Copyright: ©Author(s) 2026.
World J Clin Cases. Mar 26, 2026; 14(9): 118634
Published online Mar 26, 2026. doi: 10.12998/wjcc.v14.i9.118634
Published online Mar 26, 2026. doi: 10.12998/wjcc.v14.i9.118634
Table 1 Timeline of laboratory findings
| Postoperative day | Laboratory findings |
| POD 1 | Control cranial CT satisfactory (no laboratory values reported) |
| POD 2 | Serum Na 131 mmol/L; K 3.6 mmol/L; creatinine 60 μmol/L; urea 19 mmol/L; glucose 86 mmol/L |
| POD 3 | Serum Na 123 mmol/L |
| POD 5 | Serum Na 126 mmol/L |
| POD 7 | Serum Na 119 mmol/L |
| POD 8 | Serum Na 129 mmol/L; serum osmolality 254 mOsm/kg; glucose 54 mmol/L; total protein 69 g/L; triglycerides 1.3 mmol/L; urea 22 mmol/L; creatinine 58 μmol/L; uric acid 150 μmol/L; urine osmolality 560 mOsm/kg; urine Na 68 mmol/L; urine K 28 mmol/L; urine specific gravity 1.020; morning cortisol 520 nmol/L; TSH 1.6 mIU/L; free T4 14 pmol/L |
| POD 10 (discharge) | Serum Na 132 mmol/L |
| POD 14 | Serum Na 134 mmol/L |
| POD 19 | Serum Na 136 mmol/L |
| 3-month follow-up | Serum Na 136 mmol/L |
Table 2 Summary from literature search
| Ref. | Country | Study design | Indication for CBZ: Dose/regimen | Sodium values after CBZ exposure | CBZ discontinued? | Hyponatremia treatment | Patient outcomes |
| Kuz and Manssourian[3], 2005 | United States | CR (n = 1) | Psychiatric illness (on CBZ chronically): CBZ 400 mg BID (morning/noon) + 600 mg HS; took 1200 mg the night before admission + 200 mg the next morning | Serum Na 122 mEq/L, corrected to 136 mEq/L within 24 hours | Yes (withheld) | 0.9% NaCl IV: 1-L bolus, then another liter at 125 mL/hour | Seizures associated with acute hyponatremia; sodium normalized; discharged with counseling about avoiding large CBZ doses |
| Kaeley et al[4], 2019 | India | CR (n = 1) | Focal seizures with secondary generalization; CBZ 600 mg/day (200 mg TID) | Na 118 mEq/L at presentation; then 122 (day 3), 125 (day 4), 135 (after 7 days) | Yes | Fluid restriction + tolvaptan 30 mg PO daily; switched to levetiracetam 500 mg TID for seizures | Asymptomatic/ambulatory; sodium corrected to 135 mEq/L on follow-up |
| Vieweg et al[5], 1987 | United States | Retro (n = 33) | Psychiatric diagnoses (e.g., organic affective disorder, schizoaffective disorder, major depression with psychosis, bipolar disorder) and seizure disorders (generalized + partial complex seizures). CBZ dose/regimen not reported; ≥ 2 weeks of therapy before labs | Mean serum Na: 138.4 ± 4.3 mEq/L (CBZ alone) vs 141.8 ± 1.6 mEq/L (CBZ + Li). Lowest Na reported: 113 mEq/L (CBZ alone; associated with generalized seizures) vs 132 mEq/L (CBZ + Li) | No | Not an acute treatment study; lithium coadministration was associated with “protection against hyponatremia” (higher Na; fewer episodes) | The CBZ + Li group had a higher mean Na and fewer hyponatremia episodes; severe low Na (113) in the CBZ-alone group was linked to generalized seizures |
| Sordillo et al[6], 1978 | United States | CR (n = 1) | Trigeminal neuralgia; CBZ 600 mg/day; the day before hospitalization, CBZ 1200 mg was used; additional phenytoin 300 mg | 118 mEq/L | No | Addition of phenytoin (suppression of ADH) | Three days after hospitalization, and phenytoin dosage correction value of sodium 139 mEq/L |
| Scoccia and Scommegna[7], 1988 | United States | CR (n = 1) | Seizure disorder (grand mal); CBZ 1200 mg (300 mg QID); clonazepam 0.5 mg | Serum Na 123 mEq/L on ER admission (serum osmolality 246 mOsm/kg H2O) | NR | IV saline + furosemide overnight; discussion describes hypertonic IV saline until mildly hyponatremic + furosemide to prevent volume expansion | Nausea/vomiting then grand mal seizure; electrolytes/osmolality corrected within 36 hours |
| Krysiak and Okopień[8], 2007 | Poland | CR (n = 1) | Facial neuralgia; CBZ 1200 mg/day (600 BID) | Na 126 mmol/L after starting CBZ (initial mild hyponatremia); Na 112 mmol/L on admission; 3% saline stopped when Na reached 125 mmol/L; Na normal by hospital day 5 | Yes (discontinued on admission) | Fluid restriction + 3% hypertonic saline infusion | Presented with cerebral edema symptoms (incl. seizures); stabilized with correction; 12 months later, the patient remained stable without recurrent hyponatremia |
