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Amazing, Amusing & Awesome Acidosis Anecdotes. . . And Gnarly Mnemonics
Kent R. Olson, MDMedical Director
California Poison Control System
Clinical Professor of Medicine
UC San Francisco
Case 1: An Acidic Alcoholic
A 44 yo man was found unconscious, with a suicide note and a half-empty bottle of Jim Beam.
BP 110/80 HR 110 RR 24 pH 7.47 pCO2 22 pO2 88 Na 140 K 3.8 Cl 106 HCO3 18 ETOH 0.18 gm/dL
Causes of Metabolic Acidosis:
“MUDPILES” Methanol Uremia DKA Phenformin, Paraldehyde INH, Iron Lactic acid Ethylene glycol Salicylate
Salicylate Intoxication:
Typical mixed acid-base abnormality:– Respiratory alkalosis– Metabolic acidosis
May be acute or chronic Large OD may cause delayed peak Treatment:
– Alkalinize urine, restore serum pH– Hemodialysis
Case 2: A Gapped Gipper
30 yo M found comatose Temp 86F, pH 6.9 Na 147, K 4.9, Cl 105, Bicarb 5
– Anion gap 37 Glu 166, BUN 16, Cr 1.5 Measured Osm 331
– Osm gap 23 Ethanol “zero”
The Osmolar Gap:
Osm = 2 (Na) + BUN/2.8 + Glucose/18Gap = Measured - Calculated Osm = 0 + 5
Causes of Osm Gap:– Ethanol– Isopropyl alcohol & Acetone– Methanol & Ethylene glycol– Other alcohols & glycols
Erroneous results:– Wrong tube; Different specimen times– Falsely normal gap with vaporization
method
Methanol poisoning
METHANOLMETHANOL
FORMALDEHYDEFORMALDEHYDE
FORMIC ACIDFORMIC ACIDANION GAPACIDOSIS
ANION GAPACIDOSIS
ELEVATEDOSMOLAR GAP
ELEVATEDOSMOLAR GAP
Ethylene Glycol & Methanol:
Osmolar gap Anion gap
– Lactate low, does not account for gap– Early in the intoxication, anion gap may
be absent Additional clues: (may be unreliable)
– EG: urine crystals, fluorescence– Methanol: visual disturbance
Ethylene Glycol & Methanol:
Main DDx: Alcoholic Ketoacidosis– Anion and Osmolar gaps– Low lactate– AKA clues:
• GETS BETTER over a few hrs with fluids and dextrose
• Ketone levels +/- (beta-hydroxybutyrate)
Case 3: Not on the List
A 15 year old young woman was found comatose (GCS 7)
BP 92/34 mm Hg HR 120/min RR 24/min pulse ox 94% (room air) pH 7.16 pCO2 27 pO2 127 Anion gap 20
– Salicylate negative– Methanol, EG negative
Case 3, cont.
She became more obtunded and was intubated
Treated with IV fluids Received bicarbonate 50 mEq x 1 Recovered, extubated in 12 hours
Admitted to ingesting 500 ibuprofen tablets (200 mg size)
Seifert SA et al: J Tox Clin Tox 2000; 38:55-7
Ibuprofen
Common NSAID Propionic acid derivative
– Contributes to acidosis– (Naproxen is also a PA derivative)
Moderate OD: GI upset Severe OD:
– Coma, seizures– Hypotension, renal failure– ARDS
Case 4: A Surprising Finding
28 yo F found comatose in a hotel room, 2 empty bottles of Extra Strength Tylenol (total about 150 gm)
BP 120/50, HR 130, pupils midrange pH 7.03, HCO3 4, anion gap 25 ASA negative, APAP 850 mg/L AST 70 Lactate >11 mmol/L
Acetaminophen
Case (continued): – ETOH, Methanol, Ethylene Glycol tests
all negative– Patient later developed liver, renal
failure
Acetaminophen
Massive ingestion:– Rare cause of early onset metabolic
acidosis– Mechanism unknown, probably acute
metabolic dysfunction in liver cells– Can also cause coma, hypotension
Different mechanism than hepatic injury
Cases 5-6: Metabolic Madness
Ataxic 2 yo child– Na 152– HCO3 12, pH 7.24– Ammonia 80
Obtunded 25 yo F– BP 60s systolic– pH 7.16, pCO2 37, pO2 66– Hypoglycemia (glucose = 50s)– Calcium 6.6
Valproic acid (Depakote)
Common anticonvulsant Increasing use in psychiatry Metabolic dysfunction
– Hypoglycemia– Hypocalcemia– Elevated ammonia– Encephalopathy
Coma and rarely cerebral edema Consider hemodialysis if VPA>1000
Cases 7-8: Caustic Cocktails
A sulfuric anion gap: 33 yo M ingested "Hot Shot Drain
Cleaner" containing 9% sulfuric acid BP 110-120/palp, drooling, in pain ET intubated shortly after arrival Initial Na 143, K 8.1, Cl 97, HCO3 <5,
– Anion gap >40 Lactate 2.1
Caustic Cocktails, continued...
Not an anion gap: 43 yo F ingested Lysol Toilet Bowl
Cleaner (HCl 8.5-9.5%, pH <1) Pain! Serum CPK 26,812 pH 7.19, CO2 24 Na 144 Cl 121 HCO3 18.6
– Anion gap = 4.4
A Final Stumper:
A 5 year old Laotian immigrant girl was brought to the ED at 3 AM very lethargic
History of nausea and vomiting starting at 1 AM
BP 89/42 HR 103 R 16 T 97 Pupils 4 mm, skin normal Mouth dry, active peristalsis
Case 9 Continued...
According to the father, at 6 pm the previous evening the family had eaten a meal of steamed wild root
They collected it near the Berkeley Marina and considered it a tasty substitute for bamboo shoots
At 1 AM all 5 family members experienced nausea and vomiting; the 5 yo also had diarrhea
Case 9, Continued...
Shortly after admission, the child's pupils were noted to be dilated and poorly reactive
Respirations were shallow, and the HR was 65/min
pH 6.8 pCO2 21 pO2 220 Shortly after, the child had a tonic-
clonic seizure
Case 9, Continued...
Further Hx: The family said a brother was taking
some type of “chest medicine” A family member was sent home to
retrieve the bottle….
Common causes of seizures
Cocaine/amphetamines Tricyclic antidepressants Bupropion Diphenhydramine Tramadaol Isoniazid (INH) Phenothiazines & antipsychotics
Case, continued
The bottle contained erythromycin
A blood cyanide level was 6 mg/L
The wild root was identified as pampas grass; although usually non-toxic, at certain times of the year it elaborates cyanogenic (cyanide-producing) glycosides.
“MUDPILES” revised?
Methanol or metformin Acetaminophen or AKA (“maudespil?”) Uremia DKA or Depakote Phenformin or paracetamol INH, Iron or ibuprofen Lactic acid Ethylene glycol Salicylate or syanide?
A Shorter Mnemonic:
SALAD: Lab Test:– Salicylate ASA
– Alcohols Osm
– Lactic acid Lactate
– Anuria BUN/Cr
– DKA Glucose
California Poison Control System
Public Hotline: 1-800-876-4766
Medical Consult: 1-800-411-8080
Nationwide: 1-800-222-1222