Emergency Medicine

180 Tox icolog y

SPECIFIC POISONS

2 Acute overdose

(i) Clinical manifestations of acute overdose include:

(a) gastrointestinal: anorexia, nausea, vomiting

(b) CNS: similar to chronic intoxication, but features develop

slowly enough for treatment with i.v. crystalloid therapy.

3 Chronic toxicity

(i) This is commonly associated with renal impairment,

dehydration, diuretic use and congestive cardiac failure.

(ii) Clinical manifestations of chronic toxicity include:

(a) CNS:

• mild: tremor, hyper-reflexia, ataxia, muscle weakness


• moderate: rigidity, hypotension, stupor


• severe: myoclonus, coma and convulsions
  (b) gastrointestinal symptoms are not present in chronic
  toxicity.
  4 Gain i.v. access and send bloods for U&Es, blood sugar and serum lithium
  level.
  5 Perform an ECG.

MANAGEMENT

1 Acute overdose

(i) Do not administer activated charcoal.

(ii) Commence normal saline to correct hypotension, salt and water

deficits, and to maintain a urine output >1 mL/kg per h.

(iii) Most patients recover quickly with adequate fluid resuscitation.

Observe until they have a normal mental status, the serum

lithium level is falling and is <2.5 mmol/L.

(iv) Consider haemodialysis in a patient with impaired renal

function, late presentation, a serum lithium level of >3.5 mmol/L

or progressive neurological signs. Contact the ICU.

2 Chronic toxicity

(i) Discontinue lithium medications. Commence normal saline to

correct hypotension, salt and water deficits, and to maintain a

high urine output.

(ii) Refer the following patient to ICU for consideration of

haemodialysis:

(a) neurological abnormalities such as an altered mental state,

coma or convulsions

(b) serum lithium level of >3.5 mmol/L and significant

neurotoxicity.