MATRIZ FODA

The majority of the patients in this study were aged between 20 and 59 years. This is consistent with studies from other centers in Africa1,7,8,23,26 but in contrast to what obtains in developed countries where majority of the patients with MIO are in the 7th decade and above.^24,25 This may be due to the generally younger population pattern in

The male to female ratio is 1.8 : 1(p< 0.05) This gives a male preponderance which was found in other Nigerian series.^8,41 Obstructed external hernias accounted for most of the cases of MIO in Aba – 67 patients (64.4%). This is in consonance with the general pattern in developing countries. In developed countries on the other hand, adhesive bands constitute greater percentage of cases of MIO in adults. Obstructed inguinal hernias accounted for 54.8% of the patients. Researchers in Nigeria and indeed other developing countries have established a similar pattern although with wide variation in the proportion of MIO due to obstructed inguinal hernias.^1,3,8,41 In our environment, probably because of poverty, ignorance, unavailability of adequately staffed health institutions especially in the rural areas, most patients with external hernias do not get the needed attention early.

The second commonest cause of MIO in this study is post-operative adhesions which accounted for 24.0% of all the patients seen with a female : male ratio of 4:1. Other workers in developing countries have found a similar trend where MIO from adhesions is second to obstructed external hernias in the etiology of MIO.^1,3,38,44 In the developed world on the other hand, adhesive band as a cause of intestinal obstruction accounts for most of the cases of MIO. This higher incidence has been attributed to large number of surgical procedures on the abdomen and pelvis being performed among the population studied.^1,14,22

All the patients with MIO from adhesions had previous surgery on the abdomen or pelvis. This is unlike the experience of other workers where adhesions also resulted from congenital bands and inflammatory condition in the abdomen and pelvis.^32,41,44 Spencer⁴⁶ in Calabar recorded 74% adhesions being post inflammatory while Emmanuel⁴⁷ in Lagos recorded 54.5% due to post-operative adhesions and 45.5% due to post inflammatory causes. When the cause of irritation is removed, early fibrinous adhesions may disappear

or they may become vascularised and replaced by mature fibrous tissue. In the early post-operative period, the onset of MIO due to adhesions may be difficult to differentiate from paralytic ileus.¹⁸

Congenital bands are seen in Meckel’s diverticulum and intestinal malrotation. In Western series, they are seen in 2% of the population.² Post-inflammatory adhesions may follow acute appendicitis, typhoid infection, previous pelvic inflammatory disease and other causes of primary peritoneal irritation.^1,2

Adhesions may cause intestinal obstruction by kinking or angulation or by creating bands of tissue that compress the bowel.² In this work, all the cases of intestinal obstruction from adhesions were caused by bands of fibrous tissue which compressed the bowel.

Obstruction from intestinal tumours was the third commonest cause of adult MIO in Aba. Of the 4 patients (3.8%) with intestinal tumours, 2 were malignant rectal tumours, 1 occurred on the splenic flexure of the colon, while the other patient had leiomyoma of the ileum. Malignant intestinal obstruction though uncommon is by no means rare in our sub-region.^6,40,41 In this study, the patients with malignant intestinal obstruction were aged between 60 and 89 years. There were 3 patients (2.9%) with sigmoid volvulus and 3 patients (2.9%) with intussusception. All the cases of sigmoid volvulus were males. The incidence of sigmoid volvulus in this study and previous works in the West African sub region is not as high as it is in East Africa.^1,4 Histology report revealed that 1 (33.3%) of the 3 patients with intussusception in Aba had leiomyoma of the small intestine. In 2 patients (66.7%), the intussusception was idiopathic.. Nmadu⁴⁸ from Northern Nigeria had only one case of intussusception due to tumour.

Two elderly patients (a male and a female) aged between 80 to 89 years presented

Faecal impaction is commoner in the mentally diseased patients and in those with painful anal conditions like fissure in ano.^1,2

The early clinical features of patients in this study consisted mainly of abdominal pains, vomiting, abdominal mass, dehydration, abdominal distention and increased bowel sounds. These are consistent with studies elsewhere.^2,5,8 Most of the patients who presented early had obstructed external hernias. They required intravenous fluid, minimal investigations followed by surgical intervention to relieve the obstruction. Patients who presented 72 hours after the onset of symptoms had physiological and biochemical derangements, which resulted in protracted pre-operative preparations and correction before surgical intervention. Late presentation (more than 72 hours after the onset of symptom) was recorded in 39 patients (37.5%). This is similar to the experience of other investigators in Nigeria^23,41 and other developing countries.^3,44 Whereas 7 of the 35 patients (20.0%) who presented within 72 hours of the onset of symptom had bowel resection, 33 out of 59 patients (55.9%) who presented after 72 hours had bowel resection because of non-viable bowel. This is statistically significant (P < 0.05). The resection rate in this study is 42.6%. This is slightly higher than the rates by other workers in the country,^41,47 and could be due to the fact that majority of the patients presented late.

