| Cerebral spinal fluid (CSF) findings as per notable CNS infections | ||||||
| Glucose (mg/dL) |
Protein (mg/dL) |
Predominant WBC cell type | WBC count (cells/mm3) |
RBCs (cells/mm3) |
Opening pressure (mm H2O) |
|
| Normal CSF | 50 to 80 | 15 to 60 | Mononuclear | 0-5 | None | 60-200 |
| Bacterial | ↓ | ↑ (100-500) | Neutrophils (Polymorphonucleocytes; PMNs) |
>1,000 | None | ↑ |
| Viral (aseptic) | Normal | Normal or ↑ (<95) | Lymphocytes | <100 | None | Usually normal |
| Fungal | ↓ | Normal or ↑ (20-150) | Lymphocytes | 10-500 | None | ↑ (HY on USMLE!) |
| Tuberculosis | ↓ | ↑ (100-500) | Lymphocytes | 100-500 | None | Normal or ↑ |
| Herpes simplex virus | Normal or ↓ | ↑ (>60) | Lymphocytes | >100-250 | Usually ↑ (HY on USMLE!) |
Normal or ↑ |
| Cerebral spinal fluid (CSF) findings as per notable CNS infections | |||||
| Glucose (mg/dL) |
Protein (mg/dL) |
WBC type (cells/mm3) |
RBCs | Opening pressure (mm H2O) |
|
| Normal CSF | 50 to 80 | 15 to 60 | Mononuclear (0-5) |
None | 60-200 |
| Bacterial | ↓ | ↑ | ↑ Neutrophils (PMNs) |
None | ↑ |
| Viral (aseptic) | Normal | Normal or ↑ | ↑ Lymphocytes | None | Usually normal |
| Fungal | ↓ | Normal or ↑ |
↑ Lymphocytes | None | ↑ (HY on USMLE!) |
| TB | ↓ | ↑ |
↑ Lymphocytes | None | Normal or ↑ |
| HSV | Normal or ↓ | ↑ |
↑ Lymphocytes | Usually ↑ (HY on USMLE!) |
Normal or ↑ |
| MEHLMANMEDICAL.COM | ||||||
| Hepatitis B serology interpretation | ||||||
| HBsAg | HBsAb | HBcAb | HBcAb IgM | HBcAb IgG | HBeAg | |
| Acute infection (low infectivity) |
+ | – | + | + | – | – |
| Acute infection (high infectivity) |
+ | – | + | + | – | + |
| Chronic infection (low infectivity) |
+ | – | + | – | + | – |
| Chronic infection (high infectivity) |
+ | – | + | – | + | + |
| Immune (previous infection) (<6 months) |
– | + | + | + | – | – |
| Immune (previous infection) (>6 months) |
– | + | + | – | + | – |
| Immune (vaccinated) |
– | + | – | – | – | – |
| Window period | – | – | + | + | – | – |
| Susceptible (not immune) |
– | – | – | – | – | – |
| MEHLMANMEDICAL.COM | ||
| Common skin and soft tissue infections (SSTIs) |
||
| Skin infection type | Most common pathogen | Treatment |
| Non-bullous / non-purulent Erysipelas | Strep pyogenes > Staph aureus | Oral dicloxacillin, cephalexin, penicillin* |
| Bullous / purulent Erysipelas | Staph aureus > Strep pyogenes | Oral dicloxacillin, cephalexin |
| Cellulitis | Staph aureus > Strep pyogenes | Oral dicloxacillin, cephalexin, clindamycin IV flucloxacillin, cephazolin |
| Non-bullous impetigo | Staph aureus > Strep pyogenes | Topical mupirocin, retapamulin, fusidic acid Oral dicloxacillin, cephalexin |
| Bullous impetigo | Staph aureus | |
| *Penicillin considered an acceptable first-line option in non-bullous / non-purulent erysipelas only; it does not cover S. aureus. | ||