Share on Facebook
Share on Twitter
Share on LinkedIn
Share by Email
Print
DISCUSSION
Anaplastic large cell lymphoma is a rare form of non-Hodgkin lymphoma. It has 3 different subtypes based on presentation at diagnosis and comprises only 3% of all cases of NHL annually.1
Patients usually present with symptomatic fever, night sweats, fatigue, loss of appetite, and swollen lymph nodes. The cutaneous form of the disease can either identify early disease or indicate disease progression. If localized, cutaneous disease has a successful cure rate with 5-year survival at 70% to 90% with a positive mutation. ALK-negative disease, as in this case, overall 5-year survival drops to 40% to 60%.2 Even if treatment is initially successful, some patients relapse despite achieving remission.
This patient presented with severe disease burden as evidenced by his high WBC count, complaints of worsening symptoms, and newly developed infiltrating rash on his body.
Pseudohyperkalemia is a phenomenon that occurs when very delicate lymphocytes, as those seen in lymphoid-type cancers, rupture and their intracellular contents are released in the blood sample.4 This lysis can be caused by multiple variables, including a tourniquet tied too tight, delay in sample processing, the use of pneumatic tube transport, and temperature at time of sampling.5
In this case, the falsely high potassium level was caused by potassium leakage from the excessively high and extremely fragile lymphocytes. These cells break with minimal manipulation, and their cellular contents are released into the blood sample. At this facility, samples are transported to the laboratory via pneumatic tube system, which shakes the sample, leading to cell lysis.
Because the potassium level was a false high, administering IV dextrose, insulin, and kayexelyate would actually cause the patient’s potassium level to drop below normal levels. Furthermore, some patients undergo emergent dialysis, which could cause severe drops in potassium levels.3 By eliminating the use of the pneumatic tube transport and immediately processing the sample, the lab test results accurately reflected that the patient’s potassium levels remained out of critical levels.
Amy Walton is a staff nurse at Billings Clinic, Inpatient Cancer Care in Billings, Montana.
References
1. Getting the facts: anaplastic large cell lymphoma. Lymphoma Research Foundation website. http://www.lymphoma.org/atf/cf/%7B0363cdd6-51b5-427b-be48-e6af871acec9%7D/ANAPLASTIC10.PDF. Accessed October 12, 2016.
2. Hapgood G, Savage KJ. The biology and management of systemic anaplastic large cell lymphoma. Blood. 2015;126(1):17-25.
3. Katkish L, Rector T, Ishani A, Gupta P. Incidence and severity of pseudohyperkalemia in chronic lymphocytic leukemia: a longitudinal analysis. Leuk Lymphoma. 2016;57(8):1952-1955.
4. Mansoor S, Holtzman NG, Emadi A. Reverse pseudohyperkalemia: an important clinical entity in chronic lymphocytic leukemia. Case Rep Hematol. 2015;2015:930379. doi: 10.1155/2015/930379.
5. Asirvatham JR, Moses V, Bjornson L. Errors in potassium measurement: a laboratory perspective for the clinician. N Am J Med Sci. 2013;5(4):255-259.
TEACHING POINTS
- Pseudohyperkalemia, although a rare, can occur in patients with lymphoid-type cancers, specifically in those with a high cell burden at diagnosis
- Review previous lab values, if available, and note preceding potassium levels. A previous abnormally high potassium level is predictive of this rare potassium elevation.
- When collecting and handling the blood sample: avoid using a tourniquet, use gentle technique when drawing blood from the patient or a central access device and when transferring the sample into the tube, minimize shaking the tube including hand deliver samples to the laboratory.
- Communicate the need for these interventions to all staff involved to assure every attempt is made to preserve the specimen and prevent lysis.
- Treating a false potassium elevation can lead to serious complications related to a significant drop in circulating potassium.