| Palacios Argueta et al[9], 2018 | Guatemala | CR (n = 1) | Pain complaint (left knee pain; reason CBZ prescribed “unknown”, likely chronic pain); CBZ initially 300 mg (daily) then self-increased to 600 mg approximately 7 days prior (also prednisone) | Na 119 mmol/L (initial); Na 128 mmol/L at discharge (day 3); Na 138 mmol/L at 1-week follow-up | Yes | Fluid restriction (1.5 L/day) + correction of hypokalemia with IV potassium | Fatigue/cramps resolved by follow-up; sodium/osmolality normalized; no neurologic deficits reported |
| Fadili et al[10], 2019 | Morocco | CR (n = 1) | Schizoaffective disorder; started risperidone + CBZ with progressive dose increases; at 1 week: Risperidone 8 mg + CBZ 1200 mg | Na 128 mmol/L at 1 week; Na 119 mmol/L at day 10; after treatment Na corrected to 134 mmol/L | Yes (stopped both drugs) | Fluid restriction; ICU transfer for severe hyponatremia; 3% NaCl hypertonic saline with lab monitoring | Symptoms included fatigue/somnolence; sodium corrected; then switched to clozapine with stable sodium (on clozapine 400 mg at 8 months follow-up) |
| Kamiyama et al[11], 1993 | Japan | CR (n = 1) | Low back pain; CBZ 400 mg (200 mg BID), after rechallenge 600 mg | Serum Na 120 mmol/L persistent; rechallenge to 117 mmol/L (day 2) | Yes | Mild water restriction (initially); diagnostic/treatment infusion of hypertonic saline (10% NaCl) described during evaluation | Sodium normalized after stopping CBZ; rechallenge reproduced acute symptomatic hyponatremia; authors diagnosed partial central diabetes insipidus (based on water restriction/desmopressin response) |
| Tanaka et al[12], 2008 | Japan | CR (n = 1) | Temporal lobe epilepsy; CBZ started 400 mg/day, then increased to 800 mg/day (treated approximately 6 years). Concurrent meds included warfarin + bucolome; hyponatremia developed after starting interferon-α2b + ribavirin | Blood Na 124 mEq/L (week after admission) | No (CBZ continued; adjunctive strategies used) | Water intake restriction (20 mL/kg) + dimethylchlortetracycline 900 mg/day; later lithium 400 mg/day (maintained approximately 1 year) | Hyponatremia improved; after interferon-α2b stopped, hyponatremia completely recovered by 6 months; later, Na 137 mEq/L reported |
| McCauley and Thiraviaraj[13], 2017 | United Kingdom | CR (n = 1) | Epilepsy (also myasthenia gravis; seizure-free for years); carbamazepine Tegretol-PR 400 mg BID (also on omeprazole + fluoxetine initially) | Sodium persistently 122-128 mmol/L despite treatment (per report summaries) | No (strong reluctance/“unable to forego” carbamazepine) | Stopped omeprazole + fluoxetine; fluid restriction; demeclocycline 300 mg BID (ineffective + worsened myasthenia); tolvaptan 15 mg twice weekly (marginal effect; thirst/nausea) | Clinically euvolemic and asymptomatic throughout; chronic refractory hyponatremia considered a “reset osmostat” baseline; elective thymectomy deferred, but authors argue surgery could proceed with closer peri-op surveillance |
| Ponte et al[14], 1990 | United States | CR (n = 1) | Postherpetic neuralgia; CBZ 600 mg/day (300 mg BID) | Na 133 mmol/L at discharge after starting CBZ; later Na 120 mmol/L on readmission; after approximately 4 days fluid restriction Na rose to 131 mmol/L (also 131 at discharge) | Yes | Fluid restriction; concomitant HCTZ/triamterene was discontinued | Symptoms (nausea/vomiting, ataxia/disequilibrium, syncope) improved after stopping CBZ; after fluid restriction, sodium/electrolytes normalized; discharged ambulatory with minimal residual ataxia; electrolytes normal at follow-up |
| Joseph et al[15], 2023 | United States | CR (n = 1) | Bipolar affective disorder; CBZ 600 mg (300 mg BID) (+ lorazepam 2 mg daily) | Serum Na 104 mmol/L on admission; 136 mmol/L by discharge | Yes | 3% saline for 24 hours (rate approximately 0.5 mEq/L/hour) + supportive therapy; later ICU care with ventilatory/supportive management | Improved and discharged day 5 after initial correction; returned approximately 2 weeks later with neurologic deficits and imaging consistent with osmotic demyelination; became conscious day 7 but rigidity/hyperreflexia persisted; discharged to ongoing rehab with follow-up |
