Infectious Diseases Flashcards
What is the most important factor that increases the risk for fungal infection?
The use of steroids, especially in high doses or intranasal with Diabetic pts
How do fungal infections present?
In a progressive manner, very slowly.
What are the top 3 things to know in order to diagnose a pt with Criptococcus?
- Number of white cells found in lumbar puncture
- High opening pressure form puncture
- Increased protein levels found in the CSF
What is the hallmark of Criptococcus?
High opening pressure (anything higher than 180)
What two species can cause Criptococcus?
C. Neoformans and C. Gatti
How is Criptococcus infected?
Via air droplets and bird droppings
What is the most common manifestation of cryptococcal infection?
Meningitis
What are the main characteristics of a cryptococcal infection?
Malaise, fever (above 38.4), N/V, Cough/SOB, Altered mental status
What else can be seen with Criptococcus?
Papilledema, meningeal signs, cryptococcal antigen present in CSF
The treatment for Criptococcus is?
Amphotericin B and Fluconazole
Which infectious disease involves exposure to chicken coops?
Histoplasmosis
What are the main characteristics of Histoplasmosis?
Fever, weight loss, skin ulcers, Hepatosplenomegaly, lymphadenopathy
Which tests are utilized to detect Histoplasmosis?
Urine: H. Capsulatum antigen sensitivty
What is the treatment for Histoplasmosis?
Amphotericin B and or Itraconazole total 12 weeks (any -azole will work)
Pt has bilateral diffuse reticulonodular infiltrates in the lungs, and budding yeast forms from lymph node biopsy
Histoplasmosis
What are the four types of OPC Candidiasis?
- Erythematous
- Hyperplastic
- Angular Cheilitis
- Pseudomembranous
Oropharyngeal candidiasis is more common if the CD4 cell count is below what?
300
Esophagitis (candidiasis) is more common if the CD4 cell count in below what?
100
In most candidiasis cases, the strain causing the disease comes from where?
Patients own GI flora
What is the treatment for OPC?
Fluconazole 100mg/d x 14d or
Itraconaozle 200mg/d x 14d
Why should you avoid topical treatments for OPC?
Lower cure rates, higher relapse rates
What is the most common cause of dysphagia and odynophagis in AIDS?
Esophageal candidiasis
Fluconazole is the DOC for what?
Esophageal Candidiasis
What is the dosing for Fluconazole for esophageal candidiasis?
200 mg/d first day
100 mg/day other 13 days
Can use IV if pt cannot swallow
Which fungus has a unique tropism for the lung and rarely invades the host?
Pneumocystis Jirovecii
This fungus attaches to the alveolar epithelium causing inflammation, interstitial edema and diffuse alveolar damage
Pneumocystis Jirovecii
What is the clinical presentation of pneumocystis jirovecii?
Gradual onset & progression of fever, dry cough and dyspnea. Av 1 mo before medical consult
What is the best imaging test for pneumocystis jirovecii?
HRCT chest (high resolution CT)
What is the best lab test for pneumocystis jirovecii?
BAL+immunofluorescence
What is the preferred tx for pneuymocystis jirovecii?
TMT-SMX IV for 21 days or oral for 21 days
Which virus targets the retina?
Cytomegalovirus. Also affects the CNS and GI
What are the si/sx of CMV retinitis?
No pain but floaters, blurry vision, decr peripheral vision, light flashes or sudden vision loss, blindness
What are some complications of CMV retinitis?
Blindness, retina detachment 2-6 if untreated, often involves both eyes
How can you diagnose CMV retinitis?
Perivascular fluffy yellow-white retinal infiltrate +/- hemorrhage
What is the tx for CMV retinitis?
IV Ganciclovir, lifelong
What is the best diagnostic tool for Toxoplasmosis?
MRI of the brain
What will the scans look similar to with Toxoplasmosis?
Look very similar to a scan of lymphoma
How else can you diagnose Toxoplasmosis?
