Thread by @SandhyaRheumat

While looking through case reports of #Sjogrens and renal tubular acidosis, came across a peculiar neurological demyelinating disorder...
A long 🧵
#rheumtwitter #neurotwitter #MedTwitter

Intriguingly, there were multiple reports of osmotic demyelination syndrome (ODS), aka central pontine/extrapontine myelinolysis.

#Sjogren has varied neurological features and its association with #NMOSD, a demyelinating autoimmune disorder is well-known but ODS is non-inflammatory and ...
🤔Neither Sjogren nor RTA is an established risk factor for ODS

So what are the risk factors for ODS?
👉most commonly reported in context of rapid correction of chronic hyponatremia
👉Others- alcoholism, anorexia nervosa, malnutrition, burns, post-liver transplant, hyperemesis gravidarum, hyperglycemia, hypokalemia, hypernatremia

So we set out...
⭕A systematic search of case reports to identify cases of ODS & #NMOSD in #Sjogren
⭕Looked at frequency of comorbid RTA
⭕Also screened for ODS in RTA (without #Sjogren)

🔵15 case reports of #Sjogren-ODS, 100 % had RTA
🟠67 case reports of #Sjogren-#NMOSD, 3(4.5%) had RTA
🟡Only 3 ODS in RTA (without #Sjogren)

❓What were the clinical and laboratory features of #Sjogren-ODS
🔵 All women, median age: 40 yrs
🔵Heterogeneous clinical manifestations and outcomes
🔵Most common was quadriparesis in 14/15 patients

🔵11/15 had one of the following either alone or in combination; either at onset or during the course
👉Worsening of the sensorium
👉Extensor plantar response
👉Dysphagia /dysarthria
👉 Facial palsy
🔵Ocular palsy in 4/15 patients as a late manifestation
🔵1 died, most recovered

❓Risk Factors
⭕Prior Hyponatremia - 0%
⭕Hypokalemia -100%
⭕Hypernatremia at baseline-4 or during course-5(repeat values available in 8 only)

This previously unreported manifestation of ODS in #Sjogren-RTA aroused our curiosity and we came up with this explanation
🟡Hypokalemia ---> nephrogenic diabetes insipidus (NDI)-->subsequent hypernatremia ---> osmotic stress
🟡Pre-existing NDI could be part of RTA

⭕Aquaporin (AQP) in astrocytes is implicated in ODS
⭕Renal AQP downregulated in NDI
⭕Antibodies against AQPs(esp AQP5) described in some patients with #Sjogrens

🔵Defective AQP is therefore a common link underlying all the connected diseases namely #Sjogren, NDI & ODS
❓ possibility of immune-mediated AQP dysfunction in the pathogenesis

Learning points
🔵1. In the setting of SS-RTA, suspect ODS when a patient with flaccid quadriparesis
👉does not respond to the correction of potassium
👉develops additional neurological features along with a rise in sodium

🔵2. Be mindful of the possibility of underlying NDI in these patients even with normal baseline sodium
🔵3. Monitor sodium while correcting hypokalemia
🔵4. Use hypotonic fluids to correct hypokalemia

This paper was a tremendous learning experience
Immunology--->renal--->endo-->neuro and back to immunology
Wonderful experience collaborating with Japanese neurologists -Tetsuya Akaishi, Kazuo Fujihara & Masashi Aoki- from @TohokuUniPR
authors.elsevier.com/a/1gKJI7skof9k…