Ch. 8 ID Flashcards
1
Q
List characteristics of Clostridium botulinum bacteria
A
Gram +
Anaerobic rod
spore-forming
prevalent in soil an marine sediment
heat and acid resistent
2
Q
What is the mechanism of action of botulinum toxin?
A
blockage of presynaptic release of acetylcholine at the neuromuscular junction –>
flaccid descending paralysis
mydriasis, ptosis, respiratory paralysis
3
Q
what is the primary cause of death in botulism?
A
respiratory paralysis
4
Q
What is the treatment of botulism?
A
Botulinum Antitoxin
Adults –» trivalent antibodies to toxin (derived from horse serum)
Infants –» human-derived botulinum Ig IV (BIG-IV)
5
Q
What toxin causes tetanus?
A
exotoxin tetanospasmin
6
Q
List characteristics of Clostridium tetani bacteria
A
gram + Rod
anaerobe
spore-forming –> “drumstick appearance”
found in soil and animal feces
7
Q
What is the mechanism of action of exotoxin tetanospasmin?
A
Blocks release of inhibitory neurotransmitters (glycine and GABA) at motor endplates of skeletal muscle, spinal cord, brain and sympathetic nervous system –> spastic paralysis and tetany
8
Q
What type of poisoning can have a similar presentation to tetanus?
A
Strychnine poisoning
(found in pesticides, homeopathic meds, street drugs)
- waxing and waning intense muscle contractions, back arching, grimacing
Tx with benzos
9
Q
How is tetanus diagnosed?
A
Clinical diagnosis
SPATULA TEST - a tongue depressor is used to touch the posterior oropharynx, will cause a patient with tetanus to uncontrollably bite down on the depressor
(reported sensitivity and specificity of > 90% for tetanus infection.)
10
Q
What is the treatment for tetanus?
A
- aggressive supportive care
- Human Tetanus Ig (TIG) 3000-5000 units IM
- Tetanus immunization (opposite side)
- +/- Abx (Metronidazole) (questionable utility)
- other meds:
- Benzos to relax muscles
- Magnesium and labetalol for sympathetic hyperactivity
penicillin and isolated beta blockade are contraindicated
11
Q
If you have a wound that requires debridement should you do it before or after administration of tetanus immune globulin?
A
After. Debridement can release additional toxins
12
Q
How is gonorrhea diagnosed?
A
Nucleic acid amplification test (NAAT) of urethral/first-catch
urine, cervical, pharyngeal, or rectal specimen; sensitivity approximately
95%
13
Q
What is the treatment for disseminated gonorrhea?
A
Ceftriaxone 1 g IV daily
14
Q
What organism causes syphilis?
A
Treponema pallidum
15
Q
Describe the characteristics of the organism treponema pallidum?
A
Gram negative
obligate intracellular
spirochete (corkscrew shaped)
visible with darkfield microscopy
16
Q
What is the incubation period of syphilis?
A
2-4 weeks
17
Q
Describe primary syphilis
A
painless genital ulcer with indurated border (chancre) that heals spontaneously over 2-6 weeks
18
Q
What do you call a wartlike genital lesion?
A
condyloma lata (secondary syphilis)
19
Q
What are the 4 components of tertiary syphilis?
A
- tabes dorsalis - myelopathy involving dorsal columns of spinal cord
- dementia
- gummatous lesions of mucous membranes
- Thoracic aortic aneurysms
20
Q
What stage of syphilis does neurosyphilis occur?
A
can occur in ANY stage!
21
Q
How is syphilis diagnosed?
A
screening test = serum rapid plasma reagin (RPR) or VDRL
confirmatory test = serum florescent treponemal antibody absorption test (FTA-ABS)
22
Q
What is the treatment of primary or secondary syphilis?
A
Benzathine penicillin 2.4 million U IM (alternative = doxycycline × 14 days)
23
Q
What is the treatment of latent or tertiary syphilis?
A
Benzathine penicillin 2.4 million U IM weekly × 3 (alternative = doxycycline PO × 28 days)
24
Q
What is the treatment of neurosyphilis?
