Perioperative management of cranial diabetes insipidus in a patient requiring a tracheostomy

Abstract

Cranial diabetes insipidus (DI), which can cause life-threatening dehydration, is treated with desmopressin, often intranasally. This is challenging in patients whose nasal airflow is altered, such as those requiring tracheostomy. We report the case of a patient, taking intranasal desmopressin for cranial DI, who underwent partial glossectomy, free-flap reconstruction and tracheostomy. Postoperatively, she could not administer nasal desmopressin due to reduced nasal airflow. She developed uncontrollable thirst, polyuria and hypernatraemia. Symptoms were relieved by switching to an enteric formulation. A literature review showed no cases of patients with DI encountering difficulties following tracheostomy. The Royal Society of Endocrinology recommends perioperative planning for such patients, but gives no specific guidance on medication delivery in the context of altered airway anatomy. Careful perioperative planning is required for head and neck patients with DI, particularly for those undergoing airway alteration that may necessitate a change in the mode of delivery of critical medications.

Background

Diabetes insipidus (DI) is a rare syndrome characterised by the excretion of large amounts of hypotonic urine with associated polydipsia.¹ It has a prevalence of 1 in 25 000.² The most common form, cranial DI, is due to the inadequate production and secretion of arginine vasopressin (AVP) from the posterior pituitary gland. This can result from pituitary pathology, head trauma or iatrogenic injury during surgery, although up to 50% of cases are idiopathic.³ Other forms include nephrogenic DI, primary polydipsia and gestational DI.²

The aims of treatment are to normalise fluid balance and control symptoms. For chronic cranial DI, treatment is the long-acting, synthetic AVP analogue, desmopressin (DDAVP).⁴ This is available as an oral, intranasal or parental formulation.⁵ Intranasal preparations offer the advantage of a lower dose delivered locally, with rapid and predictable efficacy.⁶ However, they require clear nasal passages and the ability to sniff—the latter becoming physiologically impossible if a patient becomes an obligate neck-breather, such as following laryngectomy or the insertion of a cuffed tracheostomy.⁷

A literature review showed no previous case reports, or published guidance, on this subject. We present the first published case of a patient with cranial DI requiring a tracheostomy and the lessons learnt for perioperative management of DI in this situation.

Case presentation

A 48-year-old woman presented with a 3-month history of a lesion on the left side of her tongue. It was noted that 9 months previously, she had been diagnosed with idiopathic cranial DI for which she took 10 µg of intranasal desmopressin two times per day (one spray into one nostril two times per day). She took no other medications except for the contraceptive pill. She was a non-smoker, had never smoked and drank four units of alcohol a week. Intraoral examination revealed a lesion of the left lateral tongue consistent with a T2 squamous cell carcinoma or severe dysplasia.

Investigations

MRI showed a plaque-like lesion of the left tongue and likely infiltration of the hyoglossus muscle. Biopsy was consistent with squamous cell carcinoma of the lateral tongue.

Treatment

In consultation with the patient, a decision was made to undertake a wide local excision of the lesion, neck dissection and immediate reconstruction of the lateral tongue with a free flap. It was explained that a temporary covering tracheostomy would be required while the flap settled.

The patient was seen preoperatively in the head and neck oncology multidisciplinary assessment clinic, including by a dietitian and speech and language therapist. On one pre-assessment form, her medical history was recorded as ‘diabetes’. Separately, the dietitian recorded that the patient had DI and noted that she took desmopressin. The patient reported that she drank five to six cups of tea and coffee daily, but no water, saying that she had excess urine output. It was explained to the patient that she would be nil by mouth postoperatively and that she would undergo nasogastric (NG) tube feeding initially, with the aim of progressing to oral diet.

On the morning of surgery, the patient took her nasal desmopressin as usual, and her regular nasal desmopressin was prescribed for use postoperatively. Of note, the patient’s anaesthetic chart recorded her medical history as syndrome of inappropriate antidiuretic hormone secretion (SIADH).

The patient underwent a left partial glossectomy, selective neck dissection (levels I–III), a medial sural artery perforator free flap and a temporary, covering tracheostomy. The procedure was uncomplicated and the patient was routinely transferred to intensive care for an overnight stay. At the intensive care handover postoperatively, particular mention was given to the importance of ensuring the nasal desmopressin was delivered as prescribed. The patient was stepped down from the intensive care unit on day 1 postoperatively. The tracheostomy cuff was deflated on day 3 postoperatively.

Outcome and follow-up

On day 3 postoperatively, the patient reported that she found the desmopressin difficult to administer as she could not adequately perform nasal inspiration. She reported excessive thirst and needing to urinate every 2 hours. It was also noted that her serum sodium had increased from 133 to 147 mmol/L.

Endocrinology colleagues were consulted that day and advised switching to oral desmopressin tablets, which could be crushed and administered via the NG tube, at a dose of 100 µg three times per day. Four days later, her sodium had normalised but she remained symptomatic until the following day. Endocrinology further advised waiting 2 days after the removal of the tracheostomy, and for the removal of NG tube, before restarting the intranasal desmopressin.

