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Symptoms and Signs – Differential Diagnosis of Hypokalaemia
Gastrointestinal loss
Vomiting, diarrhoea, villous adenoma, VIPoma, fistulae, ileostomies
Renal loss
Excess mineralocortcoids (--potassium excretion)
Hyperaldosteronism
Increased Glucocorticoids: Cushing's syndrome, liquorice (inhibits 11 [3-hydroxysteroid
dehydrogenase and l glucocorticoid metabolism), 11 [3-hydroxysteroid
dehydrogenase deficiency
Congenital adrenal hyperplasia (11 [3-hydroxylase and 17 cr-hydroxylase
deficiency)
Increased Na+ delivery to distal nephron (-> i Na+ absorption and K' secretion)
Osmotic diuresis (e.g. in glycosuria)
Diuretics: thiazides and loop diuretics (also T aldosterone secretion)
Bartter's syndrome, Gitelman's syndrome
Others
Hypomagnesaemia
Renal tubular acidosis (type I & II)
Renal tubular damage
Liddle's syndrome (autosomal dominant condition, primary T in collecting tubule
sodium reabsorption and often potassium secretion)
Redistribution into the cells
Insulin, beta-agonists, alkalosis
Gastrointestinal loss
Vomiting, diarrhoea, villous adenoma, VIPoma, fistulae, ileostomies
Renal loss
Excess mineralocortcoids (--potassium excretion)
Hyperaldosteronism
Increased Glucocorticoids: Cushing's syndrome, liquorice (inhibits 11 [3-hydroxysteroid
dehydrogenase and l glucocorticoid metabolism), 11 [3-hydroxysteroid
dehydrogenase deficiency
Congenital adrenal hyperplasia (11 [3-hydroxylase and 17 cr-hydroxylase
deficiency)
Increased Na+ delivery to distal nephron (-> i Na+ absorption and K' secretion)
Osmotic diuresis (e.g. in glycosuria)
Diuretics: thiazides and loop diuretics (also T aldosterone secretion)
Bartter's syndrome, Gitelman's syndrome
Others
Hypomagnesaemia
Renal tubular acidosis (type I & II)
Renal tubular damage
Liddle's syndrome (autosomal dominant condition, primary T in collecting tubule
sodium reabsorption and often potassium secretion)
Redistribution into the cells
Insulin, beta-agonists, alkalosis
- Published on
Symptoms and Signs – Differential Diagnosis of Hypokalaemia
Gastrointestinal loss
Vomiting, diarrhoea, villous adenoma, VIPoma, fistulae, ileostomies
Renal loss
Excess mineralocortcoids (--potassium excretion)
Hyperaldosteronism
Increased Glucocorticoids: Cushing's syndrome, liquorice (inhibits 11 [3-hydroxysteroid
dehydrogenase and l glucocorticoid metabolism), 11 [3-hydroxysteroid
dehydrogenase deficiency
Congenital adrenal hyperplasia (11 [3-hydroxylase and 17 cr-hydroxylase
deficiency)
Increased Na+ delivery to distal nephron (-> i Na+ absorption and K' secretion)
Osmotic diuresis (e.g. in glycosuria)
Diuretics: thiazides and loop diuretics (also T aldosterone secretion)
Bartter's syndrome, Gitelman's syndrome
Others
Hypomagnesaemia
Renal tubular acidosis (type I & II)
Renal tubular damage
Liddle's syndrome (autosomal dominant condition, primary T in collecting tubule
sodium reabsorption and often potassium secretion)
Redistribution into the cells
Insulin, beta-agonists, alkalosis
Gastrointestinal loss
Vomiting, diarrhoea, villous adenoma, VIPoma, fistulae, ileostomies
Renal loss
Excess mineralocortcoids (--potassium excretion)
Hyperaldosteronism
Increased Glucocorticoids: Cushing's syndrome, liquorice (inhibits 11 [3-hydroxysteroid
dehydrogenase and l glucocorticoid metabolism), 11 [3-hydroxysteroid
dehydrogenase deficiency
Congenital adrenal hyperplasia (11 [3-hydroxylase and 17 cr-hydroxylase
deficiency)
Increased Na+ delivery to distal nephron (-> i Na+ absorption and K' secretion)
Osmotic diuresis (e.g. in glycosuria)
Diuretics: thiazides and loop diuretics (also T aldosterone secretion)
