Mushroom worker's · excess of urobilin and urobilinogen was found in the urine. Serum proteins: total 5-8 g.0/0, albumin 2-15 g., globulins: alpha 1 0-66 g., alpha 2 1 2 g., beta

Thorax (1970), 25, 25.

Mushroom worker's lungEDWARD JACKSON, K. M. A. WELCH

The Royal Hospital, West Street, Sheffield

Two cases of an acute chest illness occurring in mushroom workers are described. In one patient,who was severely ill, a lung biopsy was obtained which showed a pattern of alveolitis andinterstitial fibrosis. The serum of both patients gave a precipitin reaction to an extraction ofmushroom compost after spawning, but no reaction occurred to a variety of hay antigens usedin the diagnosis of farmer's lung. A provocation test undertaken in one patient demonstrated areaction to the inhalation of a dilute extract of mushroom compost after spawning. The mostseverely ill patient made a full clinical and functional recovery without steroid therapy.

Allergic alveolitis has been described in recentyears as an occupational hazard of mushroomworkers (Sakula, 1967; Bringhurst, Byrne, andGershon-Cohen, 1959). We wish to describe twopatients with this condition, one exceptionally ill,in whom lung and liver biopsy material wasexamined.

CASE REPORTS

CASE 1 A man of 58 developed increasing breathless-ness and tight upper chest pain after a period of six

weeks' employment in the spawning process of mush-room farming. In addition he complained of cough,gross weight loss, rigors, and night sweats.On admission to hospital he was pyrexial (1000 F.),

markedly wasted, and dyspnoeic at rest with centralcyanosis. Extensive fine crepitations were heard inthe chest. The liver edge was palpable one finger-breadth below the costal margin. No other abnorm-ality was noted.

Investigations Chest radiography showed extensivenodular opacification, confluent in some areas (Fig. 1).

FIG. 1. Case 1. Chest radiograph onadmission showing widespread nodularopacities, confltuent in some areas.

25

on February 23, 2020 by guest. P

rotected by copyright.http://thorax.bm

j.com/

Thorax: first published as 10.1136/thx.25.1.25 on 1 January 1970. D

ownloaded from

http://thorax.bmj.com/

Edward Jackson, K. M. A. Welch

phages were present. The alveoLi were lined by hyper-plastic epithelial cells, apparently desquamating inareas. The alveolar walls were thickened by banas offibrous tissue and there was an extensive fibrosis ofthe interstitial tissues. The dominant inflammatorycell present in the interstitial tissue was the lympho-cyte, with occasional plasma cells. No giant cell sys-tems were seen. No evidence of vasculitis was notedin those vessels seen in the specimen. Respiratoryfunction tests are shown in the Table.

FIG. 2. Case 1. Tomogram of the most seriously affectedarea in the right upper lobe, showing apparent cysticspaces.

Tomography suggested cyst formation in the mostseriously affected area (Fig. 2). Sputum: no acid fastbacilli demonstrated. Mantoux testing 1: 10,000 nega-tive, 1:100 positive; haemoglobin 104%, E.S.R. 57mm. in one hour (Westergren). Liver function: bili-rubin 1-2 mg., thymol flocculation and turbiditynegative, S.G.O.T. 120 King units, S.G.P.T. 150 Kingunits, alkaline phosphatase 26 King units. A moderateexcess of urobilin and urobilinogen was found in theurine. Serum proteins: total 5-8 g.0/0, albumin 2-15 g.,globulins: alpha 1 0-66 g., alpha 2 1 2 g., beta 0-55 g.,

gamma 1-3 g. Coombs test negative.Because of the severity of the illness and the un-

usual radiographic appearances. lung biopsy was per-formed three weeks after admission. The biopsymaterial was taken from the worst affected area inthe right upper lobe (Figs 3 and 4). This showed asevere inflammatory reaction affecting both thealveoli and the interstitial tissues. Many of the alveoliwere filled with cells which had a granular P.A.S.staining cytoplasm and which resembled granularpneumocytes. In addition occasional alveolar macro-

