Diagnosing an acute abdomen

How are you going to diagnose all the many causes of an acute abdomen, if the pattern of the symptoms they produce is so similar? Here is a check list of the more important features of each to help you sort them out, together with an indication of their frequency, and whether they are seen all over the developing world, or in some areas only. As is usual in medicine, a patient is more likely to have a rare presentation of a common disease, than a common presentation of a rare one. Don't be alarmed by the complexity of the check lists that follow! Take a careful history and examine him; consult the list, and then if necessary, extend your history and examination.

Be familiar with the pattern in your own area. For example, the causes of acute abdomens in Uganda in 1960 were: intestinal obstruction 93%, appendicitis 3%, and perforated peptic ulcer 2%. Cholecystitis, renal calculi, and pancreatitis together accounted for about 1%. The causes of intestinal obstruction were: external hernias 71%, volvulus 13%, intussusception 4%, bands and adhesions 4%. Adult pyloric stenosis, congenital anomalies and malignant disease each comprised about 1%. In another area (Kilimanjaro) intussusception was a more common cause of obstruction than hernias.

If you think that diagnosis is difficult, you can comfort yourself with the thought that, in a developing country, few of your patients will be hysterical, and that you are most unlikely to see the Munchausen syndrome (a clever group of patients who persistently fake their symptoms). When it does happen, you will be lost!

Fig. 10-3 DISEASES WHICH MAY PRESENT AS AN ACUTE ABDOMEN. 1, a liver abscess. 2, biliary colic. 3, appendicitis. 4, renal colic (very rare in some countries, but not uncommon in others). 5, sigmoid volvulus. 6, a perforated peptic ulcer. 7, a perforated gastric ulcer. 8, a ruptured spleen. 9, intussusception. 10, perforation of a typhoid ulcer. 11, a strangulated hernia. 12, acute cholecystitis. 13, acute pancreatitis. 14, volvulus of the small gut. 15, amoebic colitis. 16, rupture of an ectopic pregnancy. 17, PID. 18, torsion of an ovarian cyst.

THE GENERAL METHOD [s8]FOR AN ACUTE ABDOMEN[md]TWO CAUTION ! (1) Don't be frightened by this list. It is more important to decide when to operate and when not to operate, than the exact diagnosis. (2) ''If in doubt, it is better to look and see than to wait and see''. (3) The terms ''common' and ''uncommon' in the list below are relative only, because incidence varies geographically. (4) Read the list and refer to it, but don't try to learn it.

SHOULD YOU OPERATE ? THE INDICATIONS FOR OPERATION after adequate resuscitation are: (1) Diagnosis made and condition needing operation, for example, appendicitis or perforated ulcer. (2) Diagnosis not made, and no improvement in spite of 4 hours of conservative treatment (fluids, nasogastric suction, morphine).

CAUTION ! Always operate if there are signs of peritoneal irritation, unless the patient has: (1) A typhoid perforation of slow onset (31.8). (2) Acute pancreatitis (13.9).

THE INDICATIONS FOR NON-OPERATIVE TREATMENT are: (1) Diagnosis made, condition not needing operation: for example, acute cholecystitis, pancreatitis, uraemia. (2) Diagnosis not made, but patient improving.

THE DIAGNOSIS [s7]OF AN ACUTE ABDOMEN If a patient has CENTRAL ABDOMINAL PAIN, consider the the early stages of small gut obstruction (10.3), or appendicitis (12.1), or acute pancreatitis (uncommon in much of the developing world, but not so in urban areas where the alcohol intake is high). Examine him in a few hours, when you will probably find some other sign, such as vomiting, fever, or local abdominal (or rectal) tenderness, which will point to the diagnosis.

If he has SEVERE CENTRAL ABDOMINAL PAIN AND SHOCK, consider volvulus of the small gut (10.9), rupture of an ectopic pregnancy (16.6), acute pancreatitis, coronary thrombosis (rare), mesenteric thrombosis (rare), or a dissecting aneurysm (very rare).

