Pearls from Dr. Marcus Pereira
- Usually associated with severe hypertension
- Usually occurs 3-6 months after initiation of immunosuppression
- Can present with seizures, HA, AMS, visual disturbances
- Typical imaging pattern in symmetrical white matter edema in the posterior cerebral hemispheres
Posted 07/27/16 11:07:52 AM by Adam Faye
Brain Abscesses: Common Bugs
- Bacteria - Strep (mouth/sinuses), Staph, Nocardia (look for lung nodule, weakly acid-fast), Actinomyces, Mycobacteria
- Fungal - Aspergillus (Lung/Sinus), Mucor
- Parasite - Toxoplasmosis
*If it were septic emboli to the brain - often localizes to grey-white matter junction
Posted 07/27/16 11:13:55 AM by Adam Faye
Patients with focal neuro signs from possible mass effect - CT Head before LP to minimize the possibility of herniation.
Posted 07/27/16 11:17:49 AM by Adam Faye
- For severe infection use 2-3 agents for empiric coverage: TMP-SMX/Carbepenem. usually 6-12 months of therapy needed.
- Linezolid can also be used but can lead to thrombocytopenia (usually 10 days after initiation of treatment).
- Sulfadiazine + Pyrimethamine
Posted 07/27/16 11:23:44 AM by Adam Faye
Ring Enhancing Lesions Differential:
- Brain Abscess
- CNS Lymphoma
- Infarct (Subacute phase)
- Demyelination lesion
- Radiation Necrosis
Posted 07/27/16 11:25:17 AM by Adam Faye
- Infection typically occurs hematogenously (bacteremia from other sources/indwelling catheter/IVDU) OR by direct extension from infected vertebra (osteomyelitis) or disk (diskitis), alternatively following spinal surgery or epidural anesthesia
- Most commonly S. aureus (>60%) >>> GNR > Strep (but think sequelae of vertebral TB if risk factors)
- Classic indications for surgery: increasing neurologic deficit, persistent severe pain, or persistent fever and leukocytosis despite abx
- Early surgical consult is essential component of mgmt
Posted 11/23/16 10:44:45 AM by Matthew Cummings
Clindamycin and D-test
- S. aureus --> some strains (typically MSSA) possess inducible resistance gene --> alters the common ribosomal binding site for macrolides, clindamycin rendering them resistant when exposed, even though sensitivities may report macrolides/clindamycin as being sensitive
- Positive D-test indicates that there IS THE POSSIBILITY of this resistance emerging and thus clindamycin should be avoided, especially for severe infections
Posted 11/23/16 10:49:12 AM by Matthew Cummings
Multiple GNR infections (esp. separated in time and anatomic location)? Think Strongyloides (GNR translocation in gut)
Posted 11/23/16 10:50:01 AM by Matthew Cummings
- Gram-negative filamentous, rod, found in soil, plants, foodstuffs and water sources including (vents/HD circuits in hospitals)
- Emerging cause of highly-resistant hospital-acquired infections (VAPs)
- Mortality for bacteremia ~60%
- Emergence likely related to increasing use of tigecycline and colistins for other resistant GNRs
- Often resistant to carbapenems/colistin/polyB, sensitive to TMP-SMX/quinolones
Posted 11/23/16 10:55:29 AM by Matthew Cummings
For further reading...
Posted 11/23/16 10:57:35 AM by Matthew Cummings
Acute Renal Necrosis DDx (emphasis on infectious agents)
- Viral: HSV, VZV, CMV
- Behçet’s disease
- Intraocular lymphoma
Posted 03/22/17 09:57:10 AM by Matthew Cummings
Multiple-ring enhancing CNS Lesions = MAGIC DR
- Abscess --> bacterial (Mycobacteria, Nocardia, Actinomyces, Listeria); fungal (endemic mycoses, Aspergillus); parasitic (neurocystircercosis, Echinococcus, and Entamoeba);
- Glioma/CNS neoplasms (e.g. lymphoma)
- Demyelination (e.g. MS, ADME)
- Resolving hematoma/radionecrosis
Posted 03/22/17 10:01:52 AM by Matthew Cummings
- Nocardia: Gram-positive branching, filamentous rod.
- DDx includes Actinomyces --> Nocardia is weakly acid fast, Actinomyces is not
- Sites of infection (1994 review of 1050 cases):
- Pulmonary (most common): diverse symptoms (acute/subacute), imaging w/ nodules/mass/interstitial infiltrates/consolidation/pleural effusion
- CNS: abscess (ring-enhancing--single or multiple), meningitis
- Cutaneous: ulcerations, pyoderma, cellulitis, nodules, and subcutaneous abscesses
- Other extra-pulmonary sites: eyes (endopthalmitis, retinitis), bone (osteomyelitis)
- TMP-SMX is mainstay of therapy often in combination w/ carbapenem/linezolid
Posted 03/22/17 10:15:51 AM by Matthew Cummings
For further reading...
Posted 03/22/17 10:18:33 AM by Matthew Cummings
Immunosupressed patients who present with diffuse rash has broad differential. Think: VZV, HSV, coxsackie, mycobacterium, actinomyces, cryptococcus (usually not vesicular, more nodular), histoplasmosis, sporotrichosis (usually lymphatic spread confined to one limb).
Posted 07/05/17 10:24:09 AM by Emily Miller
Disseminated viral infection - look for atypical lymphocytes of CBC differential. Helpful, but not diagnostic.
Posted 07/05/17 10:24:51 AM by Emily Miller
Tzanck smear can be helpful in narrowing differential if multinucleated giant cells are present. However, cannot differentiate between VZV and HSV.
Posted 07/05/17 10:35:54 AM by Emily Miller
Acyclovir does not treat CMV, but ganciclovir does treat VZV. Think of Ganciclovir is the broad spectrum herpesvirus antiviral.
Posted 07/05/17 10:37:19 AM by Emily Miller
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