A
Aqueous penicillin G 3-4 million units IV q4h × 10-14 days
or
benzathine penicillin 2.4 million units IM qd plus probenecid PO qid × 10-14 days
25
Describe a Jarisch-Herxheimer reaction and when does it typically occur?
Acute fevers, headaches, myalgias, sweating within 24 hours of initial treatment of spirochete infections;
26
What is the treatment of Jarisch-Herxheimer reaction?
self-limited
supportive treatment
27
Describe the microbiology of the influenza virus.
single-stranded RNA
Orthomyxoviridae virus
28
How is EBV typically transmitted?
bodily secretions
29
What lab finding is common in those with mono?
transaminitis
30
How is Mono diagnosed?
Heterophil antibody tests, eg, Monospot (viral capsid immunoglobulin M [IgM])
31
What organism causes rabies?
Lyssavirus (specifically genotype 1)
32
What are the symptoms of encephilitic form of rabies?
- periodic episodes of hyperactivity
- hypersalivation
- periodic spasms, including inspiratory (aerophobia) and (pharyngeal) hydrophobia
33
What organism causes sporotrichosis?
fungus -- Sporothrix schenckii
34
How is sporotrichosis diagnosed?
biopsy/fungal cultures
however, treat based on clinical suspicion
35
What is the treatment for sporotrichosis?
Intraconazole for 3-6 MONTH
36
What should you consider in travelers, immigrants or patients with unexplained fever, abdominal pain, diarrhea, or eosinophilia?
parasitic helminths
37
What is the most common helminth infection in the US?
Pinworm (Enterobius vermicularis)
which is a type of nematode aka roundworm
38
How is pinworms diagnosed?
via scotch-tape swab of anal verge and direct visualization of worms
39
How is Pinworms/Enterobius vermicularis treated?
Albendazole or mebendazole
40
Which parasite hatches eggs in the small intestine, mature in the lungs and ascend the bronchial tree to be swallowed?
Common Roundworm
(Ascaris Lumbricoides)
Hookworm and strongyloides also ascends bronchial tree but eggs hatch into larvae in soil and travels via blood to lungs (rather than eggs hatching in intestine)
41
What do you call the dry cough, chest pain, and low grade fever due to eosinophilic pneumonitis during migration through lungs associated with ascaris lumbricoides?
Loeffler Syndrome
42
How is Common Roundworm (Ascaris Lumbricoides) diagnosed?
stool microscopy (Ova and parasites)
43
How is Common Roundworm (Ascaris Lumbricoides) treated?
albendazole or mebendazole
44
How does Hookworm cause anemia?
1. chronic blood loss from attaching to intestinal mucosa
2. iron deficiency anemia and nutritional deficiencies
45
Which parasite is known to occasionally cause rectal prolapse?
whipworm (trichuris triciura)
46
How is Strongyloides (Strongyloides stercoralis) treated?
Ivermectin or albendazole
47
Which parasite commonly causes muscle pain and tenderness, fever, and periorbital swelling?
Trichinella (Trichinella spiralis)
48
Which nematode uses mosquitos as its vector?
Lymphatic Filariasis/Elephantiasis (Wuchereria bancrofti and Brugia malayi )
49
How is Lymphatic Filariasis/Elephantiasis (Wuchereria bancrofti and Brugia malayi) treated?
diethylcarbamazine (DEC) or ivermectin
50
What vector does Onchocerciasis/River Blindness (Onchocerca volvulus) use?
Blackfly (simulium) - found near fast-flowing rivers and streams
51
How do you treat Onchocerciasis/River Blindness (Onchocerca volvulus)?
Ivermectin
52
What vector does Loa loa use?
deerfly
53
How does loa loa present and how do you treat Loa Loa?
worm can be visible on conjunctival exam of eye
tx: DEC
54
Which tapeworm can cause a megaloblastic anemia due to B12 deficiency?
Diphyllobothrium latum
55
How is Diphyllobothrium latum ingested?
undercooked fish
56
How is Echinococcus species ingested?
Feces of sheepdogs, cattle,
wolves, foxes
57
Which parasite causes larval cysticerci in brain, striated muscle, and liver (aka cysticercosis)?
T. solium
58
How is T. Solium treated?
Praziquantel
59
How long does HIV seroconversion take?