If he has severe central abdominal pain and shock, as above, AND RIGIDITY, consider a perforated peptic ulcer (11.2), or a perforated gall-bladder (uncommon in most areas).

If he has PAIN, VOMITING, AND INCREASING DISTENSION, BUT NO RIGIDITY, he probably has small gut obstruction (10.3). Most acute abdomens cause a single initial vomit, but persistent vomiting indicates mechanical obstruction or ileus, or, if there is also rigidity, peritonitis.

If he has ABDOMINAL PAIN, with CONSTIPATION, increasing DISTENSION, and little or NO VOMITING his large gut is probably obstructed, probably by sigmoid volvulus (10.10) if he is an adult, or intussusception, if he is a child.

If he has LOCALIZED PAIN, TENDERNESS, and RIGIDITY, the causes depend on where they are:

In his right hypochondrium, consider a leaking duodenal ulcer (11.2), a liver abscess (31.12), or acute cholecystitis (13.3).

In his left hypochondrium (rare), consider a splenic infarct (if sickle-cell disease is endemic in your area), bleeding from an injured spleen, a leaking gastric ulcer (11.2), or acute pancreatitis (13.9).

In his right iliac fossa (very common), consider acute appendicitis (12.1) and most of its differential diagnoses.

In his left iliac fossa, consider diverticulitis (very rare in Africa).

In his, or her, hypogastrium, consider appendicitis, or PID (6.6).

A CHECK-LIST [s7]OF THE CAUSES OF AN ACUTE ABDOMEN INTESTINAL OBSTRUCTION is the commonest cause of an acute abdomen in most parts of the developing world.

Small gut obstruction (everywhere, common)[md]colicky central or upper abdominal pain, severe early vomiting, distension, characteristic high-pitched bowel sounds, commonly a tender, tense, hard lump at a hernial orifice.

Volvulus of the small gut (everywhere, uncommon)[md]short history, sudden onset, constant acute pain, vomiting, a tender central abdominal mass increasing in size, collapse.

Intussusception (everywhere, fairly common)[md]children, previous episodes, colicky pain with vomiting, a mobile mass, usually on the right but moves around, ''red currant jelly stools' (10.8), usually described by the child's mother as bloody diarrhoea. This blood is often found on a rectal examination.

Large gut obstruction (everywhere, common)[md]moderate colicky pain, little vomiting, much distension, no flatus, obstructive bowel sounds (10.3). In sigmoid volvulus, which is the common cause, the patient will probably have had previous subacute episodes, and may have extreme distension and a large tender tympanitic swelling (10.10). If his gut is strangulated he will be in severe pain and ill.

PERFORATIONS all of which need surgery, include:

A perforated peptic ulcer (everywhere, common)[md]the sudden onset of rapidly spreading abdominal pain, with diffuse abdominal tenderness, boardlike rigidity, and a previous history of dyspepsia (11.2). After 6[nd]8 hours his symptoms improve temporarily.

A perforated typhoid ulcer of the ileum (fairly common everywhere in the developing world, very common in West Africa)[md]headache, fever, and malaise for 2 weeks, followed by a dull pain suddenly getting worse and spreading, moderate tenderness, and guarding (31.8). The association of intestinal obstruction with protracted fever.

TROPICAL DISEASES. Here are the specifically tropical causes of an acute abdomen. Amoebiasis and its complications are uncommon except in certain areas, mainly humid low-lying ones, where they may be very common.

Amoebic colitis [md]cramps, diarrhoea with blood and mucus, slight tenderness over his colon, perhaps pain and a tender mass in his right hypochondrium (31.10).

Amoebic perforation of the gut[md]an acute abdominal catastrophe in a patient complaining of fever, pain, and diarrhoea (typically bloody), with a large tender mass in his right iliac fossa.

Amoebic liver abscess [md]fever, diffuse pain and tenderness in his right hypochondrium, a large diffusely tender liver, a rapid response to amoebicides, right iliac and shoulder pain (31.12).

