endemic area
- sand flies are less active during the hottest hours of the day
- fans or ventilators might inhibit the movement of sand flies
What is the gram-positive genetically distinct strain of staphylococcus aureus?
Methicillin-resistant Staphylococcus Aureus (MRSA)
What is the scientific name for MRSA?
staphylococcus aureus
What are the subtypes of MRSA?
- community associated (CA-MRSA)
- healthcare associated (HA-MRSA)
What is the prevalence of MRSA?
worldwide and increasing
What are predisposing factors of MRSA?
- hospitals
- prisons
- nursing homes
- close living quaters
- military
- athletes
- weaked immune system
How is MRSA transmitted?
- direct contact
- sharing peronal/hygiene items
- surfaces or items contaminated with MRSA
- 5% of patients in U.S. hospitals carry MRSA in their nose or on their skin
- NOT vector borne
What is the incubation period of MRSA?
high variable
4-10 days , but asymptomatic years
What is the lethality of MRSA?
20,000 deaths in the US in 2019
What is any strain of S.aureus that has developed multiple dri=ug resitance to beta-lactam antibiotics?
MRSA
What is any strain of S. aureus susceptible beta-lactam antibodies?
MSSA
What is the most frequently reported clinical manifestation of MRSA?
SSTIs specifically…
- furuncles
- carbuncles
- abscesses
Patients with c/c of what kind of bites should raise suspicion for S. arues infection?
spider bite
- areas of fluctuance and purulent drainage are commonly present
What is the mainstay therapy for any fluctuant lesion secondary to MRSA?
I & D
What antibiotics can be used to treat MRSA infection?
- TMP-MX
- clindamycin
- doxycycline
What is the disposition for MRSA infection?
uncomplicated MRSA ROB
An MO should be consulted for what complications of MRSA?
- SSTI on face, neck, or head that may require I&D
- orbital cellulits
- SSTI unresponsive for 48 hours after ABx
- osteomyelitis
- any signs of NECFASC
- patients with reoccurent infection
- may require Derm
An MO should be consulted for what complications of MRSA?
- SSTI on face, neck, or head that may require I&D
- orbital cellulits
- SSTI unresponsive for 48 hours after ABx
- osteomyelitis
- any signs of NECFASC
- patients with recurrent infection
- may require Derm
An MO should be consulted for what complications of MRSA?
- SSTI on face, neck, or head that may require I&D
- orbital cellulits
- SSTI unresponsive for 48 hours after ABx
- osteomyelitis
- any signs of NECFASC
- patients with recurrent infection
- may require Derm
What is the 3rd most common bite wound after dogs and cats?
human
What are the two basic categories of human bites?
- occlusive; teeth closing over and breaking skin
- clenched fist “fight bite”
Typical human oral and skin flora cause what infections?
- eikenelle
- group A streptococcus
- fusobacterium
- staphylococcus
- prevotella
What are the typical locations for fight bites?
3rd, 4th, or 5th MCP joint
- most common in adolescent boys and adult men
What ABx do you NOT use on human bites?
- cephalexin (keflex)
- penicillinase-resistant penicillin PRPs (dicloxacillin)
- macrolides (erythromycin & azithromycin)
What is the early antibiotic for an uninfected human bite?
amoxicillin clavulanate
What labs should be ordered for concerns of osteomylitis?
- CBC
- ESR
- CRP
What is an acute or chronic inflammatory process involving bone and structures secondary to infection with pyogenic organisms, including bacteria, fungi, and mycobacteria?
osteomyelitis
Among younger adults OM occurs most commonly in what settings?
- trauma, and related surgery
Among older adults, OM occurs most commonly as a result of?
contagious spread of infection to bone from adjacent soft tissue and joints
In adults OM most often affects what bones?
vertebrae or hips
- extremities are frequently involved due to skin wounds, trauma and surgies
What are risk factors of OM?
- bacteremia
- endocarditis
- IV drug use
- trauma
- open fractures
What are some local findings of OM?
- tenderness
- warmth
- erythema
- swelling
What are some systemic symptoms of OM?
- fever
- rigors
What is an essential component in evalutating suspected OM?
radiographs
What are the most useful studies for OM?
- MRI
- technetium-99 bone scintigraphy
What is the most common cause of scute OM in adults and children?
- MSSA
- MRSA
What are the 2 pillars of OM treatment?
- surgical containment
- prolonged ABx therapy
What is the prolonged ABx therapy medication of choice for OM?
- IV vancomycin
- IV ceftriaxone
What is the disposition for OM?
