Poisoning and Electrolyte Disturbances

Question 1

A 26 year old unconscious man is brought into A&E having been found lying alone on the street with needles next to him. The patient’s GCS = 11, RR = 10, BP = 97/65 mmHg and has pinpoint pupils. This patient likely has:

A.  Alcohol toxicity
B.  Aspirin overdose
C.  Opiate overdose
D.  Paracetamol overdose 
E.  Warfarintoxicity

Answer 1

c) Opiate Overdose

Pinpoint Pupils
Respiratory depression

Question 2

A 26 year old unconscious man is brought into A&E having been found lying alone on the street with needles next to him. The patient’s GCS = 11, RR = 10, BP = 97/65 mmHg and has pinpoint pupils. The most appropriate treatment is:
A.  IV naltrexone
B.  IV naloxone
C.  Mechanical Ventilation 
D.  IV N-Acetyl-Cysteine 
E.  IVSodiumBicarbonate

Answer 2

b) IV Naloxone

Antidote to opiate overdose.

Question 3

A 25 year old man is rushed to A&E after presenting with vomiting, hyperventilation and ringing in his ears. ABG shows a respiratory alkalosis.
The most likely cause of his presentation is:
A. Alcohol toxicity
B. Aspirin Overdose
C. Opiate Overdose
D. Paracetamol Overdose
E. Warfarintoxicity

Answer 3

b) Aspirin Overdose

Hyperventilation - respiratory alkalosis
Tinnitus

Question 4

A 70 year old woman undergoes a bowel resection for colorectal cancer. She is well prior to the operation. The operation is successful but two days after the operation she becomes very agitated.

Na = 124 (135-145)
K = 3.3 (3.5-5)
Ur = 3.1 (3-7)
Serum Os. = 265 (275-295)
Urine Os. = 150 

The most likely cause of the hyponatraemia is:
A.  Addison’sDisease
B.  Hypothyroidism
C.  SIADH
D.  Use of Diuretics
E.  Water overload

Answer 4

e) Water Overload

Post operation - being given fluids

Question 5

A 58 year old woman with metastatic pancreatic cancer attends an oncology clinic. Her husband mentions there has been occasions where she has been confused. Her U&Es show a serum sodium of 116mmol/L. Urine specimen is sent off and confirms a diagnosis of SIADH.

The most appropriate initial treatment is:
A.  Demeclocycline
B.  Desmopressin
C.  Fluid restriction to 1L per day
D.  IV infusion 5% dextrose
E.  IV infusion of normal 0.9% saline

Answer 5

c) Fluid Restriction to 1L per day

1st line treatment for SIADH

Demeclocycline (ADH inhibitor) = 2nd line

Question 6

Clinical Features Aspirin overdose?

Answer 6

Hyperventilation, Tinnitus, Sweating, Vomiting

Question 7

Opiate overdose features?

Answer 7

Low GCS, Low RR, pinpoint pupils, constipation

Organophasphates can also give pinpoint pupils - but cause diarrhoea + sweating

(TCA depressants = dilated pupils)

Question 8

Paracetamol overdose features?

Answer 8

Asymptomatic 1st 24hr, then liver failure (vomiting, abdo pain, confusion)

Question 9

Antidote Opiate overdose?

Answer 9

IV Naloxone

Question 10

Antidote Paracetamol overdose?

Answer 10

IV N-Acetyl-Cysteine

Question 11

Management aspirin overdose?

Answer 11

Acute: Fluid Resuscitation

Within 1 hour of known dose: Oral Activated Charcoal
(and/or Gastric Lavage if severe)

Moderate poisoning (>500 mg/L) : IV Sodium Bicarbonate infusion =(Alkalinediuresis)

Severe Poisoning (>750mg/L): Haemodialysis

Question 12

Lithium overdose can cause

Answer 12

Nephrogenic Diabetes Insipidus

Question 13

A 54 year old with background of high BP presents to GP with a 2 week Hx of diarrhoea following a trip to South East Asia. He was prescribed Tetracycline but his symptoms have persisted. PMHx: Undisplaced skull fracture at age 10.
What is most likely to have caused the hypernatraemia?

