Endemic fluorosis presenting as cervical cord compression

Adult-onset spastic paraparesis: an approach to diagnostic work-up

Adult-onset, chronic progressive spastic paraparesis may be due to a large number of causes and poses a diagnostic challenge. There are no recent evidence-based guidelines or comprehensive reviews to help guide diagnostic work-up. We survey the literature on chronic progressive spastic paraparesis, with special emphasis on myelopathies, and propose a practical, MRI-based approach to facilitate the diagnostic process. Building on neuro-anatomic and radiographic conventions, we classify spinal MRI findings into six patterns: extradural; intradural/extramedullary; Intramedullary; Intramedullary-Tract specific; Spinal Cord Atrophy; and Normal Appearing Spinal Cord. A comprehensive differential diagnosis of chronic progressive myelopathy for each of the six patterns is generated. We highlight some of the more common and/or treatable causes of progressive spastic paraparesis and provide clinical pointers that may assist clinicians in arriving at the diagnosis. We outline a practical, comprehensive MRI-based algorithm to diagnosing adult-onset chronic progressive myelopathy.

Tropical myelopathies

A large number of causal agents produce spinal cord lesions in the tropics. Most etiologies found in temperate regions also occur in the tropics including trauma, herniated discs, tumors, epidural abscess, and congenital malformations. However, infectious and nutritional disorders occur with higher prevalence in tropical regions. Among the most common infectious etiologies are tuberculous Pott's disease, brucellosis, and neuroborreliosis. Parasitic diseases such as schistosomiasis, neurocysticercosis, and eosinophilic meningitis are frequent causes of nontraumatic paraplegia. The retrovirus HTLV-1 is a cause of tropical spastic paraparesis. Nutritional causes of paraparesis include deficiencies of vitamin B12 and folate; endemic clusters of konzo and tropical ataxic myeloneuropathy are associated in Africa with malnutrition and excessive consumption of cyanide-containing bitter cassava. Other toxic etiologies of tropical paraplegia include lathyrism and fluorosis. Nutritional forms of myelopathy are associated often with optic and sensory neuropathy, hence the name tropical myeloneuropathies. Acute transverse myelopathy is seen in association with vaccination, infections, and fibrocartilaginous embolism of the nucleus pulposus. Multiple sclerosis and optic myelopathy occur in the tropics but with lesser prevalence than in temperate regions. The advent of modern imaging in the tropics, including computed tomography and magnetic resonance imaging, has allowed better diagnosis and treatment of these conditions that are a frequent cause of death and disability.

Neurologic presentations of nutritional deficiencies

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. The first section of this review discusses neurologic manifestations related to deficiency of key nutrients such as vitamin B(12), folate, copper, vitamin E, thiamine, and others. The second section addresses neurologic complications related to bariatric surgery. The third sections includes neurologic presentations caused by nutrient deficiencies in the setting of alcoholism. The concluding section addresses neurologic deficiency diseases that have a geographic predilection.

The impact of the hyperacid Ijen Crater Lake: risks of excess fluoride to human health

The Asembagus irrigation area (East Java, Indonesia) receives a high input of fluoride (F) via surface water that partially originates from the hyperacid crater lake of the Ijen volcano. Endemic dental fluorosis among local residents has been ascribed to F in water wells. In this study, the total F intake by children and adults was estimated, based on concentrations in well waters and foods throughout the area. These values were compared with the Lowest Observed Adverse Effect Level (LOAEL) for dental fluorosis among children and skeletal fluorosis among adults. Fluorosis hazard maps were prepared, identifying the most hazardous locations in the area. It was concluded that there is not only a high risk of dental fluorosis, but also of skeletal fluorosis. Based on the total daily intake, the lowest F concentration in drinking water that poses a risk of developing fluorosis is approximately 0.5 mg/l for dental fluorosis and 1.1 mg/l for skeletal fluorosis. This is below 1.5 mg/l, which is both the guideline value for drinking water from the World Health Organization (WHO) and the Indonesian drinking water standard. This is the first documented case of human health problems that may be directly associated with natural pollutants originating from a volcano-hosted crater lake.

Ossification of the ligamentum flavum as a result of fluorosis causing myelopathy: report of two cases

OBJECTIVE AND IMPORTANCE

Ossification of the ligamentum flavum (OLF) is increasingly being recognized as a cause of myeloradiculopathy. However, the cause of such OLF has been identified only occasionally. The purpose of this case report is to highlight one more cause of OLF causing myelopathy.

