Pocket Medicine: The Massachusetts General Hospital Handbook of Internal Medicine (92 page)

Gastrointestinal & hepatobiliary

•
Esophagitis
:
Candida
, CMV, HSV, aphthous ulcers, pills; EGD if no thrush or unresponsive to empiric antifungals •
Enterocolitis
:
bacterial
(esp if acute: shigella, salmonella,
C. diff
);
protozoal
(esp. if chronic: Giardia, Entamoeba, etc.);
viral
(CMV, adeno);
fungal
(histo); MAC; AIDS enteropathy •
GI bleeding
: CMV, KS, lymphoma, histo;
proctitis
: HSV, CMV,
LGV, N. gonorrhoeae
•
Hepatitis
: HBV, HCV, CMV, MAC, TB, histo, drug-induced •
AIDS cholangiopathy
: often a/w CMV or
Cryptosporidium or Microsporidium
(at ↓ CD4)
Renal

•
HIV-associated
nephropathy (collapsing FSGS); nephrotoxic drugs (incl TDF)
Hematologic/oncologic
(
Lancet
2007;370:59;
CID
2007;45:103)

•
Anemia
: ACD, BM infiltration by infxn or tumor, drug toxicity, hemolysis •
Leukopenia
;
thrombocytopenia
(bone marrow involvement, ITP); ↑
globulin
•
Non-Hodgkin lymphoma
: ↑ frequency with any CD4 count, but incidence ↑ with ↓ CD4

•
CNS lymphoma
: CD4 count <50, EBV-associated •
Kaposi’s sarcoma
(HHV-8): at any CD4 count, incidence ↑ as CD4 ↓, usu. MSM

Mucocutaneous
(red-purple nodular lesions);
pulmonary
(nodules, infiltrates, effusions, LAN);
GI
(bleeding, obstruction, obstructive jaundice)

•
Cervical/anal CA
(HPV); ↑ rates of liver (a/w HBV/HCV), gastric & lung CA
Neurologic

•
Meningitis
:
Crypto
(p/w HA, Δ MS, CN palsy ± meningeal s/s; dx w/ CSF; serum CrAg 90% Se), bact (inc.
Listeria
), viral (HSV, CMV, 1° HIV), TB, histo,
Coccidio
, lymphoma •
Neurosyphilis
: meningitis, cranial nerve palsies, dementia, otic or ophtho s/s •
Space-occupying lesions
: may present as HA, focal deficits or Δ MS. Workup: MRI, brain bx if suspect non-
Toxo
etiology (
Toxo
sero
) or no response to 2 wk of empiric anti-
Toxo
Rx (if
Toxo
, 50% respond by d3, 91% by d14;
NEJM
1993;329:995)

•
AIDS dementia complex
: memory loss, gait disorder, spasticity (usually at CD4 ↓) •
Myelopathy
:
infxn
(CMV, HSV),
cord compression
(epidural abscess, lymphoma) •
Peripheral neuropathy
: meds, HIV, CMV, demyelinating
Disseminated
Mycobacterium avium
complex (DMAC)

• Fever, night sweats, wt loss, HSM, diarrhea, pancytopenia. Enteritis and mesenteric lymphadenitis if CD4 <150, bacillemia if <50. Rx: clarithromycin + ethambutol ± rifabutin.

Cytomegalovirus (CMV)

• Usually reactivation with ↓ CD4. Retinitis, esophagitis, colitis, hepatitis, neuropathies, encephalitis. Rx: ganciclovir, valganciclovir, foscarnet or cidofovir.

TICK-BORNE DISEASES

LYME DISEASE

Microbiology

• Infection with
spirochete
Borrelia burgdorferi
(consider coinfection w/
Ehrlichia, Babesia
) • Transmitted by
ticks
(
Ixodes
, deer tick); infxn usually requires
tick attached >36–48h
Epidemiology

• Most common vector-borne illness in U.S.; peak incidence in summer (May–Aug) • Majority of cases in MN, WI, New England, northern mid-Atlantic, northern CA • Humans contact ticks usually in fields with low brush near wooded areas

Diagnostic studies

• Often a
clinical
dx esp. in early disease; dx w/o EM requires confirmation testing (per IDSA) •
Serology
(in right clinical setting): screen w/
ELISA
, but false
from other spirochetal disease, SLE, RA, EBV, HIV, etc.; false
due to early abx or w/in 6 wk of infxn.

Confirm
ELISA results w/
Western blot
(↑ Sp)

• ✓ CSF if suspected neuro disease:
intrathecal Ab if (IgG
_CSF
/IgG
_serum
)/(alb
_CSF
/alb
_serum
) >1

Treatment (
NEJM
2006;354:2794)

• Prophylaxis (best prevention is tick avoidance): protective clothing, tick ✓ q24h, DEET

Chemoprophylaxis w/ doxycycline 200 mg PO × 1
only
if
all
of the following:

1.
Ixodes scapularis
tick attached ≥36 h

2. Local Lyme carriage in ticks ≥20% (peak season in New England, mid-Atl, MN, WI)

3. Abx can be given w/in ≤72 h

4. No contraindication to doxy (eg, preg, allergy, age <8 y)