Block 7 (GI) - L9 to L11 Flashcards

1
Q

Which type of GI bleed is more common (upper vs. lower)?

A

Upper (1.5-2x more common)

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2
Q

What anatomical structure separates the upper GI tract from the lower GI tract?

A

Ligament of Treitz

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3
Q

What are the structures of the upper GI tract?

A

Esophagus, stomach, duodenum (until ligament of Treitz)

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4
Q

What are the symptoms of upper GI bleeding?

A
  1. Hematemesis (coffe ground or bright red blood)
  2. Melena (black, tarry school)
  3. Occult blood
  4. Sometimes hematochezia (BRBPR)
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5
Q

What is the differential diagnosis for upper GI bleeding?

A
  1. Peptic ulcer
  2. Esophageal varices
  3. Erosive esophagitis
  4. Mallory-Weiss tear
    (uncommon: erosion, tumor, esophageal ulcer, portal gastropathy, Dieulafoy lesion, Cameron lesion)
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6
Q

Where are peptic ulcers found?

A

Stomach or duodenum

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7
Q

What are the two major causes of peptic ulcer disease?

A
  1. H. pylori infection

2. NSAIDs/ASA

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8
Q

What are the symptoms of peptic ulcer disease?

A

Epigastric abdominal pain, pain improved with eating, nausea, bloating, and early satiety

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9
Q

How is peptic ulcer disease evaluated?

A

EGD

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10
Q

What are complications of peptic ulcer disease?

A
  1. GI bleeding (acute leads to hematemesis, melena, orthostasis; chronic leads to iron-deficiency anemia)
  2. Perforation (sudden-onset abdominal pain, guarding, rigidity = acute abdomen)
  3. Obstruction (nausea, vomiting)
  4. Penetration (erode into adjacent organs)
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11
Q

How is peptic ulcer disease treated?

A
  1. Reduce NSAID/ASA use
  2. H2 blockers
  3. PPIs
  4. H. pylori eradication (PPI + amoxicillin + clarithromycin)
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12
Q

What causes esophageal varices?

A

Portal HTN inducing collateral circulation

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13
Q

90% of ___ patients develop esophageal varices.

A

Cirrhotic

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14
Q

How are esophageal varices treated?

A
  1. Aggressive fluid resuscitation
  2. Transfusion
  3. Sengstaken-Blakemore tube
  4. Octreotide
  5. Antibiotics
  6. EGD for variceal banding
  7. TIPS (transjugular intrahepatic portosystemic shunt)
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15
Q

What are some causes of erosive esophagitis?

A
  1. Reflux
  2. Pill-induced
  3. Infection (candida, CMV, HSV)
  4. Radiation
  5. Eosinophilic esophagitis
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16
Q

How does erosive esophagitis appear on endoscopy?

A

Linear “burns”

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17
Q

What is a Mallory-Weiss tear?

A

Hematemesis after violent retching/vomiting, usually self-limited

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18
Q

What is a Dieulafoy lesion?

A

Lesion of a large submucosal artery in the gastric cardia

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19
Q

What is a Cameron lesion?

A

Linear ulcerations found within hiatal hernias

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20
Q

How can the severity of a UGI bleed be assessed?

A
  1. Look for comorbid disease
  2. Hematemesis
  3. Hemodynamic instability
  4. Assess Hgb levels
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21
Q

Why might an NG aspiration be useful for differentiating between UGI and LGI?

A

Positive (for UGI) result: return of blood/coffee grounds
Negative (for UGI) result: return of bile without blood
Indeterminate result: return of saline without blood or bile

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22
Q

How should UGI bleeding be managed?

A
  1. Assess severity of bleed
  2. H&P
  3. ICU monitoring if needed
  4. 2 large bore IV’s for aggressive IV hydration
  5. PRBCs if needed
  6. Pre-endoscopic IV PPI
  7. Endoscope
  8. Assess risk for rebleeding
  9. Post-endoscopic IV PPI x 72 hours (decreases recurrent bleeding, need for surgery, mortality)
  10. Consult surgery/interventional radiology for severe bleeding
  11. Eradicate H. pylori if present
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23
Q

If you see a clean based ulcer with a flat, pigmented spot on endoscopy, what is recommended?

