What laboratory tests and imaging are most useful for monitoring complications of ivermectin poisoning?
Executive summary
Ivermectin overdose produces a clinical picture dominated by neurologic depression, respiratory compromise, and heterogeneous systemic effects; routine laboratory surveillance should therefore focus on electrolytes, renal and hepatic function, acid–base status, glucose and markers of inflammation/coagulopathy, while imaging is directed at the organ system involved — most commonly chest radiography/CT for respiratory failure and selective neuroimaging when focal or prolonged neurologic deficits occur [1] [2] [3]. Specific ivermectin assays exist and have been used (LC–MS/MS) but authoritative toxicology guidance advises that assay results rarely change acute clinical management [2] [4].
1. Core biochemical panel — what to draw and why
Serum electrolytes (Na+, K+), glucose, renal function (creatinine, BUN) and liver enzymes should be obtained on presentation and trended, because published human cases report hyponatremia or hyperkalemia, marked hyperglycemia in some patients, and variable renal or hepatic abnormalities that reflect systemic illness or organ dysfunction from severe poisoning or co‑existent infection [1] [5] [2]. Arterial blood gas (ABG) is essential when respiratory failure or altered mental status is present — case reports describe metabolic acidosis and frank respiratory failure necessitating intubation, making ABG useful for ventilatory and acid–base management [2] [6]. Creatine kinase may be useful if seizures or profound immobility/neuromuscular findings occur; mild CK elevations have been reported [5].
2. Hematology, inflammation and coagulation — watch for secondary complications
Complete blood count and markers of inflammation (CRP/ESR, ferritin) are commonly abnormal in reported cases where concomitant infection (notably SARS‑CoV‑2) or systemic inflammatory responses exist; elevated inflammatory markers and D‑dimer have been documented and can influence diagnostic thinking and management [1] [5]. Coagulation studies and D‑dimer are reasonable when hypercoagulability or bleeding is suspected — one fatal transdermal poisoning case documented blood hypercoagulability and abnormal coagulation parameters alongside multiorgan dysfunction [2].
3. Toxicology testing — assays available but limited clinical utility
Sensitive analytic methods such as liquid chromatography–tandem mass spectrometry (LC–MS/MS) can detect and quantify ivermectin — several case reports confirmed ivermectin peaks (e.g., 27 ng/mL) using LC–MS/MS [6] [2] — yet toxicology reference guidance states no specific laboratory test is necessary routinely and serum ivermectin assays are unlikely to change acute management, so their role is primarily confirmatory or forensic rather than therapeutic [4].
4. Imaging — tailor to the presenting organ system
Chest radiography and chest CT are the most frequently useful imaging studies because respiratory symptoms and radiographic pneumonia or consolidation appear repeatedly in case series and reports, and severe intoxication has produced respiratory failure requiring mechanical ventilation [1] [2]. Neuroimaging (cranial MRI/CT) should be considered when there are focal neurologic signs, persistent altered consciousness, seizures, or to exclude alternative diagnoses — published cases often show unremarkable cranial MRI but imaging is still indicated to rule out structural causes or complications [1]. Routine whole‑body imaging is not mandated unless clinical findings indicate specific organ involvement [4].
5. Practical monitoring plan, alternate explanations and limitations of the evidence
In practice, monitor vitals, continuous pulse oximetry, serial neurologic exams, repeat electrolytes, renal/hepatic panels, ABG if hypoventilating, CBC and inflammatory/coagulation markers as clinically indicated; obtain chest imaging early for respiratory symptoms and reserve neuroimaging for persistent or focal neurologic deficits — this strategy reflects the pattern reported in multiple case reports and poison‑center reviews, yet the literature is limited and often confounded by coinfections (notably COVID‑19) and variable dosing/formulations [7] [1]. Finally, emphasize that guidance from PIM cautions against routine reliance on ivermectin blood levels because they rarely alter management, so clinicians should prioritize supportive care and targeted monitoring of organ systems rather than waiting for confirmatory assays [4].