Sodium handling

Question 1

Choose the most appropriate answer from the list

• Addison’s Disease
• Diuretic
• Cardiac Failure
• Grave’s Disease
• Cirrhosis
• Hypothyroidism
• Conn’s Syndrome
• Lung Cancer
• Cranial Diabetes Insipidus
• Nephrogenic Diabetes Insipidus
• Cushing’s Disease
• Pneumothorax
• Cushing’s Syndrome
• Pretibial Myxoedema
• Diabetes Mellitus
• SIADH

A 53 year old woman presents with a serum Na of 129mmol/L, and complains of recent weight gain and ‘problems with her bowels’.

Answer 1

Hypothyroidism

Question 2

Choose the most appropriate answer from the list

• Addison’s Disease
• Diuretic
• Cardiac Failure
• Grave’s Disease
• Cirrhosis
• Hypothyroidism
• Conn’s Syndrome
• Lung Cancer
• Cranial Diabetes Insipidus
• Nephrogenic Diabetes Insipidus
• Cushing’s Disease
• Pneumothorax
• Cushing’s Syndrome
• Pretibial Myxoedema
• Diabetes Mellitus
• SIADH

A 27 year old man presents with polyuria and polydipsia after an operation to remove a benign brain tumour. His serum Na is 149mmol/L.

Answer 2

Cranial Diabetes Insipidus

Question 3

Choose the most appropriate answer from the list

• Addison’s Disease
• Diuretic
• Cardiac Failure
• Grave’s Disease
• Cirrhosis
• Hypothyroidism
• Conn’s Syndrome
• Lung Cancer
• Cranial Diabetes Insipidus
• Nephrogenic Diabetes Insipidus
• Cushing’s Disease
• Pneumothorax
• Cushing’s Syndrome
• Pretibial Myxoedema
• Diabetes Mellitus
• SIADH

A 72 year old woman presents to the GP with ‘dizziness on standing up’, serum Na is 133mmol/L and serum K is 5.5mmol/L.

Answer 3

Addison’s Disease

Question 4

Choose the most appropriate answer from the list

• Addison’s Disease
• Diuretic
• Cardiac Failure
• Grave’s Disease
• Cirrhosis
• Hypothyroidism
• Conn’s Syndrome
• Lung Cancer
• Cranial Diabetes Insipidus
• Nephrogenic Diabetes Insipidus
• Cushing’s Disease
• Pneumothorax
• Cushing’s Syndrome
• Pretibial Myxoedema
• Diabetes Mellitus
• SIADH

A 60 year old man with a 45 pack-year smoking history presents with a serum Na of 130mmol/L. He is euvolaemic and both TFTs and short synacthen test results were normal.

Answer 4

SIADH

Question 5

Choose the most appropriate answer from the list

• Addison’s Disease
• Diuretic
• Cardiac Failure
• Grave’s Disease
• Cirrhosis
• Hypothyroidism
• Conn’s Syndrome
• Lung Cancer
• Cranial Diabetes Insipidus
• Nephrogenic Diabetes Insipidus
• Cushing’s Disease
• Pneumothorax
• Cushing’s Syndrome
• Pretibial Myxoedema
• Diabetes Mellitus
• SIADH

A 65 year old man presents with increasing shortness of breath and serum Na 125mmol/L. On examination there are bibasal crackles in the chest, and you also note clubbing, jaundice and gynaecomastia.

Answer 5

Cirrhosis

Question 6

A 62y.o male arteriopath has a sodium of 132, mild tachycardia and reduced urine output. He has recently been treated for fluid overload and had normal sodium prior to this treatment. No other relevant signs are noted. Rank the following diagnoses given this information, putting the MOST LIKELY diagnosis first, and the least likely diagnosis last:

A) Cardiac failure

B) Diabetes insipidus

C) Adrenal insufficiency

D) Diuretics

Answer 6

Diuretics
Cardiac failure
Adrenal insufficiency
Diabetes insipidus

Diuretics - This person is most likely to have hyponatraemia caused by excessive treatment of their fluid overload, also making them hypovolaemic now.

Cardiac failure – This could explain the previous fluid overload in an arteriopath, but is less likely to explain the current hyponatraemia due to the fact that it did not appear until treatment began for fluid overload.

Adrenal insufficiency – This can cause hyponatraemia but would be expected to leave the patient euvolaemic and may also give additional examination findings.

Diabetes Insipidus – This causes hypernatraemia so does not explain the hyponatraemia at all.