Acute manic episodes linked to increased edema risk

By Lucy Piper, Senior medwireNews Reporter

Bipolar disorder patients admitted to hospital with a manic episode are at an increased risk for lower limb edema (LLE), compared with their peers with depressive or non-affective psychosis episodes, study findings show.

The results suggest a possible causal relationship between mood and fluid imbalance, says the team, and a possible role for LLE as a surrogate physical marker for acute manic exacerbation.

Researchers Eldar Hochman (Geha Mental Health Center, Petach-Tikva, Israel) and colleagues assessed the medical records of 2529 patients admitted to the center between 2002 and 2012, of whom 1563 had non-affective psychosis, 366 a manic episode, and 600 a depressive episode.

LLE was diagnosed in 3.8% of patients; the rate was highest for patients with a manic episode, at 10.4%, versus 2.6% for those with a non-affective psychosis episode, and 2.7% for those with a depressive episode.

Indeed, patients with a manic episode had a significantly 8.72-fold higher risk for LLE compared with those with a depressive episode, despite depressed patients being older and having a higher rate of cardiovascular comorbidity. And the risk for LLE was 3.96-fold higher for those with manic episodes than for those with non-affective psychosis episodes.

“Moreover, psychotropic drug treatment prior to hospitalization and other physical co-morbidities did not affect this association,” the researchers report in Progress in Neuro-Psychopharmacology and Biological Psychiatry.

They also found that LLE on admission could be used to distinguish patients with manic episodes from those with depressive or non-affective psychosis ones.

Hochman and team speculate on the possible mechanisms linking LLE with manic bipolar episodes, suggesting a role for altered monoaminergic neurotransmitter signaling. In support of this, they found that blood sodium levels were relatively lower in patients with manic episodes compared with other patients, while potassium levels were relatively higher in patients with manic episodes and LLE versus non-LLE patients.

Another possibility includes the dysregulation of albumin levels as a response to immune activation in the pathogenesis of manic episodes, they add.

The “important clinical implication of our study is the awareness that patients admitted with a manic episode are at higher risk for LLE and its possible complications,” say Hochman et al.

They call for further studies “to examine the association between symptom severity and the occurrence of LLE in acute manic patients and the resolution of LLE following remission of the manic episode.”

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