Hyperkalemia presentation at a clinic during the cold season.

Familial pseudohyperkalemia (FP) is an underrecognized cause of pseudohyperkalemia, caused by the leaking of potassium from red blood cells. This extracellular shift of potassium is temperature-dependent and occurs when blood samples are stored below room temperature or for a long time, manifesting as apparent hyperkalemia. We report a suspicious case of FP, which demonstrated an apparent seasonal trajectory of serum-potassium levels at the local clinic. At first, laboratory test results did not show an increase in the serum-potassium levels in our tertiary hospital. However, by replicating the clinic's storage conditions, the patient's serum sample showed hyperkalemia only when it was stored at a temperature of 4 °C or 20 °C for 4-8 h. Hyperkalemia was not observed in the patient's sample when it was stored at 37 °C, or in the healthy control's sample at a temperature of 20 °C or 37 °C. When encountering hyperkalemia without an obvious cause and symptoms, physicians should consider pseudohyperkalemia in the differential diagnosis. In particular, if a seasonal trajectory of serum-potassium levels is observed, FP should be suspected as a potential cause of pseudohyperkalemia. Although a genetic test is needed to properly diagnose FP, confirming it by verifying the sample storage conditions or proving it by replicating the test using different storage conditions is easy and very important, as it can prevent unnecessary treatment.

Marked hyperkalemia due to inappropriate blood sample storage in two suspected cases of familial pseudohyperkalemia.

We herein report two suspected cases of pseudohyperkalemia who presented with severe hyperkalemia examined at small primary care clinics; however, re-exams at a tertiary care hospital showed normal potassium levels. We reproduced the laboratory examination conditions of the clinics and found that hyperkalemia was due to sampling/storage condition of serum, which is strongly suggestive of familial pseudohyperkalemia (FP). FP is a possible but under-appreciated cause of hyperkalemia, which does not require treatment, so it is important to include FP in the differential diagnosis of hyperkalemia especially in cases with discrepant of serum potassium levels at different settings.

An Autopsy Case of Disseminated Varicella Zoster Virus Infection during the Treatment of Nephrotic Syndrome.

A 68-year-old woman developed systemic blisters while receiving treatment for nephrotic syndrome. As she also developed marked liver dysfunction and disseminated intravascular coagulation, she was admitted to our hospital. She was diagnosed with varicella zoster virus (VZV) infection. Treatment was administered in the intensive-care unit, but the patient died on day 24 post-admission after severe VZV infection. A post-mortem examination showed micro-abscesses and necrosis caused by varicella zoster infection in multiple organs, including the liver, kidneys, and gastrointestinal tract. Because VZV infection can become severe in immunocompromised patients, careful consideration is needed for the prevention and treatment of the viral infection.