Ainhum

Jump to: navigation, search
Ainhum
ICD-10 L94.6
ICD-9 136.0
OMIM 103400
DiseasesDB 29442
eMedicine derm/594 
MeSH D000387

WikiDoc Resources for

Ainhum

Articles

Most recent articles on Ainhum

Most cited articles on Ainhum

Review articles on Ainhum

Articles on Ainhum in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Ainhum

Images of Ainhum

Photos of Ainhum

Podcasts & MP3s on Ainhum

Videos on Ainhum

Evidence Based Medicine

Cochrane Collaboration on Ainhum

Bandolier on Ainhum

TRIP on Ainhum

Clinical Trials

Ongoing Trials on Ainhum at Clinical Trials.gov

Trial results on Ainhum

Clinical Trials on Ainhum at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Ainhum

NICE Guidance on Ainhum

NHS PRODIGY Guidance

FDA on Ainhum

CDC on Ainhum

Books

Books on Ainhum

News

Ainhum in the news

Be alerted to news on Ainhum

News trends on Ainhum

Commentary

Blogs on Ainhum

Definitions

Definitions of Ainhum

Patient Resources / Community

Patient resources on Ainhum

Discussion groups on Ainhum

Patient Handouts on Ainhum

Directions to Hospitals Treating Ainhum

Risk calculators and risk factors for Ainhum

Healthcare Provider Resources

Symptoms of Ainhum

Causes & Risk Factors for Ainhum

Diagnostic studies for Ainhum

Treatment of Ainhum

Continuing Medical Education (CME)

CME Programs on Ainhum

International

Ainhum en Espanol

Ainhum en Francais

Business

Ainhum in the Marketplace

Patents on Ainhum

Experimental / Informatics

List of terms related to Ainhum

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Overview

Ainhum is a painful constriction of the base of the fifth toe frequently followed by bilateral spontaneous amputation (autoamputation) a few years later. The disease occurs predominantly in black Africans and their descendants, and occurs worldwide e.g. as a consequence of palmoplantar keratoderma. The exact etiology is still unclear.

History

Ainhum was first reported as a distinct disease and described in detail by J. F. da Silva Lima in 1867. He recognised a disease of the fifth toe suffered by the Nagos tribe of Bahia, Brazil. This disease was called “ainhum” by the Nagos and means “to saw”, characterising the painful loss of the fifth toe. The origin of these term was thought to be African. Due to slave trade, the Nagos were related to a native tribe in Nigeria.

Epidemiology

Ainhum predominantly affects black people, living in West Africa, South America and India. In Nigeria it is a common disease with an incidence of 2.2%. Daccarett recorded retrospectively a rate of 1.7% in a mainly African American population in Chicago. Up to now only a few cases had been reported in Europe. Ainhum usually affects people between 20 and 50 years. The average age is about thirty-eight. The youngest recorded patient was seven years old. There is no predominant gender ratio.

Etiology and Pathogenesis

The true cause of ainhum remains unclear. It is not due to infection by parasites, fungi, bacteria or virus, and it is not related to injury. Walking barefoot in childhood had been linked to this disease, but ainhum also occurs in patients who have never gone barefoot. Race seems to be one of the most predisposing factors and it may has a genetic component, since it has been reported to occur within families. Dent et al. discussed a genetically caused abnormality of the blood supply to the foot. Peripheral limb angiography in five limbs with ainhum showed that the posterior tibial artery became attenuated at the ankle, and the plantar arch and its branches were absent. The dorsal pedis artery was constituting the only supply to the forefoot and little toe.

Clinical Findings

The groove begins on the lower and internal side of the base of the fifth toe, usually according to the plantar-digital fold. The groove becomes gradually deeper and more circular. The rate of spread is variable, and the disease may progress to a full circle in a few months, or still be incomplete after years. In about 75 per cent both feet are affected, though not usually to the same degree. There is no case reported where it begins in any other toe than the fifth, while there is occasionally a groove on the fourth or third toe. The distal part of the toe swells and appears like a small “potato”. The swelling is due to lymphatic edema distal to the constriction. After a time crusts can appear in the groove which can be infected with staphylococcus. While the groove becomes deeper, compression of tendons, vessels and nerves occurs. Bone is absorbed by pressure, without any evidence of infection. After a certain time all structures distal the stricture are reduced to an avascular cord. The toe’s connection to the foot becomes increasingly slender, and if it is not amputated, it spontaneously drops off without any bleeding. Normally it takes about five years for an autoamputation to occur. Cole describes four stages of ainhum:

• Grade I: groove

• Grade II: floor of the groove is ulcerated

• Grade III: bone involvement

• Grade IV: autoamputation has occurred


Symptoms

Pain is present in about 78% of cases. Slight pain is present in the earliest stage of ainhum, caused by pressure on the underlying nerves. Fracture of the phalanx or chronic sepsis is accompanied with severe pain.

Histology

Histology shows a change in the prickle cell layer, and this is responsible for the laying down of condensed keratin causing the groove. The junctional tissue is reduced to a slender fibrous thread, almost avascular, and all the tissues beyond the constricting band is repressed by a fibro-fatty mass covered by hyperkeratotic integument.

Imaging

Soft tissue constriction on the medial aspect of the fifth toe is the most frequently presented radiological sign in the early stages. Distal swelling of the toe is considered to be a feature of the disease. In grade III lesions osteolysis is seen in the region of the proximal interphalangeal joint with a characteristic tapering effect. Dispersal of the head of the proximal phalanx is frequently seen. Finally, after autoamputation, the base of the proximal phalanx remains. Radiological examination allows early diagnosis and staging of ainhum. Early diagnosis is crucial to prevent amputation.

Differential Diagnosis

Ainhum is an acquired and progressive condition, and thus differs from congenital annular constrictions. Ainhum has been much confused with other diseases such as leprosy, diabetic gangrene, syringomyelia, scleroderma or Vohwinkel syndrome.

Treatment

Incisions across the groove turned out to be ineffective. Excision of the groove followed by z-plasty could relieve pain and prevent autoamputation in Grade I and Grade II lesions. Grade III lesions are treated with disarticulating the metatarsophalangeal joint. This also relieves pain, and all patients have a useful and stable foot.



Linked-in.jpg