Infectious Disease Flashcards
What test should all patients with newly diagnosed HIV recieve?
Latent TB testing!
Either with the Tuberculin skin test (PPD) or with Interferon Gamma Release assay
What PPD induration is considred positive in HIV patients?
greater than 5mm
Active Tb must be ruled out with a CXR.
Patients with no manifestations of active Tb are treated for latent TB with 9 Months of INH!
Pyridoxine is added to prevent INH induced peripheral neuro
If an HIV patient with CD4 below 200 has a negative PPD test what should you do?
this is considered a false negative.. they dont even have enough of an immune response for the test to become positive.
On tese patients you must start HIV treatment.. and then RETEST for Tb once CD4 is above 200.
High urinary pH (above 8) raises concern for which organism.. and puts you at increased risk of which complication?
P. Mirabilis –> produces urease.. which then results in ammonium production and thus ALKALINE urine!
High urine pH reduces the solubility of phosphate –> Struvite sone formation (magnesium-ammonium-phosphate stones).
Coffin lid shaped
Toxoplasmosis symptoms
dormant in most individuals.. only becomes active in SEVERE immunoccompromise.
HIV wih CD4 below 100 is when you see it reactivate.
Causes encephalitis:
- headaches
- focal neuro defecits (twitching in arms)
- Fever / confusion
Diagnosis:
1. HIV with cd4 below 100
Positive t. gondii IgG!
Multiple RING enhancing Lesions on MRI.
Treatment :
- Sulfadiazine + Pyrimethamine (plus leucovorin)
Prophylaxis with TMP SMX (as soon as CD4 drops below 100)
MAC - mycobacterium avium complex symptoms and treatment
causs PUlmonary and GI symptoms (not CNS)
Treatment - clarithromycin
Prevention - Azithromycin
Bacterial Meningitis presentation
very ACUTE! (less than 1 day) of fever, severe headache, and AMS.
Pertussis
Symptoms:
1. Paroxysmal cough, Posttussive EMESIS, Subconjunctival HEMORRHAGES (due to increased intraorbital pressure)
LYMPHOCYTOSIS.
DIagnosis is clinical when above symptoms are present.. PCR of the nasopharynx is helpful for COnfirming diagnosis.
MACROLIDES - GOLD STANDARD for treatment.
Prevention - Acellular pertussis vaccine.
5 doses of DTaP are given during infancy and early childhood (final dose at 4-6 years of age). Tdap booster is given during adolescence (11-18 years) –> those who have not taken it have waning immunity.
What is Heterophile Antibody Testing used to diagnose?
Infectious Mono Due to EBV!
Palpable axillary / cervical lymph nodes vs Supraclavicular lymphn nodes.
Cervical Lymph nodes that are palpable but small 1cm or less and mobile and soft are normal.
Hard / immobile are large (above 2cm) lymph nodes should be looked deeper into.
Palpable Supraclavicular Lymph Nodes are considered Pathologic until proven otherwise!
Osteomyelitis in children
caused by HEMATOGENOUS spread of bacteria.
Staph Aureus!
Definitive diagnosis = biopsy
Treatment = antistaph abx (vanc)
Osteomyelitis after a puncture wound or in IVDU is most likely which organism?
P. Aeruginosa\
However the most common organim causing infective endo in IVDU is STAPH AUREUS!
HACEK organisms leading to endocarditis indicate what?
Dental work.. these organisms are found in the gingival or dental mucosa
S. BOvis or Strep Gallolyticus causing Infective Endocarditis indicates what?
Ulcerative lesins in the colon due to either Colonic neoplasia or Inflammatory Bowel Disease.
Enterococci / Enterococcus faecalis cause up to 30% of all Infective Endo and are a sign of what?
Sign of Noscomial UTIs resulting in infective endo.
How do you diagonse PCP?
Cannot culture it. MUST be examined using Special Microsocpy stains.
Best way to view sputum (least invasive) is inducing sputum (hacking up a loogy)… if that doesnt work then do a BRONCHOALVEOLAR LAVAGE!
PCP is very commonly found in patients after a TRANSPLANT!
Acute UNILATERAL lymphadenopathy in children is caused by what?
MOSt OFTEN
S. AUreus or S. Pyogenes.
Will see ENLARGED, markedly TENDER, warm and erythematous Lymph nodes.
If untreated can become an abscess.
CLINCIAL diagnosis.
EMpiric therapy - CLINDAMYCIN which covers both MRSA and S. Pyogenes.
What is the most common cause of acute BILATERAL lymphadenopathy in children?
Adenovirus!
Will also see pharyngitis, fever and conjunctivitis here.
Which Bacteria is associated with Cat bites and what is the treatment?
Pasturella Multocida!
treatment:
- Copious irrigatin and cleaning
- Prophylactic AMOXICILLIN / CLAVULANATE
- Tetanus booster as indicated
- Avoid Closure
Tetanus vaccine is indicated for those who have incomplete vaccinations as children or those whose last vaccine was OVER 5 years ago.
