Smoke on the water: A case report of chronic renal failure resulting from the ingestion of smoke machine fluid

Abstract

We report the case of an 18-year-old male admitted to the Intensive Care Unit in Basingstoke and North Hampshire Hospital, who developed chronic kidney disease following the ingestion of smoke machine fluid. Smoke machine fluid may contain ethylene glycol, and a diagnosis of ethylene glycol toxicity with calcium oxalate nephropathy was made. This case resulted in a National Poisons Information Service internal review of the subject and a new TOXBASE entry for smoke machine fluid ingestion.

Case

We report the case of an 18-year-old male presenting to the Emergency Department with vomiting and anuria following reported ingestion of 3 l of a fluid used in a smoke machine 35 h previously. The patient had mild learning difficulties and reported ingesting the liquid due to intrigue with no self-harm intent. He complained of nausea, vomiting and mild abdominal and back pain. He had been anuric for over 24 h.

Blood results taken on admission showed a raised urea (6.1 mmol/l) and creatinine (176 mmol/l) with a normal full blood count and liver function tests on a background of a normal renal function. A venous blood gas showed a metabolic acidosis with a pH of 7.21, ${\text{HCO}}_3^{-}$ 15.3 mmol/l, BE 11.7 mmol/l, lactate 1.8 mmol/l. An anion gap was calculated at 17.3 mEq/l (normal range: 3–11 mEq/l) and an osmolar gap was calculated at 4 mOsm/kg (normal range: <10 mOsm/kg). A diagnosis was made of acute kidney injury, possibly consistent with the metabolism of glycol products.

The case was discussed with a toxicology consultant at the National Poisons Information Service (NPIS) who advised intravenous hydration and hemofiltration if renal function deteriorated. Fomepizole was not recommended by the NPIS and ethylene glycol levels were not measured.

The metabolic acidosis continued to be static; however, the patient remained anuric and renal function continued to worsen.

The patient was admitted to the intensive care unit (ICU) and Continuous Veno-Veno Haemofiltration with heparin anticoagulation was commenced. Liver function tests showed raised transaminases (ALT 278 u/l) and a raised amylase (685 u/l); coagulation tests remained normal. Following normalisation of transaminases citrate anticoagulation was commenced. He also developed hypertension (170/90 mmHg) requiring amlodipine and bisoprolol.

A total of eight days of renal replacement therapy were required on ICU during which time he remained anuric before he was transferred to the regional renal unit. He remained on the regional renal unit for 20 days. His urine output recovered but further haemodialysis was required via a tunnelled RIJ central line. On day 14, he developed abdominal pain, which was traced to a 3-mm right mid-pole renal calculus, with a raised urinary oxalate. An episode of abdominal sepsis was treated with meropenem and vancomycin and resolved with no positive microbiology.

He was discharged to outpatient renal follow up after 20 days on the regional unit with a total of 28 days of renal replacement therapy. Five months post poisoning, he has a residual kidney injury with an elevated urea (20 mmol/l) and creatinine (523 mmol/l).

Discussion

Smoke machines are used to produce smoke or fog for performance purposes. The most common type is a heated system where a solution of glycol ethers including ethylene glycol and propylene glycol, glycerol and mineral oils is passed over a heated element. This solution vaporises as it passes over the element and then through an outlet on the machine producing the smoke.

Previous research has investigated the effects of inhaling this vaporised solution, rather than ingestion. Studies have linked long-term exposure to glycol-based solutions with irritation of mucous membranes, headaches and long-term respiratory symptoms.^1,2

No literature was found on the ingestion of smoke machine fluid; however, ingestion of specific compounds such as glycol ethers found within the solution is well studied. ³ In this case, identification of the particular smoke machine fluid was not possible, the packaging having been discarded.

The clinical features seen in this case can be explained by the metabolism of the compounds ingested. An indication that the ‘unidentified solution’ ingested was likely to contain glycol ethers was based on that the patient had a metabolic acidosis with a raised anion gap. The anion gap represents negatively charged proteins that are not normally measured by serum analysers and can be calculated by the following calculation: ([Na⁺] + [K⁺]) – ([Cl⁻] + [ ${\text{HCO}}_3^{-}$ ]). In this case, the raised anion gap can be explained by an increase in unmeasured serum anions of the metabolites of ethylene glycol. ⁴ We note that the osmolar gap was not elevated at presentation, possibly due to the delay between ingestion and attendance at hospital. This does not exclude ethylene glycol ingestion as delayed presentation can be associated with a normal osmlolar gap due to metabolism into toxic but osmotically inactive products. ⁵

One of the main compounds was thought to be ethylene glycol (Ethane-1, 2-diol). Ethylene glycol is an odourless, organic solvent found in many agents. The compound is not intrinsically toxic but it is metabolised into toxic substrates. One of the final metabolites produced is oxalic acid, which may crystallise to form calcium oxalate monohydrate crystals. These crystals may precipitate in the tubular lumen of the kidney causing an acute oxalate nephropathy. ⁶ Focal necrosis in the liver has also been reported.^7,8

Propylene glycol (propane-1,2-diol) is commonly used as a solvent in household domestic products and it is often used as a solvent in the pharmaceutical industry. When ingested at high levels propylene glycol toxicity can occur, clinical features due to the metabolites include hyperosmolarity, intravascular haemolysis, central nervous system toxicity and cardiac arrhythmias. ⁹ Unlike ethylene glycol, propylene glycol is not metabolised into the substrate oxalic acid and, therefore, calcium oxalate nephropathy has not been associated with propylene glycol toxicity.

This case resulted in a NPIS internal review of the subject and a new TOXBASE entry ¹⁰ for smoke machine fluid ingestion resulting!