HIV: Velocity of Change Is Key for Falling Sodium Levels

Velocity of change is key when it comes to falling sodium levels. Hyponatremia (sodium level lower than 135 mEq/L) is the most common electrolyte disorder seen in hospitals. Patients whose sodium levels fall gradually tend not to experience hyponatremia’s hallmark signs: altered mental status, confusion, cramps, falls, headache, obtundation (mental blunting with mild to moderate reduction in alertness, and a diminished sensation of pain), and possibly coma, and status epilepticus.

People living with HIV (PLWH) are at elevated risk for hyponatremia, a risk that increases if they are hospitalized. It hyponatremia is severe, morbidity, and mortality risk escalates.

Researchers from China-Japan Friendship Hospital in Beijing, China have assembled a comprehensive review of hyponatremia in PLWH. Published in the journalRenal Failure, the review describes current knowledge of this imbalance and its repercussions in the HIV-infected individual.

Serum sodium levels seem to correlate with infection severity in PLWH. The researchers report that infection is a leading cause of hyponatremia. Pulmonary tract, and central nervous infections in particular can cause release of excess antidiuretic hormome (ADH). Pulmonary infection may reduce pulmonary venous return, activate volume receptors, and increase ADH secretion. Clinicians should monitor patients who have tuberculous meningitis, encephalitis or abscesses, closely for syndrome of inappropriate ADH secretion (SIADH) and cerebral salt wasting syndrome (CSWS).

PLWH sometimes develop endocrine gland dysfunction, and clinicians may overlook this possibility unless they are vigilant. Most often, the adrenal gland is involved. An inflamed adrenal gland may follow an infection or be associated with the virus itself. The adrenal gland affects almost all organ systems, and once it is inflamed, extensive organ system failure is possible.

The researchers also cover thyroid disease, which occurs in some PLWH. Some organisms infect the thyroid, while others affect the thyroid in a ripple effect. Diarrhea, and vomiting are also more obvious contributors to hyponatremia.

Treatment proceeds as it would in patients who do not have HIV. That is, eliminating underlying causes would be the first target. If the velocity of the change in sodium exceeds 0.5 mmol/L/hour, the condition is life-threatening and needs immediate, aggressive treatment. A drug from the relatively new vaptan class of drugs is an appropriate intervention.

Volume restriction is appropriate in patients who have SIADH, but contraindicated in those with CSWS. For CSWS patients, a mineralocorticoid like fludrocortisones is a better choice.

The researchers provide additional information that clarifies hyponatremia, and its treatment in the review. The bottom line: clinicians need to be aware of the risk, and monitor patients closely especially if their HIV health status is declining, or their sodium levels are falling quickly.

Reference

Shu Z, Tian Z, Chen J, Ma J, Abudureyimu A, Qian Q, Zhuo L. HIV/AIDS-related hyponatremia: an old but still serious problem.Ren Fail. 2018;40(1):68-74. doi: 10.1080/0886022X.2017.1419975. Erratum in: Ren Fail. 2018;40(1):135.