Various investigations are performed in order to differentiate haemorrhoids from other rectal diseases:
the examination may be performed in various positions. For example, the patient may be examined bending over, lying on his side or back (the “lithotomy position”, as for a gynaecological examination) or in the knee-elbow position. Besides assessment of the perianal skin and closure of the anus, grade III and grade IV haemorrhoids may already be visible.
the rectal opening is first inspected externally. When the patient strains, haemorrhoids of grade II or above may be visible as spontaneously prolapsing, deep red, nodular protrusions.
digital rectal examination:
sphincter muscle function can be checked using a finger. In addition, grade II-IV haemorrhoids may be palpated as soft nodules.
to see inside the rectum, it is necessary to perform rectal endoscopy using special equipment. The instruments vary in length and a distinction can be made accordingly between an anal speculum, a proctoscope (approx. 6 cm long), a rectoscope (approx. 20 - 30 cm long) and a colonoscope. This allows evaluation of the intestinal mucosa and any inflammation in the various bowel segments or exclusion of a tumour in the lower rectum. Haemorrhoids usually appear as deep dark red nodules. Tissue specimens can also be taken for histological (microscopic) analysis to rule out other diseases.
the stool test for occult blood (“Haemoccult test”) is used for the detection of asymptomatic, invisible bleeding from the rectum. It involves incubation of stool specimens with a chemical substance. Blood may be detected in the stool, depending on the change in colour. Anal smears may possibly also be taken, with subsequent laboratory testing for parasites, viruses, bacteria and fungi. Patch testing can be performed to rule out allergic contact eczema. Endoscopic ultrasound may provide indications of differential diagnoses such as muscle damage and anorectal fistula disease. Manometry can show sphincter muscle tone at rest and in contraction to complement digital rectal examination.