Na = 148 (135-145)
K = 4.8 (3.5-5)
Ur = 13 (3-7)
Cr = 112 (70-110)

A.  Conn’sSyndrome
B.  Nephrogenic Diabetes Insipidus
C.  Cranial Diabetes Insipidus
D.  Tetracycline
E.  Dehydration

Answer 13

E) Dehydration

Diarrhoea

Question 14

Causes hypovolaemic hypernatraemia

Answer 14

Loss water

eg. D+V, sweating, osmotic diuresis (eg hyperglycaemia)

Question 15

Causes euvolaemic hypernatraemia

Answer 15

Not enough water
eg Inability to access water (elderly people)
Cranial/nephrogenic DI

Question 16

A 55 year old man admiped for an exacerbation of asthma, is given regular nebulizers alongside his regular anti- hypertensive medication during his stay. A final blood test was done before discharge.
Which drug is most likely to have caused the hypokalaemia?

Na = 137 (135-145)
K = 2.9 (3-5.5)
Ur = 5.1 (3-7)

A.  Ipratropium
B.  Ramipril
C.  Salbutamol
D.  Amlodipine 
E.  Paracetamol

Answer 16

c) Salbutamol

Salbutamol nebs cause K to be taken up into cells.

Question 17

A 30 year old man presents with increased skin pigmentation, vitiligo, postural hypotension and the following blood results.
What might have caused his hyperkalaemia?

Sodium = 130 (135-145)
Potassium = 6.5 (3.5-5.0)
Urea = 6.0 (3.0-7.0)

A.  ACE-I
B.  Addison’sDisease
C.  Conn’s Syndrome
D.  Rhabdomyolysis
E.  Spironolactone

Answer 17

b) Addison’s Disease

Pigmentation
Vitiligo (Autoimmune)
Postural Hypotension

Question 18

Causes Hypokalaemia?

Answer 18

GI: Vomiting
Renal Loss:
•  Diuretics
•  Primary hyperaldosteronism (Conn’s)
Redistribution into cells:
•  Insulin, Beta-agonists e.g. salbutamol
•  Alkalosis

Question 19

Presentation Hypokalaemia?

Answer 19

• Muscle weakness
• Arrhythmias
• Polyuria


Question 20

In Conn’s, is K up or down?

Answer 20

Low Potassium
(High Aldosterone)

Investigations
• Aldosterone : Renin Ratio
• ↑ in Conn’s (↑ Aldosterone)

Question 21

Management hypokalaemia?

Answer 21

• Treat the underlying cause.
• K+ <3.0mmol/L • IV potassium chloride

Question 22

Addison’s disease = High or Low K?

Answer 22

High K

Low aldosterone

Question 23

Causes Hyperkalaemia?

Answer 23

• Addison’s Disease (↓Aldosterone)

• Drugs • e.g. ACE-I, ARBs, Spironolactone
• Renal impairment

• Release from cells: • Rhabdomyolysis (Crush injuries) • Acidosis

Question 24

Management Hyperkalaemia?

Answer 24

1. 10ml 10% Calcium Gluconate
2. 50ml 50% dextrose + 10 units of insulin
3. Nebulized salbutamol
4. Treat underlying cause

Question 25

A 22 year old student revising hard for her exams begins developing numbness in her hands and twitching. ECG showed a prolonged QT interval
What might have caused his hypocalcaemia?


Ca = 2.0 (2.2 – 2.6 mmol)
PTH = 10.4 (0.8-8.5pmol/
ALP = 190 (30-150u/L)
Phosphate = 0.69 (0.8-1.2mmol/
Vitamin D =  41 (60-105 nmol/L)


A.  Primary hyperparathyroidism
B.  Tertiary hyperparathyroidism
C.  Osteoporosis
D.  Renal Failure
E.  Vitamin D Deficiency

Answer 25

E. Vitamin D Deficiency

Question 26

A 60 year old woman with lung cancer is electively admitted for her 2nd cycle of palliative chemotherapy. She has known metastasis to her ribs and vertebrae. Since her last cycle of chemotherapy she has felt lethargic and cons%pated. Her corrected calcium levels are 2.95 mmol/ L (2.15-2.65). The most appropriate treatment is:

A.  Administer chemotherapy
B.  IV rehydration alone
C.  IV rehydration and Pamidronate
D.  Delay chemotherapy until patient feels beper 
E.  VitaminDSupplements

Answer 26

C. IV rehydration and Pamidronate

Question 27

Causes Hypercalcaemia

Answer 27

PTH suppressed: Malignancy, Sarcoidosis, Multiple Myeloma (low ALP)

PTH not suppressed: Primary Hyperparathyroidism

Question 28

Causes Hypocalcaemia

Answer 28

Renal Failure 
Vit. D deficiency
Low PTH (DiGeorge Syndrome)