PART TWO
Diagnostic Cytology
Fig. 13.56
Pneumocystis carinii.
Alveolar cast stained with methenamine
Fig. 13.58
Pneumocystis carinii.
Multiple alveolar casts with honeycomb
silver, showing the typical appearance of the cyst form of the organism.
pattern. Bronchial washing (Papanicolaou x MP).
Bronchial washing (methenamine silver x OI).
Fig. 13.57
Pneumocystis carinii.
A three-dimensional alveolar cast
exhibiting the characteristic honeycomb appearance. Bronchial washing
(Papanicolaou x OI).
Fig. 13.59 Filariform larva of
Strongyloidesstercoralis.
Sputum
(Papanicolaou x HP).
Pulmonary Strongyloidiasis
Respiratory infection with
S. stercoralis
has been found mostly
in patients who are receiving high-dose steroid therapy for such
conditions as rheumatoid arthritis, renal transplantation, and
severe asthmatic bronchitis.245 Pulmonary infection is produced
when the filariform larvae migrate through the intestinal wall
into the blood stream and finally penetrate into the alveolar
space. A hemorrhagic pneumonia is produced there. The organ-
isms are readily identified in the bloody sputum expectorated
by these patients.246-249 The filariform larvae observed measure
400-500 pm in length and exhibit a closed gullet and slightly
notched tail. In extreme cases, filariform larvae, rhabditiform
larvae, and ova all may be observed in the alveoli.
Our laboratory has observed five examples of infection
of the lower respiratory tract by the filariform larval stage of
S. stercoralis
. One patient was a 45-year-old man who had
received a cadaveric kidney transplantation and, because of
increasing evidence of renal failure on the third postoperative
day, had been given high-dose steroids. He was readmitted 3
weeks later with cough, dyspnea, abdominal pain, and bloody
diarrhea. He developed pulmonary edema, and transtracheal
aspirates revealed filariform larval forms of
S. stercoralis.
In another case, a 77-year-old man had been treated with
40
mg/day of prednisone for asthma.
Sputum
cytologic
examination revealed both rhabditiform and filariform larvae
of
S. stercoralis.
The patient died 2 weeks later and was found at
autopsy to have had widely disseminated strongyloidiasis.
In Fig. 13.59 is shown the filariform larval stage of
S. stercoralis
from a nematodal infection, which was involving the intestine
and lungs of the first patient described. The primary diagnosis
was established by cytologic examination of the tracheal aspi-
rates. The organism is identified as being in the filariform larval
stage because of its length of 400-500 pm and closed gullet.
To be considered in the differential diagnosis are
Ascaris lumbri-
coides
and hookworms, both
Necator americanus
and
Ancylostoma
duodenale.
An important criterion in this differential diagnosis is
a blunt and slightly notched tail. This is in contrast to the tails
of the filariform larvae in both hookworm and
Ascaris,
which are
sharply pointed.
328
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