MRI T2/FLAIR on day 17
A 36 year old alcoholic man was admitted to hospital with obtunding, jaundice and cachexia. In addition to deranged LFTs, anaemia and thrombocytopenia, all thought to be related to cirrhosis, he had Creat 194 (eGFR 36), Na 138, K 2.6. He was treated for alcohol withdrawal but was difficult to manage; for a few days he was intubated and ventilated. Lactulose was thought to blame for very profuse diarrhoea, and he developed significant electrolyte disturbance. Serum sodium rose to 158 over 30 hours at one point; then slowly improved with water hydration over several days. Potassium rose to 3.4 then dropped back to 2.4 before slowly returning to normal.
5 days later his conscious level reduced again and he developed spastic quadriplegia. An MRI scan later that day is shown above.
Question: what is the likely caused of this problem? Could anything have been done to prevent it?
What the experts thought ...
This is osmotic demyelination (old name: Central Pontine Myelinolysis) but it is a very unusual example caused by rapid onset of hypernatraemia. Usually it is attributed to too-rapid correction of very low plasma [Na], but presumably the principle is the same. A few principles.
- The hyponatraemia needs to be of some duration (not acute).
- The delayed onset of symptoms, 2-6d after the peak change in sodium, is typical.
- A ‘safe rate’ for correction of chronic hyponatraemia is said to be less than 8 mmol every 24h (up to 10 mmol quickly for severe acute symptoms). (UpToDate)(UoE login required).
- Risk factors for its occurrence include alcohol abuse, liver disease, malnutrition, pre-existing brain disease. It is also much more likely if starting sodium is <120.
What happened? He is said to have made a good neurological recovery over a week or so. This is not always the case.
This case is adapted from Am J Kid Dis 68(5):xv-xvii (2016). The image is courtesy of Dr Lemuel Marquez Narcise, Radiopaedia.org, from the case rID: 44204
A 34 year old man presents to Queen Elizabeth Central Hospital, Blantyre with a 2 day history of frontal headaches and generalized tonic clonic seizures. His guardians report that he has had multiple nodules all over his body since childhood but has previously been well.
He has another prolonged seizure after admission. He is post-ictal on examination with a Glasgow Coma Scale 11/15 (E -4, V-2, M-5). His pupils are of normal size and equally reacting to light. His vital signs on admission are: blood pressure 121/81mmHg, pulse 94/min, temperature 37.0°C, respiratory rate 24/min. The chest and abdominal examination are normal. The rest of the neurological exam does not reveal any focal deficits.
- What is his underlying condition?
- What differential diagnoses are you considering?
- What tests would you want to do?
- What would your initial management be?
Write what you think and what you'd do
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The recent history of headaches raises the possibility that this is more than simple epilepsy, though his underlying condition is associated with epilepsy. This is a region where there is a high prevalence of HIV infection, the possibility of which broadens the differential diagnosis importantly.
His underlying condition is neurofibromatosis type 1. It is associated with epilepsy and with astrocytomas, gliomas, but at presentation it may be causative or just a coincidence.
Tests you should seek:
- Blood glucose
- Full blood count
- Malaria blood film
- Lumbar puncture with examination to include India Ink stain (if available you would test for Cryptococcal antigen)
- HIV test
- Urea and electrolytes
- Brain imaging (but CT /MRI not available here)
- Serology for syphilis
- Epilepsy – simple or caused by neurofibromatosis-associated brain lesions
- Cerebral malaria is more likely in children than adults
- Metabolic – DEFG; Don’t ever forget Glucose. Hypoglycaemia may induce coma and convulsions. Other metabolic disturbances including hyponatraemia
- Meningitis – particularly TB or Cryptococcal meningitis in the presence of HIV infection
- Infective focal brain lesions: Toxoplasmosis, primary CNS lymphoma – usually HIV-related; Cysticercosis, neurosyphilis
- Control continuing convulsions with diazepam IV.
Then in this setting:
- Phenobarbitone 600mg loading dose (infusion or slow push) the 90mg maintenance (IM or orally if patient can tolerate it) OR Phenytoin 900mg loading dose (infusion) then 100mg tds maintenance. Blood monitoring is not available.
- Empirical cover for meningitis until CSF results back: Ceftriaxone 2g bd IV
For options in other centres, see …
This case contributed by Dr Tamara Phiri