Copper deficiency myelopathy and subacute combined degeneration of the cord – Why is the phenotype so similar?

Imaging Aspects of Toxic and Metabolic Myelopathies

Metabolic and toxic myelopathies usually occurs due to several different causes. Metabolic myelopathy usually occurs due to deficiency of a nutrient, such as vitamin B12. Toxic myelopathy occurs secondary to the exposure to an external toxic agent. Although they may have a difficult diagnosis, determination of the specific cause of myelopathy is of utmost importance, because many causes are amenable to treatment. Although they have many clinical, electrophysiologic, and neuropathologic similarities, imaging may aid in the suspicion of toxic or metabolic myelopathy. The aim of this article, is to review the imaging features of the main toxic and metabolic myelopathies.

Copper deficiency, a rare but correctable cause of pancytopenia: a review of literature

INTRODUCTION

Copper is increasingly being recognized as a vital mineral required by both animals and humans. It plays a vital role in many metabolic processes such as cellular respiration, iron oxidation, and hemoglobin synthesis. Copper deficiency, which can be hereditary or acquired, can lead to a wide spectrum of disease processes such as ringed sideroblastic anemia, myelodysplasia, and pancytopenia. Timely identification and management of copper deficiency is necessary to prevent irreversible complications.

AREAS COVERED

Our study focuses on prevalence, etiology, pathophysiology, complications, and treatment of copper deficiency.

EXPERT OPINION

Copper deficiency is frequently underrecognized as the cause of anemia, neutropenia, and bone marrow dysplasia. As it is potentially treatable, it should always be kept in the differentials when patients present with neurological and hematological abnormalities.

Serum copper decrease and cerebellar atrophy in patients with nitrous oxide-induced subacute combined degeneration: two cases report

Background

Subacute combined degeneration (SCD) is a neurological complication commonly associated with vitamin B₁₂ deficiency. It can result from nitrous oxide (N₂O) abuse and cause neuropsychiatric symptoms. However, there has been no literature regarding alterations of serum copper and cerebellum in SCD patients.

Case presentation

We reported two cases of young SCD patients with histories of N₂O abuse. In these cases, elevated homocysteine, macrocytic anemia, spinal cord abnormalities, and peripheral nerve injuries were detected. In addition, decreased serum copper level and cerebellar atrophy were reported for the first time. The patients’ symptoms improved after withdrawal of N₂O exposure and vitamin B₁₂ supplements.

Conclusion

We reported two SCD cases with serum copper alteration and cerebellar atrophy after N₂O abuse for the first time. These might be crucial complements to the diagnosis of SCD.

COVID-19-Associated Myelitis Involving the Dorsal and Lateral White Matter Tracts: A Case Series and Review of the Literature

Coronavirus disease 2019 (COVID-19) myelitis is a rare condition, most commonly presenting with nonenhancing central expansile cord T2 signal changes. A single case report has also described longitudinal involvement of the dorsal columns. We present 5 cases of COVID-19-associated myelitis with tract-specific involvement of the dorsal and lateral columns and discuss potential pathophysiologic pathways for this unique pattern.

Copper deficiency-associated myelopathy in cryptogenic hyperzincemia: a case report

Copper deficiency syndrome is an underestimated cause of posterior myelitis. We describe the case of a 41-year-old woman, who developed a subacute ataxic paraparesis associated with low back pain. Her 3T spine MRI showed a thin hyperintense FS-Echo T2 longitudinally extensive lesion involving the posterior columns of the cervical cord (from C2 to C6). An extensive diagnostic work-up excluded other causes of myelopathy and blood tests pointed out hypocupremia and mild hyperzincemia. Patients affected by this rare form of oligoelement deficiency typically develop progressive posterior column dysfunction with sensory ataxia and spasticity, sometimes associated with sensori-motor polyneuropathy. Clinical and radiological characteristics of posterior myelopathy due to copper deficiency are briefly reviewed. Physicians should be aware of this condition since a prompt introduction of copper supplementation can avoid progression of the neurological damage. (www.actabiomedica.it)

Diagnostic Approach to Intrinsic Abnormality of Spinal Cord Signal Intensity

Intramedullary cord hyperintensity at T2-weighted MRI is a common imaging feature of disease in the spinal cord, but it is nonspecific. Radiologists play a valuable role in helping narrow the differential diagnosis by integrating patient history and laboratory test results with key imaging characteristics. The authors present an algorithmic approach to evaluating intrinsic abnormality of spinal cord signal intensity (SI), which incorporates clinical evaluation results, time of onset (acute vs nonacute), cord expansion, and pattern of T2 SI abnormality. This diagnostic approach provides a practical framework to aid both trainees and practicing radiologists in workup of myelopathy.^©RSNA, 2019.

