A woman aged 83 presented with increasing shortness of breath of a few weeks' duration. Air entry was reduced and percussion on the right side of her chest produced a dull note. The skin on the right side of her face was dry, in addition to the features seen in the photograph (fig 1).
Fig 1 Note the drooping of the upper eyelid and the smaller pupil on the right; the right side of her face was also dry to the touch.
Pharmacological tests based on the ability of the normal (unimpaired) sympathetic postganglionic nerve to synthesise and release norepinephrine at its terminals may be used to localise the level of the lesion. 5 Instillation of a 10% solution of cocaine in the conjunctival sac causes mydriasis in the normal eye by inhibiting reuptake of synaptic norepinephrine. There is no dilatation of the pupil in the affected eye even after