Ch 13. Infections and III Flashcards
Encapsulated organisms (7)
Some Nasty Killers Have Some Capsule Protection 1. Streptococcus pneumoniae 2. Neisseria meningitidis 3. Klebsiella pnemoniae 4. Haemophilus influenzae 5. Salmonella typhi 6. Cryptococcus neoformans 7. Pseudomanas aeruginosa
HIV infections at CD4 levels 200-500 (2) and less than 200 (4) and less than 50 (2)
- 200-500 = oral candidiasis, TB, ITP, hairy leukoplakia, Kaposi sarcoma
- <200 = PCP pneumonia, TB, toxoplasmosis, cryptosporidiosis, esophageal candidiasis, Cryptococcus, histoplasmosis, progressive multifocal leukoencephalopathy
3. <50 = MAC, CMV (retinitis)
PCP pneumonia symptoms, treatment (2)
- PCP (Pneumocystis jirovecii) symptoms=non-productive cough, fever, profound SOBOE
- Rx. TMP-SMX and steroids if PaO2 <70
Dx. Bronch + lavage
How long does it take for the ELISA HIV antibody test to become positive? (1)
- 28 days (1 month) “HIV routine serology”
What is the earlier HIV screening test? (1)
- P24 antigen or HIV viral RNA PCR “HIV rapid assay”
* Exposure within 1 month, call the virologist for high suspicion *
What is the HIV acute retroviral syndrome? (1)
- Acute exposure (75% of people get it): fever, lymphadenopathy, malaise, lasts weeks
HIV diarrhea DDx (4)
- Secondary to HIV medication side-effects
- Normal bacteria that cause diarrhea (SSEYC)
- Cryptosporidium
- Malignancy (lymphoma, bowel Ca)
5. C Diff
How do you measure a CD4 count? (1)
- Take the CD3+4+ count and times by 1000 CD3+4+ of 0.025 is a CD4 count of 25.
DDx HIV pneumonia (3)
- Your normal pneumonia’s (Strep pneumo, H flu, M catarrhalis)
2. TB
3. PCP (CD4 <200)
What defines AIDS? (2)
- CD4 <200 (lymphocyte surrogate <1.0) or
2. HIV+ and AIDS-defining illness (ex. opportunistic infection)
What is the risk of contracting HBV, HCV, HIV from a needle stick injury contaminated with blood from aknown positive source?(3)
1.Rule of 3s: HBV, HCV, HIV: 1/3, 1/30, 1/300 risk of acquiring blood-borne infection. high HBV risk is assuming unvaccinated host. Risk if vaccinated is veryyyy low.
What is the recommended antibiotic treatment for pneumonia in the following settings:
- Outpatient (healthy, immunocompetent)
- Outpatient (comorbidities and or antibiotics in last 3 mo)
- Inpatient (Ward)
- Inpatient (ICU)
- Outpatient (healthy, immunocompetent):
Doxyclycline 100mg PO BID Or Clarithoromycin 1g BID
- Tetracyclines cover: Gram + (strep, staph), Gram - (H. flu), Atypicals (mycoplasma, chlamydophila) - Outpatient (comorbidities and/or antibiotics in last 3 months): Levofloxacin 750 for 5 days
OR Amoxicillin + Doxyclycline
-Levofloxacin adds pseudomonal coverage - Inpatient (ward)
Ceftriaxone + Azithro (can consider antiviral if appropriate)
-Ceftriaxone provides broader gram negative coverage while also having strong staph/strep coverage. - Inpatient (ICU)
PipTazo + Vancomycin(can consider antiviral if appropriate)
- Vanco providing MRSA coverage
PO and IV Antibiotic to treat MRSA (4+3)
MRSA antibiotics:
-PO: Doxy, Septra, Clinda, Linezolid
-IV: Vancomycin, Daptomycin, Linezolid
PO and IV Antibiotic to treat pseudomonas (1+4)
Pseudomonas antibiotics:
-PO: cipro
-IV: Carbapenems (imipenem, meropenem), Ceftazamine/Cefepime, PipTaz, Aminoglycosides (Tobramycin, Gentamicin)
DDx of cellulitis (6)
Cellulitis = red warm painful. Also fever, streaking lymphangitis, regional lymphadenopathy
*Itchy, bilateral, not improving with AB’s, or in a risky location (groin, genitals, joint) think of other Dx
