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symptom.hyponatremia-workup.v1PRODUCTION
symptom.hyponatremia-workup.v1

Hyponatremia symptom-triage (ED workup + cross-engine to syndrome)

symptomacutesubacuteundifferentiatedadultgeriatric
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12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Sodium severity (severe ≤120 / moderate 121-129 / mild 130-134); acuity (acute <48 h vs chronic >48 h or unknown); chronicity drives correction rate (acute → tolerant; chronic → SLOW max 8-10 mEq/24h to prevent ODS) (Verbalis PMID 24484567; Sterns PMID 30207998)

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severity + acuity stratified

Patient inputs (29)

Age shifts priors: elderly → thiazide / SIADH / hypovolemic from GI losses + medication; young adult → MDMA / psychogenic polydipsia / exercise / adrenal; pediatric → CSW post-meningitis (Verbalis PMID 24484567)

Premenopausal female + post-op hyponatremia → high ODS / cerebral edema risk (lower osmotic threshold); pregnancy → physiologic dilutional

Thiazide (HCTZ, chlorthalidone), SSRI (especially elderly), carbamazepine, oxcarbazepine, MDMA, chemotherapy (cyclophosphamide, vincristine), desmopressin, NSAIDs → drug-induced; discontinue or substitute

CHF / cirrhosis / nephrotic syndrome → hypervolemic hyponatremia; fluid restrict + diuretic; route cardio.acute-hf.core.v1 / gi.cirrhosis.core.v1; AVOID over-correction

Hypothyroidism (myxedema) + adrenal insufficiency (Addison) → endocrine hyponatremia; cortisol + TSH + ACTH stim; STAT hydrocortisone if adrenal crisis suspected (Spasovski PMID 25411137)

Hypotension + hyponatremia → adrenal crisis OR severe hypovolemia OR sepsis; STAT IVF + hydrocortisone empiric if adrenal suspected

Tachycardia → volume depletion / sepsis; bradycardia → hypothyroid

Bradypnea (RR <8) → severe hyponatremia with cerebral edema / brainstem compromise → STAT 3% saline + airway

Severe sx (seizure, coma, AMS, vomiting, RR <8) → STAT 3% saline regardless of acuity; moderate sx (headache, nausea, confusion) → cautious 3% saline if severe Na; asymptomatic → cause workup

Hypovolemic (orthostatic, dry mucosa, decreased turgor, JVD flat, hemoconcentration) → IVF NS; euvolemic (no edema, no orthostatic) → SIADH workup; hypervolemic (edema, JVD, ascites) → fluid restrict + diuretic

Severity by Na: severe ≤120, moderate 121-129, mild 130-134 — drives 3% saline indication + monitoring intensity (Verbalis PMID 24484567)

Acute (<48 h) → tolerant to faster correction (cerebral edema risk dominates); chronic (>48 h or unknown) → SLOW correction (max 8-10 mEq/24h) to prevent ODS / central pontine myelinolysis (Sterns NEJM PMID 30207998)

Na (confirm), K (hyperK + Na low → adrenal), Cl, HCO3 (anion gap), BUN/Cr (volume status, AKI), glucose (pseudohypona correction), Ca, Mg, PO4

Serum osm <275 → true hypotonic hyponatremia; isotonic (280-295) → pseudohyponatremia (hyperlipidemia, paraproteinemia); hypertonic (>295) → hyperglycemia, mannitol, glycine (TURP) — different management

Urine osm <100 → primary polydipsia / beer potomania / reset osmostat (max dilution); urine osm >100 → SIADH / hypovolemic / hypervolemic / endocrine (Verbalis 2014 PMID 24484567)

Urine Na <20 → hypovolemic (extrarenal losses), hypervolemic (CHF/cirrhosis); urine Na >40 → SIADH, CSW, adrenal, thiazide, renal salt-wasting

TSH + free T4 → hypothyroid; AM cortisol + ACTH stim → adrenal insufficiency; both endocrine causes correctable with replacement

Glucose >200 → corrected Na (add 2.4 mEq/L per 100 mg/dL above 100); pseudohyponatremia must be corrected before treatment

Uric acid <4 in SIADH (low due to dilution); uric acid normal/high in CSW + hypovolemic — helpful adjunct to distinguish CSW from SIADH

Severe hyperlipidemia / paraproteinemia → pseudohyponatremia on standard ion-selective electrode (less common with direct ISE)

CXR / CT chest — pneumonia, TB, small-cell lung cancer (SIADH cause); empyema; abscess

CT head / MRI — SAH, TBI, stroke, abscess, mass (SIADH or CSW cause); CT before LP for meningitis if AMS

Small-cell lung cancer + head/neck cancer + lymphoma + bladder + GI malignancy → SIADH ectopic ADH production; CT chest / imaging workup

SAH / TBI / stroke / meningitis / abscess → SIADH OR CSW (distinguish — volume status critical); CSW → volume replacement; SIADH → fluid restrict (Sterns CSW PMID 27797307)

