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Plant Poisoning, Glycosides - Cardiac: Differential Diagnoses & Workup
Updated: Jan 27, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
Other Problems to Be Considered
Baclofen toxicity
Consider in the differential diagnosis entities in which GI upset is associated with hypotension, dysrhythmias (eg, bradycardias, tachycardias), or altered mental status (think TIPS AEIOU; trauma, infection, psychogenic causes, seizure/syncope, alcohol, encephalopathy/endocrinopathy/electrolytes, insulin, opiates, uremia). Consider co-ingestants. Address the possibility of intentional ingestion as a suicide attempt.
Other plants that may produce similar cardiac effects include Aconitum napellus (Monkshood) and other Aconitum species, Veratrum album (and other veratridine alkaloids), yew (Taxus brevifolia), and grayanotoxins (rhododendron). The cane toad (Bufo marinus) contains the cardioactive compound bufadienolide in its dried secretions that also has resulted in cardiac glycoside toxicity.4 Dried toad venom is used in China as a traditional medicine known as chan su and is a major component of kyushin, another popular herbal medication used in Asia.
Workup
Laboratory Studies
- Fingerstick glucose determination: Assess for hypoglycemia as a possible cause of altered mental status.
- Complete blood count (CBC): Determine if anemia is a cause or potential complicating factor of dysrhythmia or hypotension.
- Electrolytes
- Hyperkalemia is a primary manifestation of acute cardiac glycoside toxicity and an early predictor of need for antidotal therapy.
- Hypokalemia exacerbates cardiac glycoside toxicity, and it is more typical in chronic toxicity. It is usually secondary to the use of loop diuretics, poor dietary intake, diarrhea, and administration of potassium-binding resins.
- Hypercalcemia and hypomagnesemia exacerbate cardiac glycoside toxicity. Magnesium and ionized calcium levels may be helpful, but serum magnesium levels do not reflect total body load of magnesium.
- BUN and creatinine
- Renal impairment negatively impairs elimination of glycosides and may exacerbate hyperkalemia.
- In addition to certain medical conditions (eg, pregnancy, liver disease, subarachnoid hemorrhage, CHF, IDDM, stress, hypothermia), renal insufficiency is associated with elevated endogenous digoxinlike immunoreactive factors that can give false-positive digoxin assay results.
- Cardiac glycoside level
- Some plant glycosides cross-react with commonly used digoxin radioimmunoassays (RIAs) and digoxin fluorescence polarization immunoassays. Detectable levels of cardiac glycosides have been associated with ingestion of foxglove and oleander; however, levels do not correlate with severity of illness.
- Negative digoxin RIA does not rule out a plant glycoside exposure.
- Consider other tests, such as cardiac enzymes, thyroid function tests (TFTs), arterial blood gasses (ABGs), or urine drug screens, depending on the patient's presentation.
- Consider checking acetaminophen (APAP), salicylate (ASA), and ethanol (ETOH) levels, especially if overdose is suspected.
- Consider a pregnancy test for women with intentional ingestions or suicidal ideation.
Imaging Studies
- Chest x-ray (CXR) may be indicated for patients with severely toxic reactions or patients with pulmonary findings on physical examination.
Other Tests
- Electrocardiogram (ECG) and continuous cardiac monitoring
- Assess cardiac rhythm and look for signs of ischemia or infarction.
- Nonspecific ST segment and T wave abnormalities, consistent with "dig effect," (ST "scooping" or "strain"-like pattern) may be noted. This does not signify toxicity merely the presence of cardiac glycoside.
- Peaked T waves may occur in hyperkalemia.
- Pulse oximetry to monitor oxygen saturation and heart rate
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 Differential Diagnoses & Workup: Plant Poisoning, Glycosides - Cardiac |
| Treatment & Medication: Plant Poisoning, Glycosides - Cardiac |
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References
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el Bahri L, Djegham M, Makhlouf M. Urginea maritima L (Squill): a poisonous plant of North Africa. Vet Hum Toxicol. Apr 2000;42(2):108-10. [Medline].
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Goldfrank, Flomenbaum, Lewin, et al. Cardiac glycosides. In: Goldfrank's Toxicologic Emergencies. 7th ed. 2002:724-734.
Rich SA, Libera JM, Locke RJ. Treatment of foxglove extract poisoning with digoxin-specific Fab fragments. Ann Emerg Med. Dec 1993;22(12):1904-7. [Medline].
Plants - cardiac glycosides. In: Rumack BH, ed. Poisondex. 1997:94.
Slifman NR, Obermeyer WR, Aloi BK, Musser SM, Correll WA Jr, Cichowicz SM. Contamination of botanical dietary supplements by Digitalis lanata. N Engl J Med. Sep 17 1998;339(12):806-11. [Medline].
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Further Reading
Keywords
cardiac glycosides, cardiac glycoside toxicity, cardiac glycoside poisoning, treatment of glycoside poisoning, symptoms of glycoside poisoning, glycoside toxicity, glycoside poisoning, plant poisoning, glycoside, Digitalis purpurea, Digitalis lanata, foxglove, Nerium oleander, common oleander, Thevetia peruviana, yellow oleander, Convallaria majalis, lily of the valley, Urginea maritima, Urginea indica, squill, Strophanthus gratus, ouabain, herbal cardiac glycosides