A

Change IV PPI to PO PPI, no endoscopic therapy needed

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24
Q

If there is an ulcer with an adherent clot, what is recommended?

A

Dislodge the clot with irrigation, endoscopically treat as low or high risk depending on ulcer characteristics, IV PPI

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25
If there is an ulcer with a visible vessel, what is recommendd?
Endoscopic therapy and IV PPI
26
What factors increase risk for rebleeding?
1. Active bleeding during endoscopy 2. Ulcer >2cm 3. Ulcer location (posterior duodenum, high lesser curvature of stomach) 4. Age >60 5. Comorbid illnesses 6. Hgb < 10
27
What are the symptoms of LGI bleeding?
BRBPR
28
What is the differential diagnosis for LGI bleeding?
1. DiverticulOsis 2. Colitis (ischemic, IBD, radiation) 3. Hemorrhoids 4. Post-polypectomy (uncommon: colon polyps or cancer, rectal ulcer, angiodysplasia)
29
What is diverticulosis?
Asymptomatic mucosal outpouchings that cause acute, painless bleeding
30
Where is diverticulosis common?
Sigmoid colon
31
How is diverticulosis treated?
Colonoscopy
32
What are the symptoms of ischemic bowel colitis?
Abdominal pain and rectal bleeding
33
Where is ischemic bowel colitis common?
Splenic flexure, transverse colon
34
What are the two types of IBD?
1. Crohn's disease | 2. Ulcerative colitis
35
What are the symptoms of ulcerative colitis?
Bloody diarrhea, abdominal pain
36
What are the symptoms of Crohn's disease?
Abdominal pain, diarrhea, bleeding (less likely)
37
What are hemorrhoids?
Dilated anal and perianal collateral vessels, leading to pain and bleeding (small volume, red blood on toilet paper)
38
How are hemorrhoids treated?
Sclerotherapy and band ligation
39
How is LGI bleeding managed?
1. H&P 2. IVFs and PRBCs if needed 2. EGD if hemodynamic instability to rule out upper GI bleed 3. Colonoscopy
40
5% of GI bleeding occurs where?
Between the papill and the ileocecal valve
41
What is the most common cause of lower GI bleeding in children?
Meckel's diverticulum
42
What is the first line step after a negative EGD or colonoscopy in the setting of bleeding?
Capsule endoscopy
43
What is on the differential diagnosis for upper GI bleeding in neonates?
1. Swallowed maternal blood 2. Vitamin K deficiency 3. Coagulopathy 4. Milk protein intolerance
44
What is on the differential diagnosis for upper GI bleeding in infants/children/adolescents?
1. Mallory-Weiss syndrome 2. Foreign body 3. PUD 4. Pill esophagitis 5. Esophageal varices
45
What is the most common cause of severe bleeding in children?
Esophageal varices
46
What is on the differential diagnosis for lower GI bleeding in neonates?
1. Anal fissures 2. Swallowed maternal blood 3. Necrotizing enterocolitis 4. Malrotation with midgut vovulus 5. Hirschprung disease
47
Necrotizing enterocolitis is generally seen in ___ and it has an unclear etiology.
Premature
48
What are the symptoms and imaging findings of necrotizing enterocolitis?
Non-specific symptoms (fever, lethargy), abdominal distention, vomiting, diarrhea, bleeding Pneumatosis intestinalis (air in colon/wall of colon)
49
How does malrotation with midgut vovulus present?
Abdominal distension, emesis, melena, or hematochezia, bilious emesis
50
What is on the differential diagnosis for lower GI bleeding in infants/toddlers?
1. Anal fissures 2. Milk or soy-induced colitis 3. Intussusception 4. Meckel's diverticulum
51
What is intussusception?
Telescoping of part of the intestine into itself
52
How does intussusception present?
Severe abdominal pain with passage of bloody/mucoid stool (currant jelly appearance), sausage shaped abdominal mass