Feline irradiated diet-induced demyelination; a model of the neuropathology of sub-acute combined degeneration?

Irradiation of food at 50–55 kGy results in a profound, chronic demyelinating-remyelinating disease of the entire central nervous system (CNS) in cats, named Feline Irradiated Diet-Induced Demyelination (FIDID). This study examines the early stages of demyelination and long-term consequences of demyelination and remyelination on axon survival or loss. Myelin vacuolation is the primary defect leading to myelin breakdown, demyelination then prompt remyelination in the spinal cord and brain. There is no evidence of oligodendrocyte death. The spinal cord dorsal column is initially spared yet eventually becomes severely demyelinated with subsequent loss of axons in the core and then surface of the fasciculus gracilis. However remyelination of the sub-pial axons in the dorsal column results in their protection. While there was a lack of biochemical evidence of Vitamin B12 deficiency, the pathological similarities of FIDID with sub-acute combined degeneration (SCD) led us to explore treatment with Vitamin B12. Treatment led to recovery or improvement in some cats and neurologic relapse on cessation of B12 therapy. While the reason that irradiated food is myelinotoxic in the cat remains unresolved, nonetheless the neuropathological changes match exactly what is seen in SCD and its models and provide an ideal model to study the cellular and molecular basis of remyelination.

A case of subacute combined degeneration of the spinal cord due to folic acid and copper deficiency

Subacute combined degeneration of the spinal cord (SACD) is a rare neurologic disorder manifesting progressive symptoms of paresthesia and spastic paralysis. Herein we present an autopsy case of SACD caused by folic acid and copper deficiency. A 16-year-old male presented with gradually worsening unsteady gait, and bladder and rectal dysfunction. He had a medical history of T-cell acute lymphoblastic leukemia (T-ALL), diagnosed 1.5 years previously. The patient had undergone chemotherapy, including methotrexate, as well as allogeneic bone mallow transplantation. Laboratory tests revealed normal vitamin B₁₂ and methylmalonic acid concentration, but reduced serum copper, ceruloplasmin and folic acid concentrations. Magnetic resonance imaging revealed symmetrical T2 signal hyperintensities in the posterior and lateral spinal cord. The patient was treated with oral copper, oral folate, and intravenous vitamin B₁₂. A month after this treatment, the patient's symptoms were unchanged, and 2 months later he died of acute adrenal insufficiency. The pathological findings of the spinal cord were compatible with SACD. Because SACD is usually reversible with early treatment, it should be suspected in high-risk patients undergoing chemotherapy or those who are malnourished with characteristic symptoms of SACD, even in young patients.

Neurological presentations revealing acquired copper deficiency: diagnosis features, aetiologies and evolution in seven patients

BACKGROUND

Acquired copper deficiency (ACD) is a rare condition usually diagnosed from haematological changes.

AIMS

To characterise the diagnosis features and the evolution of patients with ACD revealed by neurological symptoms.

METHODS

Clinical, biological and magnetic resonance imaging (MRI) data were prospectively analysed at diagnosis and during follow up under copper supplementation.

RESULTS

Seven patients were studied over a 5-year period. Time to diagnosis ranged from 2.5 to 15 months. Subacute ascending paraesthesias and gait disorder were the first symptoms. All patients had a posterior cord syndrome (PCS) with sensory ataxic gait associated with superficial hypoesthesia of the feet; 50% had also lateral cord signs. Electrodiagnostic tests diagnosed a lower limb sensory neuropathy in four patients. Spinal cord MRI was normal in three of seven patients. Anaemia and lymphopenia were diagnosed in six of seven patients. Serum copper was always low, and urinary copper was low or normal. Serum and urinary zinc were high in four patients. Decreased copper intake (stoma/parenteral nutrition, malnutrition, malabsorption with lack of vitamin supplementation after bariatric or other digestive surgeries) was found in four patients, and the chronic use of denture adhesive paste containing zinc was discovered in four patients. One patient had both the causes recorded. After copper supplementation, copper balance and then haematological disturbances were the first features to normalise gradually in 2 months. Radiological myelitis disappeared in 10 months, whereas neurological symptoms improved in six of seven patients after a mean follow up of 2 years.

CONCLUSIONS

Progressive PCS with anaemia and lymphopenia must raise the possibility of an ACD. Early copper supplementation could increase the neurological prognosis.