TABLERESPIRATORY FUNCTION

Case I On Admission 3 Weeks Later 6 Latehs

Vital capacity (inl.) 1 ,400 2,000 3,000Predicted 3,440 _

F.E.V., ,5 % .. 45 80 73Total lung vol. (ml.) 3,160 4,514P.E.F.R. (I./min.) .. 160 325 525DLCO single breath(nlI./min./mm.HgCO) 7 9 19Arterial gas Rest Exercise Rest ExercisepH.7-47 7 51 7-38 7-38PcO (mm. Hg) 29 26 36 5 36P02 (mm. Hg) 83 71.5 117-5 94Compliance (17 breaths/min.) 0 052 1./cm. H2O (Normal 0-2 I./cm. H2O)

Case 2 On Admission 3 Weeks Later 3 Months

Vital capacity (ml.) 2,800 (80 ,')Predicted 3,370

F.E.V. 0.75% 80Total lung vol. (ml.) 6,065P.E.F.R. (I./min.) .. 490DLCO Single breath 7-1 10-8Arterial gas Rest Exercise RestpH..7-46 7-46 7-4Pco .. 31*4 26 5 40P02 .. 82-0 80 91

Serology: No antibodies were found to a variety ofhay antigens, but there was a positive precipitin reac-tion to an extract of mushroom compost after spawn-ing. When he had recovered, an inhalation test wasundertaken with dilute saline extracts of hay andcomposts. There was no reaction to hay extracts orto mushroom compost before the stage of spawning,but there was a pyrexial response to a dilute extractof mushroom compost after the spawning stage. Liverbiopsy was performed because of hepatomegaly andabnormal liver function tests. This showed onlymoderate centrilobular and sinusoidal venous con-gestion.

Initially he was treated with a week's course oftetracycline with no apparent improvement. Nofurther therapy was given and steady improvementfollowed in the ensuing weeks. A chest radiographsix months after admission showed a slight reticularnodular pattern with some fibrosis in the right upperlobe (Fig. 5).

CASE 2 A man of 64 was first employed in the spawn-ing process at the same mushroom farm as case 1only 19 days before admission. He had developed a

26



j.com/


ownloaded from


Mushroom worker's lung

FIG. 3. Case 1. Lung biopsy. General appearance showing intra-alveolar exudate, alveolar wall fibrosis, and extensivefibrosis of the interstitial tissues (H. and E. x 115).

cough and increasing breathlessness. In addition hehad noticed a swelling and blistering of the lips.His appetite was poor and he had lost a stone (6-3kg.) in weight over a period of two and a half weeks.On examination he was thin and slightly cyanosed,

but there was no evidence of respiratory distress. Inthe chest there were fine crepitations over the midand lower zones posteriorly.

Investigations His chest radiograph showed severalill-defined opacities in the peripheral fields of bothlungs, with scattered nodular shadowing (Fig. 6). HIishaemoglobin was 99%, E.S.R. 70 mm. in one hour(Westergren), liver function tests normal, no L.E. cellsseen in the blood, latex test negative, and no sputumcould be obtained for examination. His respiratoryfunction is shown in the Table.

Serology: As in Case 1 there was no reaction toa variety of hay antigens, but there was a positive

precipitin reaction to an extract of mushroom com-post after spawning.

His progress has been slow so far. Although thesigns in the chest resolved over a period of six weekson no therapy, he is still breathless on effort 12 monthslater.

DISCUSSION

We were impressed by the severity of the illnessin case 1, and in both cases there was a seriousconstitutional upset with much weight loss, as inthe third case described by Sakula (1967). Bothpatients were employed in the spawning processof mushroom cultivation. At this farm the pre-pared compost, which has reached a temperatureas high as 1300 F., is mixed mechanically with themushroom spawn. A fine dust is released andworkers in close proximity cannot avoid inhalingsome of it.

27



j.com/


ownloaded from



FIG. 4. Case 1. Lung biopsy. Higher power view showing intra-alveolar exudate consisting of large P.A.S. stainingcells, resembling type II granular pneumocytes. There is hyperplasia of the alveolar epithelial cells (H. and E.x 430).

In our patients, testing for precipitin antibodiesto specific thermophilic actinomycetes was nega-tive and there was no reaction to a mixed hay anti-gen used in the diagnosis of farmer's lung. Inboth patients, however, there was a precipitin re-action to a crude extract of mushroom compostafter spawning.