| Inamura et al[16], 1999 | Japan | CS (n = 2) | Case 1 epilepsy; CBZ 600 mg/day → 1000 mg/day (with phenobarbital + phenytoin). Case 2 Facial pain after meningioma surgery; CBZ 400 mg/day (with valproate) | Case 1 Na 128 mmol/L. Case 2 Na 116 mmol/L | Yes (rapid improvement after withdrawal) | Case 1 CBZ withdrawal. Case 2 CBZ withdrawal + water restriction | Case 1 symptoms resolved promptly; Na corrected within approximately 3 days. Case 2 symptoms improved; Na corrected to approximately 138 mmol/L within approximately 3 days |
| Ballardie and Mucklow[17], 1984 | United Kingdom | CR (n = 1) | Epilepsy; CBZ 1100 mg/day; evaluated before/after demeclocycline | Hyponatremia episodes mentioned; sodium value 121 mmol/L | No (“partial reversal” strategy) | Demeclocycline added (1200 mg QID) | Water handling/osmolality improved, but not normalized |
| Brewerton and Jackson[18], 1994 | United States | CS (n = 6) | Psychiatric inpatients; CBZ rechallenge after normalization | Hyponatremia occurred on CBZ | Initially, yes (Na normalized after CBZ discontinuation), then CBZ rechallenged | Demeclocycline is used to prevent recurrent Na decline in 5/6 | Prevention was successful in 5/6 on rechallenge |
| Pham et al[19], 2021 | United States | CR (n = 1) | Bipolar illness/vascular dementia; recurrent CBZ-associated SIADH; CBZ dose N/A | Hyponatremia on two CBZ trials (numeric Na N/A) | No (strategy aimed to allow continued CBZ) | Low-dose lithium to correct/maintain Na | Prompt normalization was maintained for approximately 8 weeks |
| Morimoto et al[21], 2020 | Japan | CS (n = 3) | Localization-related epilepsy. Case 1 (A): Carbamazepine 300 mg/day; replaced with lacosamide 400 mg/day. Case 2 (B): Carbamazepine 400 mg/day; replaced with lacosamide 200 mg/day. Case 3 (C): Carbamazepine 800 mg/day; replaced with lacosamide 400 mg/day | Mean Na (mEq/L): On carbamazepine/after replacement - A: 132.0 ± 2.82/137.0 ± 2.83; B: 131.5 ± 0.70/138.5 ± 0.70; C: 133.0 ± 1.41/136.0 ± 1.41 | Yes | Gradual switch over approximately 3 months (taper carbamazepine while titrating lacosamide) | Serum sodium improved significantly in all 3; seizure frequency did not change substantially |
| Prakash et al[22], 2016 | India | CR (n = 1) | Epilepsy; “taking carbamazepine regularly” for 34 years (dose/regimen not reported), planned for post-burn debridement and skin grafting | Na 128 mEq/L, repeat 129 mEq/L; normalized pre-op to 142 mEq/L | No (continued; not stopped peri-op) | Increased oral salt intake + fluid restriction | Uneventful anesthesia and recovery after Na normalized; advised to consult a physician about drug-induced hyponatremia |
Table 3 Differential diagnosis of postoperative hyponatremia
| Feature | SIADH | CSWS | Findings in this case |
| Volume status | Euvolemia or mild hypervolemia | Hypovolemia (effective volume depletion) | Clinically euvolemic; stable hemodynamics; no orthostasis |
| Urine output | Normal to low (variable) | Often increased (polyuria) | No polyuria documented; no negative fluid balance reported |
| Serum osmolality | Low | Low | Low (254 mOsm/kg) |
| Urine osmolality | Inappropriately high (> 100 mOsm/kg) | Often high | High (560 mOsm/kg) |
| Urine sodium | > 30-40 mmol/L | > 40 mmol/L | High (68 mmol/L) |
| Response to isotonic saline | Often minimal or may worsen | Improves sodium/volume | Sodium continued to decline despite 0.9% NaCl |
| Uric acid/FEurate | Often low uric acid; FEurate elevated (may normalize after correction) | Often low uric acid; FEurate elevated and may persist | Low uric acid (150 μmol/L) |
| Key therapeutic approach | Fluid restriction, treat trigger; hypertonic saline if severe symptoms | Volume and salt repletion, optional fludrocortisone, hypertonic saline if severe symptoms | Trigger removed (CBZ stopped) and hypertonic saline; sodium normalized |
- Citation: Begagić E, Bečulić H, Mašović A, Alić F, Huremović M, Vranić S. Carbamazepine-induced hyponatremia following meningioma surgery: A case report. World J Clin Cases 2026; 14(9): 118634
- URL: https://www.wjgnet.com/2307-8960/full/v14/i9/118634.htm
- DOI: https://dx.doi.org/10.12998/wjcc.v14.i9.118634