management of diabetic ketoacidosis (DKA) in adults

DKA Basics
-Definition:  Blood glucose >250 (e.g. diabetic), moderate ketonemia, anion gap >10, Bicarbonate <15, and pH <7.3 (acidosis)

-Metabolic acidosis, hyperglycemia, hyperosmolality, potassium depletion, and hypovolemia

-Infection is often a precipitating event

Initial Labwork:

-Serum electrolytes

-Calculate Anion gap
-CBC
-UA
-Plasma osmolality
-ABG
-EKG
-Blood cultures, urinalysis, CXR to determine possible infectious cause

Hyperglycemia and Serum Sodium:

-Corrected Serum Na = Measured Na + 0.024 * (Serum glucose - 100)

-boils down to this: add 1.2 to the sodium for every 50 mg/dL over 100

Management:
Order of priorities is volume first, correction of potassium deficits, and then insulin administration
1.      ABCs
2.      get labwork and investigate source of DKA/HHS (infectious causes)
3.      Fluid resuscitation with isotonic saline (Increases insulin responsiveness by lowering plasma osmolality)
4.      Insulin therapy (after confirmation of potassium greater than 3.3) --bolus of Regular Insulin IV followed by an insulin drip

5.      KCl is generally added to the replacement fluid once the serum K+ falls below 5.3
6.      When the serum glucose reaches 200 in DKA or 250-300 in HHS, saline is switched to dextrose containing solution
NOTE:  Use of supplemental bicarbonate in the DKA is not recommended

Submitted by J. Grover.

Reference(s): Tintinalli’s 7^th edition, uptodate.com, picture

lithium and hypothyroidism

LITHIUM & THE THYROID:
--not always best friends

--multiple mechanisms by which Lithium causes hypothyroidism:

• inhibits thyroid hormone release and increases TRH-stimulated TSH. 
• concentrated by the thyroid gland and inhibits iodine uptake.
• interferes with the deiodination of T4 to T3
• may have an immunostimulant effect, either by inducing or exacerbating a preexisting autoimmune disease.

--Rates of overt hypothyroidism can vary from 0 – 47% (average 10%) in people on long term lithium treatment.  


BOTTOM LINE:
--if you have a patient who is taking lithium, and you're sending off labs (lithium level, sodium/lytes, etc) for some [presumably good] reason, might be worth adding a TSH to the mix


Submitted by J. Gullo.


Reference(s): a review, another source, picture

thyroid storm treatment

Treat symptoms with Beta blocker:

--propranolol: also slows peripheral conversion of T4 to T3

--lesser options: esmolol, metoprolol, calcium channel blockers (diltiazem)

Inhibit thyroid hormone synthesis (works in 1-2 hrs):

--propylthiouracil (PTU): blocks thyroidal peroxidase, also inhibits T4 to T3 conversion

--lesser options: methimazole

Block release of thyroid hormone:

--iodine: give ~1 hour AFTER other stuff, otherwise it’ll form MORE thyroid hormone

Steroids (thyroid storm can precipitate adrenal insufficiency, maybe autoimmune effects if Grave's disease):

--dexamethasone: also blocks T4 to T3 conversion

--other options: hydrocortisone

10-SECOND RECAP:

--thyroid storm is not awesome

--treat symptoms, stop thyroid hormone synthesis, inhibit release, give steroids

--ideally: propranolol, PTU, waaaaaiiit an hour, iodine, dexamethasone

Reference(s): uptodate.com: thyroid storm, Tintinalli p. 1312-3, picture