3-12 weeks after exposure
60
What is the treatment for AIDS patient with Histoplasmosis?
Severe --> IV amphotericin
mild --> itraconazole
61
What is the treatment of coccidiomycosis in AIDS patient?
Same as Histoplasmosis
Severe --> IV amphotericin
mild --> itraconazole
62
What organism causes PCP (pneumocystis) pneumonia?
P. jirovecii -- a yeast-like FUNGUS
63
What lab finding is common in PCP pneumonia?
elevated LDH
(also elevated A-a gradient)
64
What is the treatment for PCP pneumonia?
TMP-SMX
(in sulfa allergy, treat with clindamycin + primaquine)
■ Prednisone if A-a gradient > 35 or Pao2 < 70 mm Hg
■ Prophylaxis with TMP-SMX, 1 DS tab daily is indicated for CD4 < 200 cells/
mm3 and greatly decreases the incidence of PCP.
65
Cryptococcal meningitis is most commonly in patients with CD4 <_____ cells/mm3
100
66
How is cryptococcal meningitis diagnosed?
LP -- fungal cultures is definitive
CSF cryptococcal antigen -- is highly sensitive and specific
(India ink stain of CSF is only positive 75% of time)
67
What is the treatment for cryptococcal meningitis?
Admit for IV amphotericin and PO flucytosine, then requires lifelong tx with fluconazole
68
Describe microbiology of toxoplasma gondii
Protozoan parasite
Obligates intracellular
Found worldwide
Felines are host
69
What is the treatment for toxoplasmosis?
Pyrimethamine + sulfadiazine (+ folinic acid)
■ Steroids are indicated for significant edema/mass effect.
70
Primary CNS lymphoma occurs most commonly with CD4 < ___ cells/mm3
50
71
What is the CT appearance of Primary CNS lymphoma?
Focal lesion (usually solitary) that enhances with contrast. Hyperdense/ isodense periventricular enhancement is often seen.
72
What is the treatment for Primary CNS lymphoma?
Chemotherapy + radiation
(median survival <1 month)
73
How does Progressive Multifocal Leukoencephalopathy (PML) appear on CT?
Single or multiple NON-enhancing white-matter lesions
74
What is the treatment for PML?
Highly active antiretroviral therapy (HAART)
prognosis is poor
75
What is the treatment of thrush?
mild --> nystatin or clotrimazole topical therapy
recurrent/refractory or severe disease --> fluconazole
76
What are the three most common causes of esophagitis in HIV-positive patients?
candida albicans (especially if with thrush)
HSV
CMV
77
What is the treatment for esophagitis in HIV patient?
Presence of thrush: Empiric trial of fluconazole
Absence of thrush or no response to fluconazole: Endoscopy and biopsy to guide treatment
78
What is the treatment for Mycobacterium avium-intracellulare (MAI) infection?
Clarithromycin or Azithromycin +Ethambutol
79
What do you call the angioproliferative disease occurring in HIV patients with prior HHV-8 infection?
Kaposi sarcoma
80
What are the signs and symptoms of Kaposis Sarcoma?
■ Papules or nodules that are pink, red, or purple in color
■ Painless/nonblanching
■ Commonly on lower limbs, face, mouth, and genitals
■ Respiratory and GI involvement can occur
81
What is the treatment for Kaposi Sarcoma?
antiretroviral therapy -- disease may regress as CD4 counts rise
Palliation:cryotherapy, radiotherapy, systemic chemo
82
What is the #1 cause of AIDS -associated blindness?
CMV retinitis (occurs with CD4 <100)
causes a severe necrotic vasculitis and retinitis
83
Describe the eye / retinal exam of CMV retinitis
Retina: Fluffy white perivascular lesions (“cotton-wool spots”)
84
What is the treatment for CMV retinitis?
Ganciclovir
85
What is a common complication of treatment with NRTIs? (eg, stavudine, zidovudine, didanosine, and lamivudine)
Lactic acidosis -- untreated mortality rate of 50%
86
How is Hantavirus spread?
inhalation of feces/urine or direct bite from rodents (primarily deer mouse)
majority occur in southwestern united states
87
What is Hantavirus Pulmonary Syndrome?
characterized by a flulike prodrome for
3-4 days, followed by noncardiogenic pulmonary edema and hypotension
88
What is Hantavirus hemorrhagic fever?
fever,
hemorrhage, hypotension, and renal failure
89
What are common lab findings in Hantavirus infections?
