Making the most of your pathology lab Flashcards
Differential diagnosis of breathlessness.
Left ventricular failure.
Pulmonary oedema.
Pleural effusion.
Pneumonia.
Patient with breathlessness, on examination: expansion reduced on right, tactile vocal remits reduced on right, percussion = stony dull at right base, auscultation = reduced breath sounds on right.
What is the likely diagnosis?
Pleural effusion.
What is the single most useful investigation for clinical diagnosis of pleural effusion?
Chest x-ray.
Following chest x-ray showing pleural effusion, what is the next step?
Find the underlying cause. Pneumonia? Lung cancer? Heart failure?
ASPIRATE (pleural tap).
What should you do with the fluid from a pleural tap (aspirate)? Which lab should it go to?
a) clinical chemistry
b) microbiology
c) cytology
d) all of the above
Send it to the lab: all of the above.
Why should you send pleural aspirate to clinical chemistry lab?
Measure amount of protein present in the effusion.
Transudate: protein <30g/dL. Caused by heart failure.
Exudate: protein >30g/dL. Caused by cancer and infection (pneumonia).
Why should you send pleural aspirate to the microbiology lab?
Microscopy and culture, sensitivity. (MCS).
Gram stain.
Likely organisms: pneumococcus (strep pneumoniae, Gram +ve diplococcus, use penicillin); haemophilus influenzae (COPD patients most commonly, Gram -ve rod, use broader abx like coamoxiclav).
What is the commonest brain tumour?
a) glioblastoma
b) meningioma
c) haemangioblastoma
d) craniopharyngioma
e) metastases
Metastases. (from lung in men, breast in women)
If both adrenal glands are very enlarged (bilateral adrenal hyperplasia), what test is required?
Possibly replaced. Tests for Addison’s.
9am cortisol.
ACTH.
34y/o patient presents with a fit and is found to have a space occupying lesion (metastasis), and bilateral adrenal hyperplasia- what is the next step?
a) remove both adrenals (not working anyway)
b) liver biopsy of lesion
c) keep comfortable and palliate
d) start chemotherapy
e) discuss all these options with the patient and get the patient to choose.
Discuss all these options with the patient and get the patient to choose.
Histopathology report of an adrenal mass: sections show fibroconnective tissue and skeletal muscle with well-formed confluent epithelioid granulomata, caseating (cheese-like), with necrosis and Langerhan’s multinucleated giant cells.
The features are those of a necrotising granulomatous inflammation.
What is the final diagnosis?
TB
What are the causes of adrenocortical failure?
Tuberculous Addison’s disease (commonest worldwide).
Autoimmune Addison’s disease (commonest in UK).
What is the treatment for systemic TB?
4 antibiotics for 2 months then 2 antibiotics.
e.g. isoniazid, rifampicin, ethambutol, etc.
