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Symptoms and Signs – Differential Diagnosis of Hypogammaglobulinaemia
Congenital
X-linked, or as part of a combined immunodeficiency state

Acquired
Leukaemia (CLL)
Lymphoma
Marrow hypoplasia, myeloclerosis
Myeloma
Nephrotic syndrome, malnutrition, malabsorption, protein-losing enteropathy
Uraemia, steroids, severe infections






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Symptoms and Signs – Differential Diagnosis of Hypoglycaemia
Addison's disease
Alcohol
Excess insulin (or diabetics not having a snack after insulin injection), sulphonylureas, salicylate, pentamidine, quinine
Liver failure
lnsulinomas, hepatomas, sarcomas
Malaria
Post-gastrectomy
Renal failure


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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


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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


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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



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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 Hypogonadism
Female
1° hypogonadism (hypergonadotrophic)
Gonadal dysgensis
The genotype may be XO (Turner's syndrome), XX, XY (with disruption of the SRY
gene on Y chromosome or the downstream pathway), XO/XY or XO/XX
(mosaicism)
Gonadal damage
Infection (e.g. mumps)
Autoimmune
Surgery (pelvic)
Radiation
Chemotherapy, e.g. cyclophosphamide
Genetic mutations
LH/FSH beta subunit, LH receptor, FSH receptor, enzymes involved in oestrogen
synthesis (e.g. 17-hydroxylase deficiency), galactosaemia
2° hypogonadism (hypogonadotrophic)


Hypopituitarism
Pituitary tumour/surgery/radiation, infiltrations (e.g. lymphoma, sarcoidosis,
Langerhans cell histiocytosis, lymphocytic hypophysitis)
Functional/hypothalamic, e.g. strenuous exercise, weight loss
Congenital GnRH deficiency (when associated with anosmia: Kallmann's
syndrome), other genetic mutations, e.g. DAX1 (associated with congenital
adrenal hypoplasia), HESX1 (associated with septo-optic dysplasia), isolated LH
or FSH deficiency
Other causes of hypopituitarism: vascular/infection, etc. (See Hypopituitarism)
Hyperprolactinaemia


Systemic diseases
Cystic fibrosis
Crohn's disease/ulcerative colitis, malnutrition of any cause
Cirrhosis
Chronic renal failure
Thalassaemia: repeated blood transfusions leads to haemosiderosis and
hypothalamic dysfunction
Rare causes
Laurence-Moon-Beidl syndrome
Prader-Willi syndrome

Male
1° hypogonadism (hypergonadotrophic):
Gonadal dysgensis
Klinefelter's syndrome (XXY): testes are small and firm with dysgenetic
seminiferous tubules
Cryptorchism: undescended testes
Anorchia: Vanishing testis syndrome: testicular tissue present in fetal life but
absent in the adult
Gonadal damage
Infection (e.g. mumps, echovirus, group B arbovirus, lymphocytic
choriomeningitis),
Trauma, torsion
Autoimmune
Surgery (orchidectomy)
Radiation

Drugs/toxins: cyclophosphamide
Alcohol, marijuana, heroin: l testosterone levels

Genetic mutations
LH/FSH b subunits, LH receptor, FSH receptor, defects in enzymes involved in
testosterone synthesis, myotonic dystrophy
2° hypogonadism (hypogonadotrophic):


Hypopituitarism
Pituitary tumour/surgery/radiation/infiltrations; See Hypopituitarism
Congenital GnRH deficiency (idiopathic hypogonadotrophic hypogonadism)
(Kallmann's syndrome: GnRH deficiency+ one or more non-gonadal
congenital abnormalities e.g. anosmia), other genetic mutations, e.g. DAX1,
HESX1, Prop-1


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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
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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

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