This case report outlines an interesting first presentation of MS in a 28 year old man.
The levels of water in your bloodstream are maintained at the right level by a process called homeostasis and more specifically by a hormone called antidiuretic hormone (ADH). Diuresis is the process of passing urine so the hormone does exactly what it says in the tin – it stops you peeing.
ADH is produced in a neuroendocrine structure called the hypothalamus and is stored in the pituitary gland which is located in your brain just behind and between your eyes.
When you don’t have enough water on-board i.e. you’re dehydrated or have been sweating, your pituitary gland releases ADH and this acts on the kidneys to make them reabsorb more water and you pee less.
When you’ve drunk too much water, less ADH is released and you therefore have a ‘diuresis’ i.e. you pass more urine through your kidney.
Sometimes your brain fails to produce/release the ADH or your kidneys don’t respond to it and this is known as Diabetes Insipidus (not to be confused with diabetes mellitus that involves insulin). In this condition, your body works on the assumption that you always have too much water on board (the right hand side of diagram) resulting in loss of huge amounts of urine from the kidneys. You end up needing to drink lots of water to stay hydrated which is sometimes easier said than done.
This case report describes a gentleman who presented with a 7 year history of drinking >10 litres of water per day. When he was given a form of ADH by a doctor, he was able to concentrate his urine which proved that he was not producing ADH himself but that his kidneys were able to respond to the hormone. He was diagnosed with diabetes insipidus. Interestingly, he re-presented two months later with optic neuritis and a diagnosis of MS was made. An MRI of his brain showed lesions in his hypothalamus which accounted for his inability to produce ADH.
The most common first presentation of MS is optic neuritis. In contrast, there have only been three documented cases of MSers presenting with diabetes insipidus in the literature. One reason for this may be that demyelinating lesions are hardly detectable in the hypothalamus using conventional MRI.
Did you first present with an uncommon symptom related to MS?
Did it take a while for you to be referred to a neurologist?
Was your diagnosis delayed in any way?
The current paradigm of MS focuses on the importance of starting treatment early – (Prof G calls this ZeTo) and therefore any delay could potentially represent a missed opportunity to start treatment. This makes it important that people are referred to neuros early if their GP suspects they may have MS.
Neurology. 2011 May 31;76(22):1939-40. doi: 10.1212/WNL.0b013e31821d750c.
Diabetes insipidus as a first manifestation in multiple sclerosis.