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COMPREHENSIVE NOTES

1. Core Difference: DKA vs HHS
   DKA (Type 1 diabetic, absolute insulin deficiency)

No insulin → body burns fat → ketones formed → metabolic acidosis

Deep, rapid Kussmaul respirations

Total body potassium depleted though serum may appear high

State of starvation + dehydration

HHS (Type 2 diabetic, relative insulin deficiency)

Some insulin remains → prevents ketones → no significant acidosis

Extreme hyperglycemia (often 600–1200+)

Severe dehydration + high serum osmolality

Slow onset, often in older adults

1. Diagnostic Markers
   DKA Diagnostic Triad

Hyperglycemia > 250

Metabolic acidosis

pH < 7.30

Bicarb < 18

Anion gap elevated

Ketones moderate to large (blood or urine)

HHS Diagnostic Markers

Extreme hyperglycemia > 600 (often > 1000)

Serum osmolality > 320

Minimal or no ketones, pH > 7.3

1. DKA Treatment Priorities (FIK Sequence)

This is a major NCLEX priority sequence.

F – Fluids first

Severe dehydration: 4–6 liters lost

Start aggressive normal saline

About 1 liter in the first hour

Goal: restore perfusion and blood pressure quickly

I – Insulin second

Only after fluids have begun

Regular insulin IV bolus → insulin infusion

Critical NCLEX rule: Check potassium FIRST

K – Potassium last

Insulin drives potassium into cells → serum potassium drops fast

If potassium < 3.3 → HOLD insulin and replace potassium immediately

Begin potassium replacement once potassium < 5.2 AND urine output is present

When glucose reaches 200–250

Switch to D5 ½ NS

Purpose: prevent hypoglycemia while continuing insulin to clear ketones and acidosis

1. HHS Treatment Priorities
2. Fluids (most critical)

Fluid loss often 9–12 liters

More aggressive initial resuscitation than DKA

Start 0.9% normal saline, often 1–2 liters in the first hour

1. Slow, careful insulin

Lower dose: ~0.05–0.1 units/kg/hr

Begin only after fluid resuscitation

Target glucose drop: 50–70 per hour

Purpose: prevent cerebral edema, caused by rapid osmotic shifts

1. Prevent thrombosis (HHS-specific)

Hyperosmolar blood → massive thrombosis risk

Early low molecular weight heparin unless contraindicated

Fluid transition

Switch fluids when glucose reaches 250–300

Use 0.45% sodium chloride

1. High-Yield Scenarios
   Scenario 1: DKA with potassium 3.0

Priority:

Start normal saline

Hold insulin

Immediate aggressive potassium replacement

Once potassium rises above 3.3 → start insulin infusion

NCLEX trap: Giving insulin first.

Scenario 2: HHS elderly patient, glucose 1250, osmolality 400

Priority:

Aggressive normal saline

Insert Foley catheter for hourly urine output

Start LMWH for clot prevention

Delay insulin until hydration improves

Then start low-dose insulin infusion slowly

1. Prevention and Patient Education
   Who is high risk for DKA?

Type 1 diabetics

Young adults

Those experiencing diabetes burnout

Patients omitting insulin doses

Any illness that increases metabolic demand

Discharge teaching essentials

Sick-day rules: Never skip insulin

Check blood glucose 4–10 times/day

Check ketones when glucose > 250

1. Evolving Role of Technology

Continuous glucose monitors (e.g., Eversense 365)

Automated insulin delivery systems

Omnipod 5

iLet / Twist system

These systems significantly reduce DKA admissions (40–60%)

Nurses increasingly become educators and system managers rather than crisis responders

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Comprehensive Notes

1. Core Concept

Both conditions revolve around one hormone: ADH, the body’s water-saving signal.

SIADH: Too much ADH → body holds water (soaked inside)

DI: Not enough ADH or kidneys ignore ADH → body loses water (dry inside)

The blood and urine move in opposite directions in each disorder.

1. SIADH — “Soaked Inside, All Diluted”
   What Happens

ADH is high → kidneys save water

Blood becomes diluted

Urine becomes concentrated

Classic Causes

Small cell lung cancer (ectopic ADH)

Head trauma

Pituitary surgery

SSRIs

Carbamazepine, vincristine

Severe pneumonia, meningitis

Severe pain or nausea

Hallmark Labs

Low sodium

Low serum osmo

High urine specific gravity

High urine osmo

Typical Patient Picture

Confusion, headache, lethargy

Weight gain (one kilogram equals one liter held)

High blood pressure

Puffy face or eyes

Not thirsty

Very low urine output, dark concentrated urine

Priority Interventions

Strict fluid restriction

Daily weights

Neuro checks every few hours

Seizure precautions (especially when sodium drops below one twenty)

Critical Medication

Hypertonic saline (three percent) for seizures or very low sodium

Must use a central line

Must correct sodium slowly (no more than eight to twelve points in twenty-four hours)

Major Warning

Correcting sodium too fast risks central pontine myelinolysis, an irreversible brainstem injury.

Never Do

Never give hypotonic fluids

Never give normal saline

Never increase free water

1. Diabetes Insipidus — “Dry Inside, All High”
   What Happens

Little or no ADH signal

Kidneys dump water

Blood becomes concentrated

Urine becomes extremely dilute

Two Types

Central DI

Pituitary does not make ADH

Causes: head trauma, brain tumors, pituitary surgery

Nephrogenic DI

Kidneys ignore ADH

Causes: lithium, some antibiotics, chronic high calcium

Hallmark Labs

High sodium

High serum osmo

Very low urine osmo

Very low specific gravity

Typical Patient Picture

Intense thirst

Clear water-like urine

Ten to twenty liters of urine per day

Rapid weight loss

Tachycardia, low blood pressure

Signs of hypovolemic shock

Priority Interventions

Aggressive fluid replacement (D5W or free water)

Hourly intake and output

Daily weights

Watch closely for shock

Stopping the Water Loss

Central DI: Give desmopressin (DDAVP)

Nephrogenic DI:

Stop lithium or offending drug

Give a thiazide diuretic (paradox: triggers earlier sodium and water reabsorption)

Major Warning

Never fluid restrict DI — causes immediate circulatory collapse.

1. SIADH vs DI: The Instant EN-KLEX Pattern
   Think Like a Nurse Bow-Tie Pattern

Low sodium + high urine osmo → SIADH

Action: fluid restrict

Safety: neuro checks, seizure precautions

High sodium + low urine osmo → DI

Action: free water, D5W, desmopressin

Safety: hourly intake and output, watch for shock

1. Bedside Pearl

If a post-pituitary surgery patient suddenly puts out large amounts of clear urine and their sodium is rising past one forty-five:
→ Stop what you’re doing and call the provider immediately.
This is a DI crisis until proven otherwise.

Need to reach out? Send an email to Brooke at ThinkLikeaNursePodcast@gmail.com