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​Symptoms and Signs – Differential Diagnosis of ANCA
p-ANCA
Microscopic polyangiitis
Churg-Strauss disease
Also: inflammatory bowel disease, sclerosing cholangitis, biliary cirrhosis, autoimmune hepatitis, rheumatic autoimmune diseases

c-ANCA
Infections, e.g. amoebic colitis
Wegener's granulomatosis
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​Symptoms and Signs – Differential Diagnosis of Annular skin lesions
Erythema annulare centrifugum
Erythema chronicum migrans
Erythema multiforme
Granuloma annulare
Leprosy
Nummular eczema
Pityriasis rosea
Psoriasis
Sarcoidosis
Subacute cutaneous lupus erythematosus
Tinea corporis
Urticaria
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​Symptoms and Signs – Differential Diagnosis of Alkalosis
Metabolic
GI loss of H+
Vomiting, laxative abuse, villous adenoma, VIPoma
Renal loss of H+
Increased  Mineralocorticoid activity (stimulates H+ secretion):
Hyperaldosteronism
Increased  Glucocorticoids: Cushing's syndrome, liquorice (inhibits 11-hydroxysteroid
dehydrogenase and reduced glucocorticoid metabolism)
increased Na+ delivery to distal nephron
Diuretics: thiazides and loop diuretics (also increased aldosterone secretion)
Bartter's syndrome, Gitelman's syndrome
Intracellular shift of H+
Hypokalaemia (also note that the above causes of GI/renal loss of H+, also induce
K+ loss)

Other
Compensation for respiratory acidosis
Excessive alkali ingestion (e.g. increased sodium bicarbonate administration in treatment
of acidotic states)
Fulminant hepatic failure (failure to synthesize urea and neutralize bicarbonate
derived from amino acid metabolism)
Respiratory
Hyperventilation:
Physiological (anxiety, pain, fever, pregnancy, high altitude
Mechanical overventilation
Respiratory failure (type I): asthma, COPD, pneumonia, pulmonary oedema,
pulmonary embolism, ARDS, fibrosing alveolitis, right -, left shunt
Salicylate poisoning, CO poisoning
CNS disease (CVA, infection, tumour, trauma)
Others: liver failure (acute), Gram -ve septicaemia
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​Symptoms and Signs – Differential Diagnosis of Acidosis 
Normal anion gap
Reduced  HCO3 GI loss: diarrhoea, fistula (biliary, intestinal, pancreatic), ileostomy,
ureterosigmoidostomy
Renal loss: renal tubular acidosis (type 2), renal tubular damage (e.g. drugs/
heavy metals), hyperparathyroidism, acetazolamide
Inceased H+ Renal tubular acidosis (1 & 4), ammonium chloride ingestion)

High anion gap
Ketoacidosis: diabetes mellitus, excess alcohol, starvation
Lactic acidosis:
Tissue hypoxia, e.g. shock (haemorrhagidseptic), severe exercise, severe
anaemia
Drugs: metformin, ethanol, methanol, ethylene glycol, zidovudine
D-Lactic acidosis (short gut syndrome)
Leukaemia
Lymphoma
Liver failure
Glucose-6-phosphatase deficiency, mitochondrial disorders (e.g. MELAS)
Renal failure
Salicylate poisoning

Respiratory
CNS
Organic disease involving respiratory centre (e.g. vascular, infection,
inflammation, trauma, tumour)
Drugs: opiates, benzodiazepines, barbiturates and other anaesthetic agents

Lungs
Severe asthma (uncommonly), COPD, large airway obstruction, obstructive sleep apnoea



Neuromuscular
Motor neurones: Guillain-Barre syndrome, motor neurone disease, poliomyelitis, acute porphyria

Neuromuscular junction/muscle: myasthenia gravis, muscular dystrophies, muscle
relaxants, diaphagmatic paralysis

Chest wall
Severe kyphoscoliosis, severe obesity, traumatic 'flail chest'
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Kembara Xtra 

Facts about medicine and its subtopic such as anatomy, physiology, biochemistry, pharmacology, medicine, pediatrics, psychiatry, obstetrics and gynecology and surgery.