1.Vasculidities that consume complement:
- Hep C cryoglobulinemia
- Lupus vasculitis
2. Drug induced lupus: INH, procainamide, hydralazine, dilantin, anti-TNFa (etanercept, etc)
3. Lyme disease 
- Early localized (days to weeks): erythema marginatum (80% of patients), fatigue, mlaaise, lethargy; mild HA and neck stiffness; pain in muscles and joints
- Early disseminated (weeks to months): carditis (5% untreated - AV block, cardiomyopathy), neuro (15% of untreated patients: unilateral/bilateral CN deficits like 7, meningitis, encephalitis), muscular (60% untreated - migratory arthralgais), conjunctivitis (10% untreated)
- Late/chronic: migratory arthalgias, encephalomyelitis, peripheral neuropathy
- titers are insensitive in early localized disease; IgM antibodies to B.Burgdorferi appear usually around 1-2 weeks, IgG within 2-6.
- If there is clinical suspicion of lyme, the correct management is to treat with PO doxy (if pt is >=8  years old and not pregnant)
4. DMARDs should be started asap in RA as they slow joint damage (begins early in disease): MTX, hydroxychloroquine, sulfasalazine, azathioprine). If DMARDs are not enough, can add another DMARD or add biologic. Can use steroids and NSAIDs to manage symptoms, but steroids do not prevent long term joint destruction.
5. Patients with HIV who complain of esophagitis/odynophagia with evidence of oral thrush should get an empiric treatment with 3-5 days of PO fluconazole. If that fails to improve symptoms, or if there is no evidence of oral thrush, then they should get scoped to look for other causes - CMV, HSV.
6. Emphasematous cholecystitis: acute chole in old, diabetic males- infection of GB wall with gas-forming bacteria.
7. Absent ankle reflexes can be a normal finding in aging, elderly patients.
8. Management of aortic dissection: 
- Beta blocker, as it prevents tachycardia and hypertension, which can exacerbate the dissection (if you use a BP-only agent like nicardipine or hydralazine, you may cause reflex tachycardia which may worsen dissection).
- Anticoagulation (heparin, tPA) should be avoided - as the theoretical risk of extending the dissection
9. Acute pain and swelling over coccyx- likely pilonidal cyst (common in young men with large amounts of body hair) - theorized to be a follicular infection that forms an abscess that spread subcutaenously, then ruptures and forms a sinus tract, that can then itself become obstructed and repeatedly infected. Treat by drainage and excision.
10. Drug toxicity: 
- Salicylate: resp acidosis, metabolic alkalosis, tinnitus, n/v, fever, AMS. Treat with sodium bicarb (alkalinizes urine; also works for TCA o/d, phenobarb, MTX)
- Serotonin (ie serotonin syndrome): flushing, HTN, tachycardia, hyperthermia, diaphoresis. Treat with cyproheptadine
- Cocaine: HTN, tachycardia, cardiac ischemia, intracranial hemorrhage. Manage vital sign abnormalities with benzos.
- Anticholinergics: drowsiness, confusion/AMS, dry mouth, dilated pupils/blurred vision, constipation, urinary retention; treat with physostigmine
- Theophylline: seizures, hyperthermia, cardiac arrhythmia, hypotension. Treat seizures with benzos.