CAUSES :
A. CNS CAUSES
1. DISORDERED AUTONOMIC FUNCTION
- CEREBROVASCULAR ACCIDENTS
- SHY-DRAGER SYNDROME
- PROGRESSIVE SUPRANUCLEAR PALSY
- OLIVOPONTOCEREBELLAR ATROPHY
2. SPINAL CORD LESIONS
3. PERIPHERAL NERVE,NEUROMUSCULAR JUNCTION DISORDERS
- PERIPHERAL NEUROPATHIES LIKE IN
* DIABETES
* AMYLOIDOSIS
* CHR ALCOHOLISM
* PORPHYRIA
* GUILLAIN-BARRE SYNDROME
- BOTULISM
- LAMBERT-EATON SYNDROME
4. PURE AUTONOMIC FAILURE
5. POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME
6. RILEY-DAY SYNDROME
B. OTHERS
- FROST BITE ( IN MILD CASES )
- PRIMARY HYPERHYDROSIS
- AUTOIMMUNITY ( AUTOANTIBODIES AGAINST ACETYLCHOLINE RECEPTORS IN AUTONOMIC GANGLION )
- INFECTIONS
- POISONING ( ORGANOPHOSPHORUS )
- MALIGNANCY
- AGING
- DISORDERS OF HYPOTHALAMUS
- PYROGENS
- ANXIETY
- DRUGS LIKE ALCOHOL, PILOCARPINES, TRICYCLIC ANTIDEPRESSANTS
- HYPOGLYCEMIA
- DUMPING SYNDROME
- ALCOHOL / DRUG WITHDRAWAL
- SHOCK / SYNCOPE
- INTENSE PAIN
- RICKETS
- INFANTILE SCURVY
- PINK DISEAASE
- HYPERTHYROIDISM
- HYPERPITUITARISM
- ACROMEGALY
- PHAECHROMOCYTOMA
- CARCINOID SYNDROME
- GOUT
- PACHYDERMOPERIOSTOSIS
- GRANULOSIS RUBRA NASI
OTHER TESTS :
* TEST FOR THE INTEGRITY OF THE AUTONOMIC NERVOUS SYSTEM - VALSALVA RESPONSE ( NORMAL PERSON ) - DONE WITH SUBJECT SITTING, A CONSTANT EXPIRATORY PRESSURE OF 40 MM HG IS MAINTAINED FOR 15 SEC WHILE CHANGES IN HEART RATE & BEAT TO BEAT BP ARE MEASURED. FOUR PHASES . PHASE 1 - BP RISES DUE TO AORTIC COMPRESSION & HEART RATE DECREASES.
PHASE 2 (EARLY STAGE) - REDUCED STROKE VOLUME & VENOUS RETURN CAUSES FALL IN BP, REFLUX TACHYCARDIA & INCREASED TOTAL PERIPHERAL RESISTANCE WHICH ARRESTS FURTHER BP DROP APPROXIMATELY 5 - 8 SEC AFTER THE ONSET OF VALSALVA MANEUVER.
PHASE 2 ( LATE STAGE ) - PROGRESSIVE RISE IN BP TOWARDS BASELINE.
PHASE 3 - BP FALLS DUE TO INCREASED CAPACITANCE OF PULMONARY BED & BP IS FURTHER INCREASED
PHASE 4 - VENOUS RETURN & CARDIAC OUTPUT RETURNS TO NORMAL. PERSISTANT PERIPHERAL ARTERIOLAR VASOCONSTRICTION RESULTS IN TEMPORARY BP OVERSHOOT & BRADYCARDIA.