Epidemiology
- Due to ingestion of fruit from the flowering shrub/small tree, Karwinskia humboldtiana (aka Coyotillio or Humboldt Coyotillo) in the buckthorn family (Rhamnaceae)
- Geographic Distribution: Karwinskia humboldtiana plant is found in the southwestern US and Mexico
- Prevalence in Humans: children are the most commonly affected
- Prevalence in Animals: cattle and goats are the most commonly affected
- Cattle are the most susceptible
- In animals, disease is called “Limberleg”: presents with incoordination and ataxia
Physiology
- Exposure: ingestion of buckthorn fruit (Karwinskia humboldtiana)
- Severity of toxicity is proportionate to the amount of fruit ingested
- Toxic Substance: Peroxisomicine (aka T-514, Tullidol)
- Mechanism
- Peroxisomicine destroys peroxisomes -> generation of free radicals -> lipoperoxidation of cell membranes -> cell death
- Peroxisomicine specifically targets thick, distal nerve segments, resulting in demyelination
- Histologically, there is widening of the periaxonal space and a redistribution of axonal organelles to a marginal position
- Eventually, axons undergo wallerian degeneration
Clinical
Neurologic Adverse Effects
- Demyelinating Peripheral Neuropathy (see Peripheral Neuropathy)
- Diagnosis
- LP: normal CSF
- Clinical
- Latency of Onset: 5-20 days after ingetsion
- Course: rapid progression
- Motor Findings
- Lower>upper extremity weakness
- May progress to severe quadriparesis with bulbar and respiartory involvement
- Cranial Nerves: normal
- Sensory Findings: mild and distal
- Pathology
- Segmental demyelination ± axonal swelling and loss
- Experimental: axonal loss (motor) is more prominent with systemic experimental administration of toxin
- Occasional degeneration of skeletal muscle fibers
- Treatment: supportive care
- Prognosis: may improve spontaneously over 3-12 mo
- Diagnosis
- Muscle Cramps
Pulmonary Adverse Effects
- Acute/Chronic Hypoventilation (see Acute Hypoventilation and Chronic Hypoventilation)
- Due to phrenic neuropathy
Other Adverse Effects
References
- http://neuromuscular.wustl.edu/nother/toxic.htm
- Intoxication with buckthorn (Karwinskia humboldtiana): report of three siblings. Pediatr Dev Pathol. 2007 Jan-Feb;10(1):66-8 [MEDLINE]
- Karwinskia humboldtiana (buckthorn) fruit causes central nervous system damage during chronic intoxication in the rat. Toxicon. 2009 May;53(6):645-51 [MEDLINE]