MEDEVAC for defenitive treatments
- radigraphs
- long term ABx
- MO should be contacted to determine in empiric oral antibiotics should be started before transport
What is a spore-forming, anaerobic, gram-positive bacterium?
tetnus
What is the scientific name for tetanus? what is the common name?
- clostsridium tetani
- lockjaw
What are the predisposing factors of tetanus?
- inadequate TD immunization
- no TD booster in last 10 years
- puncture wound
- penetrating injury with retained foriegn body
- untreated necrotic tissue
- crushing injury
How is tetanus transmitted?
direct contact of open wound and non-contact skin
- NOT vector borne
What is the incubation period for tetanus?
3 to 21 days, usually 8 days
- the further the inoculation site is from the CNS the longer the incubation period
Is tetanus lethal?
yes
What is an acute, often fatal, exotoxin-mediated disease produced by gram positive, spore-forming anaerobic rod, clostridium?
tetanus
What causes the symptoms of tetanus and is one of the most potent toxins known?
tetanus toxin
What are the first commonly presented symptoms of tetanus?
- lockjaw
- nuchal rigidity
- dyshphagia
- rigidity of abdominal muscles
- frequents muscles spasms
- hyperthermia
- diaphoresis
- hypertension
- episodic tachycardia
What are the common late symptoms of tetanus
- periods of apnea due to contraction of thoracic muscles or pharyngeal muscle contraction
- fracture from muscles spasms
- nosococmial infections
- aspiration pneumonia
- death typically occurs secondary to respiratory arrest
What re the two classifications of wound cleanliness?
- clean vs. contaminated/dirty
- superficial vs. deep/penetrating
What antibiotic do you prescribe for prophylaxis against tetanus?
None, there is no benefit unless other SSTIs from organisms other than tetanus is present
What is the treatment if you suspect tetanus in a patient?
- urgent MEDEVAC
- clean/debride wound
- supportive therapy and airway protection
What antibiotic is used to treat antibiotics?
- metronidazole or pen G 2-2
- Tetanus Immune Globulin (TIG,HTIG)
How long is the recovery from tetanus?
months to years
What are the bacterial etiologies of meningitis and encephalitis?
- streptococcus pneumonia
- group B streptococcus
- N. echoviruses
- H. influenza
- E.coli
- listeria monocytogenes
What are the viral etiologies of meningitis and encephalitis?
- enteroviruses
- coxsackieviruses
- echoviruses
- WNV
- influenza
- HSV
- VZV
- EBV
- arbovirus
What is the most common viral etiology of meningitis and encephalitis?
enteroviruses
What are some risk factors that should increase clinical suspicion for meningitis?
- close contact exposures (military barracks, college dorms)
- incomplete vaccinations
- immunosuppression
- > 65 y/o and <6 y/o
- alcohol use disorder
Meningitis typically occurs through what two routes of inoculation?
- hematogenous seeding
- direct contagious spread
When bacteria colonize in nasopharynx and enter bloodstream. Upon making their way to the subarachnoid space, the bacteria cross the blood-brain barrier, causing a direct inflammatory and immune-mediated reaction is known as?
hematogenous seeding
When organisms enter CSF via neighboring anatomic structures (otitis media, sinusitis) or foreign objects (medical devices, penetrating trauma) is known as?
direct contiguous spread
What is the classic meningeal tetrad?
- fever
- nuchal rigidity
- altered mental status
- severe HA
What lab is used to distinguish between bacterial and septic meningitis?
lumbar puncture with CSF analysis
What is the preferred imaging modality for meningitis?
CT
What ABx are used for meningitis?
- ceftriaxone IV
- pen- G IV
What steroid is used because of its association with reduction in rate of healing loss, neurologic complications, and decreased mortality for meningitis?
dexamethasone
What are signs of ICP?
- altered mental status
- neurological deficits
- non-reactive pupils
- bradycardia
What should be done for patients with ICP?
- elevate the head of the bed 30 degrees
- induce mild hyperventilation in the intubated patient
- osmotic diuretics (25% mannitol, 3% saline)
What is the chemoprophylaxis regime for meningitis?
- ceftriaxone 250mg IM one time
- Ciprofloxacin 500mg PO one time
What is the scientific name for mono?
eptien-barr virus
What are the common names for mono?
- kissing disease
- glandular fever
How is mono transmitted?
- saliva
- bodily fluids
What is the incubation period of mono?
