100 Cases in Clinical Medicine

CASE 44: UNCONSCIOUS AT HOME

History

A 28-year-old woman is admitted to the emergency department in a coma. The patient
was found unconscious on the floor by her boyfriend. She had not been seen by anyone
for the previous 48 h. No history was available from the patient, but her partner volun-
teered the information that they are both intravenous heroin addicts. She is unemployed,
smokes 25 cigarettes per day, drinks 40 units of alcohol per week and has used heroin for
the past 4 years. They have occasionally shared needles with other addicts. They both had
negative HIV tests about 1 year ago. She has not made any suicide attempts in the past.
She has had no other medical illnesses. She has lost touch with her family.

Examination

There are multiple old scarred needle puncture sites. Her pulse is 64/min regular, blood pres-
sure 110/60 mmHg, jugular venous pressure not raised, heart sounds normal. Her respiratory
rate is 12/min, and she has dullness to percussion and bronchial breathing at the left base
posteriorly. Abdominal examination is normal. Her conscious level is depressed but she is
rousable to painful stimuli. She has pinpoint pupils, but has no focal neurological signs. A
bolus injection of intravenous naloxone causes her conscious level to rise transiently. Her
left arm is swollen and painful from the shoulder down.

Normal

Haemoglobin 13.6 g/dL 13.3–17.7 g/dL

White cell count 9.2% 109 /L 3.9–10.6% 109 /L

Platelets 233 % 109 /L 150–440% 109 /L

Sodium 137 mmol/L 135–145 mmol/L

Potassium 7.8 mmol/L 3.5–5.0 mmol/L

Urea 42.3 mmol/L 2.5–6.7 mmol/L

Creatinine 622 &mol/L 70–120&mol/L

Bicarbonate 14 mmol/L 24–30 mmol/L

Glucose 4.1 mmol/L 4.0–6.0 mmol/L

Calcium 1.64 mmol/L 2.12–2.65 mmol/L

Phosphate 3.6 mmol/L 0.8–1.45 mmol/L

Creatine kinase 68 000 IU/L 25–195 IU/L

Arterial blood gases on air

pH 7.27 7.38–7.44

pCO 2 7.5 kPa 4.7–6.0 kPa

pO 2 9.2 kPa 12.0–14.5 kPa

Urinalysis:'protein;'''blood

Urine microscopy: brown urine; no red cells; many granular casts

Electrocardiogram (ECG): flattened P-wave; peaked T-waves

Chest X-ray: extensive left-lower-zone consolidation

INVESTIGATIONS

Questions

• What is the cause of this patient’s acute renal failure?


• What further immediate and longer treatment does this woman need?