Transformation of tetrabromobisphenol A by Rhodococcus jostii RHA1: Effects of heavy metals

Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants in the world but it is also a pollutant of global concern. In the present study, we studied the transformation of ¹⁴C-labeled TBBPA by a polychlorinated-biphenyl-degrading bacterium, Rhodococcus jostii RHA1 (RHA1), under oxic conditions. During the 5-day incubation, TBBPA was biotransformed rapidly first to its monomethyl ether MeO-TBBPA and then to its more hydrophobic but less toxic dimethyl ether diMeO-TBBPA. The biotransformation followed pseudo-first-order decay kinetics, with a half-life of TBBPA of 0.32 days and only 0.6% of the initially added amount being mineralized. Considering the frequent co-occurrence of TBBPA with heavy metals in the natural environment, we also investigated the effects of three heavy metals (Cd, Cu, and Fe) on the transformation of TBBPA by strain RHA1. While TBBPA transformation was not significantly altered by Cd, it was accelerated by Cu and Fe, presumably due to the effects of these two essential metals on O-methyltransferase activity. Overall, the present study showed that RHA1 is an effective transformer of TBBPA and that certain essential metals, including Cu and Fe, promote the transformation.

Progressive myelopathy mimicking subacute combined degeneration after intrathecal chemotherapy

Intrathecal chemotherapy including methotrexate is well documented for neurotoxicity of diverse clinical manifestation. Acute or chronic leukoencephalopathy is the most common type of methotrexate-induced neurotoxicity, and subacute myelopathy is rare. Although its pathogenesis is not fully understood, it is postulated that direct damage of methotrexate to the central nervous system plays a major part and elevated levels of homocysteine and its excitatory amino acid neurotransmitter metabolites (homocysteic acid and cysteine sulfinic acid) could mediate, in part, MTX-associated neurotoxicity. On the while, subacute combined degeneration is a progressive degeneration of the dorsal and lateral columns of the spinal cord, mostly due to vitamin B12 deficiency. The authors report a case of a 15-year-old boy with Burkitt leukemia who developed progressive myelopathy after intrathecal triple therapy (methotrexate, cytarabine, and hydrocortisone) whose clinical and radiologic features were compatible with subacute combined degeneration. The pathogenic mechanism could be explained by biochemical alteration by methotrexate and a possible treatment strategy was discussed.

Optic neuropathy associated with copper deficiency after gastric bypass surgery

PURPOSE

Patients undergoing gastric bypass procedures are predisposed to many vitamin and mineral deficiencies including copper, which can lead to optic neuropathy.

METHODS

A 35-year-old woman complained of progressive vision loss bilaterally 3 years after gastric bypass surgery (GBS).

RESULTS

Ophthalmic examination revealed the presence of subnormal visual acuity and pale optic nerves bilaterally. Laboratory testing showed copper deficiency. Complete improvement in vision was noted after copper was replenished.

CONCLUSION

Nutritional deficiencies occurring after gastric bypass procedures are well reported. They happen and occur due to reduced gastric and enteral absorption and cause many systemic and neurologic manifestations. Optic neuropathy occurring after GBS is often due to vitamin B12 and folic acid deficiency. Copper deficiency causing systemic symptoms is very rare and usually takes decades to manifest. Our case is unique in that copper deficiency was noted as early as 3 years after GBS. Moreover rapid copper replenishment led to a dramatic recovery of vision. Our case underscores the need for maintaining high suspicion when evaluating patients with suspected optic neuropathy occurring after GBS since prompt diagnosis and treatment may lead to reversal of visual loss.

The neurologic complications of bariatric surgery

Bariatric surgery has been increasingly employed to manage morbid obesity. Approximately 150000 bariatric procedures are performed in the US annually. Neurologic complications arise in as many as 5% of individuals having this surgery. Although the etiology of some of these complications remains obscure, the majority are the consequence of vitamin (most commonly thiamine and vitamin B12) or mineral (most commonly copper) deficiency and familiarity with these disorders is essential. Their rapid diagnosis and appropriate treatment is essential to avoid long-term, irreversible consequences including, in some instances, death.

