The painless lump

The lump in the groin may have been a chance finding by the patient and may not be associated with symptoms. Each of the conditions listed in Box 21.1 may present as a painless lump. Indeed, pain does not occur with a saphena varix, lipoma of the cord, encysted hydrocoele of the cord, hydrocoele of the canal of Nuck, or testicular maldescent. Hernias, inguinal lymphadenopathy and femoral aneurysms may or may not be associated with pain. Historically, the development of a hernia may have been preceded by groin pain after a heavy lift or ‘strain’. However, many hernias appear without any such antecedent history.

The painful lump

Hernias can be associated with several types of pain.

First, there may be a dull ache in the groin experienced when the hernia is filled with intraabdominal contents, such as bowel or omentum. This ache is relieved by spontaneous reduction of the hernia, such as often occurs when the patient lies down. In these patients, the ache is typically worse at the end of a long, physically active day when the intraabdominal contents have filled and distended the hernial sac.

Secondly, there is the pain secondary to venous congestion of the intraabdominal contents of the hernial sac, caused by the constrictive effect of the neck of the hernia on venous outflow of the contents. This is a more severe, constant pain that may increase in intensity should venous congestion progress to arterial insufficiency (strangulation). In this circumstance, the hernia will not be reducible and will be locally tender to palpation. These symptoms and signs are related to inflammation in the tissues around the hernial sac.

Incarceration of the contents of a hernia within a hernial sac may be associated with intestinal obstruction, which is more commonly small bowel than large bowel. Small bowel obstruction is associated with central abdominal colicky pain, vomiting, abdominal distension and constipation (Ch 4).

A painful enlarged lymph node is always inflamed. An inflamed lymph node is associated with a constant ache without abdominal symptoms. Not uncommonly, the cause of the inflamed lymph node, such as an infected ulcer or boil on the foot, will also be a source of pain.

A femoral artery aneurysm, or pseudoaneurysm, is rarely painful. This is because the rate of expansion of the aneurysm is usually slow. Rapid expansion is more common with a pseudoaneurysm than a true aneurysm, and can be associated with a dull ache. A false aneurysm is secondary to puncture or rupture of the artery, as can occur after angiography or penetrating trauma. If the puncture site does not close or seal, there is a communication between the lumen of the artery and the haematoma outside the artery. A true aneurysm is surrounded by attenuated arterial wall, while a false aneurysm is surrounded by a fibrous capsule.

Reducibility

There are three causes of a reducible lump: an inguinal hernia (most common); a femoral hernia; and a saphena varix (least common). A saphena varix is always reducible as it always disappears when the patient lies down. An inguinal hernia is commonly reducible, while a femoral hernia is less often reducible because the neck is usually narrow and rigid.

An incarcerated hernia is where the contents of a hernial sac are irreducible. This may lead to intestinal obstruction or even strangulation of the hernial contents (as above).

Anatomical localisation of the lump

The initial step in the physical examination is to stand the patient to define whether the lump is in the inguinal or femoral region, whether or not there is a cough impulse and also observe if there is bilateral swelling. The two regions are separated by the inguinal ligament, which stretches between the anterior superior iliac spine laterally and the pubic tubercle medially. Both of these bony prominences are readily palpable.

The other useful landmark to determine the precise position of lumps in the femoral region is the femoral artery, located just below the midinguinal point and identifiable by its pulsatile nature. The midinguinal point is situated midway between the anterior superior iliac spine and the pubic symphysis.

Figure 21.1 details the various groin lumps above and below the inguinal ligament.

Figure 21.1 Groin lumps below and above the inguinal ligament.

Lumps in the inguinal region (above inguinal ligament)

Inguinal hernias

Inguinal hernias exit from the abdominal cavity and then pass along the inguinal canal together with the spermatic cord in the male. The inguinal canal passes medially from the deep inguinal ring, the surface marking of which is the midinguinal point (see above) to the superficial inguinal ring, which is just above and medial to the pubic tubercle (Fig 21.2).

Figure 21.2 Anatomy of the inguinal region and important landmarks.

From Browne NL. An introduction to the symptoms and signs of surgical disease. 3rd edn. New York: Oxford University Press; 1977.

