Tuesday, July 31, 2007

Tox: Salicylates

Salicylates
-Pepto, oil of wintergreen, liniments in vaporizers
-delayed or erratic absorption; toxic levels usu in 6 hrs; peak 10-60 h with syst release preps
-gelatinous gastric mass and delays gastric emptying
-ASA > hyrolyzed to salicylate > pH 7.40 all ionized; acidemia inc passage through BBbarrier
-1) stim medulla > inc in resp rate -> resp alk
2) inc cat, inc CO2, inc glycolysis, production of organic acids incl lactate, pyruvate, ketoacids > met acidosis w/inc gap
3) vomiting > vol contraction alkalosis
-salicylate's struct is similar to vit K, lg chronic doses my cause low PT by inhibition of vit K

si/sx
-acute < 150 mg/kg mild tox with n/v/gi irritation
-acute 150-300 mg/kg mod tox w/v/hypervent, sweating, tinnitus; asa level 30 mg/dl
-if coingest resp suppressive drugs > resp acidosis
-acute >300mg/kg severe tox w/fever, ams, renal fail, pulm edema, ards, rhabdo, gi perf, gi hem
-kids - present w/in few hours; <4>4 have mixed acid-base disturb as in adults
-chronic - usu elderly, hypervent, tremor, pailledema, agitation, paranoia, bizarre behav, mem loss, confusion, stupor; consider in unexp nonfocal neuro and behav abnl, w/acid-base disturb, tachypnea, noncard pulm edema
-kids - hypervent, vol depletion, acidosis, marked hypokalemia, cns disturbance, fever (often mistaken for infxn), renal failure

Rx:
-monitor
-IV
-FSBS
-labs: lytes, glc, bun, cr, cbc, pt, salicylate level, tylenol level, abg
-act charcoal 1g/kg, multiple doses not helpful
-whole bowel irrigation if sustained release or enteric coated
-Fluids (NS) for vol dep, all subs fluids in D5
-second IV line for
-bolus 1-2 meq sodium bicarb, then 100-150meq (2-3 amp) sod bicarb to 1 L D5W infused at 1.5 to 2.0 x pt's maintenance rate; adjust to maintain urine pH > 7.5
-potassium 40 meq when uop is established
-monitor lytes - alkalinization decreases K level, keep at least 4.0
-HD for clinical deterioration despite rx, renal insuff or failure, severe acid-base disturb, ams, ARDS
-FFP and vit K for hemorrhage due to elevated PT
-salycilate levels q 2 hrs until peak, then q 4-6 hrs unti nontoxic
-except w/ ecasa or sr formulations, can d/c from ed if improvement occurs, not sig acid-base abnlty, and declining serial salicylate levels
-psych referral if intentional

Tox: Tylenol

Tylenol
-rapidly absorbed, peaks 2h except delayed absorption with tylenol-propoxyphene and Tylenol Extended Relief
-liver > sulfation and glucuronidation and cyt p450 oxidation > napqi > hepatic glutathione > nontoxic cmpd > renal excretion
-hepatic glutathione stores depleated, NAPQI accumulates > centrilobular necrosis
-alcoholics and aids pts have low glutathione stores; alcs and anticonvulsant and antitb drugs rev up p450
-NAC blocks binding of NAPQI to hepatic prtns, glutathione precursor, directly reduces napqi to tylenol

si/sx
1) day 1 - no sx, or anorexia, n/v, malaise
2) day 2-3 - n/v improve; RUQ (hepatotox), inc ast/alt/bili
3) day 3-4 - fulminant hep failure; lactic acidosis, coagulopathy, renal failure, encepahlopathy, recurrent n/v
-toxicity if ingest > 140 mg/kg or >7.5 g in adult in 24h
-single large od, use Rumack-Matthew Normogram, based on serum tylenol level 4-24 hr after time of ingestion; 4h level > 150 mic/dl is toxic; after 24 hr, a detectable tylenol level or presence of inc transaminases may predict toxicity
-multiple ingestions - assume a single ingestion at the earliest possible point in time and use normogram
-Tylenol ER - add 2 hr to time of ingestion and interpret the normogram

