QUIZ 19

A 38-year-old male who has committed suicide in the past is behaving oddly. You note that he has tremors and is agitated. He has the following electrolytes.

Na 144  K 3.9   Cl 117     HCO3 24     BUN 32     Cr 1.2    Glucose 98

Q1. Which of the following is a likely explanation for his behavior:

  1. PCP
  2. Amphetamines
  3. Methanol
  4. Isopropyl alcohol
  5. Lithium

The answer is choice 5. If you look carefully, this patient's anion gap is only 3. It is low. 2 things that you have to keep in mind for low anion gaps are Lithium and myeloma. The cations (positive ions) increase, and to maintain neutrality, sodium and potassium are suppressed. Lithium also causes Nephrogenic Diabetes insipidus therefore you see a raised sodium in this case and the BUN & creatinin are also depicting dehydration.

Q2. Which of the following situations is compatible with the condition?

  1. Urinary findings : Osmolality 1.005
  2. Urinary finding : Osmolality 1.035
  3. Urinary oxalate crystals
  4. UTI
  5. None of the above

The answer is choice 1. The urine is dilute in Diabetes insipidus and that is what is shown here as Specific gravity that is low. High osmolality is found in dehydration and osmotic diuresis. Oxalate crystals are seen with ethylene glycol ingestion.