1. The lung is diffusely abnormal.

There are macrophages and sloughed alveolar pneumocytes within the alveolar spaces. The septa are widened by edema and/or mononuclear inflammatory cells. Some slides have alveolar septa that are markedly thickened by fibrous tissue, edema and a few mononuclear inflammatory cells while in other slides there is only minimal thickening with a few mononuclear cells (esp lymphocytes). Some slides have proteinaceous material and in some areas form hyaline membranes. The alveolar spaces, however, are not packed with cells. The findings are most consistent with an interstitial pneumonia and not a typical bacterial pneumonia in which a neutrophilic response is usually present.

2. Opportunistic infections which occur in the lung such as CMV, pneumocystis carinii, cryptococcus and Mycobacterium intracellulare and Herpes simplex (not very common) would be common ones to look for.

These organisms often disseminate in patients that are immunosuppressed.

3. The large red-purple nuclear inclusions, sometimes with a surrounding halo, along with the cytoplasmic inclusions suggest the diagnosis of cytomegalovirus. Herpes does not have cytoplasmic inclusions and often there are multinucleated cells. The nuclear inclusions in Herpes simplex (type 1 or 2) as well as Varicella Zoster causing chickenpox or herpes zoster can be a diffuse ground glass type or eosinophilic surrounded by a halo.

The diagnosis can be confirmed by stains for CMV, either by immunoperoxidase or immunofluorescence stains which depend on antibodies to the virus.

4. Patients who are immunosuppressed for any reason: Cancer patients who are treated with chemotherapy, transplant patients who are treated to prevent graft rejection, and AIDS patients are common examples. Immunosuppression results in decreased numbers and response of lymphocytes resulting in increased susceptibility to certain opportunistic infections by organisms such as viruses, some protozoans such as pneumocystis carinii, some fungi, and some mycobacteria that do not normally infect healthy patients. Routine bacterial infections are not the typical infection that occurs in most patients with AIDS, or in patients with suppression of their lymphocytes such as occurs in renal or heart transplants.

5. Herpes Virus family including the following:

1. FTA-ABS (fluorescent treponema antibody absorption test (which react against treponema antigens and is the most specific, although as many as 2 % of patients may have a false positive treponema test due to incomplete removal of antibodies to nonpathogenic treponemas) and RPR (rapid plasma reagin) test or the VDRL (Venereal Disease Research Laboratory) test (which react to host tissue reagin or cardiolipin antigens, and are cheaper but nonspecific) are serologic tests for syphilis which could be performed. In tertiary syphilis, the nontreponemal tests are negative in 30% of the cases. Usually the nontreponemal tests are used for screening and treponemal tests for confirmation of the screening test. Both treponemal and nontreponemal tests can be negative in early syphilis (usually positive 4-6 weeks after infection or 3 weeks after appearance of the chancre); so, in early syphilis darkfield examination of wet mount exudate would be used to evaluate for spirochetes.

2. This would fit with the fact that 30% of patients with tertiary syphilis will have negative nontreponemal antibody tests.

3. During the earliest weeks of syphilis, both tests are negative and darkfield microscopy can be used to make the diagnosis

4. Aortic valve insufficiency or regurgitation from dilatation of the aortic ring. He probably has neurosyphilis most likely general paresis which causes progressive cortical destruction which results in personality changes and may progress to dementia and paralysis.

5. All tissues and all stages of syphilis can have a proliferative endarteritis, a perivascular infiltrate of lymphocytes and plasma cells. In the aorta endarteritis obliterans of the vasa vasorum lead to microscopic foci of necrosis (microgummas) of the aortic media. Irregular fibrous scars weaken the aortic wall and the intima appears rough and pitted (tree-bark appearance) grossly and results in ectasia or saccular aneurysms of the ascending aorta.