Rx:
-ABC's
-tylenol level within 4 to 24 hrs of ingestion
-lytes, glc, bun, cr, ast/alt, cbc, pt
-activated charcoal 1g/kg
-NAC po or ng tube 140 mg/kg load, then 70 mg/kg q 4hr x 17 additional doses, can give immediately after charcoal, safe in pregnancy; dilute in a beverage and give with zofran or reglan
-correct coagulopathy/acidosis
-treat cerebral edema

Dispo:
-nontoxic tylenol levels based on nomogram d/c from ED if no other drug ingestion and not

Proced: Sutures

Procedure: Sutures
-Scalp 3-0 or 4-0 nylon or polypropylene
-Pinna 5-0 vicryl/dexon in perichondrium
-Eyebrow 4-0 or 5-0 vicryl (sq), 6-0 nylon
-Eyelid 6-0 nylon
-Lip 4-0 vicryl (mucosa) 5-0 vicryl (sq or muscle), 6-0 nylon (skin)
-Oral cavity 4-0 vicryl
-Face 6-0 nylon (skin) 5-0 vicrl (sq)
-Trunk 4-0 vicryl (sq,fat) 4-0 or 5-0 nylon (skin)
-Extremity 3-0 or 4-0 vinyl (sq, fat, muscle) 4-0 or 5-0 nylon (skin)
-Hands and feet 4-0 or 5-0 nylon
-Nail bed 5-0 vicryl

Suture removal:
Face, eylid, ear, nose 3-5 days
Neck 5-7
Scalp, trunk 7-12
Arm, hand 8-12
Leg, foot, extensor surface of joints 10-14

All: Anaphylaxis/Acute allergic rxn

Rx
-vitals, high-flow O2, monitor, IV
-Airway-intubate early, esp hoarse pts, "lump in my throat"; may need 1-2 tube sizes smaller due to edema; get cric kit ready
-Breathing - high-flow o2, albuterol neb
-Circulation - 1-2L IVfluids -> IV epi
-D/C antigen - remove stinger, d/c IV drug infusions
1) Epinephrine - less severe signs, give subq/IM epi .3-.5 cc (.3-.5mg) (0.01mg/kg max 0.5) 1:1000 q 5-10 min -> repeat -> repeat -> go to IV; antlat thigh>delt
- for severe resp distress, laryngeal edema, severe shock; .1 cc of 1:1000 in 10 cc saline over 5-10 min infuse -> no response -> epi infusion 1 mg (1cc of 1:1000) in 500 cc saline at .5 to 2 cc/min (1-4 mic/min), titrate to effect (also 1-4 mic/min of 1:10,000)
-5-10mic iv bolus (0.2mic/kg) for hypotn; 0.1-0.5mg IV if CV collapse
2) antihistamines - diphenydramine 25-50 mg IV (1mg/kg upto 50mg), ranitidine 50 mg
3) steroids - severe - methylprednisolone 125 mg IV (1-2mg/kg), oral prednisone 60 mg (1.0mg/kg) less severe
4) glucagon 1-5mg (20-30mic/kg) over 5min q5 min (in pts taking bblockers), drip 5-15 mic/min - hypotension refractory to epi, causes emesis
5) vasopressors - norepi, vasopressin, metaraminol

dispo
-mild rxn - observe 1 hr
-given epi - observe 6 hr
-severe rxn - admit to ICU
-discharge pts with Rx for antihistamines and prednisone for 4 days

-common causes - PCN, asa/other nsaids, ACEI, bactrim, contrast, hymenoptera stings, peanuts, shellfish, milk, eggs, monosodium glutamate, nitrites, dyes, idiopathic
-concurrent use of Bblockers is a risk for severe, prolonged anaphylaxis
-rxns are biphasic, with further mediator release 4-8 hrs later in up to 20% of cases

si/sx
-urticaria (hives) cutaneous, IgE mediated reaction, yielding itchy red wheals
-angioedema - face and neck
-anaphylaxis includes cv or resp compromise by definition
-resp - stridor, dyspnea, wheezing
-gi - n, cramps, diarrhea, vomiting
-pruritis and urticaria most common itial sx

