altered glucoregulation is an established risk factor predisposing to myriad complications such as endothelial dysfunction , post - operative sepsis , impaired wound healing and cerebral ischaemia in surgical patients . in rare instances , severe metabolic complications such as diabetic ketoacidosis ( dka ) and hyperglycaemic hyperosmolar state ( hhs ) might aggravate the pre - existing deranged glucoregulation and precipitate severe hyperglycaemia leading to unfavourable prognostic consequences . dka as the presenting feature of diabetes has been reported previously but its occurrence in the immediate post - operative period following perioperative stress has not been reported . we wish to report a case where dka in the early post - operative period was the initial presentation of a pre - existing latent disturbed glucoregulation following elective spinal surgery . the patient did not provide any prior history nor had any clinical manifestations of diabetes mellitus ( dm ) before this event . a 52-year - old female patient ( 55 kg , 163 cm ) was scheduled for d10 neurofibroma excision . detailed medical history elicited during her pre - anaesthetic check - up ruled out the presence of any medical comorbidities . baseline routine investigation was unremarkable , and random blood sugar ( rbs ) reading was found to be 144 mg / dl . duration of pre - operative fasting period was 7 h for solid food and 2 h for clear water in our patient . the patient underwent an uneventful laminectomy and tumour excision under general anaesthesia in prone position over a period of 4 h. steroids were not administered throughout the intraoperative period . analgesia during the intraoperative period was maintained with intermittent doses of intravenous ( iv ) fentanyl . paracetamol ( 1 gram iv ) was also administered 30 min prior to completion of surgery . following completion of surgery , reversal of neuromuscular blockade and extubation of trachea was done uneventfully . about half an hour later she started complaining of nausea , abdominal pain and became agitated and tachypnoeic . her mouth , tongue and lips appeared dry , and she started developing hypotension and tachycardia ; she was afebrile . an urgent blood sample for estimation of arterial blood gases ( abg ) and sugar was drawn and analysed . it was found that the blood glucose levels had increased to 464 mg / dl as compared to the fasting blood sugar ( fbs ) of 102 mg / dl before surgery . abg analysis revealed high anion gap ( ag ) metabolic acidosis ( ph-7.12 , bicarbonate ( hco3 ) 8 mmol / l , base deficit 18 , ag 22 , potassium ( k ) 4.2 mmol / l , sodium ( na ) 132 mmol / l ) . urinary sample was tested using dipsticks which revealed the presence of glucose and ketone bodies . serum -hydroxybutyrate was determined using an enzymatic end - point spectrophotometric method and found to be elevated ( 5.8 mmol / l ) and diagnosis of dka was established . as a part of management , fluid resuscitation was initiated with 0.9% normal saline ( ns ) ( 500 ml / h for first 4 h followed by 250 ml / h ) until euvolaemia was achieved ( tirated against vitals , urine output , state of hydration ) . insulin bolus ( iv ) of 6 u was administered followed by continuous infusion titrated according to sliding scale . ( 210 u / l ) , but lipase was within normal range ( 155 u / l ) . with the resolution of ketoacidosis , the general condition of the patient improved . the patient could be shifted to the ward on the third post - operative day . during the period of indoor admission , the glycosylated haemoglobin ( hba1c ) levels were also estimated which was found to be 7.2% . samples of blood and urine that were sent for culture during the acute event turned out to be sterile . blood glucose levels remained reasonably normal for the next 7 days on subcutaneous insulin therapy following which she was discharged with the advice to continue the same and subsequently follow - up in the endocrinology outpatient section . in our case , based on the negative history and normal level of pre - operative rbs ( 144 mg / dl ) , we did not estimate the hba1c levels . presumably , intraoperative stress accompanying surgery and anaesthesia activated the dormant dm to such an extent that the initial manifestation was of frank dka . the apparently uneventful intraoperative course could be explained based on concealment of dka symptoms under effects of general anaesthesia . overt manifestations were apparent only in the early post - operative period after anaesthetic effects had worn off . diverse circumstances ( infectious diseases , omission / inadequate dose of insulin , alcohol consumption , surgical procedures , periods of long fasting or dietetic transgressions ) can give rise or accelerate the evolution of a dm ( sometimes surreptitious ) and determine its acute dbut as a dka . nausea , vomiting and abdominal pain anaesthesia and surgery cause stereotypical metabolic stress which provokes the release of the catabolic hormones epinephrine , norepinephrine , cortisol , glucagon and growth hormone . in addition to insulin resistance induced by circulating stress hormones , surgical stress deleteriously affects pancreatic cell function . the mechanism of impairment is unclear , and the defect correlates poorly with ambient intraoperative catecholamine levels . postoperatively , however , there is a close inverse correlation between plasma epinephrine and insulin secretion . perioperative hyperglycaemia may be caused by administration of dextrose - containing fluids , hypothermia , increased lactate , steroids and heparin administration . in our case , , 7 h pre - operative fasting period combined with severe hyperglycaemia and high ag metabolic acidosis would not be expected to indicate starvation ketoacidosis . the presence of gastrointestinal symptoms consistent with dka , significant ketoacidosis and mildly elevated serum osmolality ( 293 mosm / kg ) aided in exclusion of hhs . poor pre - operative glucose control , as measured by the hba1c level , is an independent predictor of adverse perioperative outcome . american diabetes association recommends a target hba1c of < 7% . in our case , though we did assess hba1c levels preoperatively subsequent investigations revealed the values of 7.2% ( higher than the recommended target ) . in a recently published study , in 9% of all intensive care unit ( icu ) admission with elevated hba1c ( > 6% ) mortality caused by acute hyperglycaemia was highest in unknown diabetics ( increased hba1c on admission , without a history of diabetes ) than in non - diabetics , controlled diabetics and uncontrolled diabetics . thus post - operative abdominal pain and agitation should raise suspicions regarding dka amongst other causes ( surgical pain , bladder distention , etc . todi recently emphasised on routinely measuring hba1c levels in all icu patients with rbs above 140 mg / dl and categorising them as non - diabetic with stress hyperglycaemia , diabetic and stress hyperglycaemia , controlled diabetics , uncontrolled diabetics and unknown diabetics . extrapolating these findings , on pre - operative patients , assessment of the premorbid diabetic status based on hba1c can be used to stratify intra - operative management and outcome . identification of patients with latent glucose intolerance in the pre - operative period in the absence of overt history and symptoms and their proper optimisation can reduce the incidence of complications such as dka or hhs . with a substantial prevalence of unknown diabetes in the general population ,
hyperglycaemia following surgical and anaesthetic stress is a well - established entity which might have undesirable clinical consequences in known diabetics . 
 we encountered a rare event where an undiagnosed diabetic patient developed ketoacidosis in the immediate post - operative period which was her initial presenting symptom of deranged glucoregulation . presumably , the stress induced by surgery and anaesthesia lead to the genesis of this event . 
 we discuss the management of this case . 
 in addition , we highlight the importance of glycosylated haemoglobin as a subject of future research in identifying such  at risk  patients and for stratifying the risk of hyperglycaemic complications in perioperative settings .