Ehrlichiosis findings
transmitted by dear tick.
Flu like illness:
- ACUTE febrile illness with malaise and Alterted MENTAL STAUS.
- NOT associated with rash (described as RMSF without the spots).
- CONFUSION, change in mental status, CLONUS. NECK STIFFNESS
Labs = DECREASED WBCs, and DECREASED PLATELETS.
Elevated LIVER ENZYMES and LACTATE DEHYDROGENASE
CLINICAL DIAGNOSIS
DOXYCYCLINE is treatment of choice.
Distinguishing from LYME?
Lyme will have a rash in 80% of patients. The absence of a rash and the presence of a high fever and hematologic and liver enzyme abnormalities = Ehrlichiosis.
Distinguisihgn from RMSF?
RMSF will have a maculopapular rash (involving palms and soles) in 90% of patients.
Unnoticed bite leading to rabies.. what animal caused it?
Bats!
The majority of rabies transmission in the U.S comes form Bat bites!.
Other high risk reservoirs = racoons, foxes and skunks.. but you will def notice these bites.
For rabies bites must do POSTEXPOSURE PROPHYLAXIS:
Rabies IMMUNE GLOBULIN and Rabies VACCINE immediately after exposure to high risk wild animal.
Rubella (german Measles) presentation
Prodrome of Mild fever, lymphadenopathy and mailaise.
RASH = MACULOPAPULAR erupts on the face and SPREADS CAUDALLY within 24 hours, SPARES palms and soles!!!
Patients can have POLYARTHRALGIA or ARTHRITIS.
Most symptoms resolve in a few days.. but arthritis can las up to a month.
Vaccination is done with the LIVE ATTENUATED VACCINE!
Congenital manifestations:
- Sensorineural Hearing loss
- Cataracts
- PDA
Patient with fever and cervical lymphadenopathy gets antibiotics and then develops a Maculopapular rash.. what happened?
this patient has mono.
giving mono patients and Antibiotic –> maculopapular rash!
Rash of Secondary syphilis vs Rubella
Secondary Syphilis:
Maculopapular rash that involves the ENTIRE TRUNK and Extremities –> INCLUDES the PALMS and SOLES
Rubella –> Palms and soles are spared!
Chicken pox rash
Fever and malaise followed by rash.
VESICULAR (rubella is maculopapular).
Appears in crops and crusts after several days.
Scarlet Fever cause and Presentation
Caused by GROUP A Strep (S. Pyogenes)
Strep Pharyngitis - Tonsilar erythema and exudates.
STRAWBERRY Tongue, Tonsillar EXUDATES, PALATAL PETECHIAE.
The ERYTHROGENIC EXOTONXINS, released by S. Pyognes cause the rash!
Rash: Sprreads across the TRUNK, GROIN!!, and Axillae.
SANDPAPER texture.
DESQUAMATIVE Rash –> Peeling of Hands and Feet.
CIRCUMORAL PALLOR (pale mouth with super red cheeks)
Treatment = PENICILLIN (eg. amoxicillin)
DIagnoiss is confirmed by Rapid Strep antigent TEST or Throat culture.
Kawasaki Disease Diagnosis
Requires teh following to make diagnosis.
- More than 4 days of fever and 4 or more of the following clinical criteria:
- 1.5cm or larger CERVICAL lymph nodes
- Polymorphous Rash
- Edema of the HANDS / FEET
- CONJUNCTIVITIS
- MUcosal changes (STRAWBERRY tongue, Dry/ Cracked lips)
Roseola presentation
High fever followed by a MORBILLLIFORM RASH which comes AFTER the patient has gotten better!!!
FOr patients exposed to B. Pertussis who should get prophylaxis?
Pertussis is HIGHLY contagious - spread by respiratory droplets.
the 1st line treatment is a MACROLIDE antibiotic.
ALL CLOSE CONTACTS should recieve PROPHYLAXIS. MAcrolides are also the PREFERRED PROPHYLAXIS antibiotis.
Contacts who are less than 1 month old should get AZITHROMYCIN for 5 days.
Contacts older than 1 month should get one of the following macrolide treatments:
1. Azithromycin for 5 days or 2. Clarithromycin for 7 days or 3. Erythromycin for 14 days.
Patients who are infected with pertussis and are less than 3 months old should be hospitalized because of the risk of APNEA.
Patients should be isolated from others.. but dont need to necessiarily hospitalize for isolatin.. just keep them out of daycare / school.
Mycoplasma pneumo vs Miliary TB presentation on CXR.. how to differentiate.
Both will have a reticulonodular pattern on CXR.. which looks much worse than the patient feels.
The way to tell the difference is by clinical symptoms in the stem:
Tb will cause symptoms for a long time until treated.
Mycoplama is limited to 2-3 weeks of symptoms then it resolves.