Looking out for SIADH and Diabetes Insipidus
In order to understand better regarding pituitary tumor, it's best that we know the normal pituitary, it's anatomy and physiology. I hope this entry is not too academic for you. In fact, it's good to have some basic medical knowledge to spice up your social conversations, :p

The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea that sits in a small, bony cavity (pituitary fossa) covered by a dural fold (sellar diaphragm) at the base of the brain. The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoid bone in the middle cranial fossa at the base of the brain. The pituitary gland secretes hormones regulating homeostasis, including trophic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamus by the median eminence.

It is divided into two lobes: the anterior or front lobe (adenohypophysis) and the posterior or rear lobe (neurohypophysis). The hormones secreted by the posterior pituitary are Oxytocin and Antidiuretic hormone (ADH - also known as vasopressin and AVP, arginine vasopressin). Anterior pituitary secrete growth hormone, prolactin, follicle-stimulating hormone, luteinizing hormone , thyroid-stimulating hormone , adrenocorticotropic hormone (ACTH),endorphins .

The most common risk of a pituitary surgery is damage to the normal pituitary gland. This means that new hormone replacement might be required after the surgery, possibly including thyroid hormone, cortisol and ADH. Thus, an endocrinologist was necessary to help in the joint management especially in assessing the hormonal disturbances, should there be any.

One of the immediate and serious complication after a pituitary operation is Diabetes Insipidus, a condition marked by frequent urination and excessive thirst, since the kidneys will no longer adequately concentrate the urine. In most cases, DI is self-limited and resolves within a week to 10 days after surgery.

The syndrome of inappropriate antidiuretic hormone (SIADH) is another condition commonly found after brain surgery. As the name states, this is a syndrome characterized by excessive release of antidiuretic hormone (ADH or vasopressin) from the posterior pituitary gland . The result is hyponatremia, and sometimes fluid overload.

11th Feb
The next morning, with permission I managed to see him early. Alhamdulillah he was more alert albeit still weak and semi-drowsy. As one of the complication of general anesthesia, he had developed a right upper lobe lung collapse causing him to be dyspnoeic. For this he had to be on oxygen therapy via mask. With the nasal packing which forced him to breathe through his mouth and the lung collapse, the shortness of breath was exaggerated unbearably. The humidified dry oxygen caused his lips and tongue to be cracked and painful. Pinching my nose and trying to breathe through the mouth, simulating almost a similar state, I find it very taxing and burdensome to the point of almost gasping for air! Alhamdulillah that he was given great patience to not panic and endure the dire circumstance. I can't say the same if it was me! And to think that he was to suffer in that manner for almost 11 days!Subhanallah!

Meanwhile, the ICU staffs were diligently monitoring his input/output, in order to enable them to detect the slightest sign of emergence of SIADH and also DI. Once the urinary output exceeds 800 ml in 4 hours, they were instructed to administer Minirin (desmopressin) to prevent severe dehydration and hypernatremia (concentrated sodium in blood).

Managing DI can be quite exasperating as there are many overlapping symptoms originating from other causes and other post-op complications that can exaggerate the condition further which can tempt overzealous treatment. For instance, in Azmi's case, as he was on continuous oxygen inhalation through his mouth, dryness of the buccal mucosa triggered his thirst centre, which caused him to consume more fluids than usual and this would naturally increase his urine output. However despite the increased in output volume, his urine was always concentrated, a sure sign that DI had not set in.

A useful drinking gadget
Another thing that I marveled about Azmi's post-op disposition is his unaltered thinking capacity. He could grasp anything being explained by the surgeons regarding his illness and its treatment and apply on himself wherever possible. When he needed to have frequent sips of water to wet his dry mouth, he designed a drinking gadget in his mind and asked Dr Zurin to set it up. The long tube of a drip set was sacrificed and cut at both ends and connected to a drinking bottle. Incidentally the bottle, which was used to hold 'air zam-zam' had a special pout to smugly fit the tube and not easily slip through. Through out his 9 days in ICU, the gadget served as his drinking vessel, filled with 'air zam-zam'. Perhaps we should patent this idea eh? By the way, we had constant supply of air zam-zam, thanks to relatives and friends.

An unlikely menu
When he was allowed solids, we tried giving him rice porridge with soup. However he had difficulty in swallowing it without having some of the rice regurgitating into the back of his nostrils. Thus they requested blended porridge which is an unlikely item in his normal day menu! Once, they even pureed his oats! But, Alhamdulillah, he was very patient and feeding him was no problem at all.

Having a sip of air zam-zam from his 'designer' bottle

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Meanwhile, visitors kept popping in, in twos, i.e. the number of visitors allowed each time. As Azmi was weak , I had to do the talking. Mostly, I had to explain how the op was done as many were still unaware of the nature of the surgery. Alhamdulillah, this time, they restricted their visiting ado and quietly prayed for him. Even though he was still weak from the anesthesia and all, falling asleep off and on, his progress was very encouraging. And when the DI surveillance showed that he was fairly out of danger, they decided to move him out on 12th Feb, to an isolated private cubicle in CICU upstairs which offers more privacy and convenience for me as it was on the same floor as our ward-room.

Next: Lumbar drain and CSF leak