IgG serology for T. gondii, look for MORE THAN ONE lesion in the MRI, order PCR for T. gondii
What is the treatment for toxoplasmosis?
Pyrimethamine+Sulfadiazine+Leucovorin
What is an epidemic?
An increase, often sudden, in the number of cases of a disease above what is normally expected in a population in a certain area
what is an outbreak?
Carries the same definition as epidemic, but is often used for a more limited geographic area
What is a cluster?
Aggregation of cases grouped in place and time that are greater than the number expected
What is an endemic?
Amount of a particular disease usually present (expected) in a community
An epidemic that has spread over several countries or continents, affecting a large number of people
Pandemic
A case with an epidemiological exposure and 2 or more symptoms is what?
Suspected case
A case with relevant epidemiological exposure, no disease symptoms and positive Zika IgM is what?
Probable case
A case with laboratory confirmation by viral RNA or antigen, Zika IgM antibody and positive PRNT is what?
Confirmed case
The Flavivirus causes what?
Zika Virus
How is Zika transmitted?
Mosquitos
Zika virus is carried by which mosquito?
Aedes aegypti, lives in tropical locations and Aedes albopictus, lives in temperate climates
Where do the mosquitos breed?
Standing water
Where was Zika virus first isolated?
Ugandan forest in 1947
What were some of the zika outbreaks?
2007 in Micronesia with 5,000 infections, 2014 French Polynesia with 32,000 infections, 2014 Chile
Have there been Zika cases in the US?
Yes, Florida and Texas. Some travel-reported cases in NY and sexually transmitted in Texas 2016
Transmission of Zika
Bite from mosquito, maternal-fetal, sex, blood transfusions, organ transplants, lab exposure
What are the si/sx of Zika?
Acute onset low-grade fever, pruritic rash, arthralgia and conjunctivitis
How long does is take for Zika symptoms to resolve?
2-7 days
Can you get immunity from Zika?
Yes, follows primary infection
Physical exam findings of Zika
Low grade fever, maculopapular pruritic rash, small joints of hands and feet (arthralgia), non-purulent conjunctivitis. Diagnose if 2 or more present!!!
What are complications from Zika?
Fetal loss, microcephaly, Guillian-Barre syndrome, brain ischemia, myelitis, meningoencephalitis
How can you diagnose Zika?
rRT-PCR (+real time reverse transcription-polymerase chain reaction) confirms it
Can also do an ELISA (can cross-react with other flaviviruses)
What is MAC-ELISA?
Developed by CDC for Zika, Zika IgM Antibody Capture ELISA test
How long are you serum positive with Zika?
3-7 days
How long are you urine positive with Zika?
Up to 14 days
Which lab test should you use for a pt presenting <7days Zika?
rRT-PCR urine or serum for IgM and PRNT
Which lab test should you use for a pt presenting 15 days to 12 weeks?
Serum for IgM and PRNT
How can you treat Zika?
Supportive, NSAIDs avoid until Dengue ruled out
Which disease involves the Alphavirus?
Chikungunya
How is Chikungunya transmitted?
Mosquitos, vertical, blood donation and organ transplant, nosocomial transmission
Who can carry Chikungunya?
Aedes aegypti and aedes albopictus
Epidemiology of Chikungunya
Outbreak in Tanzania in early 1950s, first case documented outside African was Thailand 1958
Where was the first US case reported of Chikungunya?
Florida July 2014
Clinical manifestations of Chikungunya
Fever and malaise, incubation period of 3-4 days
What will physical exam of Chikungunya show?
High grade fever 2-5 days long, polyarthralgia begins after fever onset, symmetrically involves joints, pain is usually intense and disabling. Maculopapular rash starting on limbs and trunk
What are the most common lab findings for Chikungunya?
Lymphocytopenia and thrombocytopenia
Complications of Chikungunya?
Rarely neurologic, death in pts older than 65, persistent debilitating and immobilizing arthritis, respiratory renal and CV failure
Diagnosis of Chikungunya?