If the patient in fact had neurosyphilis, his symptoms suggest general paresis (progressive cortical destruction), which results in diffuse cortical atrophy with destruction of neurons. Luetic vasculitis can be found in any tissue at any stage of syphilis. Gummas, which are central areas of coagulation necrosis surrounded by a rim of granulomatous inflammation and granulation tissue or fibrous tissue are found in tertiary syphilis such as cardiovascular or neurosyphilis.

1. Segmented neutrophils

Bacterial.

Yes, organisms can be seen .

No, you can not distinguish gram positive from gram negative organisms on a H and E stain. You need a gram stain.

2. Gram negative rods.

It is consistent with the age and symptoms. Hemophilus is a gram negative rod that causes meningitis in childhood.

3. In newborns, group B strep (not group A strep) are common causes of meningitis.

1. No, a tumor is not present.

2. Macrophages (some epithelioid histiocytes), lymphocytes and multinucleated giant cells.

Caseous necrosis

Mycobacteria, fungi, syphilis brucellosis and some other infections can cause granulomatous reaction by cell mediated hypersensitivity. The reaction usually occurs to organisms that tend to survive within macrophages for long periods of time. (It can also occur in tumor necrosis.) It is the result of cell mediated immunity.

3. Acid fast (red) beaded rods

4. Tuberculosis

5. Post primary (secondary)

Secondary tuberculosis arises in previously sensitized individuals (whether endogenous or exogenous source). It begins in the apical segments of one or both upper lobes. This location seems to be favored because of the higher pO₂ content and lower blood flow with possibly fewer inflammatory cells. No significant enlargement of mediastinal lymph nodes occurs with secondary TB. The small calcification located in the subpleural location may have been the site of original infection-the Ghon focus. Primary tuberculosis may occur in any lobe.

6. Tuberculous skin test and chest x-ray and sputum cultures.

1. Neutrophils and foreign material (skeletal muscle fibers) within the alveolar spaces. The tissue is lung.

2. Bronchopneumonia (aspiration pneumonia). The lack of marked hemorrhage and necrosis indicates this may have been aspiration of oral bacteria with some residual food fibers rather than gastric contents with lots of acid.

The subarachnoid hemorrhage suppressed his control of swallowing and gag reflexes predisposing him to aspirating or he is likely to have undergone surgical repair and anesthesia predisposes to aspiration.

Alcohol, anesthesia and coma or other suppressive agents of the CNS can predispose to aspiration. Ethanol also suppresses cilia function and mobilization of macrophages, depresses granulopoiesis, dulls reflexes favoring aspiration and inhibits emigration of leukocytes in response to bacteria in tissues.

Muscle and vegetable fibers indicate aspiration.

3. Gram positive cocci and gram negative rods of variable appearances

You would expect a mixed infection in an aspiration pneumonia from mouth flora.

4. The mediastinal nodes were most likely from acute lymph adenitis and his spleen was acute splenic hyperplasia. The urinary changes of blood and neutrophils indicate the possibility of septicemia with microabscesses and pyelonephritis. The abdomen is most likely adynamic ileus 2nd to the pyelonephritis.

1. Lung with foamy or frothy eosinophilic material within some alveolar spaces and alveolar septa thickened by mononuclear inflammatory cells and edema. Some macrophages are in the alveolar spaces. The frothy eosinophilic intra-alveolar material is highly suggestive of pneumocystis.

2. Silver stain. (GMS)

3. Pneumocystis carinii.

It typically infects persons with AIDS (80% of all AIDS patients develop pneumocystis pneumonia during the course of their illness).

The marked prolonged immunosuppression to try to control his symptoms from regional enteritis.

4. Yes. Pneumocystis has an interstitial component and is usually classified as an interstitial pneumonia, the severe widening of the septa and the filling of the alveolar spaces by the organisms and debris can, if widespread result in severe shortness of breath due to lack of oxygen transfer.

5. Protozoa (or possibly fungus).

6. May be rapidly expanding perihilar shadows but the appearance often mimics other infections or ARDS.