CLINICAL PRESENTATION

Two middle-aged men residing in an area endemic for fluorosis presented with the insidious onset of myelopathy. Clinical examination revealed evidence of thoracic cord compression in both patients. Plain x-rays revealed markedly increased bone density characteristic of fluorosis. Magnetic resonance imaging revealed OLF in the lower thoracic region causing cord compression (at one level in the first patient and at three consecutive levels in the second patient). Plain x-rays of the forearm revealed ossification of the interosseous membrane, which is characteristic of fluorosis.

INTERVENTION

Both patients underwent decompressive laminectomy with removal of the OLF. The laminae and ossified yellow ligaments formed one mass of bone, which was removed with rongeurs and drills. After surgery, the first patient demonstrated improvement in motor power, whereas the second patient did not demonstrate any change in neurological status.

CONCLUSION

Fluorosis should be entertained in the differential diagnosis of OLF, especially in patients from endemic areas. The magnetic resonance imaging appearance of the spine in such cases is characteristic. In properly selected cases of fluorotic myelopathy, surgery is indicated. However, the prognosis is guarded, and long-term follow-up of these patients is necessary given the nature of the underlying disease.

Paleopathology of skeletal fluorosis

Skeletal fluorosis is one of a range of conditions causing excessive ossification and joint ankylosis in skeletons. It is rarely considered, however, in differential diagnoses of palaeopathological lesions. This paper considers the identification of skeletal fluorosis in a skeletal sample from the island of Bahrain, Arabian Gulf, dating to ca. 250 BC-AD 250. Approximately 4% of 255 adult skeletons in the sample have hyperostosic lesions resulting in joint ankylosis primarily of the lumbar vertebrae, as well as the major joints. These lesions most frequently occur among males in the 50+ age group. Chemical analysis on a small series of bone and dental samples confirmed the presence of high levels of fluoride, while staining of the teeth is evidence of dental fluorosis. The level of dental fluorosis is comparable with a naturally occurring fluoride level in water of between 1-2 ppm. The prevalence of hyperostosic lesions, however, appears higher than expected, and two possible reasons are suggested: confusion between a diagnosis of diffuse idiopathic skeletal hyperostosis and skeletal fluorosis on partial or less severely affected skeletons; and the presence of predisposing factors for skeletal fluorosis on the island in the past.

Fluoride levels in well-water from a chronic arsenicism area of Northern Mexico

This paper reports on the concentrations and geographical relationships between fluoride and total arsenic in 129 water wells of the Región Lagunera, Mexico, where arsenic has caused severe health effects. Fluoride concentrations ranged from less than 0.5 to 3.7 mg liter(-1); 25 samples (19.4%) had levels above 1.5mg liter(-1), the current WHO and Mexican drinking water standard, whereas 45 (34.9%) had levels below 0.5 mg liter(-1). The range of total arsenic concentrations was 0.008-0.624 mg liter(-1) and 64 (50%) had levels above 0.050 mg liter(-1), the current WHO standard. A linear regression analysis of arsenic and fluoride concentrations showed a highly positive correlation (r = 0.774), consistent with their geographical distribution. The highest concentrations of both elements were found in the northeastern part of the Región, mostly corresponding to rural areas, whereas the lowest concentrations were found in the southwestern part of the Región, as well as in the cities of Torreón in the state of Coahuila, and Gómez Palacio and Lerdo in the state of Durango. In consequence, people exposed to high arsenic concentrations are also exposed to fluoride at levels above the drinking water standard. The possibility of interactions between both elements is also discussed.

Screening vs. individual detection of industrial fluorosis: a decision analysis model

In preventive medicine and occupational health, decision-makers face uncertainty, divergent opinions, and varying needs. In the Swiss aluminum industry, screening for industrial fluorosis illustrates how decision analysis and cost-effectiveness analysis can provide rational and explicit models of decision-making in such contexts. Data on fluoride-exposed potroom workers are used to compare the cost-effectiveness of two strategies: mass screening of fluorosis versus individual detection of the disease on the basis of the worker's symptoms. A decision-analysis and a sensitivity analysis are performed to assess the impact of the screening program for different levels of expected prevalence of the disease. The optimal decision, in economic terms, is the one that minimizes the pension and screening-related costs and maximizes the number of years of full working capacity. Swiss data suggest that a diagnosis of clinical fluorosis is unlikely before 10 years of exposure to fluoride. Between 10 and 30 years of exposure to fluoride, mass screening may be more cost-effective than individual detection of the disease, even when the expected prevalence of the disease in a given industrial setting is less than 10%.