1-7 days use RT-PCR, >8 days use ELISA IgM
How long will the IgM antibodies be present for Chikungunya?
5 days after onset of symptoms and up to 3 months
How to manage Chikungunya
Supportive, NSAIDs, steroids, methotrexate, immunomodulating agents, no vaccine!
What does Genus flavivirus cause?
Dengue virus. Mosquito born as well
How many different strains are there of Dengue?
47
What are the different classifications of Dengue?
Dengue Fever, Dengue hemorrhagic fever, Dengue shock syndrome
What is another way to classify Dengue?
Dengue without warning signs, Dengue with warning signs, severe Dengue
Leading cause of illness and death in the tropics and subtropics
Dengue
Epidemiology of Dengue
Originated in monkeys and independently jumped to humans in Africa or Southeast Asia
Transmission of Dengue
Bite from mosquito, rare in organ donation or blood transfusion, maternal-fetal transmission possible
Physical exam findings of Dengue w/out warning signs
N/V, rash, headache, eye pain, muscle and joint aches, leukopenia, positive tourniquet test
Physical exam findings of Dengue with warning signs
Abdominal pain and tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy or restlesness, hepatosplenomegaly, increase in HCT w/decrease in platelets
Physical exam findings of severe Dengue
Severe plasma leakage leading to shock and fluid accumulation with respiratory distress, severe bleeding, severe organ failure, impaired consciousness
What is the febrile phase of infection for Dengue?
Sudden onset high fever, HA, rash, vomiting, myalgia, arthralgia. Lasts 3-7 days. Also conjunctival injection, pharyngeal erythema, LAD, hepatomegaly, facial puffiness, petichiae
Can patients recover from febrile phase of Dengue?
Yes, without complications
Critical phase of infection for Dengue
Systemic vascular leak syndrome-plasma leak, bleeding, shock, organ failure. Days 3-7 and lasts 24-48 hours
Convalescent phase of infection of Dengue
Plasma leakage and hemorrhage resolve, vital signs stabilize, typically lasts 2-4 days, profound fatigue that may take days-weeks to recover
How can you diagnose Dengue?
1st week- Rt-PCR and viral antigen nonstructured protein
When can you do an ELISA for Dengue?
IgM as early as 4 days after onset of illness
Management of Dengue?
Supportive, fever management, acetaminophen no NSAIDs, blood replacement, volume replacement, shock treatment
Prevention of Dengue
Vaccination (outside of US only), mosquito control, limit travel
Filoviridae family causes what?
Ebola Virus
What does Ebola resemble?
Rabies and Measles/Mumps
How id Ebola spread?
Direct contact with infected body fluids
What are the 5 species of Ebola?
- Zaire
- Sudan
- Ivory Coast
- Bundibugyo
- Reston
Zaire Ebola
Recognized in 1976, responsible for 2014-15 outbreak in west africa
Sudan Ebola
50% case fatality in 4 epidemics
Ivory Coast Ebola
Only identified in 1 case. Exposure occurred in an ethologist who performed a necropsy on a chimp found dead
Bundibugyo Ebola
Uganda 2007 outbreak. Case fatality of 30%
Reston Ebola
Different as it has maintained an animal reservoir only.
Which outbreak was the largest of all previous combined for Ebola?
2014-16 in West Africa
Epidemiology of Ebola
881 infected healthcare workers-60% died. September 2014 first case in US
Transmission of Ebola
Through contact w.meat or body fluids of infected animal or human. Ritual washing of Ebola victims at funerals, Vomit feces and blood most infectious.
How long can the Ebola virus live?
On surfaces for hours to days, no known airborne or mosquito infections
Clinical manifestations of Ebola
Major hemorrhage is less common, volume loss form V/D, symptoms occur suddenly, incubation is 6-12 days. Produces a systemic inflammatory response
What will you find on a physical exam of Ebola
Fever, chills, malaise, rash maculopapular, watery N/V/D and abdominal pain, blood in stool, petechiae, mucosal bleeding
What can be seen in the early phase of Ebola?