Bartter's syndrome, Gitelman's syndrome
Others
Hypomagnesaemia
Renal tubular acidosis (type I & II)
Renal tubular damage
Liddle's syndrome (autosomal dominant condition, primary T in collecting tubule
sodium reabsorption and often potassium secretion)
Redistribution into the cells
Insulin, beta-agonists, alkalosis
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Symptoms and Signs – Differential Diagnosis of Hypomagnesaemia
Renal losses: Diuretics (loop and thiazides)
Reduced Intake or GI losses: malnutrition, alcoholism, diarrhoea, malabsorption,
Other: Post-operative, post-parathyroidectomy, pancreatitis (acute), foscarnet
intestinal resection, intestinal fistulae
Drugs: nephrotoxins, e.g. aminoglycosides, amphotericin B, cyclosporine, cisplatin
Diabetes mellitus, hypercalcaemia, hyperthyroidism, hyperaldosteronism, tubular dysfunction (post-acute tubular necrosis, postobstructive diuresis, Bartter's or Gitelman's syndrome)
Alcohol abuse
Renal losses: Diuretics (loop and thiazides)
Reduced Intake or GI losses: malnutrition, alcoholism, diarrhoea, malabsorption,
Other: Post-operative, post-parathyroidectomy, pancreatitis (acute), foscarnet
intestinal resection, intestinal fistulae
Drugs: nephrotoxins, e.g. aminoglycosides, amphotericin B, cyclosporine, cisplatin
Diabetes mellitus, hypercalcaemia, hyperthyroidism, hyperaldosteronism, tubular dysfunction (post-acute tubular necrosis, postobstructive diuresis, Bartter's or Gitelman's syndrome)
Alcohol abuse
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Symptoms and Signs – Differential Diagnosis of Hyponatraemia
Pseudohyponatraemia:
Hyperproteinaemia (e.g. multiple myeloma), hypertriglyceridaemia Hyperglycaemia
Artifactual: taking blood from the arm into which low sodium solution is infused
Hypervolaemic (oedematous) patients:
Cirrohsis, CCF, nephrotic syndrome, renal failure (urine Na+>20)
Hypovolaemic (dehydrated) patients:
Renal loss (urine Na+>20): Diuretics (thiazides), renal tubular acidosis, saltlosing
nephropathy, adrenal insufficiency
Extra-renal loss (urine Na+ <20): diarrhoea, vomiting, burns, pancreatitis< />pan>
Euvolaemic patients:
Hypothyroidism, adrenal insufficiency, SIADH
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Symptoms and Signs – Differential Diagnosis of Hyperprolactinaemia
Physiological: pregnancy, lactation, stress
Prolactinoma, rarely ectopic prolactin (lung, kidney tumours)
Reduced Dopamine transport to the anterior pituitary: pituitary tumour compressing
pituitary stalk (pseudoprolactinoma affect)
Drugs:
Depletion of central dopamine stores: reserpine, methyldopa
Dopamine receptor blockers: (chlorpromazine, haloperidol, sulpiride,
metoclopramide, domperidone)
Increased TRH secretion stimulates prolactin release (1° hypothyroidism)
Oestrogens: HRT/OCP, PCOS (oestrogen stimulates lactotrophs)
Chest wall injury (stimulation of the reflex pathway normally activated by
suckling in lactating women)
Others: liver failure, l dopamine synthesis/release from the hypothalamus
(tumour, inflammation, arteriovenous malformations)·
Physiological: pregnancy, lactation, stress
Prolactinoma, rarely ectopic prolactin (lung, kidney tumours)
Reduced Dopamine transport to the anterior pituitary: pituitary tumour compressing
pituitary stalk (pseudoprolactinoma affect)
Drugs:
Depletion of central dopamine stores: reserpine, methyldopa
Dopamine receptor blockers: (chlorpromazine, haloperidol, sulpiride,
metoclopramide, domperidone)
Increased TRH secretion stimulates prolactin release (1° hypothyroidism)
Oestrogens: HRT/OCP, PCOS (oestrogen stimulates lactotrophs)
