A Rare Case of Ross Syndrome.

Sir,

A 32-year-old female presented to us with complaint of loss of sweating on most of the left side of the body along with generalized burning sensation on sun exposure. There was no history of headache, dyspnoea, palpitation, giddiness, hypotension, pain abdomen, or diarrhoea. There was no history of any trauma to the spine and syncopal attacks. Family history was not contributory.

Cutaneous examination showed anhidrosis over left side of the trunk, bilateral upper limbs, lower limbs, right side of face, palms, and soles associated with compensatory hyperhidrosis on right side of the abdomen [Figure 1] (dermatomal distribution T8–T12) and left side of face. Moreover, there was hypoplasia of bilateral 4th and 5th toe. On nervous system examination, deep tendon reflexes including knee, ankle, biceps, and supinater of both sides were absent. Blood pressure was normal in supine as well as sitting position. Rest of the cutaneous and systemic examination was normal.

Figure 1

Anhidrosis on the left side with compensatory hyperhidrosis on the right side (T8–T12)

Pupillary examination showed anisocoria, with the left pupil larger than the right [Figure 2]. Left-sided pupil was dilated and sluggishly reacting to light [Figure 3]. Consensual light reaction of the right pupil was normal and absent in the left pupil. Bilateral visual acuity, color vision, accommodation reflex, external ocular movements, fundus examination, and visual fields were normal. There was no ptosis. Findings of eye examination suggest Adie's pupil in the left eye.

Figure 2

Sluggishly reacting left pupil and normally reacting right pupil to light

Figure 3

Closer view of the dilated left tonic pupil

Laboratory investigations including hemogram, liver and kidney function tests, urine analysis and thyroid function tests, HIV, VDRL, ANA, and rheumatoid factor revealed no abnormality. X-ray of chest and lumbar spine and MRI of spine was normal. Cerebrospinal fluid examination did not reveal any evidence of infection. Histology of the anhidrotic skin showed sparse sweat glands and of the hyperhidrotic region showed increased numbers of sweat glands [Figure 4].

Figure 4

(a) Anhidrotic skin showing absent eccrine glands; (b) Hyperhidrotic skin showing abundant eccrine glands; (H and E, ×100)

Based on the above findings, diagnosis of Ross syndrome was made. Ross syndrome, first described by Ross in 1958, is an uncommon disorder of thermoregulation characterized by the triad of hyporeflexia or areflexia, tonic pupil, and segmental anhidrosis with or without compensatory hyperhidrosis.[1] The first two components define the Holmes–Adie syndrome and the last component defines the Harlequin syndrome.[2] Tonic pupil and reduced sweating can be attributed to affection of postganglionic cholinergic fibres projecting to the iris and sweat glands.[3] The number of sweat glands may be decreased in the anhidrotic skin.[4] Depression of deep tendon reflexes is due to dorsal root ganglionic degeneration and spinal interneuron loss. Anhidrosis may be accompanied by other alterations of the autonomic nervous system such as cardiac dysautonomia, diarrhea, and coughing.[5] Ross syndrome may be associated with cytomegalovirus infection, in which the symptoms improved partially with the infection resolution.[6]

Our patient presented with all typical features of Ross syndrome along with an additional finding of toe hypoplasia. The differential diagnoses of anhidrosis such as Shy Drager syndrome, multiple sclerosis, harlequin syndrome, diabetes mellitus, leprosy, and polyneuropathies were excluded as tonic pupil and areflexia are not features of these disorders. We also considered and ruled out the differentials of Holmes–Adie syndrome, Horner's syndrome, and hereditary sensory autonomic neuropathy [Table 1]. The case is reported due to its rarity.

Table 1

Differential diagnosis of Ross syndrome

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