53
Meckel's diverticulum involves incomplete obliteration of the ___.
Omphalomesenteric duct
54
What is on the differential diagnosis for lower GI bleeding in older children?
1. HUS (microangiopathic hemolytic anemia, E.coli 0157) 2. HSP 3. Infectious colitis
55
What are the two types of human parasites?
1. Protozoa | 2. Helminths
56
What are the 5 species of Plasmodia?
1. P. vivax 2. P. falciparum 3. P. malariae 4. P. ovale 5. P. knowlesi
57
What is sporogony?
The sexual cycle of reproduction that takes place in mosquitos. Gameocytes form a zygote, which becomes an oocyst, which becomes a sporozoite.
58
What is schizogony?
The asexual cycle of reproduction that takes plan in man.
59
What is the exoerythrocytic cycle?
Schizogony that takes place in the liver shortly after infection; Sporozoites enter the bloodstream and are carried to the liver where they invade hepatocytes. Schizonts form, and reproduce asexually, bursting the hepatocytes and releasing merozoites into the blood.
60
What is the erythrocytic cycle?
Schizogony that takes place in RBCs. Merozoites infect circulating red cells. These become trophozoites, which form RBC schizonts. These reproduce asexually and burst red cells, repeating the cycle. Merzoites can also progress to gametocytes.
61
What are some diagnostic characteristics of malaria?
1. P. vivax and P. ovale - Schuffne'rs dots (vesicle complexes in red cells) 2. P. falciparum - electron dense knobs (facilitate binding to endothelium and uninfected RBCs) 3. Pigment-degraded hemoglobin
62
What happens to people with sickle cell anemia and malaria?
S hemoglobin impairs falciparum growth
63
Which two species of plasmodium stay dormant in the liver?
P. vivax and P. ovale
64
Discuss the pathogenesis of malaria.
1. Fever is associated with schizont rupture 2. Anemia can lead to hemolysis, which can cause renal failure 3. Tissue hypoxia is caused by sludging of parasitized RBCs 4. Immunopathologic events (cytokine release, immune complex nephritis)
65
Describe the clinical manifestations of malaria.
1. Prodrome - flu-like illness 2. Chills, cyclic fever, headache, myalgias, nausea, splenomegaly, hemolytic anemia, thrombocytopenia 3. Organ dysfunction with P. falciparum (cerebral malaria, renal failure, pulmonary edema)
66
What are the unique clinical feature of P. falciparum?
1. High level of parasitemia 2. Microvascular events due to high parasitemia and sludging 3. Cerebral malaria 4. Pulmonary edema (vascular events and severe anemia) 5. Renal failure (severe hemolysis and shock)
67
What are the unique clinical feature of P. vivax and P. ovale?
1. Moderate parasitemia 2. NO microvascular events 3. Hypnozoites in liver can lead to relapse
68
What are the unique clinical feature of P. malariae?
Low parasitemia, mild symptoms, prolonged infection
69
What is P. knowlesi?
Parasite of monkeys, but some human cases have been seen; it has a unique 24-hour cycle, no sludging
70
How is malaria diagnosed?
1. Demonstration of parasite stages in the blood (blood smear) 2. PCR 3. Rapid diagnostic tests 4. Serology
71
How is erythrocytic malaria treated?
1. Chloroquine (falciparum has resistance) 2. Quinine/quinidine 3. Others
72
How is exoerythrocytic malaria treated?
1. Primaquine
73
How is malaria transmitted?
Mosquitos
74
What is the vector of Babesiosis?
Ixodes scapularis (tick)
75
What is the reservoir of Babesiosis?
Small rodents
76
Babesiosis can be co-transmitted with ___.
Lyme borreliosis
77
Describe the life cycle of Babesiosis.
