Journal Article Annotations
2022, 1st Quarter
Annotations by Sahil Munjal, MD
This cross-sectional study looked at a cohort of lithium-treated patients and found that lithium treatment duration, age, albuminuria, hypertension and hypothyroidism were inversely correlated with renal function (mGFR). Fifty-one percent of patients with renal MRIs had micro-cysts, often uniformly and symmetrically distributed throughout the kidneys. mGFR and lithium treatment duration were correlated in patients with microcysts—but were not correlate in pa-tients without microcysts.
Strength and weaknesses:
This study boasted a larger sample size compared to previous studies of MRI and microcysts. A third of patients were missing lithium levels, and the use of a single plasma lithium measurement is not representative of long-term cumulative exposure to the drug. Also, the lithium level was not measured the same day as the renal evaluation. There was a very low preva-lence of diabetes in the sample size. Given the cross-sectional design, the predictive value of lithi-um treatment duration on mGFR decline could not be analyzed.
The study adds to an already established risk of renal function decline in certain patients with chronic lithium treatment. Here, the strongest determinant of mGFR decline was the lithium treatment duration, then age. The association with hypothyroidism is also an interesting finding which needs replication. There was a strong relationship between the presence of microcysts and mGFR decrease. MRI might be a useful tool to detect microcysts even during early stages of treat-ment; here, some study patients developed microcysts as soon as 1 year after lithium treatment. Study authors point out that the presence of these microcysts may inform strategies to prevent irreversible kidney damage, perhaps by decreasing lithium exposure or other nephrotoxic agents. It is not clear if these changes are reversible, and any potential benefit of treatment discontinuation should be weighed against the risk of destabilization and suicidality.
Two cases are described of patients whose bipolar disorder was in remission on lithium but who then developed nephrotoxicity after COVID-19 infection.
Strength and weaknesses:
Other confounding variables may have indirectly affected renal function and led to lithium toxicity including dehydration, electrolyte and acid-base imbalance, cardiac insufficiency, inflammatory cascade secondary to COVID-19 or other surreptitious medications.
C-L psychiatrists should monitor lithium levels more frequently in patients with COVID-19. It has been proposed that some of lithium’s anti-inflammatory effects might be beneficial in patients with COVID-19 infection. However, the virus may cause renal damage and subsequently lithium toxicity. This case series describes how COVID-19 patients can develop acute renal injury due to direct viral infection of the kidney. SARS-CoV-2 spike protein binds to the angiotensin converting enzyme 2 receptor to enter human renal cells. Larger studies are needed to ascertain the direct effect of the virus on renal function, as damage may also be immune-mediated.