Ileocaecal tuberculosis with subacute obstruction (common in some areas)[md]wasting, mild colic getting worse week by week, fever, distension, perhaps a mass in his right lower quadrant, or periumbilical area, ascites sometimes (29.5).

''Pigbel' disease (common in some areas, 31.9)[md]he presents with severe colicky pain, vomiting, and foul flatus.

Pyomyositis [md]an alert patient with a painful, warm, tender abdominal wall, fever, and no nausea, vomiting, anorexia, diarrhoea or constipation. He usually has normal bowel sounds and no rebound tenderness (7.1).

THE APPENDIX is only beginning to cause trouble in the developing world.

Acute appendicitis [md]anorexia, nausea, low-grade fever, central pain settling in the right lower quadrant, localized tenderness (12.1).

ABSCESSES in the abdominal wall and the iliac glands can mimic an acute abdomen.

Pyomyositis[md]local tenderness in the abdominal wall, perhaps abscesses elsewhere (7.1).

Extraperitoneal abscess, suppurating iliac adenitis [md]swinging fever, acute lower abdominal pain, hip flexed, tender induration of the abdominal wall extending upwards from the groin, minimal gastrointestinal disturbances (5.12).

TRAUMA. A ruptured spleen and a bowel perforation can both present as an acute abdomen.

Ruptured spleen[md]fainting, pallor, shock, a tender mass in the left hypochondrium, peritoneal irritation, the signs of hypovolaemia, shoulder pain, and a history of an injury (66.6).

Gut perforation[md]signs of peritonitis following a history of a blunt injury (66.9).

CAUTION ! Remember that signs of a large gut perforation are minor for several hours.

GYNAECOLOGICAL CAUSES. A ruptured ectopic pregnancy is the most important of these.

Ruptured ectopic pregnancy (everywhere, common)[md] missed or scanty periods, sometimes followed by a small dark vaginal loss, moderate lower abdominal pain suddenly getting worse and spreading, pallor, tachycardia, perhaps shock. Occasionally, symptoms are chronic (16.7).

Intermenstrual ovarian bleeding (''mittelschmertz')[md]mid-cycle sharp lower abdominal pain, variable abdominal tenderness, normal periods.

PID[md]fever, vaginal discharge, pain in one or both suprapubic areas, tender adnexae on vaginal examination (6.6).

Tubo-ovarian abscess with pelvic peritonitis[md]recent abortion or delivery or neglected salpingitis, followed by fever, toxaemia, lower abdominal pain, perhaps a suprapubic mass, a tender mass on vaginal examination. Induration and tenderness are usually such that fluctuation is not felt.

Torsion of an ovarian cyst[md]sometimes a pre- existing mass, sudden pain and vomiting, a tense, tender, firm mass palpable bimanually on pelvic examination (20.7).

RENAL CONDITIONS can sometimes present as an acute abdomen.

Renal colic (occasionally everywhere but common or very common in some regions)[md]a sharp severe colicky pain spreading from the patient's loin down to his groin, vomiting, a vague diffuse tenderness in his flank. Reflex intestinal ileus is not uncommon (23.12).

Pyonephros (everywhere, uncommon)[md]a high fever, pain in his costovertebral angle, often toxaemia, a tender enlarged renal mass.

THE GALL-BLADDER commonly causes trouble in the industrial world, and in North India but seldom does so in Africa.

Biliary colic [md]dyspepsia, colicky pain in the epigastrium or right hypochondrium, and below the right scapula, slight tenderness (13.2).

Acute cholecystitis [md]a history of dyspepsia, acute constant pain and narrowly localized tenderness in the right hypochondrium or epigastrium, Murphy's sign is positive, fever (13.3).

Empyema of the gall bladder (uncommon)[md]as for acute cholecystitis, but the pain is more intense, he is more ill, and you may be able to feel the fundus of his gall bladder (13.3).

