An anal fissure is a break or tear in the skin of the anal canal. Anal fissures may be noticed by bright red anal bleeding on toilet paper and undergarments, or sometimes in the toilet. If acute they are painful after defecation, but with chronic fissures, pain intensity often reduces. Anal fissures usually extend from the anal opening and are usually located posteriorly in the midline, probably because of the relatively unsupported nature and poor perfusion of the anal wall in that location. Fissure depth may be superficial or sometimes down to the underlying sphincter muscle. Untreated fissures develop a hood-like skin tag (sentinel piles) which cover the fissure and cause discomfort and pain. Causes
Most anal fissures are caused by stretching of the anal mucous membrane beyond its capability.Superficial or shallow anal fissures look much like a paper cut, and may be hard to detect upon visual inspection; they will generally self-heal within a couple of weeks. However, some anal fissures become chronic and deep and will not heal. The most common cause of non-healing is spasming of the internal anal sphincter muscle which results in impaired blood supply to the anal mucosa. The result is a non-healing ulcer, which may become infected by fecal bacteria. In adults, fissures may be caused by constipation, the passing of large, hard stools, or by prolonged diarrhea. In older adults, anal fissures may be caused by decreased blood flow to the area.
However apparent autosomal dominant transmission of disease associated with mutations in COL4A3 and COL4A4 does occur.Clinical utility gene card for: Alport syndrome. Diagnosis
The diagnosis can usually be made on a combination of clinical, family history, and biopsy criteria. Biopsy of kidneys or skin
To be helpful, kidney biopsies need to be taken before the disease is too advanced. Changes on conventional (light) microscopy are not characteristic, and the possibility of other diagnoses, particularly focal segmental glomerulosclerosis (FSGS), may be raised. Electron microscopy shows a characteristic sequence of changes from thinning of the glomerular basement membrane (GBM), developing into areas of thinning and thickening, and finally into a complex appearance with apparent splitting, often described as a basketweave appearance. Early or very localised changes on this spectrum are not diagnostic, but the later changes are considered diagnostic.Immunohistochemistry or immunofluorescence studies to identify the COL3-4-5 proteins in GBM can be helpful. However, these studies may be normal in some patients with Alport syndrome, especially milder variants.The skin contains type IV collagen in a 556 network. Skin biopsies have been used to show the absence of the COL4A5 gene product, but these techniques are not straightforward, only apply to patients with severe COL4A5 mutations, and are not widely available. Genetic testing is now a better alternative if kidney biopsy is not possible. Family history
A family history of end-stage renal disease with hearing impairment is suggestive of Alport syndrome, but other conditions can cause this combination of abnormalities. Most can be distinguished by clinical features.