1. Tick takes a blood meal from a mouse and infects the mouse (gametes produced) 2. Tick takes a second blood meal from an infected mouse (gametes ingested and fertilized) 3. Tick takes a blood meal from human (introduces sporozoites) 4. Transmitted from human-to-human via blood transfusion
78
What are the clinical features of Babesiosis?
1. Majority are asymptomatic 2. Can have fever, headache, fatigue, hemolytic anemia 3. Severe sepsis can occur in the immunocompromised or splenectomized
79
How is Babesiosis diagnosed?
1. Blood smear (small rings to tetrads = cross-like) 2. PCR 3. Serology
80
How is Babesiosis treated?
Atovaquone + azithromycine OR Clindamycin + quinine
81
What are the reservoirs of Toxoplasma gondii?
Cats primarily (also sheep, pigs, cattle)
82
How is Toxoplasma gondii transmitted?
1. Ingestion of cat feces containing an oocyst 2. Ingestion of inadequately cooked meat containing cysts 3. Intrauterine 4. Blood transfusion/organ transplant
83
Describe the life cycle of Toxoplasmosis.
1. Sexual reproduction in the gut of a cat. 2. Feces excreted contains oocysts 3. These can be ingested by others.
84
What are the three clinical syndromes of toxoplasmosis?
1. Acute: fever and generalized lymphadenopathy (mononucleosis-like) 2. Congenital: multisystem disease including CNS and chorioretinitis 3. Immunocompromised: encephalitis
85
When is the baby at greatest risk of acquiring toxoplasmosis from the mother during pregnancy, and when are manifestations most severe?
Greatest risk: when acquired by mom in 3rd trimester Severe manifestations: 1st trimester
86
How is toxoplasmosis diagnosed?
1. Tissue biopsy (can see cysts or tachyzoites) | 2. Serology (IgG or IgM responses)
87
How is toxoplasmosis treated? In pregnanct women?
Pyrimethamine + sulfadiazine Spriamycin in pregnant women
88
How is toxoplasmosis prevented in people with HIV/AIDs?
Bactrim
89
Cryptosporidium is a coccidian protozoan which carries out its life cycle entirely in the ___ of animals and man.
Intestinal villi (on the surface)
90
What is the reservoir of Cryptosporodium?
Domestic animals and humans
91
How is Cryptosporidium transmitted?
Fecal-oral ingestion of cysts or sexually
92
Describe the clinical features of Cryptosporidiosis in the immunocompetent.
Explosive, watery diarrhea and abdominal pain lasting 1-2 weeks
93
Describe the clinical features of Cryptosporidiosis in the immunocompromised.
Severe, watery diarrhea with malnutrition and biliary disease; continues until immunity is restored
94
How is Cryptosporidium diagnosed?
1. Acid-fast stain of cysts in feces 2. Direct fluorescence 3. PCR 4. Biopsy
95
How is Cryptosporidium treated?
Nitazoxanide
96
What are the reservoirs of amebiasis?
Infected humans
97
How is amebiasis transmitted?
Fecal-oral, sexually
98
How can amebiasis be distinguished as pathogenic from commensals?
Markers of pathogenicity: Zymodene, DNA analysis, monoclonal staining Ab formation
99
What are the virulence factors of amebiasis?
1. Endocytic capacity 2. Adherence via galactose-specific lectin 3. Lytic capacity 4. Extracellular proteinases
100
What are the pathologic features of infection with Entamoeba histolytica?
1. Flask ulcers 2. Ameboma (mass of granulation tissue) 3. Abscess-metastatic spread to liver, pleura, pericardium, lung, brain
101
What are the symptoms of amebiasis?
1. Intermittent diarrhea, flatulence, pain 2. Dysentery (tenesmus, bloody diarrhea, severe pain) 3. Abscesses in liver, lungs, pericardium, brain 4. May be asymptomatic
102
How is amebiasis diagnosed?
1. Stool exam for trophozoites and cysts 2. Serology 3. PCR (to distinguish pathogenic from non-pathogenic)