Thrombocytopenia and marked leukocytosis
90
How is Hantavirus definitively diagnosed?
Immunofluorescent or immunoblot assays
91
What is the treatment for Hantavirus infections?
Supportive care
92
What type of virus is west nile virus?
Flavivirus
93
What are the symptoms of West Nile fever?
fever, flu-like illness with URI
and maculopapular central rash
symptoms last about 3-6 days
94
What are CSF findings of meningoencephalitis?
increased lymphocytes and protein,
normal glucose
95
How is meningoencephalitis diagnosed?
IgM antibody in CSF or serum.
96
What is the treatment for west nile virus?
supportive
97
What organism causes Lyme disease?
Borrelia burgdorferi
98
What is the microbiology of Borrelia burgdorferi?
Gram-negative bacterium
Spirochete (helical shape)
Extracellular
Tick transmitted
99
What are the three stages of lyme disease?
Early localized
early disseminated
late disseminated
100
How is Lyme Disease diagnosed?
Screening test: ELISA (89% sensitive, 72% specific, false positives common)
Confirmatory test: Western blot assay
101
What is the treatment for Lyme Disease?
Depends on the stage
1. early localized --> doxycycline PO x 21d
2. Early disseminated with arthritis --> Doxycycline PO x30d
3. Early disseminated with neuro or cardiac sx
- if isolated CN palsy or first degree AV block --> Doxycycline PO × 21 d
OR
--> Ceftriaxone IV at meningitic doses (all other presentations)
102
When is Lyme Disease prophylaxis indicated? Dose?
Ixodes tick bite and only if tick is attached > 36 hours
Single 200-mg dose doxycycline within 72 hours of tick removal
103
Which ticks are responsible for the spread of Rickettsia ricketsii (RMSF)?
Dermacentor variabilis (dog tick) and Dermacentor andersoni (wood tick)
104
Describe the pathogenesis of RMSF?
Tick bite and transmission → invasion and proliferation of organism within
capillary and precapillary endothelial cells → perivascular inflammation →
platelet and fibrin occlusion of vessels and multisystem disease
105
Describe the rash of Rocky Mountain Spotted Fever.
Maculopapular → petechial/purpuric
■ Starts on wrists/ankles
■ Spreads centripetally (extremities → trunk)
■ Classically involves palms and soles (50%)
106
How is Rocky Mountain Spotted Fever diagnosed?
based on clinical suspicion
Serology can be done but takes 6-10 days
107
Which lab findings are common in RMSF?
Hyponatremia and thrombocytopenia (in advanced disease)
108
What is the treatment for RMSF?
■ Treat empirically for clinical suspicion due to high mortality rates (roughly
3%-5% despite treatment, 25% if untreated).
■ Supportive therapy, low threshold for admission
■ Antibiotics: Doxycycline, tetracycline, or chloramphenicol
109
What are common complications of RMSF?
ARDS
myocarditis, CHF
DIC
seizures, encephalitis
110
What are the two types of ehrlichiosis?
human monocyte ehrlichiosis
human granulocytic ehrlichiosis
(depends on which immune cell is invaded)
111
What organism causes human monocyte ehrlichiosis?
Ehrlichia chaffeensis
112
What organism causes human granulocytic ehrlichiosis?
Anaplasma
phagocytophilum.
113
Describe the microbiology of Ehrlichia chaffeensis and Anaplasma phagocytophilum.
Gram-negative coccobacilli
Obligates intracellular (monocyte or
granulocyte)
Tick transmitted
114
What lab findings are commonly seen in Erhlichiosis?
Leukopenia, thrombocytopenia, transaminitis (50%-90%)
115
How is Erlichiosis diagnosed?
IgG antibody titers or culture/biopsy
■ Definitive: PCR
116
What is the treatment for Erlichiosis?
Doxycycline, tetracycline, or rifampin
117
What organism causes Babesiosis?
