Tuesday, 19 October 2010

Noma (cancrum oris)

Noma (Gk nomē feeding; related to Gk nemein to devour). The Greek origin of the word reflects the rapid progression of this condition. It is also called cancrum oris (cancrum: L crab, eroding ulcer).

Essentially it is a gangrenous stomatitis, which starts in the mouth as a gingival lesion and rapidly destroys both the soft and hard tissues of the mouth and face. It predominantly affects malnourished or immunocompromised young children and is mostly encountered in developing countries. Nigeria probably has the highest incidence. Failure to adequately treat acute necrotizing gingivitis may lead to noma in malnourished or immunocompromised patients. In the developed world, noma is typically seen in immunocompromised persons such as those with HIV infection and leukaemia.

Noma neonatorum is thought to be a related but separate entity from noma. Noma neonatorum is a gangrenous disorder of the nose, lips, mouth, perianal area and, occasionally, the scrotum and eyelids, occurring in low birth weight and/or premature malnourished neonates almost exclusively in the developing countries and it is usually related to Pseudomonas aeruginosa septicaemia. It is almost invariably lethal in the absence of appropriate antibiotic treatment. A form of noma neonatorum has been seen in Native American infants who present with perineal and oral ulcerations in the setting of severe combined immunodeficiency (immunodeficiency of both B and T lymphocytes). Because most cases of noma neonatorum are caused by Pseudomonas aeruginosa, it is possible that this represents a severe form of ecthyma gangrenosum.

Noma appears to be a polymicrobial infection with Prevotella intermedia and Fusobacterium necrophorum being the two most frequently isolated organisms. Although organisms are isolated from the lesions, there is a low likelihood of transmissibility (groupings of noma seem to be more associated with common risk factors rather than true transmission).

The presenting feature is red or purplish-red spot usually on the gingiva, which enlarges and ulcerates rapidly, spreading to the labiogingival or mucobuccal fold, and exposing the underlying bone. There is pain (usually with foetor and cervical lymphadenopathy). A blue–black area of discolouration appears on the skin overlying the intraoral lesion and leads to a perforating wound. As it becomes black, this necrotic zone expands and forms a classic cone shape, cone gangreneux, with internal destruction greater than external involvement. Sequestration of the exposed bone and loss of teeth are rapid and then the wound heals slowly by secondary intention, often leaving a defect. In former times, noma was often a lethal condition.

Gangrenous stomatitis does not respond readily to treatment unless the underlying disease is controlled. The wound should be cleaned regularly with chlorhexidine and/or saline and/or hydrogen peroxide. A soft cotton gauze or tulle gras dressing may be used but changed frequently. Any loose slough, loose teeth and bony fragments should be removed (but invasive intraoral procedures are contraindicated). Parenteral fluids should be given to correct any dehydration and electrolyte imbalance. Some recommend broad-spectrum antibiotics, whereas others believe that metronidazole is adequate as anaerobic organisms predominate.

Healing lesions of noma are difficult to manage because of extensive fibrous scars. These scars can lead to strictures of the mouth, severe dental malposition, defective speech, and even complete closure of the mouth from contractures. 

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Main Works of Reference List (The first eight are my top favourites)

  • British National Formulary
  • British National Formulary for Children
  • Guidelines (BAD - BASHH - BHIVA - Uroweb)
  • Oxford Handbook of Genitourinary Medicine, HIV, and Sexual Health
  • Oxford Handbook of Medical Dermatology
  • Rook's Textbook of Dermatology
  • Simple Skin Surgery
  • Weedon's Skin Pathology
  • A Concise Atlas of Dermatopathology (P Mckee)
  • Andrews' Diseases of the Skin
  • Andrology (Nieschlag E FRCP, Behre M and Nieschlag S)
  • Bailey and Love's Short Practice of Surgery
  • Davidson's Essentials of Medicine
  • Davidson's Principles and Practice of Medicine
  • Fitzpatrick's Colour Atlas and Synopsis of Clinical Dermatology (Klaus Wolff FRCP and Richard Allen Johnson)
  • Fitzpatrick’s Dermatology in General Medicine
  • Ganong's Review of Medical Physiology
  • Gray's Anatomy
  • Hamilton Bailey's Demonstrations of Physical Signs in Clinical Surgery
  • Hutchison's Clinical Methods
  • Lever's Histopathology of the Skin
  • Lever's Histopathology of the Skin (Atlas and Synopsis)
  • Macleod's Clinical Examination
  • Martindale: The Complete Drug Reference
  • Oxford Handbook of Clinical Examination and Practical Skills
  • Oxford Textbook of Medicine
  • Practical Dermatopathology (R Rapini)
  • Sexually Transmitted Diseases (Holmes K et al)
  • Statistics in Clinical Practice (D Coggon FRCP)
  • Stockley's Drug Interactions
  • Treatment of Skin Disease: Comprehensive Therapeutic Strategies
  • Yen & Jaffe's Reproductive Endocrinology