5/20/2023 “Wernicke-Korsakoff encephalopathy” Post activity summary
By Dr. Tao Wang
Editor: Dr. Charles Ce Wang
“Wernicke-Korsakoff encephalopathy” the first ANACP CME lecture held on 5/20/2023 (EST 9pm-10:20pm) via ANACP zoom, 83 attendees participated this activity.
Moderator Dr. Lishi Sun introduced the ANACP lecture series, and CME announcement. Appreciated Dr. Ce Wang for starting the CME lecture series by presenting “Wernicke-Korsakoff encephalopathy”.
Dr. Charles Wang started with a case, a 56 yo obesed nonalcoholic male complaints of nausea, vomiting for 6 weeks, presented with drowsy. Significantly nystagmus, ataxia were noted on physical exam. Labs are nonspecific. MRI brain showed high signal in mammillary bodies. Patient had a rapid and dramatic recovery after iv thiamine use, confirmed the diagnosis of Wernicke encephalopathy (WE). From the case, Dr. Wang reviewed the concepts of normal consciousness; the level of “altered mental status” includes confusion, drowsiness and stupor, coma. Dr. Wang emphasized the hallmark of encephalopathy is an altered mental status.
Wernicke-Korsakoff syndrome (WKS) composed with Wernicke encephalopathy as acute disease phase and Korsakoff amnesic state as chronic phase after acute life threatening encephalopathy. The cause of WKS is Thiamine (Vit B1) deficiency. From epidemiology stand point, WKS is about 0.4-2.8% of the general population, under-recognized clinically. About 77% of WKS is related to chronic alcoholism. However, other conditions that can cause thiamin deficiency should be considered as a risk of WKS. WE is considered as a medical emergency, it can be life threatening if not treated early. Simple iv thiamin treatment can receive dramatic response. Therefore recognizing the risk of WKS in nonalcoholic patient is critical.
Dr. Wang briefly went through the contribution of Dr. Carl Wenicke and Dr. Korsakoff to the understanding of this disease. He also reviewed the pathophysiology, biochemistry and pathology of WKS. Thiamine, as a cofactor for several energy metabolism key enzymes, its requirements increase greatly during high metabolic demand and high glucose intake. Highly specific pathology finding of WKS is atrophy of the mammillary bodies, upto 80% of the case.
For WKS clinical feature, the acronym of the classical triads is “COAT”: Confusion, ophthalmoplegia, Ataxia, Thiamin (response). Nystagmus is the most common ophthalmoplegia. Rapid response to thiamin is the strongest diagnosis evidence for WE.
For differential diagnosis, common causes of delirium and confusion status should be considered, for example: drugs and toxins, Infections, metabolic derangements and brain disorders.
When suspect WE, especially for the nonalcoholic patient, thiamine early replacement is highly recommended. The response to thiamine is diagnostic. In chronic alcoholic patient, thiamin treatment should be initiated urgently once patient meet two out of four Caine criteria: 1) Dietary deficiency; 2) Oculomotor abnormalities; 3) Cerebellar dysfunction; 4) Either altered mental status or mild memory impairment.
No lab studies are diagnostic. Erythrocyte thiamine transketolase activity (ETKA) is usually a send out test, not very practical to use. Blood thiamine level does not correlate with brain thiamin level, therefore a normal blood thiamine level cannot exclude the possibility of WKS. CSF test, Pleocytosis or protein>100 mg/dL suggest alternative diagnoses.
Usually, EEG is recommended to rule out non-convulsive seizure. CT head is an insensitive test. MRI brain is more sensitive than CT. Mamillary body atrophy is a relatively specific abnormality for WKS.
Do not wait for labs or imaging study, if you suspect patient has WKS, iv thiamin should be given to patient right away. The regimen is 500mg iv over 30min TId for 2 days, followed by 250mg iv or im QD for 5 days, then 100mg po qd. Be sure to give thiamin before glucose. Magnesia and other vitamins may need to be replenished as well.
Usually, WKS patient has prompt response to Thiamin treatment. Ocular sign will improve within hours and days. If not response, other diagnoses need to be considered. Recovery of vestibular function begain in 2 weeks. improvement in gait ataxia coincided with recovery of vestibular function. Confusion subsides over days and weeks.
To prevent WKS, give thiamin before glucose use to avoid iatrogenic cause, give thiamin for alcohol withdrawal patient, give oral administration of thiamine to outpatients at risk. Thiamin is a safe, low cost, easy use medication. If patient is at risk of WKS, thiamin is highly recommended.
Regarding alcoholism definition, psychiatrist Dr. Zhang referred to DM-5 for full diagnostic criteria. Point out that “CAGE” questionnaire used in primary care setting is just a screening tool.
Dr. Wang finalized the lecture with a take home message “COAT ROCK”. Wernicke’s encephalopathy (acute phase): “COAT” Confusion; Ophthalmoplegia; Ataxia; Thiamine tx.
Korsakoff’s psychosis (chronic phase): “RACK” Retrograde amnesia; Anterograde amnesia; Confabulation; Korsakoff’s psychosis
Emphasize WE is a medical emergency, low threshold to use high dose thiamin for at risk patients.