Konzo

Neurological disease caused by cyanide poisoning

Konzo is a neurological disease that results from cyanide poisoning, primarily due to the consumption of insufficiently processed cassava roots. It is characterized by a sudden onset of irreversible spastic paraparesis, which predominantly affects the legs. The disease is endemic in certain regions of Africa, particularly in areas where cassava is a staple food and where food insecurity leads to inadequate processing of the cassava.

Epidemiology

Konzo is most prevalent in rural areas of the Democratic Republic of the Congo, Mozambique, and Tanzania. The disease is associated with poverty and food scarcity, which force communities to rely heavily on cassava as a primary food source. Outbreaks of konzo often occur during periods of drought or conflict, when food processing practices are compromised.

Pathophysiology

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Illustration of a boy affected by konzo

The pathophysiology of konzo involves the consumption of cassava that contains high levels of cyanogenic glycosides. When cassava is not properly processed, these compounds release cyanide, which is toxic to humans. The body detoxifies cyanide by converting it to thiocyanate, but this process requires adequate dietary intake of sulfur-containing amino acids. In populations where protein intake is low, the detoxification process is insufficient, leading to cyanide accumulation and subsequent neurological damage.

Clinical Features

Konzo is characterized by a sudden onset of spastic paraparesis, which is a form of paralysis that affects the legs. Patients typically present with difficulty walking, increased muscle tone, and exaggerated deep tendon reflexes. The condition is non-progressive, meaning that it does not worsen over time, but the initial disability is often permanent.

Diagnosis

The diagnosis of konzo is primarily clinical, based on the characteristic presentation of spastic paraparesis in individuals from endemic areas. There are no specific laboratory tests for konzo, but elevated levels of thiocyanate in the urine can support the diagnosis by indicating recent cyanide exposure.

Prevention

Preventing konzo involves improving the processing of cassava to reduce cyanide content. This can be achieved through methods such as soaking, drying, and fermenting the cassava before consumption. Public health interventions also focus on diversifying diets to reduce reliance on cassava and improve overall nutritional status.

Treatment

There is no specific treatment for konzo, and management is primarily supportive. Physical therapy can help improve mobility and function, but the neurological damage is often irreversible. Efforts to prevent new cases through education and improved food processing are crucial.

Related pages

• Cassava
• Cyanide poisoning
• Spastic paraparesis