1-3 days, fever, malaise
What can be seen in shock from Ebola?
With or without major hemorrhage, 7-12 days in
Convalescence of Ebola
Up to 2 years, prolonged sx of arthralgia, weakness, fatigue, insomnia
Lab studies useful for Ebola
Leukopenia, thrombocytopenia, hematocrit may be high or low, ALT and AST increase, PT and PTT abnormalities (severe cases), proteinuria and renal insuff, hyponatremia, hypokalemia
Diagnosis of Ebola
RT-PCR for specific RNA sequences, negative RT-PCR collected >72 hrs after symptoms onset rules OUT Ebola
Management of Ebola
Supportive care, aggressive fluid and electrolyte resuscitation, antiemetics, antipyretics, blood products, TPN, antivirals
Management of Ebola (under investigation)
Favipiravir-2 trials, Artesunate-amodiaquine antimalarial, Zmapp- promising results
Prognostic factors of Ebola
Younger age-lower mortality, higher fatality in men, higher rate of fatality with diarrhea
Most common cause of community-acquired bacteremia?
Staph aureus
What is the most common tick borne illness in the US and europe?
Lyme Disease
Transmission of lyme dx occurs how?
Bite of infected Ixodes ricinus complex ticks. Transmitted by tick int he nymph stage of life
What are some risk factors for lyme dx?
Outdoor occupational workers, recreational activities in wooded areas
What are the 3 tick species that bite humans?
- Blacklegged tick (I. scapularis)
- Lone star tick (Amblyomma americanum)
- American dog tick (Dermacentor variabilis)
What types of Qs can you ask pts with lyme dx?
Was the tick attached? How long was it attached for?
SPirochetes are rarely transmitted within the first __ hours of tick attachment
48
If the tick is attached for how long there is a high risk of transmission?
> 72 hours
What are the 3 phases of lyme disease?
- Early localized disease
- Early disseminated disease
- Late disease
Which phase of lym dx involves the rash erythema migrans with viral symptoms?
Early localized disease
When does the rash occur for lyme dx?
At the site of tick bite, usually appears within 7-14 days after bite but can take anywhere from 3-30 days
Erythema migrans occurs in what percentage of pts with lyme disease?
80%
Qualities of Erythema migrans
Painless, mild burning or pruritis, erythematous with a range form light pink to well defined, circular in appearance, often large in diameter, central clearing with a “bulls-eye or target lesion”
What are some associated viral symptoms with early localized lyme?
Fatigue, anorexia, HA, neck stiffness, myalgia/arthralgia, lymphadenopathy, fever
If your pt has upper repiratory symptoms or GI symptoms in the absense of erythema migrans…
Diagnosis is unlikely Lyme
Early disseminated Disease (Lyme)
Neurologic or cardiac involvement, occurs weeks to several mos after the tick bite
What is multiple EM lesions suggestive of?
Disseminated disease, not multiple bites
What are some neurologic manifestations with lyme?
Unilateral or bilateral cranial nerve palsy, facial nerve commonly. Radiculopathy, peripheral neuropathy, lymphocytic meningitis, encephalopathic features
What is the triad of neurologic abnormalities found in lyme disease?
- Meningitis
- Cranial neuropathy
- Sensory or motor radiculoneuropathy (irritation of nerve)
Cardiac involvement (Lyme)
Can cause carditis that may manifest as heart block or myopericarditis
What are some si/sx of late disease (Lyme)
Occurs mos to yrs after initial infection, arthritis in one or more joints, cognitive disturbances can also occur
Lyme Arthritis
Intermittent or persistent arthritis in a few large joints, especially the knee
Is serologic testing necessary for early disease (lyme)
No, if presence of EM and/or viral symptoms with a history of exposure to endemic area, no lab indication
Is serologic testing necessary for early disseminated or late disease (Lyme)?