Chest wall injury (stimulation of the reflex pathway normally activated by
suckling in lactating women)
Others: liver failure, l dopamine synthesis/release from the hypothalamus
(tumour, inflammation, arteriovenous malformations)·
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Symptoms and Signs – Differential Diagnosis of Hyperproteinaemia
Haemoconcentration: dehydration, prolonged application of tourniquet
Hypergammaglobulinaemia:
Haemoconcentration: dehydration, prolonged application of tourniquet
Hypergammaglobulinaemia:
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Symptoms and Signs – Differential Diagnosis of Hypertension
Vascular: coarctation of aorta, renal artery stenosis
Renal disease: chronic glomerulonephritis, chronic pyelonephritis, cystic kidney disease, renal carcinoma
Pre-eclampsia
Essential (idiopathic)
Endocrine disease: Cushing's syndrome, Conn's disease, phaeochromocytomas, acromegaly, primary hyperparathyroidism
Drugs: oestrogen-containing OCPs, steroids
Vascular: coarctation of aorta, renal artery stenosis
Renal disease: chronic glomerulonephritis, chronic pyelonephritis, cystic kidney disease, renal carcinoma
Pre-eclampsia
Essential (idiopathic)
Endocrine disease: Cushing's syndrome, Conn's disease, phaeochromocytomas, acromegaly, primary hyperparathyroidism
Drugs: oestrogen-containing OCPs, steroids
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Symptoms and Signs – Differential Diagnosis of Hyperthyroidism
TSH-receptor mutations, McCune-Albright syndrome
Toxic multinodular goitre
Toxic adenoma
Thyroiditis (subacute/viral, post-partum)
Struma ovarii
Secondary hyperthyroidism (TSH)
Rarer causes
Graves' disease
Gestational thyrotoxicosis (raised hCG)
Follicular carcinoma of thyroid
Drugs: amiodarone, surreptitious thyroxine consumption (thyroiditis factitia)
Choreocarcinoma
TSH-receptor mutations, McCune-Albright syndrome
Toxic multinodular goitre
Toxic adenoma
Thyroiditis (subacute/viral, post-partum)
Struma ovarii
Secondary hyperthyroidism (TSH)
Rarer causes
Graves' disease
Gestational thyrotoxicosis (raised hCG)
Follicular carcinoma of thyroid
Drugs: amiodarone, surreptitious thyroxine consumption (thyroiditis factitia)
Choreocarcinoma
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Symptoms and Signs – Differential Diagnosis of Hypertrichosis
Local
Lichen simplex
Melanocytic naevi
Spina bifida
Generalized
Anorexia nervosa
Malnutrition
Medication (minoxidil, ciclosporin, phenytoin),
Malignancy
Porphyria cutanea tarda
Local
Lichen simplex
Melanocytic naevi
Spina bifida
Generalized
Anorexia nervosa
Malnutrition
Medication (minoxidil, ciclosporin, phenytoin),
Malignancy
Porphyria cutanea tarda
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Symptoms and Signs – Differential Diagnosis of Hyperuricaemia
Reduced Renal excretion
Psoriasis
Increase Synthesis: Lesch-Nyhan syndrome (HGPRT deficiency)
Increase Nucleic acid (purine) turnover: lymphoma, leukaemia, polycythaemia vera,
Increase Intake/production
Increase Dietary intake
Idiopathic
ethambutol, alcohol, pyrizinamide)
Drugs: ciclosporin, aspirin (low-dose), nicotinic acid, thiazides, loop diuretics,
Chronic renal disease, e.g. in diabetes mellitus, hypertension
Reduced Renal excretion
Psoriasis
Increase Synthesis: Lesch-Nyhan syndrome (HGPRT deficiency)
Increase Nucleic acid (purine) turnover: lymphoma, leukaemia, polycythaemia vera,
Increase Intake/production
Increase Dietary intake
Idiopathic
ethambutol, alcohol, pyrizinamide)
Drugs: ciclosporin, aspirin (low-dose), nicotinic acid, thiazides, loop diuretics,
Chronic renal disease, e.g. in diabetes mellitus, hypertension
