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