Usually positive at this point, the diagnosis is based on clinical syndrome with positive serologic tests
What are the indications for serologic testing?
Reent exposure to area endemic for Lyme, risk factor for exposure to ticks, AND symptoms consistent with early disseminated or late disease
When is serology not indicated?
In pts with EM rash, screening of pts in endemic areas, pts with non-specific symptoms only
Need a two tier approach for lyme, what are they?
ELISA followed by Western blot
ELISA
Most common initial serologic test for diagnosis
Western Blot
Allows for detection of antibodies to individual components of organism, determines which specific antigens of B. burgdorferi are reacting w/serum antibodies
Testing algorithm
-ELISA: no further test
+ELISA: Western Blot next
-Western Blot: No further test
+Wester Blot: evidence of encounter with B. burgdorferi
IgM antibodies to B.burgdorfer typically appear how many weeks post op?
1-2 weeks
IgG antibodies to B.burgdorfer typically appear how many weeks post op?
2-6
Is routine follow-up serologic testing recommended for lyme?
No
Treatment for lyme disease?
Doxycyline 100mg orally twice daily for 21 days. CANNOT BE GIVEN TO CHILDREN OR PREGNANT PTS
Other treatment options for lyme disease
Amoxicillin 500mg orally 3x a day 21 days (best for children, pregnancy)
Cefuroxime 500mg twice a day 21 days
What is the treamtne for early disseminated lyme disease?
Ceftriazone IV 2g once daily, Cefotaxime IV 2g every 8 hrs, Penicillin G 18-24 mill units IV 6 daily doses (ALL IV MEDS)
How can you treat the facial palsy of lyme disease?
Oral doxycyline 100mg twice daily
How can you treat late lyme disease?
Doxycyline or amoxicillin for 1 month
What is the prophylactic antibiotic for lyme disease?
Doxycycline 200mg, single dose
What is a lethal but curable tick borne disease?
Rock Mountain Spotted Fever (R. rickettsi)
What does R. rickettsi lead to?
Gram - bacteria, leads to direct vascular injury
What are some host responses to R. rickettsi?
Pneumonitis, myocarditis, encephalitis
How is RMSF transmitted?
By tick bite, transmits the infection during feeding
What are some clinical manifestations of RMSF?
Fever, HA, rahs in a person with history of tick bite. Malaise, N/V, myalgias and arthralgias
Hallmark rash or RMSF is
Blanching erythematous rash with macules that become petechial over time
Empiric therapy for RMSF should be initiated when?
Within 5 days of symptom onset
When should a skin biopsy be performed for RMSF?
Before or within 12 hours of administering antibiotics. Should NOT withhold treatment in attempt to get skin biopsy within time frame
The diagnosis of RMSF can be confirmed by what?
IFA: indirect fluorescent antibody
What is the treament for RMSF?
Doxycyline, avoid in children and pregnancy
Babesiosis is what?
Infection caused by protozoa of genus Babesia. Causes lysis of RBCs
What are the clinical manifestations of babesiosis?
Can be fatal, sx usually develop within 1-6 weeks after tick bite. Splenomegaly and hepatomegaly, neck stiffness, sore throat, dry cough, SOB, V/D
How can you diagnose Babesiosis?
Blood smear performed by pathologist
What are the most common ways of getting HIV?
Anal sex, sharing needles, snorting cocaine and sharing
When was the earliest case of HIV recorded?
1959 in a human, Kinshasa congo
How does HIV replicate?
Reverse transcriptase that is continuous viral replication
After 3 days, where does HIV travel to in body?
Lymph nodes, that is when CONTINUOUS REPLICATION OCCURS
Can you be cured from HIV?
If treated within first 3 days before travels to lymph nodes
How long does post exposure prophylaxis treatment last for?
4 weeks/1 month
How long does pre-exposure prophylaxis treatment last for?
7 days, however this is a more controversial option, bad for society can cause resistance
Is HIV 1 oncogenic?
