Polineuropatía por amiloidosis por transtiretina de inicio tardío. Caso clínico / Late-onset hereditary transthyretin amyloidosis with polyneuropathy. Report of one case

Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.

[Late-onset hereditary transthyretin amyloidosis with polyneuropathy. Report of one case]. / Polineuropatía por amiloidosis por transtiretina de inicio tardío. Caso clínico.

Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.

[Monomelic amyotrophy. Report of one case]. / Atrofia monomiélica distal de extremidad superior. Caso clínico.

Monomelic amyotrophy, also known as Hirayama disease, is a rare lower motor neuron syndrome due to localized lower motor neuron loss in the spinal cord at the cervical level. Clinically, monomelic amyotrophy is defined by the insidious onset of unilateral atrophy and weakness involving the hand and forearm, typically beginning in the second or third decade of life. We report 19-year-old man with a two years history of slowly progressive unilateral weakness and atrophy of his right-hand muscles. Neurological examination revealed weakness and atrophy in his intrinsic hand muscles, with sparing of the abductor pollicis brevis muscle. Also, mild atrophy of the ulnar aspect of the forearm was detected with sparing of the brachioradialis muscle. Electromyography showed active and chronic neurogenic changes affecting C8 and T1 myotomes, with mild chronic neurogenic changes on C7 myotome. Magnetic resonance imaging of his cervical spine revealed spinal cord atrophy involving C5 to C7 segments, associated with forward displacement of the posterior wall of the dura in cervical spine flexion. The clinical features associated with the imaging and electrophysiological findings support the diagnosis of monomelic amyotrophy.

Atrofia monomiélica distal de extremidad superior. Caso clínico / Monomelic amyotrophy. Report of one case

Monomelic amyotrophy, also known as Hirayama disease, is a rare lower motor neuron syndrome due to localized lower motor neuron loss in the spinal cord at the cervical level. Clinically, monomelic amyotrophy is defined by the insidious onset of unilateral atrophy and weakness involving the hand and forearm, typically beginning in the second or third decade of life. We report 19-year-old man with a two years history of slowly progressive unilateral weakness and atrophy of his right-hand muscles. Neurological examination revealed weakness and atrophy in his intrinsic hand muscles, with sparing of the abductor pollicis brevis muscle. Also, mild atrophy of the ulnar aspect of the forearm was detected with sparing of the brachioradialis muscle. Electromyography showed active and chronic neurogenic changes affecting C8 and T1 myotomes, with mild chronic neurogenic changes on C7 myotome. Magnetic resonance imaging of his cervical spine revealed spinal cord atrophy involving C5 to C7 segments, associated with forward displacement of the posterior wall of the dura in cervical spine flexion. The clinical features associated with the imaging and electrophysiological findings support the diagnosis of monomelic amyotrophy.

Epidemiology of chronic inflammatory demyelinating polyneuropathy in the South-Eastern area of Santiago, Chile.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an immune-mediated polyneuropathy. It usually has an insidious onset, progressive course and heterogeneous clinical features. As far as we know, there is no epidemiological information on CIDP in South America and the Caribbean. Our aim was to estimate the frequency of CIDP in the South-Eastern region of Santiago, where our hospital is based and the population number assigned is officially reported every year by the health authorities. Records of 581 patients registered with the diagnosis of neuropathy were found and all patients meeting the diagnostic criteria of the EFNS/PNS for definitive and possible CIDP were included. Data were collected using a data extraction protocol designed by the authors and which included demographic, clinical, laboratory and electrophysiological information. The estimated prevalence and incidence of CIDP were 2.95/100,000 and 0.46/100,000 respectively. Fifteen patients (8 men, 7 women) were classified as definitive or possible CIDP. Nine patients had typical CIDP and three also had diabetes mellitus. The prevalence and incidence rates were similar to those reported in other regions of the world.