1. Modified Duke criteria for infective endocarditis: Need 2 major criteria, or 1 major and 3 minor, or 5 minor.
Major criteria: 
- 2+ blood cx drawn 12 hrs apart, or 3 cx (2 of which are drawn 1 hr apart) of organisms that classically cause endocarditis (strep viridians, strep bovis, HACEK, enterococcus and s.aureus without other source)
- Echo findings: oscillating mass on valve, abscess, new valve regurg, dehiscence of part of prosthetic valve.
Minor criteria: 
- Fever > 38
- Heart valve dx, IVDU
- Vascular phenomena: arterial emboli, intracranial hemorrhages, pulmonary emboli, conjunctival hemorrhages, janeway lesions
- Immune phenomena: glomerulonephritis (immune complex deposition), rheumatoid factor (IgM against IgG), olser nodes, roth spot (immune complex mediated vasculitis leading to hemorrhages in retina)
- Blood cx findings that don't quite meet major criteria
2. Staph endocarditis: 
- Penicillins and b-lactams are the best drugs.
- In the rare incidence when it's susceptible to penicillin, use pencillin
- MSSA: use nafcillin, oxacillin, or cefazolin. Adding gent for the first 3-5 days may speed up clearance of bacteremia. Vanc is slower than these drugs, and clinda has a high failure rate in vivo (maybe because its bacteriostatic against many strains of s.aureus). Linezolid is +/- in efficacy.
- Use vanc for pen allergic people.
3. Endocarditis of prosthetic valve:
- Treat with rifampin, gent, and something to cover staph-- Naf/ox/cefazolin for MSSA or vanc for MRSA.
4. Anti-pseduomonals:
- Third gen cephalosporins: ceftazidime (no MRSA coverage), cefoperazone (has a side chain which can inhibit vitamin-K activity and cause a disulfram like reaction)
- Ag: tobra, gent, amikacin
5. Diabetic foot ulcers
- If a metal probe hits bone, 90% PPV for osteomyelitis
- Need bone bx to find the deep organisms that are responsible for the infection-- superficial ulcer organisms often do not correlate with the deep organisms.
6. Spine osteomyelitis
- If blood cx are negative, will need CT-guided needle biopsy.
7. Aplastic anemia
- Cell lines down but cell maturation normal, BM <20% cellularity
- 50% of the time no identifiable cause, 50%: drugs, chemicals, viral, collagen vascular, thymoma
- Workup: withdraw all potential causative agents, CT chest to r/o thymoma
- Interferon-activated T-cells targeting hematopoietic stem cells implicated in pathogenesis, immunosuppressives sometimes effective
8. ITP
- Platelets low, but white count normal
- May have associated hemolytic anemia, or iron-deficiency anemia from bleeding.
9. B12 deficiency:
- Serum homocysteine and MMA levels will elevate before B12 levels drop
- In folate deficiency, only homocysteine will be high.
10. Indications to screen for coagulopathy before surgery: 
- Personal or family history of bleeding
- Heavy alcoholism: alcohol partially inhibits platelets, reduces fibrinogen/factor VII/wWF levels, activates tPA -- this is perhaps responsible for the decreased risk of cardiovascular disease seen with mild or significant alcohol consumption. {source} The truth is that raging alcoholics don't get heart disease-- they die young of liver disease, or cancer, or accidents, or any of the other comorbidities of alcoholism, but they don't die of cardiovascular disease.
- Liver disease
- Malnutrition
- Anticoagulation
- For the purposes of exams, people without the above risk factors do not need a PT/PTT/INR before surgery.