Heamatology , Genetics , Infectious Diseases Flashcards
What is the IM dose of adrenaline for an adult in anaphylaxis
: 500 micrograms (0.5 mL of 1:1000 solution).
• Repeat every 5 minutes if no improvement.
What is the IM dose of adrenaline for children in anaphylaxis?
<6 years: 150 micrograms (0.15 mL).
6–12 years: 300 micrograms (0.3 mL).
>12 years: 500 micrograms (0.5 mL).
Why is adrenaline given IM for anaphylaxis instead of IV?
IM has a lower risk of complications.
IV adrenaline is only for specialists in critical care settings.
What is the classic diagnostic triad of multiple myeloma?
Bone marrow: Clonal plasma cells >10%.
CRAB criteria:
Calcium ↑ (hypercalcemia).
Renal impairment.
Anemia.
Bone lesions (lytic lesions, fractures).
Presence of a monoclonal protein (e.g., M protein) in serum/urine.
What tests confirm the diagnosis of multiple myeloma?
Serum/urine protein electrophoresis → Monoclonal (M) protein.
Bone marrow biopsy → >10% clonal plasma cells.
Imaging (X-ray, MRI, or CT) → Lytic bone lesions.
What are the key features of iron-deficiency anemia?
Labs: Microcytic, hypochromic anemia, ↓ serum ferritin, ↑ TIBC.
Causes: Blood loss (e.g., GI, menstruation), poor diet.
Treatment: Oral ferrous sulfate.
What is the main finding in pernicious anemia?
Vitamin B12 deficiency due to autoimmune destruction of gastric parietal cells → ↓ intrinsic factor.
Macrocytic anemia, neurological symptoms, and glossitis.
What anemia is associated with chronic disease?
Labs: Normocytic or microcytic anemia, ↓ iron, ↓ TIBC, ↑ ferritin.
Pathophysiology: Inflammatory cytokines (e.g., IL-6) trap iron in macrophages and suppress erythropoiesis.
What are examples of X-linked dominant conditions?
V F A R H
Vit D difficient rickets
Fragile X syndrome
Alport’s syndrome
Rett syndrome.
X-linked hypophosphatemia.
What are examples of X-linked recessive conditions?
Duchenne muscular dystrophy.
Hemophilia A/B.
Red-green color blindness.
G6PD deficiency.
How do males and females differ in X-linked inheritance patterns?
Recessive: Males more affected; females are carriers.
Dominant: Both sexes affected, but males often more severe.
What is the causative agent of typhoid fever?
Salmonella typhi (gram-negative bacillus).
What are the key clinical features of typhoid fever?
Stepwise fever.
Abdominal pain, constipation/diarrhea.
Rose spots (pink macules on trunk).
Hepatosplenomegaly.
How is typhoid fever treated?
First-line antibiotics: Azithromycin or ceftriaxone.
Supportive care: Hydration and antipyretics.
What are key features of Edwards syndrome (trisomy 18)?
Clinical: Micrognathia, clenched fists, rocker-bottom feet, cardiac defects.
Poor prognosis (often fatal in infancy).
What are key features of Patau syndrome (trisomy 13)?
Clinical: Midline defects (holoprosencephaly, cleft lip/palate), polydactyly, cardiac defects.
Poor prognosis (often fatal in infancy).
What are key features of Turner syndrome (45, X)?
Clinical: Short stature, webbed neck, shield chest, streak ovaries (infertility), coarctation of the aorta.
Labs: ↓ estrogen, ↑ LH/FSH.
What are key features of Klinefelter syndrome (47, XXY)?
Clinical: Tall stature, gynecomastia, small testes (infertility).
Labs: ↓ testosterone, ↑ LH/FSH.
What is the most likely diagnosis for a 23-year-old man with small bowel obstruction and mucocutaneous melanocytic macules?
Peutz-Jeghers syndrome (PJS)
PJS is an autosomal dominant disorder characterized by pigmented lesions in the buccal mucosa and gastrointestinal polyps.
What type of genetic inheritance is Peutz-Jeghers syndrome?
Autosomal dominant
The mutation associated with PJS is found on chromosome 19.
What are the characteristic mucocutaneous features of Peutz-Jeghers syndrome?
Pigmented lesions in the buccal mucosa
These lesions are often referred to as mucocutaneous melanocytic macules.
What type of intestinal lesions are associated with Peutz-Jeghers syndrome?
Hamartomas
Although classified as hamartomas, patients with PJS have an increased cancer risk.
What is the increased risk of developing intestinal cancer for patients with Peutz-Jeghers syndrome compared to the general population?
15 times
This significant risk underscores the importance of monitoring patients with PJS.
What is the average age of first diagnosis for Peutz-Jeghers syndrome?
23 years old
This age often correlates with the first presentation of bowel obstruction.
What is a common initial presentation of Peutz-Jeghers syndrome?
Bowel obstruction from intussusception
Other presentations may include abdominal pain, haematochezia, or prolapse of a colonic polyp.
