Cases

Question 1

• Patient on a surgical ward
• Becomes hyponatremic
• Why?
• How do you treat?

Answer 1

Very common post operative becasuse:

• Infusion of hypotonic solution
• ADH due to stress

Treat - Manage fluid input

Question 2

• exertional breathlessness
• ankle oedema
• fine basal crackles
• Hypertension
• DMII

Why hyponaetremic?

Answer 2

Hypervolaemic hyponaetremia after being in a state of reduced effective blood volume

Question 3

• Acutely confused man with finger clubbing and pleural effusion
• Hyponatremic
• Low plasma osmalality

Why?

Treatment?

Answer 3

SIADH

Associated with lung pathology

Treat with loop diuretics to lower medullary osmolality

Question 4

• 72 year old with RA
• Fainting following gasteroenteritis
• Postural hypotension
• ACTH test shows normal cortisol
• Serum aldosterone levels appropriate

What is the cause of his hyponatremia?

Answer 4

Hypovolaemic hyponatremia

This can due to:

Renal - diuretics, aldosterone deficiency, salt wasting

GI - Vomiting, diarrhoea, intestinal obstruction

Cutaneous - Sweating, CF, burns, erythoderma

Question 5

Diabetic wakes up feeling shaky so drinks some lucozade.

Why are they hyponatremic?

How do you treat?

Answer 5

Osmotically active substances cause shift of water from ICF to ECF and this causes relative hyponatremia.

This can also occue with hypertonic solutions (glucose)

Treat with mannitol (osmotic diuresis)

Question 6

Student who with polydypsia and polyuria

Blood tests shows hypernatremia

Why could this be happening?

Answer 6

Diabetes inspidus - Low ADH

Causes increase urination and volume depletion and increased relative sodium.

Causes:

Cranial - tumour, meningitis, surgery

Renal - SCA, amyloid, hypokalaemia

Question 7

• 70 year old male with congestive cardiac failure
• Stable on spiranolactone, furosemide and simvastatin.
• Started on ramopril plus NSAIDS for gout
• Developed hyperkalaemia and raised creatinine plus oliguria and pulmonary oedema.

Why and how do you manage?

Answer 7

NSAID constrict afferent and ACEI dilate efferent therefore have reduced GFR which would already be low with CCF

Stop NSAIDS and reintroduce ACEI slowly

Question 8

60 year old heavy smoker with HTN controlled with four drugs

Stable renal impairment

Started on ACEI

Develops oliguria, hypoxia, pulmonary oedema

Has asymmetrical kidneys on US

What is happening?

Answer 8

Bilateral renal stenosis so high renin state and increased sodium and water rentention making HTN worse.

ACEI also reduced renal perfusion causing oedema.

Question 9

Man develops severe right sided abdo pain and becomes oliguric and odematous

Creatine rising, BP rising and has widespread vascular bruits

He has pulmonary oedma and AF.

What could be happening and what is the treatment?

Answer 9

AF leads to embolus blocking renal artery causing all the symptoms - temporary high renin state plus low GFR.

Aggresively diuresis to increase filtration and blow clot.