Sometimes a superior surface abscess of the left lobe may expand in an upward direction and be diagnosed only when it has ruptured into the left lung or pleural cavity.^1-6 Such a rupture may occur even if the abscess has not attained a large size. Following the rupture, decompression of the left lobe may result in regression of whatever minimal abdominal symptoms and signs the patient may have had. Thus, many of these patients may seek advice from a physician, chest specialist or even a thoracic surgeon. These complications are so rare that Takaro and Bonds in a review of 293 cases of pleuropulmonary amoebiasis, found that only 10% had involvement of left hemithorax. The origin of the abscess in the left lobe of the liver and the amoebic aetiology may not be suspected at all.
Based on our observations, these patients may present with anyone of the following manifestations.⁷

1. Dry pleurisy with a pleural rub at the left base.
2. Sympathetic serous effusion on the left side.
3. Left sided empyema or pyopneumothorax (Fig. 92).
4. Pleural thickening, adhesions or fibrosis at the left base.
5. Consolidation at the left base.
6. Lung abscess at the left base (Fig. 9:3).
7. Bronchopleural or broncho-biliary fistulae at the left base.
8. An unusual shadow seen on X-ray chest at the left base (Fig. 94).

In a patient presenting primarily with the above features on the left side of the chest, the diagnosis of amoebic abscess of the left lobe rests on:

1. A high index of suspicion, especially in endemic areas.
2. A history of the shadow at the left base not responding to antibiotics, anti-tuberculous or anti-fungal treatment.⁷
3. Any history of dysentery, upper abdominal pain, referred pain in the left shoulder, other abdominal symptoms and even minimum tenderness in the epigastrium or palpable tender left lobe of the liver.
4. Features suggestive of amoebic aetiology of the lung lesions are-early haemoptysis, thick yellowish brown or chocolate coloured sputum, a greenish sputum suggestive of bile contamination, or an aspirated pleural fluid which looks chocolate coloured or brownish.
5. Mobility of the left dome of the diaphragm (whenever it is Visualized) on fluoroscope : I have observed that when the left dome is elevated by direct pressure from a superior surface abscess, the mobility is restricted markedly, while in case of elevation due to distended stomach or colon the mobility is only slightly diminished.⁸
6. Raised left dome of the diaphragm seen in the X-ray chest taken in the early part of the illness.⁹ Sometimes left dome of the diaphragm which is elevated by a left lobe abscess, returns to normal level after the abscess has ruptured and emptied itself into the chest. Hence all the previous chest X-rays should be reviewed when pulmonary amoebiasis is thought of.⁸

Once suspected, the diagnosis can be confirmed by the following investigations:

1. Demonstration of E. histolytica in the stool, sputum or pleural fluid.
2. Liver scan showing a cold area in the superior surface of the left lobe. Here liver scan is superior to peritoneoscopy.
3. Positive serological tests for amoebiasis

In the past when we had no facility for hepatic scintigraphy or serological tests; we often confirmed the diagnosis by therapeutic tests with a course emetine and chloroquine. Details of the management of such cases have been discussed elsewhere.

References

1. Alkan, W J. Kalmi, B. et al, Ann Int Med. 1961 55, 800.
2. DeBakey, M E, and Ochsner, A, Surg Gyn Obst (I A S ), 1951, 92, 209
3. Paul Milroy, B J Surg, 1960, 47, 502.
4. Shaw, R R. Surg Gyn Obst., 1940, 88, 703
5. Takaro, T and Bond W M, Surg Gyn Obst (I A S ), 1958, 107, 209
6. Wilmot, A J, Clinical Amoebiasis, Blackwell Scientific Publications, Oxford, 1962, 110
7. Kapoor, O P. and Shah, N A, Paper read at the Xlth international Congress of Internal Medicine, New Delhi, Oct. 1970
8. Kapoor, O P. and Shah, N A, Ind J Chest Dis 1972, 14, 1.
9. Ramachandran, S. Post Grad Med. J., 1974, 50, 689