Pneumonia / TB / abscess / COPD with hypoxia → SIADH; resolve with pulmonary tx

Psychiatric (schizophrenia, bipolar) + excessive water intake → psychogenic polydipsia; urine osm <100 (max dilution); restriction

Endurance event / MDMA + excessive water intake → exercise-associated / MDMA-related; 3% saline if symptomatic + ICU; high cerebral edema risk

Hypothermia → hypothyroid / adrenal; fever → infection / SIADH from CNS / pulm infection

Albumin (cirrhosis, malnutrition), LFT (cirrhosis); albumin <30 → suspect malnutrition / cirrhosis / nephrotic

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (8)

8 need judgement
  • informationallife_threateningacute_severe_symptomatic_hyponatremia_seizure_or_coma
    Na <120 + seizure / coma / RR <8 / cerebral herniation features — STAT 3% saline 100 mL IV bolus × 3 q10 min until sx improvement; AVOID overcorrection >8-10 mEq/24h to prevent ODS (Verbalis 2014 PMID 24484567)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningover_correction_with_ods_risk
    Na rise >8-10 mEq in 24h OR >18 mEq in 48h — high ODS / central pontine myelinolysis risk; STOP hypertonic + initiate D5W 3 mL/kg/h + desmopressin 1-2 µg IV q6-8h (Sterns NEJM PMID 30207998)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningadrenal_crisis_hyponatremia
    Hyponatremia + hyperkalemia + hypotension + steroid history OR hyperpigmentation / Addison features — adrenal crisis; STAT hydrocortisone 100 mg IV bolus + fluids → route endo.adrenal-crisis.core.v1
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverecerebral_salt_wasting_post_sah_tbi
    Post-SAH/TBI + hyponatremia + hypovolemic (orthostatic, hemoconcentration) + urine Na >40 + uric acid normal/high — CSW (distinct from SIADH; needs VOLUME REPLACEMENT not restriction); NS / 3% saline + fludrocortisone 0.1-0.4 mg PO daily → route neuro.sah.core.v1 (Sterns CSW PMID 27797307)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverethiazide_or_mdma_or_exercise_associated_hyponatremia
    Hyponatremia + recent thiazide (HCTZ, chlorthalidone) OR MDMA OR endurance event with excessive water intake — drug/exercise-associated; discontinue thiazide; 3% saline if symptomatic; restrict + ICU if severe
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderatehypovolemic_hyponatremia
    Na <135 + orthostatic / dry mucosa / decreased turgor / urine Na <20 (extrarenal) or >40 (renal/diuretic) — hypovolemic; NS 1-2 L bolus + cause workup + recheck Na q4h to avoid overcorrection
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderatehypervolemic_hyponatremia_chf_cirrhosis
    Na <135 + edema + JVD + ascites + CHF / cirrhosis / nephrotic — hypervolemic; fluid restrict 800-1000 mL/d + diuretic ± tolvaptan (AVOID cirrhosis — FDA boxed warning) → route cardio.acute-hf.core.v1 / gi.cirrhosis.core.v1
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderateeuvolemic_siadh
    Na <135 + euvolemic + urine osm >100 + urine Na >40 + low uric acid — SIADH; identify cause (CNS, pulm, malig, drug, postop); fluid restrict 800-1000 mL/d ± urea ± tolvaptan ± salt + furosemide (Spasovski PMID 25411137)
    Trigger could not be auto-evaluated — needs clinician judgement.

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Recommended regimen

outpatient playbook — drug actions (3)

  1. 1. deprescribe offending medication
    N/A • medication management • one-time
    trigger: Drug-induced hyponatremia identified
    First-line outpatient intervention; substitute non-offending agent
  2. 2. fluid restriction (mild SIADH / chronic)
    1-1.5 L/d total free water intake • behavioral • daily
    trigger: Chronic mild SIADH with identified cause
    Verbalis 2014 PMID 24484567 — fluid restriction first-line outpatient
  3. 3. salt + furosemide OR urea (refractory mild)
    Salt 1-2 g PO TID + furosemide 20 mg PO daily OR urea 15 g PO daily • PO • daily-TID
    trigger: Refractory chronic SIADH outpatient
    Outpatient management of refractory SIADH after specialist evaluation

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: Na <120 + seizure / coma / severe AMS — acute severe symptomatic hyponatremia; STAT 3% saline 100 mL IV bolus × 3 q10 min until sx improvement; AVOID overcorrection >8-10 mEq/24h to prevent ODS (Verbalis 2014 PMID 24484567); Chronic Na 125-134 + asymptomatic — outpatient workup; cause stratification (medication, hypothyroid, adrenal, SIADH, hypervolemic, hypovolemic, reset osmostat); slow correction to prevent ODS; Na <135 + orthostatic / dry mucosa / decreased turgor / GI losses (V/D, diuretic, hemorrhage) / renal losses (CSW) — hypovolemic hyponatremia; IVF NS 1-2 L bolus → replace volume; recheck Na + correction trajectory.