In our first patient, who underwent inhalationtests, the possibility of allergy to mushroom spawnis suggested by a reaction only to the extract ofcompost which had been spawned. It is interestingto note that two of Sakula's cases did not reactto standard actinomycete antigens. It is thoughtthat the alveolitis that develops in this disorder iscaused by a precipitin mediated type III allergicreaction (Pepys, 1967). The acute oedema andblistering of the lips seen in case 2 suggests atype I allergic reaction as well.

The histological changes described in farmer'slung have generally stressed a granulomatous re-action (Dickie and Rankin, 1958; Seal, Hapke,Thomas, Meek, and Haynes, 1968). The histo-logical features showed evidence of alveolar celldesquamation and interalveolar fibrosis and areindistinguishable from those features described inidiopathic fibrosing alveolitis (Scadding and Hin-son, 1967). So far as we are aware, this is thefirst instance in which lung biopsy findings havebeen described in mushroom worker's lung.The changes seen in the tests of respiratory

function (see Table) are typical of those seen inthis type of lung disease, namely a big reductionin the carbon monoxide diffusion capacity, hypox-aemia, and resulting hypocapnia with a respira-tory alkalosis. There was, in addition, a degree ofairways obstruction. In case 1, despite the severity

28



j.com/


ownloaded from


Mushroom worker's lung

FIG. 5. Case 1. Chest radiograph sixmonths after admission, showing almostcomplete clearing.

0..a..

...... I' i

FIG. 6. Case 2. Chest radiograph onadmission, showing scattered ill-definednodular opacities.

29



j.com/


ownloaded from



of the disease process, there was a remarkableimprovement in the CO diffusion capacity over a

period of six months.Turner-Warwick (1968) has described an asso-

ciation of chronic liver disease with idiopathicfibrosing alveolitis; the liver biopsy appearances

generally showed lymphocytic infiltration. Case 1showed a disturbance of liver function which was

presumably attributable to venous congestion,noted on the liver biopsy.

Since the inflammatory reaction in the lungbiopsy was so severe, steroid therapy may seem

to have been indicated, but by the time of thebiopsy the patient was beginning to improve. Thereturn of both radiographic and lung functionto near normal shows that steroid therapy is not

essential. Presumably the withdrawal from theantigenic environment is the most importantfactor.

Our thanks are due to Dr. T. E. Gumpert, underwhose care both patients were admitted, to ProfessorJ. Pepys and Dr. F. E. Hargreaves for serologicaltesting and advice, to Drs. T. W. Astin, P. Howard,and I. F. Webster, of the Department of Medicine, forthe investigation of pulmonary physiology, and to Dr.L. Henry, Department of Pathology, Royal Hospital,Sheffield.

REFERENCESBringhurst, L. S., Byrne, R. N., and Gershon-Cohen, J. (1959).

Respiratory disease of mushroom workers. J. Amer. mned. Ass.,171, 15.

Dickie, H. A., and Rankin, J. (1958). Farmer's lung: an acute granu-lomatous interstitial pneumonitis occurring in agriculturalworkers. Ibid., 167, 1069.

Pepys, J. (1967). Hypersensitivity to inhaled organic antigens. J. roy.Coll. Phycns Lond., 2, 42.

Sakula, A. (1967). Mushroom-worker's lung. Brit. mned. J., 3, 708.

Scadding, J. G., and Hinson, K. F. W. (1967). Diffuse fibrosingalveolitis. Thorax, 22, 291.

Seal, R. M. E., Hapke, E. J., Thomas, G. O., with Meek, J. C., andHaynes, M. (1968). The pathology of the acute and chronicstages of farmer's lung. Ibid., 23, 469.

Turner-Warwick, M. (1968). Fibrosing alveolitis and chronic liverdisease. Quart. J. Med., 37, 133.

30



j.com/


ownloaded from


Documents

Mushroom worker's · excess of urobilin and urobilinogen was found in the urine. Serum proteins: total 5-8 g.0/0, albumin 2-15 g., globulins: alpha 1 0-66 g., alpha 2 1 2 g., beta