No, but it decreases immunity which makes you more susceptible to cancer
Is there a vaccine for HIV?
No, due to the variability of the virus envelope
Is there a population that is more resistant to HIV?
Yes, people with the delta 32 gene will remain asymptomatic longer, HIV will have more difficult time invading the CD4 cells
Delta 32 gene
Pts with this do not need tx right away, but need to monitor CD4 count, HIV will eventually find a way to get into CD4 cells
What are the 3 mechanisms of HIV?
- Immunodeficiency
- Autoimmunity
- Hypersensitivity reactions
Immunodeficiency in HIV
Causes chronic inflammation
Autoimmunity in HIV
As a result of disordered cellular fxn or B cell dysfxn. Causes lymphocytic interstitial pneumonia and ITT
Hypersensitivity reactions in HIV
High rates of allergic reactions, eosinophilic pustular folliculitis, medications reactions (Bactrim)
What are the clinical findings if CD4 count is from 300-400
Bacterial infections: TB, Herpes simplex, Herpes Zoster, Vaginal candidiasis, hairy leukoplakia, Kaposi sarcoma
What are the clinical findings is CD4 count is 100-200?
Pneumocystosis, Toxoplasmosis, Cryptococcosis, Coccidioidomycosis, Cryptosporidiosis
What are the clinical findings if CD4 count is below 50?
Disseminated MAC infection, Histoplasmosis, CMV retinitis, CNS lymphoma
What are some lab findings useful for CD4?
ELIZA and Western blot
What are the si/sx of HIV?
Fever, lymphadenopathy, pharyngitis, skin rash, myalgia, arthralgia
A physical exam suggestive of HIV
Hair leukoplakia tongue, Kaposi, cutaneous bacillary angiomatosis, generalized lymphadenopathy
What to do if HIV pt has fever?
CXR, bacterial blood cultures, serum cryptococcal antigen, mycobacterial blood cultures, sinus CT
What to do if HIV pt has weight loss/waste syndrome?
ART, high calorie drinks, megestrol, medical cannabis, growth hormone and anabolic steroids
What to do if HIV pt has nausea?
Look for candida, can use medical cannabis
What to do if HIV pt has PNS complications?
Do NOT use opioids, can use gabapentin, Capsaicin, acupuncture
What is caused by neurotropic viruses in the Rhabdoviridae family?
Rabies
How does rabies affect the body?
Disseminates via peripheral nerves to the central nervous system
What are the clinical manifestations of rabies?
Nonspecific viral type symptoms, can be either encephalitic or paralytic rabies
Encephalitic rabies
More common type, causes death resulting from respiratory and vascular collapse
Classic symptoms of encephalitic rabies
Hydrophobia, aerophobia, hyperactivity of facial, back and neck muscles, autonomic instability, agitation and combativeness
Paralytic rabies
Has ascending paralysis, little CNS involvement until later in course, paraplegia occurs leading to failure of respiratory muscles and death
How can you diagnose rabies?
Staining of skin biopsy, isolation of virus from saliva and anti-rabies antibodies from serum or CSF. Mostly diagnosed postmortem
What is the treatment for rabies?
Most efforts should be on prevention, no known treatment for it
Palliative approach for rabies
Treating disease to comfort, sedatives, analgesics, etc.
Aggressive approach for rabies
Critical care unit with ID specialists, immunotherapy, antiviral therapy and neuroprotective therapies
Rabies prophylaxis
Want to give post-exposure prophylaxis (PEP)
Prophylaxis should definitely be considered in bites from what animal?
Bats*
PEP Rabies
Should begin ASAP, rabies immunoglobulin is “passive immunization” and vaccine is “active”
Who is the rabies VACCINE given to?
Pre-exposure prophylaxis
What is given to post-exposure rabies pts?
Both passive and active immunization
Post-exposure prophylaxis
For previously vaccinated person, pt should receive two intramuscular doses of vaccine
Malarial parasites
Plasmodium falciparum results in severe illness. Symptoms are anemia related
