Leukocytosis in Cannabis Hyperemesis Syndrome: Hemoconcentration and Stress Response
Yes, a WBC count of 35,000/μL in a severely dehydrated patient with cannabis hyperemesis syndrome can be primarily attributed to hemoconcentration combined with a reactive stress leukocytosis from prolonged vomiting, rather than indicating an infectious or hematologic malignancy.
Understanding the Mechanism
The marked elevation in both hematocrit (51%) and hemoglobin (18 g/dL) from previously normal values strongly supports severe hemoconcentration as the primary driver of the apparent leukocytosis 1. When plasma volume contracts from severe dehydration, all cellular blood components become concentrated, artificially elevating their measured counts.
The stress response from severe, prolonged vomiting triggers a physiologic leukocytosis through multiple mechanisms:
- Demargination of neutrophils from the vascular endothelium into circulation 1
- Bone marrow release of immature granulocytes (left shift) in response to stress hormones 1
- Cortisol-mediated neutrophilia from the activated hypothalamic-pituitary-adrenal axis 2
Cannabis Hyperemesis Syndrome Context
Cannabis hyperemesis syndrome patients characteristically present with severe dehydration and electrolyte abnormalities requiring aggressive fluid resuscitation 2, 3. The syndrome involves:
- Cyclic episodes of intractable vomiting lasting 24-48 hours 3
- Profound volume depletion from inability to maintain oral intake 2
- Metabolic stress from repeated emesis 4
Treatment prevalence data shows CHS has increased substantially, with rates as high as 6 per 1000 chronic cannabis users in younger age groups, making this diagnosis increasingly common 5.
Distinguishing from Pathologic Leukocytosis
Key features that argue against hematologic malignancy or serious infection in this case:
- The concurrent elevation of hematocrit and hemoglobin proportional to the WBC elevation strongly suggests hemoconcentration rather than true leukocytosis 1
- Acute myeloid leukemia with hyperleukocytosis (WBC >100,000/μL) would not present with elevated hematocrit, as these patients typically have anemia 1
- Chronic lymphocytic leukemia presents with progressive lymphocytosis over months, not acute elevation in the setting of dehydration 1
Clinical Approach
Immediate management priorities:
- Aggressive intravenous hydration (2.5-3 liters/m²/day) to correct the hemoconcentration 1
- Repeat complete blood count after adequate fluid resuscitation to assess true baseline values 1
- Monitor for resolution of leukocytosis with rehydration, which would confirm reactive etiology 1
If leukocytosis persists after full rehydration, consider:
- Peripheral blood smear to evaluate for left shift, immature forms, or dysplastic features 1
- Inflammatory markers (ESR, CRP) to assess for underlying inflammatory conditions 1
- Further workup only if clinical suspicion warrants based on persistent abnormalities after volume correction 1
Common Pitfalls to Avoid
Do not initiate extensive hematologic workup before correcting the dehydration. The elevated hematocrit and hemoglobin provide clear evidence that hemoconcentration is contributing significantly to the apparent leukocytosis 1. Premature testing leads to unnecessary procedures, costs, and patient anxiety.
Do not overlook the diagnosis of cannabis hyperemesis syndrome itself. Standard antiemetics are typically ineffective, and treatment requires benzodiazepines or antipsychotics for sedation, along with supportive care 2. Hot water bathing provides temporary symptom relief 3, 6. The only definitive cure is cannabis cessation 2.
Monitor for complications of severe vomiting including pneumomediastinum (from forceful retching), metabolic acidosis, and electrolyte derangements, which can occur in CHS patients 4, 3.