Fill in the blank: Peutz-Jeghers syndrome is characterized by gastrointestinal polyps and ____________.
pigmented lesions in the buccal mucosa
These pigmented lesions often appear on the lips.
True or False: Peutz-Jeghers syndrome can lead to an increased risk of cancer.
True
Patients with PJS have a significantly higher risk of developing intestinal cancer.
What is the inheritance pattern of hemophilia?
X-linked recessive inheritance pattern
Hemophilia is usually inherited and occurs almost exclusively in males.
What is the average age of first diagnosis for hemophilia?
23 years old
The first presentation is often at a young age.
What is the condition characterized by multiple polyps in the gastrointestinal tract?
Familial adenomatous polyposis (FAP)
FAP is an autosomal dominant condition that can lead to colon cancer if untreated.
What is the adenomatous polyposis gene associated with colorectal cancer?
APC gene
Mutations in the APC gene are involved in the development of familial adenomatous polyposis.
True or False: Non-neoplastic polyps are benign.
True
Non-neoplastic polyps, such as hamartomatous polyps, are self-limiting and benign.
What is the most common clinical presentation of cytomegalovirus (CMV) disease?
Retinitis
Other manifestations may include colitis and encephalitis.
What are common opportunistic infections in people living with HIV (PLWH)?
- Tuberculosis (TB)
- Mycobacterium avium complex (MAC)
- Pneumocystis pneumonia (PCP)
- Toxoplasmosis
- Cryptococcosis
- Cytomegalovirus (CMV)
The risk of these infections increases as the CD4+ count decreases.
Fill in the blank: The risk of tuberculosis (TB) increases as the CD4+ count ______.
decreases
A high index of suspicion is necessary for diagnosing TB in PLWH.
What is the primary transmission method for Mycobacterium tuberculosis?
Inhalation of particles containing tubercle bacilli
Tuberculosis can be overlooked as it may present with non-specific symptoms.
What symptoms may indicate the presence of Mycobacterium avium complex (MAC) infection?
- Persistent fever
- Night sweats
- Fatigue
- Weight loss
- Anorexia
MAC can cause severe disseminated disease in people with advanced AIDS.
True or False: Most cases of toxoplasmosis arise from new infections.
False
Most cases arise from re-activation of latent infection.
What is the leading cause of morbidity and mortality among people with HIV?
Tuberculosis (TB)
TB is a significant concern in PLWH, especially with low CD4+ counts.
What are some common symptoms of focal encephalitis due to toxoplasmosis?
- Headache
- Confusion
- Seizures
- Motor weakness
- Fever
Less common symptoms may include multi-focal organ involvement.
What is the clinical presentation of disseminated disease in cryptococcosis?
Subacute meningitis or meningoencephalitis
Symptoms may include fever, malaise, and headache.
What is a common symptom of eosinophilic esophagitis?
Dysphagia
Patients may also experience odynophagia.
What type of polyps are characterized by multiple hamartomatous growths?
Peutz-Jeghers polyps
This condition is also associated with an increased risk of gastrointestinal cancers.
What is the typical presentation of pneumocystis pneumonia in HIV patients?
Progressive shortness of breath
Symptoms may include fever and cough, often with a gradual onset.
What is the role of prophylaxis in patients with a CD4+ count less than 200 cells/microlitre?
Prophylaxis for PCP and candidiasis is recommended
This is crucial to prevent opportunistic infections in immunocompromised patients.
What are some common manifestations of abdominal pain in patients with HIV?
Abdominal pain may result from involvement of retro-peritoneal lymph nodes and chronic diarrhea from gut mucosa.
Other manifestations include hepatosplenomegaly, lymphadenopathy, and rarely jaundice.
What are some unusual presentations of infections in patients with HIV?
Unusual presentations include:
* Palatal and gingival ulceration
* Septic arthritis
* Osteomyelitis
* Endophthalmitis
* Pericarditis
* Gastrointestinal bleeding
Which organism is primarily responsible for mucosal infections in immunocompromised patients?
Candida albicans
Occasionally, infections may also be caused by C. glabrata, C. tropicalis, and C. krusei.
What is the relationship between CD4 count and the risk of opportunistic infections in HIV patients?
The risk of opportunistic infections increases as the CD4 count decreases.
For example, PCP and candidiasis are more likely when CD4 count is < 200 cells/microlitre.
What are some common opportunistic infections encountered in HIV patients?
Common opportunistic infections include:
* Tuberculosis (TB)
* Mycobacterium avium complex (MAC)
* Candidiasis
* Pneumocystis jirovecii pneumonia
* Toxoplasmosis
* Cryptococcosis
* Cytomegalovirus (CMV)
True or False: Tuberculosis (TB) can present with normal chest x-rays in some cases.
True
Chest x-rays may appear normal in about 10% of TB cases.
What symptoms may indicate the presence of tuberculosis in HIV patients?
Symptoms may include:
* Shortness of breath
* Cough
* Lymphadenopathy
* Headache
* Meningismus
* Abdominal pain
* Dysuria
* Abscess formation
Fill in the blank: Infection with Mycobacterium avium and Mycobacterium intracellulare can cause ______ in advanced AIDS patients.
severe disseminated disease
What is the main route of transmission for Mycobacterium tuberculosis?