Babesia genus;
Parasitic protozoan
Pleomorphic
Intraerythrocytic
Transmitted by ticks
118
what is the vector for babesiosis? reservoir?
Ixodes ticks with a reservoir in deer and mice
119
How does babesiosis present?
Mild --> flu-like illness +/- splenomegaly
Severe --> hemolytic anemia, jaundice, renal insufficiency, ARDS
120
How is Babesiosis diagnosed?
Thick and thin Giemsa-stained smears
■ Erythrocytes show budding tetrad in “Maltese cross” formation.
121
What is the treatment for Babesiosis?
■ Mild disease → no treatment
■ Severe disease or postsplenectomy → quinine + clindamycin
■ Exchange transfusion if fulminant
122
What pathogen causes Q fever?
Coxiella burnetii
123
Describe the microbiology of Coxiella burnetii
Gram-negative bacterium
Obligates intracellular
Transmitted by ticks, exposure to animal
products or raw milk
Highly infectious
124
What are the symptoms of Q Fever?
flulike symptoms, pneumonia, hepatitis
125
How is Q fever diagnosed?
■ Often clinical
■ Definitive: PCR, serologies (positive 2-3 weeks after infection)
126
How is Q fever treated?
Doxycycline, tetracycline, or chloramphenicol
127
What are 3 common complications of Babesiosis?
Endocarditis (up to 68%), granulomatous hepatitis, osteomyelitis (peds)
128
What pathogen causes Colorado tick fever?
Colorado tick fever virus
129
How is Colorado tick fever virus transmitted?
D. andersoni
(wood tick)
130
What are the symptoms of Colorado Tick Fever?
Classic biphasic fever and flulike symptoms, each lasting for a few days
rarely can cause meningoencephalitis
131
How is Colorado Tick Fever diagnosed?
clinically
132
What is the treatment for Colorado Tick Fever?
supportive
133
Malaria is spread by the ____ mosquito.
Anopheles
134
Describe the lifecycle of plasmodium species
Mosquito transmits asexual haploid form of Plasmodium → migrates to liver
and matures to produce merozoites → released from liver and invade RBCs →
mature in 48-72 hours causing RBC lysis and release of additional merozoites
→ invade more RBCs → hemolytic anemia
135
What are the symptoms of uncomplicated malaria?
flulike illness, mild jaundice, and splenomegaly (after several days of illness)
136
What is the presentation of severe or complicated malaria?
toxic/septic appearance
acute lung injury
137
What is the treatment for uncomplicated malaria in adults (Central American and Caribbean)?
Chloroquine phosphate
138
What is the treatment for uncomplicated malaria in PEDIATRICS (Central American and Caribbean)?
Chloroquine Phosphate
139
What is the treatment for uncomplicated malaria in adults (South American, South Asia, Africa -- chloroquine resistant)?
Quinine Sulfate (PO) + Doxycycline
OR
Atovaquone/proguanil
OR
Mefloquine
140
What is the treatment for uncomplicated malaria in PEDIATRICS (South American, South Asia, Africa -- chloroquine resistant)?
Quinine Sulfate (PO) + PYRAMETHAMINE SULFADOXINE
OR
Atovaquone/proguanil
OR
Mefloquine
141
What is the treatment for complicated malaria in adults?
Quinidine Gluconate (IV) +Doxycycline
142
What is the treatment for complicated malaria in pediatrics?
Quinidine Gluconate (IV)
143
What species typically causes complicated/severe malaria?
Plasmodium falciparum
144
How is malaria definitively diagnosed?
Plasmodial parasites on Giemsa-stained thick and thin smears
145
For P. vivax, P. ovale, which have a dormant hepatic phase, add ______ to prevent relapse, but FIRST test for _______.
primaquine
G6PD
146
What are the signs and symptoms of Ebola?
fever, headache, myalgias
n/v/d
rash
unexplained easy bruising/bleeding
causes a viral hemorrhagic fever
147
What is the treatment for ebola virus?
isolation precautions
supportive care
148
How is ebola spread?
bodily fluids
149
_____ presents with fever and dramatic bone pain in the traveler
Dengue
150
What virus causes Dengue?