Resources:
-Just the Facts in EM
-Annals EM, april 06, 47:4

Friday, July 27, 2007

Tox: Isopropanol

-rubbing alc, solvents, skin/hair products, paint thinners, antifreeze
-double potency and duration of etoh
-isoprop > liver > acetone > acetate and formate, but not enough to cause acidosis
si/sx - smell rubbing alc on breath, coma, resp depression, hypotn
-hemorrhagic gastritis is a char finding > n/v/abd pain/upper gi bleed
-also hepatic dysfxn, atn, rhabdo
-labs - ketones in blood & urine (from acetone), nl glc, absent or min acidosis, elevated osm gap
-*ketonemia, ketonuria, inc osm gap, w/min met acidosis
Management
-IVF
-FSBS
-thiamine
-naloxone if ams
-charcoal does not bind alcohols, but give if coingestion
-hemodialysis for refract hypotn or if predicted peak level of isoprop is >400 mg/dl
-labs: lytes, bun, cr, glc, isopropanol, acetone, u/a
Dispo
-if mild ingestion, asx, can d/c after 6-8hr of obs in ed

Tox: Methanol

-solvent in paint, windshield wiper fluids, antifreeze
-methanol > liver > alc dehyrogenase > formaldehyde and formic acid (+folate) > CO2
-C-OH > C=OH and COOH
-lg osmolal gap
-formaldehyde > retina > edema and optic papillitis
-formic acid > high anion gap met acidosis (Mudpiles)
-methanol is a gi irritant, can cause pancreatitis
si/sx
-no sx x 12-18hr after ingestion
-cns dep, visual disturb (*looking at a snowstorm), n/v/abd pain
-retinal edema, hyperemia of optic disk, abd tenderness
lab
-high anion gap met acid, high osm gap, methanol level
Rx
-IV fluids
-FSBS
-Thiamine
-nalaxone if ams
-charcoal - won't bind alcohols, but give if coingest
-folate 50 mg iv q 4 hr
-fomepazole 15 mg/kg IV load followed by 20 mg/kg q 12 hr x 4 doses; binds 8000x > ethanol for alc dehydrog, fewer SEs; begin if suspect meth poisoning; anion gap met acid and an osm gap; meth level >20; or pt requires dialysis
-ethanol 0.6 g/kg IV load folloed by 0.11 g/kg/h cont infusion, or 0.15 g/kg/h in heavy drinker, adjust infusion to keep etoh level 100 to 150; cont etoh treatment until methanol level is 0 and acidosis is resolved
-oral etoh bev - gram of etoh = cc beverage x .9 x (proof/200)
-dialysis indications - sig toxicity; meth level >20; presence anion-gap met acidosis
-Labs: BUN, Cr, glc, lytes
Dispo:
-any hx of ingestion admitted regardless of symptoms b/c may take 12-18 hrs to develop sx

Tox: Ethylene glycol

-antifreeze, polishes, detergents
-EG > liver > alc dehydrog > glycoaldehyde > formic acid, glyoxylic acid, oxalic acid (+thiamine or pyridoxine) > nontoxic metabolites
-lg osm gap
-high anion-gap met acidosis
-oxalic acid + ca > calcium oxalate crystals in urine
si/sx
-3 phases
1) 1-12h - cns fx; drunk, *no odor of etoh on breath
2) 12-24h - cardiopulm fx; inc bp, ht rt, resp rate, chf, resp distress, shock
3) 24-72h - renal fx; flank pain, cva tender, atn with arf
-can get tetany and inc QT int due to hypocalcemia due to caox formation
-fundoscopic exam is nl and no visual complaints (vs. methanol tox*)
-lab eval high anion gap met acid w/ high osm gap (mudpilEs)
Rx:
-IV fluids
-FSBS
-Thiamine
-nalaxone if ams
-charcoal - won't bind alcohols, but give if coingest
-pyridoxine 100 mg and thiamine 100 mg IM or IV
-Calcium replacement
-fomepazole 15 mg/kg IV load followed by 20 mg/kg q 12 hr x 4 doses; binds 8000x > ethanol for alc dehydrog, fewer SEs; begin if suspect meth poisoning; anion gap met acid and an osm gap; EG level >20; or pt requires dialysis
-ethanol 0.6 g/kg IV load followed by 0.11 g/kg/h cont infusion, or 0.15 g/kg/h in heavy drinker, adjust infusion to keep etoh level 100 to 150; cont etoh treatment until methanol level is 0 and acidosis is resolved
-oral etoh bev - gram of etoh = cc beverage x .9 x (proof/200)
-dialysis indications - sig toxicity; meth level >20; presence anion-gap met acidosis
-Labs: BUN, Cr, glc, lytes, U/A (crystals)
Dispo
-must admit ethylene glycol and methanol toxicities due to delayed onset of sx, min 12 hrs of

