Delirium in an HIV patient

Today's case featured a middle-aged man presenting with features of agitated delirium, seen after sedation in the ED.  His past medical history was only remarkable for HIV infection, with not much else clear besides a CD4 count below 50.  His phy

sical examination was helpful in that it did not suggest fever/meningismus, nor did it suggest a focal cause of neurologic compromise.  A lumbar puncture was performed which showed 3 WBC’s, a very slightly elevated protein, but was otherwise normal.  A chest X-ray showed a left basal infiltrate.  He was treated for community-acquired pneumonia and appears to be doing well.

There were multiple learning points from this case:

-We discussed a differential diagnosis and approach to altered mentation.  This will come up continuously when seeing ward patients or admitting from the ED.  Broad categories include drugs (illicits, narcotics, alcohol, CNS depressants, withdrawal), infections (meningitis is the most concerning), metabolic derangements (acidemia, hypercalcemia, B12 deficiency, thyroid disease), and structural derangements (intracranial hemorrhage, mass effect, etc).  In most cases, it is a good idea to obtain some form of neuroimaging, and some bloodwork (CBC, lytes, calcium profile, liver enzymes) +/- an arterial blood gas for acidemia.

-We talked about salient features of the past medical history for any patient with HIV.  These include year of acquisition, treatment, treating physician, previous opportunistic infections and opportunistic malignancies, most recent CD4 count, HIV viral load, adherence, and opportunistic infection prophylaxis).

-We talked about the opportunistic infections that go along with HIV (and are often AIDS-defining illnesses).  They are best categorized into CD4 count-dependent and CD4 count-independent processes.

CD4 Count-Independent:

Mycobacterium Tuberculosis

Hepatitis A/ Hepatitis B infection

Streptococcus Pneumonia

Influenza

CD4 Count-Dependent:

Nuissance infections: candidiasis, molluscum, HSV

Pneumocystis jirovecii (200/mm3)

Endemic mycoses (200/mm3)

Cryptococcus (200/mm3)

Toxoplasmosis (100/mm3)

Mycobacterium avium complex (50/mm3)

CMV (50/mm3)

-We talked about a general approach to someone who is ill with HIV.  I think it’s important to remember that patients with HIV have a right to present with things that non-HIV patients get.  Once a syndrome is identified (i.e. meningitis, pneumonia, etc) it is important to try to determine whether or not it is related to the patient’s HIV.  At that point, it’s helpful to try to categorize it as related to the HIV medications, the HIV itself, or the immune compromise as a result of HIV.  If it’s determined to be related to the immune compromise, then it’s helpful to distinguish between opportunistic infections (PJP, MAC, TB, etc) and opportunistic malignancies (lymphomas, Kaposi sarcoma, etc.).

-We talked a little bit about pneumocystis pneumonia.  Though we always associated it with HIV infection, patients with other forms of immune suppression (e.g. steroids) can also get PJP if they are suppressed for a long enough time.  The prophylaxis is with trimethoprim/sulfamethoxazole (Septra®) and is almost perfectly effective – if the patient is adherenet it is extremely unlikely that he/she will have PJP.  Other options include dapsone or atoviquone.  Usually, people suspect PJP in the right clinical setting (immune compromise/AIDS), with profound hypoxia especially on exertion, a reticular-nodular pattern on chest X-ray, a high LDH, and a profoundly elevated A-a gradient.  The test of choice is a sputum stain with fluorescence for PJP, and it tends to have a very high sensitivity.  If PJP is diagnosed, then depending on the A-a gradient, you may need to give IV or oral Septra, +/- steroids.  Paradoxically, there can be an inflammatory reaction following treatment with Septra wherein lysis of the fungi produces a worse pneumonitis leading to respiratory failure/ARDS. The steroids mitigate this.

Attached are some articles on cryptococcal meningitis, pneumocystis pneumonia, and bacterial pneumonia in HIV patients.  The images with CD4 counts and OI’s is credited to Dr. Wayne Gold and Dr. Lauren Lapointe-Shaw.  The flowchart of approach to illness in an HIV patient is credited to Dr. Paul E. Bunce.

Further Reading:

Bicanic, T., & Harrison, T. S. (2004). Cryptococcal meningitis. British Medical Bulletin, 72(1), 99-118.

Thomas Jr, C. F., & Limper, A. H. (2004). Pneumocystis pneumonia. New England Journal of Medicine, 350(24), 2487-2498.

Hirschtick, R. E., Glassroth, J., Jordan, M. C., Wilcosky, T. C., Wallace, J. M., Kvale, P. A., ... & Hopewell, P. C. (1995). Bacterial pneumonia in persons infected with the human immunodeficiency virus. New England Journal of Medicine, 333(13), 845-851.