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Hyponatremia symptom-triage (ED workup + cross-engine to syndrome)** (symptom.hyponatremia-workup.v1).
Phenotype framing: Hypovolemic: GI losses (V/D), renal (diuretic, mineralocorticoid def, salt-wasting), sweat. Euvolemic: SIADH (CNS, pulm, malig, drug, postop), hypothyroid, adrenal, reset osmostat, primary polydipsia, beer potomania. Hypervolemic: CHF, cirrhosis, nephrotic, advanced CKD. Pseudo: hyperglycemia, hyperlipidemia, paraproteinemia. Special: CSW (post-SAH/TBI), exercise-associated, MDMA, thiazide.
Scope: Sodium severity (severe ≤120 / moderate 121-129 / mild 130-134); acuity (acute <48 h vs chronic >48 h or unknown); chronicity drives correction rate (acute → tolerant; chronic → SLOW max 8-10 mEq/24h to prevent ODS) (Verbalis PMID 24484567; Sterns PMID 30207998)

No severity triggers fired against current inputs.

Plan

No regimen axis selected (engine has no regimen_axes or could not match).

Setting playbook (outpatient) — Chronic mild asymptomatic hyponatremia (Na >130) workup + maintenance; cause stratification + deprescribing offending meds + fluid restriction education + recurrence prevention
1. deprescribe offending medication N/A medication management one-time — Drug-induced hyponatremia identified (First-line outpatient intervention; substitute non-offending agent)
2. fluid restriction (mild SIADH / chronic) 1-1.5 L/d total free water intake behavioral daily — Chronic mild SIADH with identified cause (Verbalis 2014 PMID 24484567 — fluid restriction first-line outpatient)
3. salt + furosemide OR urea (refractory mild) Salt 1-2 g PO TID + furosemide 20 mg PO daily OR urea 15 g PO daily PO daily-TID — Refractory chronic SIADH outpatient (Outpatient management of refractory SIADH after specialist evaluation)

Non-pharmacologic actions:
- Endocrinology / nephrology referral
- Oncology workup if SIADH-paraneoplastic
- Cardiology / hepatology if hypervolemic
- Psychiatric if polydipsia
- Recurrence prevention education

Monitoring

Setting (outpatient) monitoring:
- BMP q1-2 weeks until stable then q1-3 months
- TSH / cortisol per specialist
- Symptom diary

Follow-up plan: Outpatient endocrinology if SIADH / hypothyroid / adrenal; nephrology if CKD / CSW / refractory; oncology if SIADH-paraneoplastic; cardiology / hepatology if hypervolemic; psychiatric if polydipsia; deprescribing thiazide / SSRI / carbamazepine if drug-induced; fluid restrict education; sodium intake counseling; recurrence prevention
- Close-out criterion: long-term plan in place + follow-up scheduled

Monitoring phase: Na q2-4h during 3% saline (target rise 4-6 mEq/L in 6 h then plateau); BMP q4-6h until stable; correction trajectory (max 8-10 mEq/24h; reverse with D5W + DDAVP if exceeded); seizure recurrence; neuro exam q1h while severe; volume status reassessment q2-4h; ICU-level if severe sx

Disposition

Current setting: outpatient — Chronic mild asymptomatic hyponatremia (Na >130) workup + maintenance; cause stratification + deprescribing offending meds + fluid restriction education + recurrence prevention

Disposition criteria:
- Continue outpatient if stable + cause identified + responsive
- ED if symptomatic or Na drop

Escalation triggers (move to higher acuity):
- Sx development → ED
- Refractory Na <130 → specialist
- Suspected malignancy → STAT imaging + oncology

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Na <120 + seizure / coma / RR <8 / cerebral herniation features — STAT 3% saline 100 mL IV bolus × 3 q10 min until sx improvement; AVOID overcorrection >8-10 mEq/24h to prevent ODS (Verbalis 2014 PMID 24484567)
- [LIFE_THREATENING] Na rise >8-10 mEq in 24h OR >18 mEq in 48h — high ODS / central pontine myelinolysis risk; STOP hypertonic + initiate D5W 3 mL/kg/h + desmopressin 1-2 µg IV q6-8h (Sterns NEJM PMID 30207998)
- [LIFE_THREATENING] Hyponatremia + hyperkalemia + hypotension + steroid history OR hyperpigmentation / Addison features — adrenal crisis; STAT hydrocortisone 100 mg IV bolus + fluids → route endo.adrenal-crisis.core.v1

Citations

- 2014 European/US Verbalis hyponatremia + 2014 Spasovski ERA-EDTA + 2015 Sterns NEJM + Hoorn pathophysiology + Sterns CSW + ODS prevention literature [PMID:24569125](https://pubmed.ncbi.nlm.nih.gov/24569125/)
- Cited evidence (PMID 32401559) [PMID:32401559](https://pubmed.ncbi.nlm.nih.gov/32401559/)

Last reconciled with current guidelines: 2026-05-30.
References
  • 2014 European/US Verbalis hyponatremia + 2014 Spasovski ERA-EDTA + 2015 Sterns NEJM + Hoorn pathophysiology + Sterns CSW + ODS prevention literature — PMID:24569125
  • Cited evidence (PMID 32401559) — PMID:32401559