Xanthochromia is a yellow, orange, or pink discoloration of the CSF, most often caused by the lysis of RBCs resulting in haemoglobin breakdown to oxyhaemoglobin, methemoglobin, and bilirubin (Seehusen et al. 2003). Xanthochromia is associated with subarachnoid haemorrhage (SAH), Guillian-Barre Syndrome, intracranial bleed, spinal cord tumours, acute purulent meningitis, blood dyscrasias, hyperbilirubinemia, high CSF protein, and traumatic spinal tap (Koton and Bisharat 2017; Seehusen et al. 2003). The most common cause of xanthochromia is subarachnoid bleed which can be missed with negative CT brain. The sensitivity for detecting a bleed by CT decreases from up to 95% on day 1 to less than 10% in 3 weeks, with the sensitivity of CSF analysis for xanthochromia remaining constant near 100% over this time (Petzold et al. 2005). Diagnosis of xanthochromia can be done by direct visualisation in which the CSF sample is centrifuged, and the supernatant is visually inspected for yellow colour. The second method is spectrophotometry which is considered superior to visual inspection (Sidman et al. 2005; Petzold et al. 2004).

One of the causes of xanthochromia was cited as subarachnoid haemorrhage. In our case, this is the probable cause as the patient had a history of fall from height. However, there were no signs or symptoms of head injuries or increased intracranial pressure and CT brain which was done within 12 h of fall was normal. We can assume that it was missed or was minor so that it was not detected. Another possibility can be spine surgery with instrumentation resulting in localised trauma. However, there was no neurological signs or symptoms to support that assumption. We consider dengue fever can be a contributing factor to xanthochromia due to an increase in serum bilirubin level. However, serum bilirubin does not cross the blood–brain barrier and was not significantly raised in our case. Viral or bacterial meningitis was the least likely cause as CSF analysis was normal with no correlating clinical signs.

Our initial plan was regional anaesthesia as surgery was of the lower limb with no major contraindications for the same. However, when we encountered yellowish CSF, we were in a dilemma whether to proceed or abandon the procedure. We considered general anaesthesia to be the safer option for surgery.

Gokahmetoglu et al. reported a similar finding of xanthocromic CSF during spinal anaesthesia; they decided to abandon the surgery for further investigation. The patient was subsequently diagnosed with Froin syndrome due to an intramedullary mass lesion resulting in spinal blockade, high CSF proteins, and xanthochromia (Gokahmetoglu et al. 2014).

In an interesting case report by Minz et al., the author encountered xanthochromia and decided to proceed with spinal anaesthesia. They were able to achieve adequate subarachnoid blockade with no postoperative complications (Minz et al. 2022).

Adabala et al. in their case report recommended that subarachnoid block should be abandoned when encountered with yellow CSF as it may be associated with CSF obstruction, spinal tumour, or vertebra deformity that may make the sensory and motor anaesthesia unpredictable (Adabala et al. 2019). In our case, considering the same possibilities, we decided to abandon the surgery under spinal anaesthesia and proceeded with general anaesthesia. We want to share our experience as we have not encountered xanthochromia previously, with limited literature and experience, proceeding with spinal anaesthesia in our case was a critical decision. After extensive literature research we found few case reports in which anaesthesiologist faced the similar problem of xanthochromia with the difficult decision-making regarding anaesthesia (Gokahmetoglu et al. 2014; Minz et al. 2022; Adabala et al. 2019; Singh et al. 2015). The opinion regarding the safety of subarachnoid block in xanthochromia varies with anaesthesiologist, so decision to proceed or abandon anaesthesia should be individualised depending on history, associated signs, and symptoms of the patient.