Infectious diseases

tuberculosis risk factors

• homeless

• foreign-born

• living or working in institutions ex. prisons, shelters, hospitals

• IV drug users

• overcrowded living conditions

• immunosuppression

what is the mode of transmission for tuberculosis

airborne droplets

manifestations of tuberculosis

• dry cough is initial symptom → becomes productive or have blood

• fatigue/malaise

• anorexia / unexplained weight loss

• low-grade fevers

• night sweats

• dyspnea is a late sign

• high-fever

• flu like symptoms

• pleuritic pain

• crackles

• hypotension and hypoxemia

latend TB infection (LTBI) vs. active TB

has no symptoms, is not infectious, has positive skin test, needs treatment to prevent it from activating

vs.

will have a bad cough, hemoptysis, chest pain, fatigue, weight loss, chills, fever, is infectious, positive skin test with abnormal chest x-ray or positive sputum culture, needs treatment

Tuberculin skin test (TST) using PPD

standard method to screen people for M. tuberculosis

inject 0.1mL of PPD intradermally on ventral surface of forearm

inspect and palpate 48-72 hours later

positive tuberculin skin test

induration - palpable, raised, hardened area and swelling (no redness) at the injection side

want to mark and measure it

means person has been exposed to TB and has developed antibodies

does not need a 2nd test but need further evaluation

contraindicated in clients who received the BCG vaccine

interferon-gamma release assays (IGRAs)

ex. QuantiFERON-TB and T-spot

preferred method for detection

blood test that screens for TB

results are available in a 23-36 hours and are not affected by BCG vaccination

if positive = patient has been infected with TB

can a chest x-ray alone diagnose TB?

no

tubercles

a capsule created when macrophages engulf the tuberculosis bacterium, but do not kill them

it heals and creates scar tissue

what is the gold standard for diagnosis of TB

sputum culture

needs 3 consecutive specimens 8-24 hours apart (at least one specimen from the early morning)

TB management and teachings

• negative pressure room and airborne precautions

• restrict visitors when infectious (first 2 weeks after starting treatment)

• avoid travel and public transportation

• teach good hand hygiene

• take 2-4 antibiotics for 6-12 months

  • directly observed therapy

• tell them to cover nose and mouth with tissues when coughing and sneezing

• screen close contacts of the patient

• sleep alone and have a well ventilated house

• spend time outside

• early recognition of recurrent infection so they can notify HCP

• smoking cessation

hepatitis A

self limiting infection transmitted through the fecal-oral route

risk factors:

• contaminated food or water

• poor hygiene

• improper food handling

• homelessness

• crowded situations

• poor sanitary conditions

• drug users

• MSM

• traveling to developing countries

hepatitis B and C

blood-borne pathogen that can cause acute or chronic hepatitis

can be transmitted by:

• percutaneous or mucosal exposure to blood, blood products, or bodily fluids

  • IV drug use, needle stick

• sexual contact

  • MSM

• perinatal

hepatitis C

can result in acute or chronic infection

can be transmitted by:

• percutaneous contact (IV drug use)

• high risk sexual behavior

manifestations of acute hepatitis

• anorexia and weight loss

• clay colored stools and dark urine

• diarrhea / constipation

• fatigue / malaise

• flu-like symptoms

• hepatomegaly and splenomegaly

• jaundice

• joint and muscle pain

• N/V

• pruritus (accumulation of bile salts under skin)

• RUQ tenderness

• decrease in taste and smell

complications include: cirrhosis, portal HTN, and liver cancer

caused by Hep. A

manifestations of chronic hepatitis

• increased AST and ALT

• ascites

• asterixis (“liver flap”)

• bleeding problems

• fatigue / malaise

• hepatomegaly

• jaundice

• joint and muscle pain

• spider angiomas

• palmar erythema

caused by Hep B and C

diagnostic tests for hepatitis

• blood testing for each specific antigen or antibody

  • HAV IgM, HAV IgG

  • Hepatitis B surface antigen, Hep. B surface antibody

  • Anti-HCV, HCV RNA

• H&P

• LFTs

• PT/INR

• FibroScan

• liver biopsy

• CBC

• stool studies

prevention of Hep. A

• hand washing

  • especially after BM and before eating

• good personal hygiene

• vaccination

  • all children below 1yr

  • travelers

  • MSM

  • IV drug users and homeless

• control and screening of symptoms of food handlers

prevention of Hep. B and C

• hand washing

• use gloves when expecting contact with blood

• do not share razors, toothbrushes, or personal items

• condoms

• HBV vaccine at 0, 2, and 6 months

• screen donated blood, organs, and tissues

• use disposable needles

management of hepatitis

• small frequent meals

  • good breakfast rather than large dinner

• mouth care

• antiemetics

• avoid very hot or very cold foods (more appetizing)

• adequate fluid intake

• rest

• increase protein and calories

most common cause of a liver transplant

Hepatitis C

where are most of HIV cases in the US located?

in the south

when. didHIV and Hepatitis begin to spread in the US?

1980s (started in 1970s)

HIV and its mode of transmission

a retrovirus that targets CD4 cells and causes immunosuppression

acquired by:

• contact with infected blood, semen, vaginal secretions, or breast milk

  • sharing needles or syringes

  • puncture wounds

• unprotected sex with a person with a high HIV viral load

• perinatally through pregnancy or delivery

  • especially if mom was not treated with ART

U=U

undetectable equals untransmissable

does not mean person is cured

manifestations of an acute HIV infection

• fever

• swollen lymph nodes

• sore throat

• HA

• malaise

• nausea

• muscle and joint pain

• diarrhea

• diffuse rash

most infectious stage

asymptomatic vs. symptomatic HIV infection

time between initial HIV infection and a diagnosis of AIDS; patient will have no symptoms (CD4 is 200-499 cells/microL)

vs.

CD4 count is below 200cells/microL and viral load increases → persistent fever, frequent night sweats, chronic diarrhea, recurrent HA, and severe fatigue; might acquire opportunistic infection

types of opportunist infections

• oropharyngeal candadiasis (thrush)

• shingles

• persistent vaginal candidal infections

• outbreaks of genital herpes

• Karposi sarcoma

• Hep. B or C

• TB

• pneumonia - most common life-threatening infection

  • fever, chills, dyspnea, chest pain, nonproductive cough

• meningitis

• diarrhea

AIDS diagnostic criteria

develops at least one of the conditions:

• CD4 below 200 cells/microL

• opportunistic infection

• opportunistic cancer

• wasting syndrome (loss of 10% or more of ideal body mass)

  • chronic diarrhea and weakness

  • protein malnutrition

acute infection of HIV

period from infection of HIV to the development of HIB specific antibodies

will have a negative HIV test but be highly contagious due to the high viral load

how long after exposure to HIV will antibodies be detected?

2-3 weeks

the delay is called the “window period”

viral set point

amount of virus in the body after initial immune response

diagnostic studies for HIV

• test for antigens and antibodies in the blood or saliva

• assess CD4 count and viral load

  • goal is to suppress it to the lowest level possible

• CDC = low platelets, WBC

• LFTs

how long are HIV patients on antiretroviral therapy and what are the side effects?

for life

can cause hepatotoxicity, nephrotoxicity, and osteopenia

Karposi’s sarcoma

cutaneous lesions that may involve multiple organ systems

can cause discomfort, disfigurement, ulceration, and potential for infection

HIV encephalopathy

progressive cognitive, behavioral, and motor decline