Following improvement of her symptoms of polydipsia and polyuria, the patient described the thirst caused by the uncontrolled DI as being like ‘uncontrollable torture’ and said that ‘the other postop challenges were minor in comparison’. She stated that seeing a glass of water while nil by mouth had been ‘unbearable’. The patient was decannulated on day 8 postoperatively, and the NG tube was removed on day 10. She was discharged home on day 13 postoperatively, when intranasal desmopressin was restarted. Three months postoperatively, the patient has returned to her preoperative weight, and is well, with no recurrence of symptoms of uncontrolled DI.

Discussion

Cranial DI requires careful perioperative management to prevent potentially life-threatening dehydration.⁸ There are no other case reports in the literature describing the deterioration of a patient with DI following airway-altering surgery.

In this case, note was made of the patient having DI, treated with intranasal desmopressin, in her very first outpatient consultation; despite this, preoperative planning regarding her DI was not optimised. Furthermore, her condition was recorded as ‘diabetes’ in one pre-assessment and as ‘SIADH’ preoperatively by the anaesthetist, demonstrating that many clinicians may lack familiarity with the condition.

National guidance exists on the inpatient and perioperative management of DI in the UK (figure 1).⁸ The Society of Endocrinology recommends that patients with cranial DI undergoing elective surgery are highlighted in the pre-assessment process and a clear plan made for perioperative management. The guidelines also recommend preoperative involvement of the endocrinology team, so that a clear plan for management can be developed prior to admission. Unfortunately in this case, the endocrinology team were not involved until the patient’s clinical status had deteriorated.

Figure 1.

Summary of organisational guidance for hospitals on inpatients with cranial diabetes insipidus (CDI). Adapted from the Society of Endocrinology Clinical Guidance: Inpatient management of cranial diabetes insipidus.⁸ DDAVP, desmopressin, a synthetic arginine vasopressin analogue.

The society provides a list of patient groups at risk of rapid deterioration of cranial DI. These include patients who are nil by mouth, fasting or have low oral intake, and those unable to self-administer DDAVP. The guidance does not cover those patients who may undergo airway alteration as a result of surgery. Nasal inspiration becomes impossible when a patient has a cuffed tracheostomy inserted or undergoes a laryngectomy, as airflow is redirected through the neck stoma and all nasal airflow is abolished.⁷ This makes the administration of nasal medications difficult and therefore alternative routes of administration should be considered. Enteral absorption via NG or nasojejunal routes is also variable and subcutaneous administration may be more reliable. The authors of this paper feel that patients with cranial DI and altered airway anatomy should be considered as at risk of deterioration, and it should be highlighted that modifications may be needed to desmopressin administration.

Patient’s perspective.

I have only had DI for a year and in that time I have had to explain very carefully to even well-established health professionals the difference between this and the more ‘normal’ diabetes. I have stopped saying it’s DI and started saying its Pituitary Insipidus, it saves a lot of confusion! My endocrinology consultant always warned me of the dangers of this condition, especially when in a hospital setting. I was therefore very insistent in discussing this with my cancer team at every opportunity. However, there was not one point when anyone considered the effectiveness of the nasal medication when fitted with a tracheostomy. I didn’t think anything of it.

I first noticed there was a problem after the operation when I started going to the toilet a lot and was desperately thirsty. DI thirst is not like a normal thirst – it is totally consuming and feels like ecstasy when you finally get a drink! As I was nil by mouth I was having to ask the nurses constantly to push water through my feeding tube – I had no voice and had to reassure them that I knew what I was doing!

At some point I realised that I had no suction in my nose when taking the desmopressin spray so alerted nurses. It took a while for anyone to understand what I meant and to know how to react – I text messaged my endocrinology consultant and showed his response on my phone to various people. He was cross that I had not been seen by an endocrinologist and told me to ensure I requested one. I guess at some point I was prescribed my dosage via feeding tube and everything became pleasant again!

Now this is all over and I am fully recovered, it does seem like there were definite errors in my care. Had I been less tenacious and aware of my condition, often having to demand water from confused nurses, I wonder how much worse it could have been? I had to tell at least two nurses to stop asking for my blood sugars to be tested. If I go into hospital again I will produce a big sign to display over my bed to highlight my condition! It was an unpleasant complication to what was faultless treatment and care. My only reason in making the above comments is that I hope it helps highlight the awareness and knowledge about this ridiculous condition which is so easily treated yet so dangerous to get wrong.

Learning points.

• Cranial diabetes insipidus is a serious, treatable condition with the potential for harm.

• Desmopressin is a life-preserving treatment and must never be omitted.

• Clinician familiarity with this condition may be variable and diabetes insipidus must never be confused with diabetes mellitus or other endocrinological diagnoses, for example, syndrome of inappropriate antidiuretic hormone secretion.

• All patients with diabetes insipidus must have a clearly documented perioperative plan and the endocrinology team should be involved early in the event of complications.

• Current national guidelines do not highlight the potential risks posed to patients using intranasal desmopressin who undergo surgery that may alter airway anatomy, such as a tracheostomy.