External hernias and adhesions were the most common causes of small bowel obstruction while volvulus and tumours were the most common cause of colonic obstruction in Aba. Of the 94 patients who had surgical operations for the relief of MIO, 40 patients (42.6%) had bowel resections. Thirty-one (32.6%) patients had bowel resection for gangrene while 9 (9.5%) had resection for carcinomas and redundant bowel in sigmoid volvulus or unreduced bowel in intussusception. The resection rate of 32.6%

for gangrenous bowel is higher than what Otu⁴⁹ reported in Calabar, Adekunle⁸ in Ibadan, and Naaeder and Archampong³ in Accra. In the USA, Shatila et al,⁵⁰ Leffall and

Syphax,⁵¹ reported rates of gangrenous bowel resection of 52% and 89% respectively.

Both studied were based specifically on mechanical strangulating intestinal obstruction and this may account for the high rate.

Intra abdominal causes of MIO were associated with higher rate of bowel resections (23.4%) than obstructed external hernias (19.2%). This is statistically significant and similar to the results from other series.^3,9,41 The features of intra-abdominal obstruction may not be easily obvious to the patients and clinician as are those of obstructed external hernias.

The post-operative complication rate of 29.8% is much higher than the figures reported by Spencer⁴⁶ in Calabar, Adekunle⁸ in Ibadan, and Odigie²³ in Zaria. The wound infection rate in this study is 16% and is similar to the figures from Enugu,⁵² Benin⁴¹ and Zaria²³ However, authors within and outside Nigeria have reported wound infection rates as low as 4-7%.^3,8 The rate of wound infection was significantly higher in patients who had bowel resection than in these who had no resection. This could have resulted from late presentation and the sequelae of MIO such as gangrene of the bowel, hypovolaemia, fluid and electrolyte derangement, and possible contamination from intestinal luminal content during resection.

The overall mortality in this study is 10.6% and is similar to the figures from within and outside the West Africa Sub-region^44,52. The post-operative mortality rate of 11.7% is slightly higher than the figures from the sub-region which range from 5 – 10%^3,8,44,49

The non - survivors in this study had a significantly longer duration of symptoms at presentation. Late presentation with its associated increased incidence of bowel gangrene was the single most important prognostic factor common to all non-survivors.

Bowel resection was associated with more morbidity and mortality than when bowel resection was not done. Contamination by toxic intestinal luminal content with attendant infection of the wound and abdominal cavity might be responsible for this.

Statistically significant prolonged period of hospitalization before surgical intervention (P < 0.05) was sadly found in non-survivors. Delays, which occurred during payment of necessary hospital fees, procurement of adequate units of blood (when necessary) and prior to obtaining results of pre-operative investigations accounted for the prolonged period of pre-operative hospitalization. These unnecessary delays depict signs of deteriorating infrastructural facilities, poor economy, poverty, ignorance, poor work attitude and the general rudimentary nature of our health care facilities.

The mortality from obstructed external hernias is 1.0% as against 9.6% for intra-abdominal causes. Achampong et al reported similar figures.^44. According to Adekunle,⁸ patients with obstructed external hernias often related their symptom(s) to their hernias and therefore tend to report early to the hospital for treatment.

The serum potassium and sodium at admission were found to be significantly lower (P < 0.05) in non survivors than in survivors. Odeyemi⁴⁵ et al in their series also found hypokalaemia to be a significant prognostic factor in MIO in adults. The hypokalaemia and hyponatraemia are attributable to prolonged loss of gastrointestinal secretions rich in potassium and sodium consequent upon late presentation.

The WBC and pulse rate at admission were significantly higher in the non survivors than in the survivors (P < 0.05). Bizer³¹ regarded WBC of more than 18,000/mm³ to have a positive correlation with the presence of strangulation but this was refuted by Delany.³²

Fever (temperature > 37.78 orally), tachycardia, (pulse > 96/min), leucocytosis (WBC > 10,000/mm³), and localized abdominal tenderness have long been regarded as

classic finding in strangulation. Stewardson²⁷ et al observed that there was no single finding that is of more value than the other in establishing the presence or otherwise of gangrenous bowel. The admission temperature, PCV, blood urea, and serum creatinine were not found to be significant prognostic factors.

The mean hospital stay was 15.0 ± 5 days. This is similar to Asbun³⁹ et al’s record of a mean hospital stay of 15.3 days. Many of the patients failed to keep their appointment on discharge. In our environment, once a patient is relieved of his/her acute symptom(s), he/she does not see any need to see the doctor again. This is a reflection of our low educational and public health awareness status.