1. Stasis dermatitis – bilateral red legs above medial malleolus. * redness resolves with a passive leg raise 1-2 mins
2. Peripheral arterial disease
3. DVT/thrombophlebitis – use Well’s. Only 1% of DVT’s have concomitant cellulitis
4. Septic arthritis – can they move the joint? Is there a large POCUS effusion?
5. Gout – looks like gout.
6. Flexor tenosynovitis – passive extension of the finger is ++ painful. Tracks up the tendon.
7. Bee sting – cellulitis after a wasp sting is uncommon and delayed days after the sting.
8. Erythema migrans (Lyme disease)
9. Necrotizing fasciitis – very sick, very rapid, extreme pain, gas
Antibiotic treatment for cellulitis (2).
When to reassess (1)
- Cephalexin (Keflex) PO x 5 days
- Doxycycline (if a true severe allergy to Penicillin or cephalosporins). Or levofloxacin.
1. Reassess at 48-72 hours. Consider treatment failure if no improvement in pain or heat or redness progresses
*Do not empirically cover for MRSA (TMP-SMX) – it doesn’t work and doesn’t have Strep coverage
Non-purulent = Strep. Purulent = staph. But still use Keflex.
Which cellulitis patients need IV antibiotics (3)
- Immunocompromised (not diabetes – they still get PO)
- Systemic signs (SIRS)
3. Hemodynamic instability - Altered mental status
- Consider in high BMI
Antibiotics for abscess (1)?
- Consider doxy (95% coverage MRSA), esp for recurrent abscess. It will decrease 7% recurrence. NNT 14.
Which abscess need packing (3)
- Large abscess >5cm
- Abscess in groin or axilla
- Diabetic foot
*Just a very small wick. Patient can take it out in 2 days.
What is the rate of true penicillin allergy? (1)
Cross reactivity to cephalosporins? (1)
- A “true” penicillin allergy is <10%
- The cross-reactivity in true allergy is <10%.
This means penicillin allergy is <1% to cephalosporins. Only avoid if true severe anaphylaxis.
Signs and symptoms of necrotizing fasciitis (8)
- SICK (SIRS criteria, fever, sepsis)
- Rapidly spreading
3. Pain out of proportion to clinical findings
4. Skin necrosis
5. Blisters/bullae
6. Tense edema
7. Palpable crepitus/gas on US
8. Local hypo-esthesia (can’t feel)
NecFas = 30% mortality.
Rx. PipTazo + Vanco + Early surgical debridement
Type 1=polymicrobial (Fournier’s gangrene)
Type 2=GAStrep. Often preceding by minor trauma even without skin tear.
TB Risk factors (9)
- Immigrant status
- HIV/immunocompromised
3. Homeless - Alcoholic
5. IVDU - First Nations
7. Elderly
8. Healthcare worker - Known TB contact
Symptoms of TB (2)
Pneumonia and B symptoms
1. Pneumonia: fever, cough, dyspnea, pleuritic CP, hemoptysis
2. B symptoms: night sweats, fatigue, weight loss
TB X-ray findings (5)
*Acute TB infection can look like a normal every-day pneumonia.
Re-activation TB looks like:
1. Upper lobe consolidation
2. Mediastinal lymphadenopathy
3. Cavitation
4. Miliary TB is the diffuse, fine granules. Often immunocompromised patient. SICK.
5. Latent TB can present with a calcified lymph node called a Ghon complex
Complications of TB (6)
- Pneumonia
- Empyema
- Sepsis (military TB)
- Peritoneal TB
5. Hepatosplenomegaly
6. Prostatitis
7. Epididymitis/orchitis - Adrenal insufficiency
9. TB osteomyelitis
10. Meningitis
What are 4 TB meds. Complications (8)
RIPE 1. Rifampin - hepatitis 2. Isoniazid (INH) – hepatitiss. B6 deficiency. Peripheral neuropathy. Seizures 3. Pyrazinamide - hepatitis 4. Ethambutol – hepatitis.
Who is asplenic? (3)
- Trauma with splenectomy
- Sickle cell
3. ITP/TTP
How does prednisone work? When is somebody immunocompromised? (2)
- Inhibits cell mediated translocation across a membrane and into tissue, inhibiting macrophages
- Immunocompromised comes after >20mg per day, chronically