From the Guidelines
LDH lab draw is recommended for a patient with persistent bilateral inguinal lymphadenopathy if lymphoma is suspected, as it is included in the laboratory work-up for follow-up after end of therapy in follicular lymphoma patients, according to the ESMO clinical practice guidelines 1. When evaluating a patient with persistent bilateral inguinal lymphadenopathy, the initial focus should be on a thorough history, physical examination, and specific tests based on clinical suspicion.
- Appropriate initial investigations typically include:
- Complete blood count
- Comprehensive metabolic panel
- Targeted infectious disease testing such as HIV, syphilis, or other sexually transmitted infections
- Imaging studies like ultrasound may be helpful to characterize the lymph nodes. While LDH can be elevated in conditions causing lymphadenopathy such as lymphoma or metastatic malignancy, it is a non-specific marker of tissue damage and cellular turnover. If the clinical picture suggests malignancy or if initial workup is inconclusive, then LDH might be included in a more comprehensive evaluation, particularly if lymphoma is suspected, as suggested by the ESMO minimum clinical recommendations for diagnosis, treatment, and follow-up of chronic lymphocytic leukemia 1. The most definitive approach for persistent unexplained lymphadenopathy is often excisional lymph node biopsy, which provides tissue for histopathological examination and more accurate diagnosis. In the context of lymphoma, LDH levels are monitored as part of the follow-up, with recommendations for testing every 3 months in the first 2 years after therapy, twice annually in years 3-5, and annually thereafter 1.
From the Research
LDH Lab Draw for Bilateral Inguinal Lymphadenopathy
- An LDH (Lactate Dehydrogenase) lab draw may be recommended for a patient with persistent bilateral inguinal lymphadenopathy, as elevated serum LDH levels can be an early marker of occult malignant lymphoma 2.
- The diagnostic value of LDH in the preclinical stage of malignant lymphoma has been established, and a patient with no apparent cause for elevated serum LDH levels warrants a thorough work-up, including abdominal CT scan and even explorative laparotomy 2.
- However, it is essential to consider other potential causes of bilateral inguinal lymphadenopathy, such as lymphogranuloma venereum (LGV) 3, tuberculosis 4, or periprosthetic joint infection 5.
- The size of inguinal lymph nodes can be a valuable indicator of periprosthetic joint infection, with a size of 19mm determined as the optimal threshold value for diagnosis 5.
- LDH can be a valuable tumor marker, with its levels and isoenzyme patterns providing information on the clinical significance of cancer 6.
Potential Causes of Bilateral Inguinal Lymphadenopathy
- Malignant lymphoma 2
- Lymphogranuloma venereum (LGV) 3
- Tuberculosis 4
- Periprosthetic joint infection 5
- Other infections or inflammatory conditions
Diagnostic Approach
- LDH lab draw to evaluate for elevated serum LDH levels 2
- Imaging studies, such as abdominal CT scan, to evaluate for lymphadenopathy or other abnormalities 2
- Ultrasound examination of inguinal lymph nodes to evaluate for size and morphology 5
- Routine screening for LGV and other sexually transmitted infections in high-risk populations 3