It is imperative to examine the patient complaining of a lump in the groin while the patient is standing because a hernia may be apparent only in this position. Having examined in the standing position, have the patient lie down and determine if the hernia is reducible—coughing should also cause it to return. By placing the fingers along the line of the inguinal canal and asking the patient to cough, a cough impulse may be elicited; this is a pathognomonic sign of an inguinal hernia. This sign refers to the sudden expansion of a bulge beneath the examining fingers, which occurs when the increase of intraabdominal pressure blows some of the intraabdominal contents out into the hernial sac. If the examiner believes that the sign has been elicited, then it is worth trying to elicit the sign on the contralateral side for two reasons. First, inguinal hernias are not uncommonly bilateral. Secondly, the cough impulse of a hernia can be confused with a normal anterior movement of the whole of the lower anterior abdominal wall anteriorly with coughing. This anterior movement is not expansile.

Lumps in the femoral region (below inguinal ligament)

Figure 21.1 details the various groin lumps below the inguinal ligament.

Management of femoral and inguinal hernias

The preferred method of treatment is surgical repair (either open surgery or laparoscopic), the only method to cure an inguinal or a femoral hernia (see Fig 21.3). This has the benefit of relieving the inconvenience or discomfort of the hernia and, at the same time, preventing complications. Technically speaking, the hernia is always better to repair when it is small.

Figure 21.3 Summary of management of a lump in the groin.

Questions that need to be addressed when an inguinal or femoral hernia is being considered for surgical repair are:

The finding of a markedly tender lump in the groin is important. The differential diagnosis is usually between a strangulated hernia (inguinal or femoral) and an inflamed lymph node. For the clinician to decide that the cause is an inflamed lymph node, the primary focus of infection must be very apparent. Otherwise the diagnosis is an incarcerated hernia with contents of doubtful viability (strangulated) until proven otherwise. If there is any doubt about the viability of the contents of a hernia, surgical repair of the hernia must be performed urgently.

The situation is less pressing if the tenderness is only minor. A minor degree of tenderness in enlarged inguinal lymph nodes is relatively common. Frequently, the cause of a minor degree of lymphadenitis is not apparent and the symptoms and signs settle spontaneously with observation.

The repair of inguinal hernias in the very young (neonates and young children) should be performed electively but as soon as possible because, at least in males, there is a risk that strangulation of the hernia may be associated with testicular infarction.

If the contents of a hernia are strangulated, then operative repair needs to be performed on an emergency basis. After initial fluid resuscitation, the hernia is opened and the viability of its contents is assessed. If the contents are viable, then the contents can be returned to the abdomen and the hernia repaired in a standard fashion. If the contents are non-viable, then they need to be resected and bowel continuity restored prior to the hernia repair.

The alternatives to surgical repair are observation alone and fitting a surgical truss. Observation alone might be considered if the patient is frail, particularly if the hernial sac is small and its neck wide. A surgical truss may relieve the dull ache of a hernia by maintaining the hernia reduced. The patient needs to be aware that, even if the truss is worn regularly, the hernia itself can cause significant discomfort and that permanent reduction is not guaranteed. Indeed, strangulation of a hernia can occur while the truss is fitted. In view of the limitations and problems with surgical trusses, most patients should have the hernia repaired surgically, especially as the procedure can be performed under local anaesthesia in most cases.

Management of an enlarged lymph node

An enlarged inguinal lymph node may be solitary, associated with other enlarged lymph nodes in the groin or associated with a more generalised process of the lymphatic system (see Fig 21.3).

Generalised lymphadenopathy

If the inguinal lymphadenopathy is part of a more generalised lymphadenopathy, then an explanation for a generalised illness is required. Investigations under these circumstances may need to include:

If the cause is not found by non-invasive investigations, then surgical biopsy may be required. Nodes other than inguinal lymph nodes are usually biopsied as non-specific inflammatory changes are commonly found in inguinal lymph nodes of normal patients.

Management of a saphena varix

The management of this lesion will be the management of incompetent veins in the leg. If the lesion is to be treated, then ligation of the saphenofemoral junction needs to be performed.

Management of a psoas abscess

A psoas abscess presenting as a groin lump is extremely uncommon. In the past, when tuberculosis of the spine was a condition commonly encountered in clinical practice, the ‘cold abscess’ (so described because of the lack of an associated acute inflammatory response and lack of pain and tenderness) could point to the groin usually lateral to the femoral artery. In current practice, the development of a psoas abscess is usually secondary to a posterior bowel perforation. The primary pathology may be retrocaecal appendicitis, an inflammatory condition of the bowel such as Crohn’s disease, diverticulitis or local invasion from an overlying colon cancer. The symptoms, loin pain and fever, generated by bowel organisms focally invading the psoas muscle are usually sufficient to demand clinical attention at an earlier stage. The diagnosis is usually confirmed by imaging the retroperitoneum by CT. Drainage of the abdominal abscess is performed either posteriorly or anteriorly, together with surgery for the primary problem.