103
How is amebiasis treated?
When invasive - metronidazole, tinidazole When cyst - lodoquinol, paromomycin, diloxanide, furoate
104
Under the microscope, E. histolytica trophozoites have ___.
Pseudopods
105
What can Naegleria fowleri cause and how is it acquired?
Encephalitis in a healthy person Acquired by swimming in brackish water
106
What can Acanthamoeba cause?
Encephalitis in immunocompromised and eye infections with trauma or contact lenses
107
What can Balamuthia cause and how is it transmitted?
Rare encephalitis; soil, associated with organ recipients
108
What is Giardia duodenalis (lamblia)?
Intestinal flagellate that causes food, water, and sexually-transmitted diarrhea
109
What is the metabolically active form of G. duodenalis and its structural features?
Trophozoite - has two nuclei, four pairs of flagella, and a sucking disc
110
What is the inactive form of G. duodenalis and its structural features?
Cyst - has a clear cyst wall, four nuclei, and can survive in cold water for 2 months
111
Describe the pathogenesis of Giardia.
Attach to villi by sucking disc, cause malabsorption diarrhea (stool has increased fat and carbs), flattening of microvilli and inflammation (seen on jejunal biopsy)
112
Describe the symptoms of Giardia.
1. Often asymptomatic 2. Diarrhea (foul-smelling, bulky, watery, non-bloody) 3. Crampy abdominal pain 4. Fever (20%) 5. May become chronic or relapse
113
How is Giardia diagnosed?
1. Trophozoites and cysts in stool 2. Direct fluorescence antibody test 3. PCR
114
How is Giardia treated?
Tinidazole, nitazoxanide
115
Describe the morphology of Trichomonas vaginalis.
Oval shaped with an axostyle, four flagella, and an undulating membrane
116
How is Trichomonas vaginalis transmitted?
Sexually
117
Discuss the pathogenesis of trichomonas.
Damages squamous mucosa of the female genital tract leading to neutrophilic inflammatory reactions and petechial hemorrhage
118
What are the clinical manifestations of trichomonas?
1. Persistent vaginitis (frothy discharge, itching, burning, vaginal erythema) 2. Associated with preterm births
119
How is trichomonas diagnosed?
1. Wet mount of vaginal discharge (see motile organisms) 2. Urinalysis 3. Culture 4. DFA
120
How is trichomonas treated?
Metronidzole or tinidazole + treat male partner
121
What is the vector for Leishmania?
Sand fly
122
What is the vector for African trypanosomiasis?
Tsetse fly
123
What is the vector for American trypanosomiasis?
Triatomid bug
124
What are the 4 morphologic forms of blood and tissue flagellates?
1. Amastigote (intracellular form found in human - Leishmania, T. cruzi) 2. Promastigote (extracellular form found in gut and mouth of insect - Leishmania) 3. Epimastigote (extracellular form in gut and mouth of insect - Trypanosoma) 4. Trypomastigote (extracellular form in human and insect - Trypanosoma)
125
Describe the life cycle of Leishmania.
1. Sandfly takes a blood meal from a human and injects promastigote 2. Promastigotes are phagocytosed by macrophages, where they transform into amastigotes 3. Amastigotes multiply in cells of various tissues 4. Sandfly takes a blood meal, ingesting macrophages with amastigates 5. Amastigotes transform into promastigotes in the gut
126
Describe the pathogenesis of Leishmaniasis.
Injected promastigotes are opsonized with complement, taken up by macrophages, released to another cell or fly
127
Describe the clinical manifestations of cutaneous Leishmaniasis.
1. Cutaneous (papule - self-limited ulcer) 2. Diffuse cutaneous (multiple lesions) 3. Mucocutaneous (local lesion heals or enlarges, can cause metastatic destructive lesions of face and perineum)
