Theophylline toxicity leading to suicidal ideation in a patient with no prior psychiatric illness

Abstract

Suicidal behavior is a common psychiatric emergency and is associated with psychiatric illness and history of prior suicide attempts. Neuropsychiatric manifestations related to theophylline toxicity are well described in literature. We report a case of theophylline toxicity manifesting as suicidal ideation in a patient with no prior psychiatric illness.

Introduction

Suicidal behavior is a common psychiatric emergency ¹ and is frequently associated with history of prior suicide attempts and underlying psychiatric disorders. ¹ We report a case of a patient with no prior psychiatric history who attempted to commit suicide in the setting of theophylline overdose.

Case report

Our Institution does not require ethics approval for reporting individual cases. Official written informed consent was obtained from the patient for the publication of this case.

A 71-year-old morbidly obese female was brought in to our emergency room for an attempted suicide. She reported hearing voices telling her to kill herself, and she tried to cut her wrist with a pair of scissors. Patient had a prior medical history of diabetes mellitus, hypertension, and obstructive sleep apnea but no history of any psychiatric disorder as per prior medical records and had never attempted to commit suicide in the past. On presentation, she was afebrile and hemodynamically stable. She then had a generalized tonic clonic seizure in the emergency room which was managed with intravenous lorazepam followed by levetiracetam. Subsequently, patient started having atrial fibrillation with ventricular rate of 140–150; she was given intravenous boluses of metoprolol and was placed on an intravenous amiodarone infusion. Her heart rate came down to 70–80 and reverted back to normal sinus rhythm. She stayed normotensive but was drowsy and post-ictal. Local examination of her left wrist showed a 6-cm laceration which was repaired; remaining physical examination including neurologic examination was unremarkable. Laboratory studies on admission: hemoglobin of 11g/dL, serum chemistry revealed potassium of 2.8 mEq/L, bicarbonate of 18 mEq/L, glucose of 333 mg/dL, and creatinine of 2.6 mg/dL. Non-contrast computerized axial tomography (CAT) scan of the head was negative for intracranial hemorrhage. On further investigation, it was noted that she was recently started on oral sustained release theophylline by her pulmonologist in the clinic to improve her respiratory drive in obstructive sleep apnea. Patient’s dose was supposed to be titrated based on theophylline levels, but she never followed up in the clinic. Her serum theophylline level on presentation was 37.1 mcg/mL (therapeutic range: 10–20 mcg/mL, 56–111 micromol/L in SI units). Her other home medications included metoprolol and aspirin, and no recent changes were made to these medications. On Psychiatric evaluation, she was diagnosed to have acute psychosis and suicidal ideation due to theophylline toxicity. Next day, upon normalization of her theophylline level, her suicidal ideation also resolved spontaneously. Her serum potassium, creatinine and acidosis also normalized with intravenous hydration. She was re-evaluated by psychiatry, was judged non-suicidal with no active psychiatric issues and stable for discharge. Patient also denied any psychiatric problems or history of taking any psychotropic drugs prior to discharge from the hospital.

Discussion

Neuropsychiatric manifestations related to theophylline toxicity are well described ² in the literature. There is one published report of theophylline-induced psychosis in a 5-year-old child. ³ Nair and Watson ⁴ described a case of suicidal ideation in a patient who presented with toxic levels of theophylline in the setting of concomitant ciprofloxacin use which increases theophylline levels. Theophylline use has also been associated with an increased likelihood of suicidal ideation in asthma patients. ⁵ Theophylline is sometimes used to improve respiratory drive in patients with obstructive sleep apnea ⁶ as a non-licensed indication. The therapeutic steady state serum concentration for theophylline ranges from 10–20 mcg/mL (56–111 micromol/L) and has a narrow clinical therapeutic index of 1.0–1.5. ² Theophylline toxicity causes metabolic, gastrointestinal, neurologic, mus-culoskeletal and cardiovascular manifestations. At toxic doses, it leads to hypokalemia, hyperglycemia, hypercalcemia, metabolic acidosis, cardiac arrhythmias like atrial fibrillation, ventricular arrhythmias, seizures and renal failure.^2,7 Patients with theophylline overdose can also have nausea, vomiting, abdominal pain, coarse muscle tremors and hypotension. ² Management includes symptom-based supportive treatment such as intravenous metoclopramide for nausea/vomiting, lorazepam for seizures and intravenous hydration for renal failure and acidosis. ⁸ Those with life threatening toxicity, however, may require extracorporeal removal of theophylline via hemodialysis. ⁸ One limitation of our case report is that we could not confidently rule out possibility of history of psychiatric illness in our patient. In conclusion, we report another case of suicidal ideation leading to an attempted suicide secondary to theophylline overdose. This exemplifies the importance of carefully monitoring theophylline levels in order to prevent serious adverse effects.