PPD Interpretation

Classification of the Tuberculin Skin Test Reaction

An induration of 5 or more millimeters is considered positive in -HIV-infected persons -A recent contact of a person with TB disease -Persons with fibrotic changes on chest radiograph consistent with prior TB -Patients with organ transplants -Persons who are immunosuppressed for other reasons (e.g., taking the equivalent of >15 mg/day of prednisone for 1 month or longer, taking TNF-a antagonists)

An induration of 10 or more millimeters is considered positive in -Recent immigrants (< 5 years) from high-prevalence countries -Injection drug users -Residents and employees of high-risk congregate settings -Mycobacteriology laboratory personnel -Persons with clinical conditions that place them at high risk -Children < 4 years of age - Infants, children, and adolescents exposed to adults in high-risk categories

An induration of 15 or more millimeters is considered positive in any person, including persons with no known risk factors for TB. However, targeted skin testing programs should only be conducted among high-risk groups.

CDC (Center for Disease Control and Prevention)

Regarding asthma treatment

Practice recommendations Every patient with persistent asthma, regardless of disease severity, should use a daily controller medication. Consider an inhaled corticosteroid (ICS) first when choosing controller medications for long-term treatment of mild, moderate, and severe persistent asthma in adults and children. Leukotriene modifiers, cromolyn, and nedocromil may be considered as alternative, not preferred, controller medications for patients with persistent asthma. Long-acting β2-adrenergic agonists should not be used as monotherapy. Long-term use of ICSs within labeled doses is safe for children in terms of growth, bone mineral density, and adrenal function; nonetheless, asthma should be monitored and ICS therapy stepped down to the lowest effective dose. Low-to medium-dose ICSs are not associated with the development of cataracts or glaucoma in children, but high cumulative lifetime doses may slightly increase the prevalence of cataracts in adults and elderly patients. ICSs are recommended for use in pregnant women with asthma; budesonide is the only ICS rated Pregnancy Category B.

 From:The Journal of Family Practice



Oral corticosteroids are used in acute exercerbations not for long term management.

Pneumococcal vaccine indications for adults

age >65yrs

Chronic diseases (hrt disease, lung disease, DM, cochlear implants, CSF leak, SCD, alcoholism)

Immunosuppressive diseases (HIV/AIDS, MM, Lymphomas,Leukemias, Chronic renal failure, organ transplant, nephrotic syndrome etc)

Immunosuppressive therapy (long term steroids, chemotherapy, radiotherapy)

Smokers

Asthmatics

Nursing home residents

Splenectomized individuals

Treatment of Pulmonary embolism

1. Anticoagulation: Heparin + Warfarin. Stop Heparin after 5-7 days when Warfarin may've kicked in. Target is INR of 2-3

2. IVC filter:
if heparin is contraindicated
if recurrent embolic event even while on heparin or therapeutic Warfarin (INR 2-3)
if there's severe disease with right ventricular dysfxn and enlargement. The next embolus could be fatal so put a filter


3. Thrombolytics (t-PA- tissue plasminogen activator): if patient is too unstable or if there's RV dysfxn

Aspirin is useless in PE

Note: watch out for HITT with heparin therapy. - monitor cbc
HITT:
Patient on heparin
Thrombocytopenia
5-10 days after start of treatment
New thrombus or expansion of old one
Mgt: stop heparin, give thrombin inhibitor: Argatroban or lepirudin

Do not transfuse platelets in HITT

histo, blasto, coccidiomycosis

This is a very common USMLE topic....

Coccidiomycosis: "cough and bumps" - pneumonia, bumps (nodules) on legs (aka Dessert bumps)
California, dessert areas

Blastomycosis: "cough and blasts"- pneumonia, ulcers and warts, may be disseminated to kidneys, liver, brain etc
Decomposing leaves, wooded areas,

Histoplasmosis: "gives no history" -Asymptomatic in many. (Serious in HIV),
Mississippi, Missouri,Ohio etc, Bat droppings, caves


All can present with granuloma in the lungs

A-a gradient

A- Alveolar pO2
a-Arterial pO2

A= 150-1.2(pCO2)

A-a gradient: (normal is 5 to 15)

What is the difference in the amount of oxygen getting into the lungs and that getting from the lungs into the blood?

Answer= A-a gradient

Higher if there's :

Impaired diffusion at alveolar level e.g pulmonary edema,  thickened alveolar membrane 

Abnormal ventilation/perfusion ratio :

• Decreased alveolar perfusion (shunt)-Pulmonary embolus
• Decreased alveolar ventilation (dead space)- obstructive diseases, ARDS (Atelectasis/alveolar collapse)

Right to left shunt (blood by passes the alveoli, goes straight back to left side of the heart without getting oxygenated)

Obstructive or Restrictive lung disease

Obstructive

Low FEV1, normal FVC

Low FEV1/FVC ratio

High Residual Vol

Restrictive

Low FEV1, Low FVC

High or normal FEV1/FVC ratio

Low Residual Vol

Cystic fibrosis

Defective Chloride transport due to defective CFTR gene (usually a 3base pair deletion)
Aut recessive
Thick mucus secretions causing recurrent sinopulmonary infections, bronchiectasis, FTT
Psedomonas causes Pneumonia (Treat with 2 agents with antipseudomonad coverage)
Pancreatic insufficiency leading to Fat malabsorption with deficiency of vitamins A D E and K, Chronic diarrhoea
Meconium ileus (failure to pass meconium, bilous vomitting, history of polyhydramnios, ground glass appearance on X ray, intestinal perforation)

Positive sweat chloride test (done twice) is diagnostic.

Tmt: high calorie diet, pancreatic enzymes replacement, fat soluble vitamins supplementation. Only life saving tmt is bilateral lung transplant.

Median survival is 30yrs