128
Describe the clinical manifestations of disseminated/visceral Leishmaniasis.
1. 3-12 months after the bite, fever develops 2. Dissemination to liver, spleen, bone marrow, lymph nodes (RES system) 3. Anemia, leukopenia, thrombocytopenia, elevated IgG 4. Progressive weakness, emaciation
129
How is Leishmaniasis diagnosed?
For localized: biopsy, smear, culture, Ag detection For visceral: aspirates, DNA detection, serology
130
How is visceral Leishmaniasis treated?
Lipo. amphotericin b, antimony, miltefosine
131
How is cutaneous/mucocutaneous Leishmaniasis treated?
1. None or topical for mild | 2. Pentavalent antimony, ketoconazole, fluconazole, lip amphotericine b, miltefosine
132
What are the two major types of African Trypanosomiasis?
T. brucei gambiense and T. brucei rhodesiense
133
What is the life cycle of African Trypanosomiasis?
1. Fly ingests trypomastigotes which develop in the midgut 2. Migrate to salivary gland and become epimastigotes, then infectious trypomastigotes 3. Fly inoculates trypomastigates, which multiply and invade the bloodstream 4. Fly infected with blood meal
134
Describe the pathogenesis of African Trypanosomiasis.
1. Change Ag structure of surface glycoprotein (immune evasion) 2. Localize in endothelium (vasculitis in heart and CNS) 3. Hemorrhage, demyelination
135
What are the clinical manifestations of African Trypanosomiasis?
1. Local chancre 2. Fever lymphadenopathy, rash, itching 3. Headache, impaired mentation 4. Rhodesian = CHF, coma, death (rapid in east) 5. Gambian = slow progression to coma (slow in west)
136
How is African Trypanosomiasis diagnosed?
1. Blood smear 2. Elevated IgM 3. Serology
137
How is African Trypanosomiasis treated?
Pentamidine, Melarsoprol (CNS)
138
What is Chagas' disease?
Acute illness with chronic heart, esophagus, and colon involvement
139
What causes Chagas' disease (American Trypanosomiasis) and where is it found geographically?
Trypanosoma cruzi Central and South America (~Southern US)
140
What are the reservoirs of T. cruzi?
Rat, cat, dog, opossum, armadillo
141
What is the vector of T. cruzi?
Reduviid (triatomid) bug (transmitted via its feeces)
142
Discuss the pathogenesis of American Trypanosomiasis.
1. Chagoma caused by local inflammation 2. Dissemination to heart, muscle, smooth muscle, nerve, adherence, endocytosis, escape, multiplication, rupture, inflammation 3. Affects blood vessels, muscle conduction, nerves of heart 4. Affects nerve, smooth muscle of GI tract
143
What are the symptoms of Chagas' disease?
1. Chagoma 2. Fever, rash, splenomegaly, lymphadenopathy, edema (acute) 3. Chronic illness (haert, megaesophagus, megacolon)
144
How is Chagas' disease diagnosed?
1. Blood smear | 2. Gene amplification
145
How is Chagas' disease treated?
Nifurtimox or Benznidazole
146
How is Pneumocystis jiroveci (carinii) classified?
Not sure - has ribosomal RNA sequences like fungi, but other features like sporozoa
147
How is P. jiroveci transmitted?
Respiratory aerosol
148
Describe the morphology of Pneumocystis.
1. Cysts (5-8 microns, contain 2-8 sporozoites) 2. Sporozoites (released with cyst rupture, combine and mature) 3. Trophozoites (matured form, make cysts)
149
What are the clinical manifestations of Pneumocystis?
1. Interstitial pneumonia in immunocompromised (fever, dry cough, severe dyspnea) 2. CXR - diffuse interstitial infiltrates 3. Low blood oxygen level
150
How is Pneumocystis diagnosed?
1. Cysts in lung tissue and secretions with silver stain and DFA
151
How is Pneumocystis treated?
Bactrim, pentamidine