Case presentation
A 61-year-old Japanese woman was referred to our psychiatric ward due to
disturbance of consciousness. She had been diagnosed with
schizoaffective disorder at 17 years of age and had been subsequently
treated with several antipsychotic drugs, including lithium. Psychiatric
symptoms were predominantly negative, and included decreased motivation,
emotional flatness, and autism. She visited an outpatient clinic
regularly for a long period of time; her last measurement of lithium
concentration in serum was 0.51 mmol/L. She had been diagnosed with
stage IIIC1 endometrial cancer with lymph node metastases (T2N1M0) at 59
years of age. She underwent total abdominal hysterectomy, bilateral
salpingo-oophorectomy, and pelvic lymph node dissection accompanied by
adjuvant pelvic radiotherapy. Within the same year, multiple distant
metastases were found, and the patient received chemotherapy consisting
of six cycles of docetaxel/carboplatin. Three months after the end of
chemotherapy, the cancer recurred in the liver and para-aortic lymph
nodes. The patient received six cycles of doxorubicin/cisplatin together
with radiotherapy for the metastatic para-aortic lymph node. However,
tumor progression could not be controlled, the patient developed ascites
and hydronephrosis, and renal function decreased. Although her serum
creatinine level was approximately 2.0 mg/dl, she refused the insertion
of a ureteral stent. She gradually became unable to walk and suffered
from appetite loss. She received palliative care, as her survival time
was estimated to be only of several months. Fortunately, she did not
suffer from severe cancer pain and did not need to be treated with any
non-steroidal anti-inflammatory drugs or opioids. Her physical functions
had deteriorated during this period; she developed a gait disturbance
and could not maintain a seated position. Subsequently, she became
confused. Her consciousness was cloudy and accompanied by dysarthria and
myoclonus. At this point the patient was admitted to the Obstetrics and
Gynecology ward of our university hospital. She had hypotension,
tachycardia, and a mild fever. The patient’s laboratory data are
presented in Table 1 . Electrocardiography and head computed
tomography revealed no abnormalities. The focus of the infection could
not be determined from blood or urine samples, or from a computed
tomography scan, and an enhanced inflammatory response due to tumor
progression was considered as a possible diagnosis. The reason for the
decreased renal function was determined to be the extreme dehydration
derived from cancer cachexia. She was referred to the outpatient
department of our hospital because of delirium associated to her
deteriorating general condition. Her total score on the delirium rating
scale-revised-98 (DRS-R-98) 8 was 23 points. Thus, we
diagnosed the patient with delirium associated with progressive-stage
cancer. Given that she was being treated with several psychotropic drugs
(i.e., lithium 300 mg/day, haloperidol 2.25 mg/day, chlorpromazine 25
mg/day, biperiden 6 mg/day, flunitrazepam 2 mg/day, and suvorexant 20
mg/day) and she demonstrated reduced renal function as assessed by the
serum creatinine test, her levels of lithium in serum were checked
and found to have a value
considered toxic (3.02 mEq/L). The patient received hemodialysis
immediately; her serum lithium concentration decreased to 1.68 mEq/lL
after the first session and finally to 0.98 mEq/L after the second
session. The clouded consciousness, dysarthria, and myoclonus recovered
and eventually disappeared in parallel to the decrease in the serum
lithium levels (her DRS-R-98 score decreased to 4 points). Moreover, the
gait disturbance and postural retention disorder were completely
resolved. Results from the blood tests after the treatment are shown inTable 1. There was no further worsening of mental status after
lithium treatment was discontinued.