1. Solitary pulmonary nodule:
- Calcifications that favor benign pathology: popcorn (hamartoma), bulls-eye (granuloma)
- In low risk (age <40), if there is evidence of no radiographic change in last 12 months its considered benign. CXR q3 months for next 12 months, if there is no growth you're done.
- If high risk (ie smokers), need more w/u - CT then FNA. If that fails open lung bx.
2. Dermatitis herpetiformis 
- Intensely pruritic papules over knees, elbows, buttocks, posterior neck, scalp.
- IF: granular IgA along dermal papillae. +anti-endomysial ab.
- Treat with dapsone and a gluten free diet. Unclear why dapsone works-- antiinflammatory/immunemodulating effects?
3. Erythemas
- Multiforme: often acral distribution + mucous membranes, target shaped, associated with many diseases incl recent HSV infection
- Nodosum: nodular, associated with sarcoid
- Marginatum: ring shaped lesions on extensor surfaces, one of the JONES criteria
- Migrans: lyme disease; target shaped
4. Bullous derm: 
- Bullous pemphigoid: benign, pruritic. Tense blisters - IgG and C3 in dermal-epidermal junction. Rarely affects mouth.
- Pemphigus vulgaris: flaccid bullae, +nikolsky sign, IgG in the epidermis - autoantibodies against desmoglein (adhesion molecule). Treat with steroids, DMARDs like azathioprine or mtx.
- Bullous impetigo: s.aureus
5. Skin cancer: 
- On the lips: squamous cell
- Basal cell almost never appears on the lip, and when it does its the upper lip. Histo: spindle cells + palisaded basal cells.
6. Adrenal insufficiency 
- AI from TB is permanent- even after you treat the TB they will need lifelong mineralcorticoid and glucocorticoid supplementation.
- In developed countries 80% is from autoimmune
- Often occurs in HIV+ patients (CMV, mycobacteria, fungi, TB). Antifungals (keto) can precipitate AI by inhibiting steroid synthesis.
- Rare from mets.
7. ADPKD: 
- Incidence 1:500
- Positive family history in 75% of cases
- 50% + have hypertension at presentation
8. PBC
- Insidious, affects middle aged women
- Exam: hepatosplenomegaly,. xanthomas => jaundice, steatorrhea, portal HTN, osteopenia
- +antimitochondrial antibodies
- Assoc with sjogrens, raynaud's scleroderma, autoimmune thyroid, hypothyroid,. celiac.
- Treat with ursodeoxycholic acid - slows progression, relieves symptoms. MTX and colchicine have shown moderate benefit. NO role for steroids.
- Without liver transplant, survival 7-10 years after onset of symptoms.
- Can manage symptoms with cholestyramine.
9. MIBG scans are more specific but less sensitive than CT for detecting pheo.
- Use it when the CT is equivocal, when there is extra-adrenal pheo, or if you suspect cancer.
10. Steroids for AI
- Stress dose is 10x the normal daily dose-- for most people this will mean 100 mg hydrocortisone IV. Give divided in 3-4 doses.
- Hydrocortisone is a glucocorticoid, but once the dose is 60mg/day, it has mineralcorticoid activity and you no longer need fludrocortisone.