Flavivirus
151
Flavivirus is transmitted to humans by the ______ mosquito.
Aedes -- bites during the day (in contrast to Anopheles which causes malaria, bites at night or dusk)
152
What is the incubation period for malaria?
1-4 weeks
153
What is the incubation period for Dengue?
5-10 days
154
What are the signs & symptoms of Dengue?
high fever, n/v, severe bone pain/myalgias/arthralgias
"Dengue facies" = classic facial edema
Pale morbilliform rash develops following defervescence; starts on trunk,
spreads to extremities/face
155
How is Dengue diagnosed?
clinically, but rule out malaria
Definitive Dx by ELISA
156
What is the treatment for Dengue?
supportive
157
What is a risk factor for Dengue hemorrhagic fever?
most often occurs following exposure to second serotype
158
Describe the course of Dengue Hemorrhagic fever.
Initial clinical course is similar to classic dengue.
Second phase of illness begins as initial symptoms are resolving
Fatigue
shock
bleeding diathesis with hemorrhagic pleural effusions
thrombocytopenia
mortality = 50% without care (<5% with care)
159
What pathogen causes Leptospirosis?
bacterial spirochete Leptospira interrogans
160
How is leptospirosis transmitted?
percutaneous or mucus membrane contact with
FRESHwater contaminated by the urine of infected rodents, livestock, or domestic animals
161
Describe the signs and symptoms of the Acute bacteremic phase of leptospirosis?
range from mild illness to abrupt high fever/chills, intense headache (often worst of life) and severe myalgias
Conjunctive suffusion (redness without exudates) = pathognomonic
162
What are the signs and symptoms of Weil syndrome caused by Leptospira?
severe icterus
renal failure
hemorrhage
acute lung injury/ARDS
163
What lab abnormalities are seen with Leptospirosis?
increased WBC and bilirubin (relative mild increase in alk phos and transaminases)
164
How is leptospirosis diagnosed?
acute phase --> clinical dx
definitive: isolation of leptospires in urine or CSF
165
How is Leptospirosis treated?
mild disease: Doxycycline/Amoxicillin
severe disease: penicillin/ampicillin/ceftriaxone
(treatment is most effective without first 4 days and may prevent Weil syndrome)
treat empirically if suspicion is high
166
What pathogen causes Chagas disease?
Trypanosoma cruzi
167
How is trypanosoma cruzi transmitted?
by contact with feces of the blood-sucking triatomine type of reduviid bugs ("kissing" bugs)
168
What are the signs and symptoms and timing of the acute phase of Chagas disease?
2-30 days after infection
weeks-months duration
edema at the inoculation site (often the eyelid)
malaise, fever, anorexia, myalgias
hepatosplenomegaly, lymphadenopathy
169
What are the signs and symptoms and timing of the chronic phase of Chagas disease?
10-20 years postinfection
Cardiomyopathy
Megaesophagus
Megacolon
170
How is Chagas disease diagnosed?
acute phase --> observe parasite on thick and thin blood smears
chronic disease --> serologic testing
171
What is the treatment for Chagas disease?
Nifurtimox
172
What medications are used for HIV post-exposure prophylaxis?
Tenofovir-emtricitabine (Truvada) + raltegravir (Isentress)
Recommended in known HIV+ or at high risk of HIV
173
What medications are used for Hep B post-exposure prophylaxis?
Hepatitis B immunoglobulin (HBIG)
Hepatitis B vaccination: Usually given as three doses over 4-6 months with first dose given with HBIG in different site
recommended for any blood or bodily fluid exposure if not fully vaccinated or known nonresponder
174
What is the only vaccine given at birth?
Hep B
175
Which 6 vaccines are given at 2 months old?
Hep B - second dose
RV (rotavirus)
DTaP (diptheria, tetanus, and pertussis)
Hib (h. influenzae type b)
PCV (pneumococcus)
IPV (polio)
176
What is the youngest age you can begin getting an annual influenza vaccine?
6 months
177
When are MMR and Varicella vaccines administered
12 months
178
In Lyme meningitis, what CSF finding is most sensitive?
Borrelia Burgdorferi Antibody
(PCR is positive in less than half of patients)
