Do all Rodenticides impact coagulation?
February 23, 2024
(another case from the national case conference)
A 40-year-old female presents with abdominal pain, hematuria, nausea without vomiting, and dark stools for 2 days. Vital signs are normal. PE reveals a diffusely tender abdomen and CVA tenderness. Fecal occult blood is positive. Abnormal blood tests reveal PTT 105.4 sec, PT/INR-no coagulation detected. Transfer to a higher level of care revealed PTT 124 sec, PT >100 sec and INR>1.0. Factor VII and X undetectable; Factor II,IX, Protein C and Protein S- Low; Factor V normal; and Factor VIII elevated.
Diagnostic consideration is a rodenticide as all Vit K dependent factors are low.
The patient and her husband own a trailer park which has well water which they use to shower, clean, drink and make ice. The husband has been using rat poison around the well and thinks it may have leeched into the well water. (All his studies are normal, as are those of the trailer park neighbors.)
He brings in the rat poison which is Bromethalin- a rodenticide which uncouples mitochondrial oxidative phosphorylation. Primary target is CNS leading to cerebral edema. Altered mental status, seizures, coma, cerebral edema, increased ICP and paralysis are presenting toxic symptoms. Clearly not the culprit.
The patient was treated with IV Vitamin K. Coagulopathy improved over 24 hours. The patient then becomes more coagulopathic.
An anticoagulant/coumarin derivative GC/MS panel is sent. Results will return in weeks.
The patient is started on a ? high dose oral Vit K regimen.
The panel returns: positive for diphacinone which is a superwarfarin (like brodifacoum)
So where did this originate? What are your next steps to determine the etiology of the exposure?
In toxicology, as in most of medicine, when something doesn’t make sense, you start from the beginning again. When asked to recount each hour of each day prior to the exposure, the patient states she cleans the trailers after the tenants move out. About two days before the onset of symptoms, she had cleaned a rat-infested trailer that the tenant had covered with “baking soda”. She used a shop vac and when she was done, she was covered from head to toe with the “baking soda”. She never wears any PPE.
So the “baking soda” was diphacinone. Literature review reveals that diphacinone is readily absorbed by dermal contact and inhalation. Onset of action is delayed up to 48 hours.
The patient was treated with oral Vit K for a number of weeks as coagulation studies were monitored.
Question prepared by Donna Seger MD
I am interested in any questions you would like answered in the Question of the Week. Please email me with any suggestions at donna.seger@vumc.org.
Donna Seger, MD
Professor Emerita
Department of Medicine
VUMC