4-6 weeks
What is the lethality of mono?
not lethal but high risk of splenic rupture
IM presents consistent with what other diseases making it often misdiagnosed by clinicians?
erythematous or exudative pharyngitis or tonsilitis
What are some common findings of mono?
- malaise
- fever
- cervical lymphadenopathy (typically posterior)
- splenomegaly
- maculopapular rash if patient is treated with cillin-class antibiotic
What labs are used for mono?
- mono spot (positive 4 weeks after onset)
- CBC
- LFT
What is the treatment for IM?
treat symptomatically
- avoid antivirals
What is the disposition of IM?
- SIQ
- light duty with no physical contact sports for 3-4 weeks due to risk of splenomegaly and splenic rupture
What is the scientific name for rabies?
lyssavirus
What are some predisposing factors for rabies?
- veterinarians
- wild life researcher
- exposure to bat colonies
- feral/unvaccinated dog and cats in developing countries
How is rabies transmitted?
spreads through infected saliva through a break in the skin
- dogs account for 99% of all rabies transmission
What is the incubation period for rabies?
1-3 months depending on site of inoculation
What is the lethality of rabies?
once the rabies virus reach the CNS is has a 99% fatality rate
What is a fatal acute, progressive encephalitis caused by neurotropic viruses in the family rhabdoviridae, genus lyssaavirus?
rabies
What are the major rabies reservoirs?
- terrestrial carnivores
- bats
Clinical rabies typically manifests as 1 of 2 forms. What are they?
- encephalitis “furious”
- paralytic “dumb”
Fever, hydrophobia, pharyngeal spasms, hyperactivity subsiding to paralysis, coma, ANS instability, hypersalivation, lacrimation, diaphoretic, “goose flesh”, and dilated pupils are all part of what major manifestation form of rabies?
encephalitic “fuirious”
Ascending paralysis that is similar to guilliain-barre, lost of DTR and plantar reflex are all part of what major manifestation form of rabies?
paralytic “dumb”
What is the most characteristic feature of rabies, when patient becomes afraid of water due to involuntary pharyngeal muscle spasms when they attempt to drink?
hydrophobia
What is a pathognomonic pharyngeal muscle spasm triggered by feeling a draft of air, leading to spiration, couching, choking, asphyxiation and respiratory arrest?
aerophobia
Fever and chills with paresthesia surrounding animal nite site is suggestive of what?
rabies
What is the definition of diarrhea?
- 3 or more loose stools within 24-hrs
- caused by increase water content of the stool, due to either impaired water absorption, or active secretion by the bowel, or both.
Time frame for acute diarrhea?
< 14 days
Timeframe for persistent diarrheas?
more than 14-30 days
time frame for chronic diarrhea?
> 30 days
What classification of diarrhea presents with blood in loose-watery stool, and fever, secondary to tissue damage to lining of the colon from certain bacteria, and/or toxins?
inflammatory diarrhea
What classification of watery stool presents with watery stool, NO blood and absence of fever?
non-inflammatory diarrhea
What are some common viral etiologies for diarrhea?
- norovirus
- rotavirus (primary children)
What are some bacterial etiologies of diarrhea?
- enterotoxigenic escherichia coli (ETEC)
- campylobacter jejuni
- shigella spp.
- salmonella spp.
- bacterial toxin-releasing
What are some protozoal etiologies of diarrhea?
- giardia
- entamoeba histolytica
What is the scientific and common names of viral infectious diarrhea?
- nonenveloped, single-stranded RNA viruses genus norovirus
- stomach flu/bug, Norwalk virus
What are some predisposing factors of viral ID?
- ready to eat cold foods
- raw selfish (especially oysters)
- contaminated ice
- close quarters living
How is viral ID transmitted?
primarily fecal-oral route
- direct person to person contact
- indirect through food and water
- spread through aerosols of vomits and contaminated environmental surfaces/objects
What is the incubation period for infectious ID?
12-48 hours
What presents with acute onset of abdominal cramps, nausea, vomiting, body aches, HA, non-bloody diarrhea and sometimes a low grade fever?
norovirus
What is an RNA virus of the orthomyxovirus genus?
influenza
What is the scientific name for influenza?
orthomyxovirus
What are the 4 subtypes of influenza?
A/B/C/D
- only A and B commonly cause illness in humans
What is the incubation period for influenza?
24-96 hours
What are the 2 distinct virion structures that surround the viral membrane which is necessary for viruses to enter cells and are also how influenza undergoes periodic changes?
glycoproteins
How are influenza virus strains identified?
by the way the glycoproteins mix