THE PANCREAS is an occasional cause of an acute abdomen in the developing world.

Acute pancreatitis[md]a history of alcohol ingestion, acute deep epigastric pain penetrating to the back, prostration, vomiting, diffuse tenderness in the epigastrium and left hypochondrium (13.9).

Pancreatic abscess (rare)[md]earlier like acute pancreatitis, later swinging fever, toxaemia, an ill-defined tender deep-seated mass in the upper abdomen (13.11).

Pancreatic pseudocyst (uncommon)[md]a history of acute pancreatitis or earlier trauma, a large deep-seated tense fluctuant mass in the upper abdomen, anorexia, fever, sometimes jaundice (13.10).

Fig. 10-4. SOME MEDICAL DISEASES MIMICKING AN ACUTE ABDOMEN. 1, acute gastroenteritis. 2, basal pneumonia and pleurisy. 3, virus infections causing muscle pain or simulating peritoneal irritation. 4, diabetic precoma. 5, a sickle-cell crisis.

SOME MEDICAL DISEASES commonly mimic acute abdomens everywhere in the world. In most of them the fever is higher, the general symptoms worse, and the abdominal ones less than in acute abdomens. But beware of peritonitis when the patient is so ill that the general signs predominate over the local surgical ones.

Acute gastroenteritis (everywhere, very common)[md]diarrhoea, vomiting and fever, colicky pains, minimal abdominal tenderness, hyperactive (but not obstructive) bowel sounds, fever early, perhaps with rigors.

Basal pneumonia and pleurisy (everywhere, common) [md]early high fever, cough, rapid breathing, spasm of the upper abdominal muscles, and tenderness. Abdominal pain and rigidity may be very marked in a child, and involve the whole of the upper half of his abdomen, or the whole of one side. Signs of consolidation in his chest, usually in his right lower lobe.

Virus infections causing muscular pain (common)[md]sudden onset with high fever, local or general abdominal and chest pain; marked superficial muscle tenderness and rigidity of variable intensity, quickly changing its position; tender intercostal muscles on one or both sides; lateral compression of his chest is painful; nausea but seldom vomiting, no chest signs. During an epidemic of ''influenza' it is easy for an occasional patient with an acute abdomen to be misdiagnosed.

Diabetic precoma (uncommon)[md]the slow onset of abdominal pain and vomiting, dehydration, sugar and ketone bodies in his urine and breath.

Sickle-cell crisis (common in some areas)vomiting, central abdominal pain, guarding frequently, rigidity sometimes, sickle test positive. Headache, a high fever, and pains in his limbs and back.

Uraemia (uncommon)[md]may simulate ileus by causing abdominal distension and vomiting. The signs and the history are vague and variable.

DIFFICULTIES [s7]DIAGNOSING AN ACUTE ABDOMEN If you are in any doubt about the diagnosis when you first see a patient, admit him, re-examine him, and monitor him carefully, if necessary every hour for the first few hours. If he deteriorates, operate. He will be easier to assess in the ward than in the outpatient or casualty department, so examine him again there. You are also likely to get a truer reading of his pulse and temperature. This is especially important if you suspect him of having a strangulated gut, appendicitis, or a peptic ulcer.

If you are worried that he might be hysterical, and he is vomiting enough to be clinically dehydrated, he probably has an organic disease.

If he is is mentally ''odd' in any way[md]''aggressive', ''violent', ''dim', ''stupid', ''apathetic', or ''uncooperative', don't forget the possibility of an organic, and particularly a metabolic cause. He may be alkalotic, anaemic, hypovolaemic, toxaemic, uraemic, alcoholic, drugged, or febrile.

If a patient happens to be on steroids, pregnant, or aged, any of the symptoms of an acute abdomen may be masked, so be prepared to do a laparotomy on minimal signs.

If he is on antibiotics, they will not seal a perforated peptic ulcer, but they may diminish the signs of a perforated appendix.