SSTI/Hyperglycemia

Etiology- Non Purulent “Simple” Cellulitis and Purulent Cellulitis

non purulent- no pus or fluid and skin is intact, cannot culture, caused by beta hemolytic strep

purulent- pus or fluid and skin is elevated, can culture, caused by staph, folliculitis, furuncle/boil, and carbuncle, or cutaneous abscess (can just I&D unless multiple lesions, immunocomprimised, >5cm, or failure of I&D)

Cellulitis Assessment

culture and vital signs

systemic inflammatory response syndrome (SIRS) criteria = WBC>12k or <4k, RR>20, HR>90, Temp>38C or <36C

• no SIRS = mild

• 1 SIRS = moderate

• 2 SIRS = severe and sepsis (very serious and needs broad spectrum coverage and fluids to reverse hypotension)

Drug Therapies

mild use PO, moderate PO or IV, severe IV

non purulent cover strep (beta lactams 1st, consider MRSA coverage if immunocompromised, have puncture wounds, IV drug use, or thermal injuries, note these also warrant other coverage IRL)

severe nonpurulent necrotizing skin infection is life/limb threatening, needs broad spectrum antibiotics and emergency surgery, use vanc + pip/tazo, consider adjunctive clindamycin to down regulate toxin production, linezolid can take place of vanc or clindamycin

recurrent nonpurulent cellulitis common if lymphatic injury, oral penicillin 1 yr for prevention, check for tinea and use antifungal

purulent cover staph (culture for MRSA or just cover empirically)

Antibiotics for SSTI

penicillin (PO/IV but too frequent), amoxicillin (PO), dicloxacillin (PO)

cefazolin (IV), cephalexin (PO)

vancomycin (IV)

daptomycin (IV)

linezolid (PO/IV)

clindamycin (PO/IV)

doxycycline (PO/IV)

Bactrim (PO/IV)

all but doxycyline and Bactrim cover beta-hemolytic strep

all but penicillin and amoxicillin cover MSSA

all but penicillin, amoxicillin, dicloxacillin, cefazolin, and cephalexin cover MRSA

note don’t use clindamycin for MRSA but use for beta lactam allergies in non purulent

Specific Use Antibiotics

ceftriaxone (IV)- covers beta-hemolytic and MSSA but used for severe cases

piperacillin/tazobactam (IV)- broad spectrum for very severe non purulent, no MRSA so use in combo with vanc

Pharmacology

linezolid DDI with SSRIs, also reserved for more severe

daptomycin monitor CPK

doxycyline separate from Ca/Mg, warfarin, photosensitivity, take with full glass water and remain upright

Bactrim DDI warfarin, hyperkalemia, crystalluria

renal adjust penicillin, amoxicillin, cefazolin, cephalexin, vancomycin, daptomycin, Bactrim, and piperacillin/tazobactam

hepatic adjust dicloxacillin, linezolid (caution), clindamycin, doxycyline, Bactrim (caution), ceftriaxone (caution)

ceftriaxone has no renal adjustments

Reassessment

5 days (drug therapies are usually 5 day course), if not resolved reconsider dx and other options

Inpatient Glycemic Goal (outpatient fasting is 80-130)

critically ill= 140-180 (110-140 if undergoing cardiac surgery)

non-critically ill= 100-180 (<250 if terminally ill, CKI, dialysis, hypoglycemia, etc)

Inpatient Treatment Critical Care

continuous IV insulin 0.05-0.1 U/kg/hr using regular or rapid, monitor BG q1-2 hrs

transitioning to subQ insulin- reduce daily infusion dose from 20%, 50:50 basal:prandial, give before turning off infusion (1-2 hrs if first SQ prandial, 2-3 hrs if basal)

Inpatient Treatment Non Critical Care

subQ insulin ± non insulin agents DPP4 (can take place of prandial if BG<200) or SGLT2 inhibitors (if HF)

basal (glargine, NPH q12, Levemir) + nutritional (glulisine, regular, lispro, aspart) + correctional

avoid correctional only (RABBIT 2 trial), premixed, and concentrated insulin

if not eating can leave out nutritional

Hyperglycemic Crisis

diabetic ketoacidosis (DKA)- absolute insulin resistance and no glucose being used so body uses ketones and this leads to acidosis

hyperglycemic hyperosmotic crisis (HHS)- relative insulin resistance that doesn’t go into DKA but causes glycosuria and severe diuresis and electrolyte loss

management of both- IV fluids, insulin, and potassium

Kidney Function

GFR<30 don’t use metformin

GFR<20 don’t use SGLT2

adjust DPP4

Outpatient DM

starting basal dose is 0.2 units/kg/day

goal fasting 80-130, prandial <180