Cyclophosphamide-induced severe acute hyponatremic encephalopathy in patients with breast cancer: report of two cases

Severe hyponatremia and diabetes insipidus caused by low-dose cyclophosphamide in breast cancer patients: A case report and literature review

RATIONALE

Cyclophosphamide (CTX) is widely used in the treatment of malignancies and autoimmune diseases. Although severe hyponatremia caused by low-dose CTX chemotherapy is uncommon, it can lead to serious complications and even death.

PATIENT CONCERNS

A 44-year-old woman with left-sided breast cancer suddenly experienced headaches, disorientation and weakness after receiving low-dose neoadjuvant chemotherapy combined with CTX and doxorubicin.

DIAGNOSES

The patient pathology showed invasive breast carcinoma. She developed severe hyponatremia and a generalized seizure after completing the first cycle of neoadjuvant chemotherapy with CTX and doxorubicin. Laboratory tests showed a serum sodium of 118 mmol/L (normal range 135-145 mmol/L) and potassium sodium 3.16 mmol/L (normal range 3.5-5.5 mmol/L). Subsequently, the patient developed secondary diabetes insipidus 4 hours after sodium supplementation, her 24-hour urine volume was 4730 mL (normal range 1000-2000 mL/24 hours), and the urine specific gravity decreased to 1.005.

INTERVENTIONS

The patient was given intravenous sodium chloride (500 mL of 3%NaCl, 100 mL/hour) and potassium chloride (500 mL of 0.3%KCl, 250 mL/hour). Meanwhile, she was advised to reduce her water intake, and pituitrin was administered to prevent dehydration caused by diabetes insipidus.

OUTCOMES

The patient completely recovered after correcting of the serum sodium concentration (137 mmol/L) without any neurological deficits. After discontinuing pituitrin, her 24-hour urine volume was 2060 mL and the urine specific gravity was 1.015.

LESSONS

This is a typical case of severe hyponatremia induced by low-dose CTX. Clinicians and healthcare providers should be aware of this potential toxicity, and appropriate monitoring should be implemented.

Cyclophosphamide-induced seizures in a patient with neuropsychiatric systemic lupus erythematosus (NPSLE): A case report

Seizures are life-threatening complications of neuropsychiatric systemic lupus erythematosus (NPSLE) and are often associated with poor outcomes. Cyclophosphamide immunotherapy is the mainstay of NPSLE treatment. We report the unique case of a patient with NPSLE who developed seizures soon after her first and second doses of low-dose cyclophosphamide. The exact pathophysiological mechanism underlying cyclophosphamide-induced seizures is not well understood. However, this unusual drug-associated side effect of cyclophosphamide is thought to be due to the drug’s unique pharmacology. Clinicians should be aware of this complication to make a correct diagnosis and adjust the immunosuppressive regimens very carefully.

Effects of Adriamycin-Cytoxan chemotherapy on hematological and electrolyte parameters among breast cancer patients

Background

Adriamycin-Cytoxan (AC) is a common chemotherapy treatment for breast cancer (BC) patients. Its electrolyte and hematological adverse effects have not been addressed adequately.

Objective

This study aimed to assess the effect of AC on hematological and electrolyte parameters among BC patients.

Methods

A hospital-based comparative cross-sectional study design was conducted from March to November 2022. Randomly selected AC-treated (n=100) and untreated (n=100) patients were included. Structured questionnaire and medical records were used to collect sociodemographic data. Anthropometric parameters, hematological indices, and serum electrolytes were measured. Cobas Integra 400⁺and SYSMEX-XT-4000i were used to analyze serum electrolytes and hematological indices respectively. The data were analyzed using SPSS version 25. Independent t-test and chi-square test were used. p-value <0.05 was considered statistically significant.

Results

AC-treated patients' mean total white blood cell (TWBC), neutrophil (NE), lymphocyte (LY), red blood cell (RBC), hemoglobin (Hgb), hematocrit (HCT), and sodium(Na⁺) values were significantly reduced (p<0.05) than patients with no treatment. However, mean eosinophils (EO), platelet (PLT) counts, red cell distribution-width (RDW), potassium (K⁺), and plateletcrit (PCT values were significantly increased (p<0.05).

Conclusion

The majority of blood cells and serum sodium were affected by AC treatment. Incorporating these parameters in the routine analysis and further studies on the detailed mechanism of action of this drug is required.

Symptomatic hyponatremia induced by low-dose cyclophosphamide in patient with systemic lupus erythematosus: A case report

RATIONALE

Cyclophosphamide (CY) is an alkylating agent used widely to treat cancer and autoimmune diseases. Hyponatremia is a common adverse effect of high-dose and moderate-dose of intravenous CY, but is rare in patients treated with low-dose (<15 mg/kg).

PATIENT CONCERNS

A 52-year-old woman with new-onset systemic lupus erythematosus (SLE) was treated with low-dose cyclophosphamide (8 mg/kg, CY), but showed sudden headaches, disorientation and weakness. Laboratory examinations revealed severe isovolumic hyponatremia along with low-serum osmolality and high urine osmolality.

DIAGNOSIS

The acute hyponatremia was consistent with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and was an adverse event of low-dose CY, with no evidence of endocrine, cancer, pulmonary, or cerebral abnormalities relevant to the SIADH.

INTERVENTION

The hyponatremia was resolved after the supplementation of NaCl solution.

OUTCOMES

The hyponatremia was resolved without any complications.

LESSONS

Hyponatremia induced by low-dose CY should be recognized as an underlying life-threatening complication in clinical practice.

Protective effect of tolvaptan against cyclophosphamide-induced nephrotoxicity in rat models

Cyclophosphamide (CP) is a chemotherapeutic agent which is extensively used in the treatment of multiple neoplastic and nonneoplastic diseases like breast cancer, lymphomas, systemic lupus erythematosus, and multiple sclerosis. Dose-limiting side effects, mainly nephrotoxicity is a major problem hindering its use in the clinical practice. CP induces nephrogenic syndrome of inappropriate antidiuresis mostly via the activation of arginine vasopressin V2 receptors. Moreover, CP produces reactive metabolites which is responsible for augmentation of lipid peroxidation and oxidative stress. Tolvaptan (TOL) is a selective vasopressin V2 receptor antagonist used in the treatment of clinically significant hyponatremia, volume overload in heart failure, and liver cirrhosis with edema. The present study aimed to investigate the potential protective effect of TOL in CP-induced nephrotoxicity. Twenty-four adult male albino rats were randomly divided into four groups: the control group, TOL group that treated daily with tolvaptan (10 mg/kg/d, orally), CP group where CP was administered intraperitoneally 75 mg/kg on days 3, 4, 5, 19, 20, and 21 of study, and the CP + TOL group where animals were treated with TOL daily with (10 mg/kg/d, orally) for 22 days with concomitant administration of CP as described before. Coadministration of TOL with CP induces significant improvement in the level of urine volume, serum Na+, serum osmolarity, urinary creatinine, and free water clearance in addition to significant reduction of body weight, serum creatinine, urea, serum K+, blood pressure, urine osmolarity, and the fractional excretion of sodium as compared to CP-treated group. In addition, coadministration of TOL significantly reduced MDA, the marker of lipid peroxidation, and different pro-inflammatory cytokines. Histopathological changes showed improvement in the signs of nephrotoxicity with the coadministration of TOL. Also, co-treatment with TOL significantly decreased the level of markers of apoptosis as caspase-3 and Bax with increased expression of antiapoptotic Bcl-2 in renal tissue as compared to CP-treated group.