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/18
Gap = 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
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)
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.