Hypocupremia associated cytopenia and myelopathy: a national retrospective review

Copper is an essential trace element that is involved in a number of important enzymatic processes throughout the body. Recent single case reports and small studies have shown that deficiency of copper can cause reversible haematological changes and irreversible neurological injury. We chose to undertake a national study, looking at all cases of copper deficiency in Scotland over a 5-yr period using information from a national reference laboratory. From 16 identified patients, we determined that 86% had both haematological and neurological features of copper deficiency, while 18% had haematological features only at presentation. Twelve of the sixteen patients had high serum zinc concentrations (>18 μm/L) nine patients were using zinc-containing dental fixatives at time of diagnosis. 94% of patients had haematological features as an initial manifestation of copper deficiency, which included anaemia, thrombocytopenia and neutropenia. Patients who underwent later bone marrow testing had appearances in keeping with refractory cytopenia with multilineage dysplasia, refractory anaemia with excess of blasts, unclassified marrow dysplasia or probable myelodysplasia (MDS). 75% of patients had neurological symptoms or signs, including progressive walking difficulties and paraesthesia, or gait difficulties without sensory signs. Clinical examination was in keeping with spastic paraparesis (either with or without sensory neuropathy). Magnetic resonance imaging (MRI) showed multifocal T2 hyper intense foci in the subcortical white matter, and atrophy of the cerebrum and cerebellum was also seen on computerised tomography (CT). MRI of the spinal cord showed signal change in the dorsal columns in either the cervical or thoracic cord. 93% of cytopenias responded to copper replacement and addressing the original cause of the copper deficiency, but only 25% of patients had improvement in their neurological function, while 33% deteriorated and 42% remained unchanged. Our study demonstrates that copper deficiency is an under-recognised cause of several types of cytopenia, which are reversible but can progress to significant neurological injury if left untreated. We illustrate the importance of identifying these patients early to prevent irreversible neurological injury.

Copper deficiency myelopathy

Acquired copper deficiency has been recognised as a rare cause of anaemia and neutropenia for over half a century. Copper deficiency myelopathy (CDM) was only described within the last decade, and represents a treatable cause of non-compressive myelopathy which closely mimics subacute combined degeneration due to vitamin B12 deficiency. Here, 55 case reports from the literature are reviewed regarding their demographics, aetiology, haematological and biochemical parameters, spinal imaging, treatment and outcome. The pathophysiology of disorders of copper metabolism is discussed. CDM most frequently presented in the fifth and sixth decades and was more common in women (F:M = 3.6:1). Risk factors included previous upper gastrointestinal surgery, zinc overload and malabsorption syndromes, all of which impair copper absorption in the upper gastrointestinal tract. No aetiology was established in 20% of cases. High zinc levels were detected in some cases not considered to have primary zinc overload, and in this situation the contribution of zinc to the copper deficiency state remained unclear. Cytopenias were found in 78%, particularly anaemia, and a myelodysplastic syndrome may have been falsely diagnosed in the past. Spinal MRI was abnormal in 47% and usually showed high T2 signal in the posterior cervical and thoracic cord. In a clinically compatible case, CDM may be suggested by the presence of one or more risk factors and/or cytopenias. Low serum copper and caeruloplasmin levels confirmed the diagnosis and, in contrast to Wilson's disease, urinary copper levels were typically low. Treatment comprised copper supplementation and modification of any risk factors, and led to haematological normalisation and neurological improvement or stabilisation. Since any neurological recovery was partial and case numbers of CDM will continue to rise with the growing use of bariatric gastrointestinal surgery, clinical vigilance will remain the key to minimising neurological sequelae. Recommendations for treatment and prevention are made.

[Acquired copper deficiency myelopathy]

INTRODUCTION

The hematological manifestations of acquired copper deficiency are well known. But the neurological manifestations have only been recognised in the past few years. The most common neurological manifestation in adults is a myeloneuropathy with prominent sensory ataxia and spastic gait. Electrophysiological tests reveal an axonal sensorimotor peripheral neuropathy. Spinal MRI shows an augmented T2 signal involving the dorsal column. The causes of acquired copper deficiency include gastric surgery, excessive zinc ingestion, and malabsorption but in most cases, the cause remains unclear. Early recognition and treatment may prevent neurological deterioration but improvement seems to be slight and inconstant.

OBSERVATION

We report two new cases of acquired copper deficiency myeloneuropathy associated with a nephrotic syndrome and, in one case, with a major iron overload syndrome. Biological abnormalities disappeared under copper supplementation. A significant neurological improvement with disappearance of ataxia occurred in one patient who received copper supplementation eight months after symptom onset.

CONCLUSIONS

Nephrotic syndrome might be another complication of acquired copper deficiency. Delayed treatment is not necessarily associated with a deleterious neurological prognosis. Significant neurological improvement under copper supplementation is possible.