Derm: Toxic Epidermal Necrolysis

-MCC drugs (sulfonamides, anticonvulsants, pcns, nsaids, cephalosporins, allopurinol
-also infxns, immunizations, leukemia/lymphoma, connective tissue d/os
-mainly adults
-tender, red skin and mucosa, then blistering and desquamation
-flu-like prodrome before lesions by 1-14d
-usually starts face/upper body as macules and targets, then rapidly spread
-epidermis becomes necrotic and sloughs off in sheets, leaves behind dermis (cleavage at derm-epi jxn)
-can involve conjuctiva
-nikolsky + (like PV)
-death due to bact infxn and fluid loss
-steroids not recommended, no studies show benefit
-treat like burn




Thursday, July 26, 2007

Tox: Tricyclic Antidepressant Overdose

Tox: Tricyclic Antidepressant Overdose

-most drug related deaths than any other rx
-myocardial sodium channel antagonism
-10mg/kg is life threatening

si/sx
-within 6hr
-hypotn, resp depression, cardiac dysrhythmias, dry mucosae, diminished bowel sounds, urinary retention, ms changes, sz's
-EKG - qrs >100 ms, RAD of the terminal 40ms >120 deg (R in AVR, S in I), indicates life-threatening complication

Labs:
-UDS/SDS (with TCA level), LFT's, CBC, lytes, bun, cr, glc, U/A

rx:
-Vitals, O2, monitor, IV, airway
-Place single-lumen nasogastric tube and lavage with 2 liters of normal saline if recent ingestion.
-Activated charcoal premixed with sorbitol 50 gm via NG tube q4-6h until the TCA level decreases to therapeutic range. Maintain head-of-bed at 30-45 degree angle to prevent charcoal aspiration.
-Magnesium citrate 300 mL via nasogastric tube x 1 dose.
-hypotn - start with fluids NS?/LR, bolus 2L first
-sod bicarb1-2meq/kg IV (50-100mEq=1-2amps) over 5-10min, followed by inf 2-3 amps sod bicarb in 1 L D5W rate 3 cc/kg/h (100-150 cc/hr) for QRS >100ms, hypotn refractory to IV fluids, vent dysrhythmias; must monitor potassium. Adjust rate to maintain pH 7.50-7.55.
-norepi infusion if refractory to fluids, bicarb
-also can use neosynephrine (phenylephrine), dobutamine
-neurochecks q1h, cont suicide obs, ECG monitoring with hourly QRS width measurements, asp and sz precautions
-If mechanical ventilation is necessary, hyperventilate to maintain pH 7.50- 7.55.

Sunday, July 22, 2007

Derm: Pemphigus Vulgaris

-bullous disease of skin and mucous membranes -40-60 year olds
-autoimmune disease with immunoglobulin attacking bridges between epidermal cells
-starts in the mouth, then to the skin after several months
-very flacid bullae, which rupture and leave erosions behind--Nikolski's sign +
-mortality rate of 5% (was higher before steroids)
-Rx: high dose steroids (pred 2-3 mg/kg/day), immunosuppressive therapy (azathiaprine and methotrexate), antibiotics for secondary bacterial infxns
-dispo: consider admission if extensive involvement





About Me

About me

I am an ER physician working in West Virginia. I recently passed my written and oral boards, and I completely stopped studying for a few months. I am glad to finally be done with the vigorous studying for 10 years, but I can feel my brain slowly turning to mush. So, I thought I would start this blog in an effort to keep myself studying. My goal is to make a post on some relevant topic on the average of once per day (I don't have internet access daily, so some days will have more posts than others). I will try to use the more commonly used resources, including River's review, Tintinalli's, Harwood and Nuss, and Rosen's texts, and I will likely throw in a journal article or two. I will also share an interesting case if one should happen to come along.

Enjoy, and good luck on the boards if you are taking them soon. All comments welcome.