Inhalation of particles containing tubercle bacilli.
What is the significance of maintaining a high index of suspicion for TB in HIV patients?
A high index of suspicion must be maintained as TB may present with signs and symptoms that can be attributed to HIV itself.
What type of vaccines are considered inactivated vaccines?
Inactivated vaccines contain whole bacteria or viruses that have been killed or have been inactivated.
They cannot cause the diseases they protect against, even in immunocompromised individuals.
True or False: Inactivated vaccines tend to produce a stronger immune response than live attenuated vaccines.
False
Inactivated vaccines produce a weaker immune response, so multiple booster injections may be required.
What are some examples of inactivated vaccines?
Examples of inactivated vaccines include:
* Inactivated poliovirus vaccine (IPV)
* Some inactivated flu vaccines
* Oral typhoid vaccine (not the injected vaccine)
Fill in the blank: The risk of opportunistic infections in people living with HIV increases as the ______ count decreases.
CD4
What genetic mutation is responsible for Paroxysmal Nocturnal Hemoglobinuria (PNH)?
A somatic mutation in the PIGA gene.
What proteins are deficient on red blood cells in PNH?
CD55 and CD59
What is the characteristic finding in the urine of patients with PNH?
Hemoglobinuria
What diagnostic test is used to confirm PNH?
Flow cytometry to detect CD55 and CD59 deficiency on red blood cells.
What is the most common life-threatening complication of PNH?
Venous thrombosis
Why is LDH elevated in PNH?
Due to intravascular hemolysis
What is the first-line treatment for PNH?
Eculizumab
How does PNH lead to pancytopenia?
Through bone marrow failure
What are the key laboratory findings in PNH?
Elevated LDH
What alternative to eculizumab can be used to treat severe PNH?
Ravulizumab
What is the primary genetic mutation in polycythemia vera (PV)?
JAK2 V617F mutation.
What is the hallmark of polycythemia vera?
Increased red blood cell mass leading to elevated hemoglobin and hematocrit.
What are the common symptoms of polycythemia vera?
Headaches
What is the most common complication of polycythemia vera?
Thrombosis (arterial or venous).
What is the first-line treatment for polycythemia vera?
Venesection to maintain hematocrit below 45%.
What medication is used for high-risk patients with PV?
Hydroxycarbamide (hydroxyurea)
What low-dose medication is recommended for all PV patients to reduce thrombosis risk?
Aspirin (75–100 mg daily).
What are the diagnostic criteria for polycythemia vera?
Elevated hemoglobin/hematocrit
What is the characteristic finding in erythropoietin levels in polycythemia vera?
Low erythropoietin levels.
What are the main causes of secondary polycythemia?
Chronic hypoxia
What is the target hematocrit level in PV management?
<45% in men and <42% in women.
What is a major transformation risk in long-standing polycythemia vera?
Progression to myelofibrosis or acute myeloid leukemia (AML).
What is the main difference between PV and secondary polycythemia?
PV is caused by a JAK2 mutation
Why is pruritus common in polycythemia vera?
Due to histamine release from increased mast cells
What is erythromelalgia
a symptom of PV?
What is the primary defect in von Willebrand disease?
Deficiency or dysfunction of von Willebrand factor (vWF).
What is the most common type of von Willebrand disease?
Type 1
What is the classic presentation of von Willebrand disease?
Easy bruising
How does von Willebrand factor (vWF) function in hemostasis?
It mediates platelet adhesion to the damaged vessel wall and stabilizes factor VIII.
What diagnostic tests are used to confirm von Willebrand disease?
vWF antigen
What is the main difference between von Willebrand disease and hemophilia A?
Von Willebrand disease is due to vWF deficiency
What is the treatment for mild von Willebrand disease?
Desmopressin (DDAVP)
What is the treatment for moderate to severe von Willebrand disease?
VWF-containing concentrates or cryoprecipitate.
What role does desmopressin (DDAVP) play in treating von Willebrand disease?
It increases vWF release from endothelial cells and improves platelet adhesion.
What is the diagnostic test for von Willebrand disease type 2
which involves defective vWF?
How do you differentiate between von Willebrand disease and platelet dysfunction?
Platelet dysfunction typically has normal vWF levels but abnormal platelet aggregation studies.
What is the most common bleeding symptom in von Willebrand disease?
Mucocutaneous bleeding
What is the inheritance pattern of von Willebrand disease?
Autosomal dominant.
What is the role of von Willebrand factor (vWF) in clotting? It helps platelets adhere to sites of vascular injury and stabilizes factor VIII
essential for clot formation.
What is the medical importance of Parvovirus B19?
Causes Fifth disease (erythema infectiosum).
What condition does HPV cause?
Warts
What is the medical importance of Adenovirus?
Causes Conjunctivitis.
What disease is caused by Hepatitis B (Hepadnavirus)?
Causes Hepatitis B.
What is the medical importance of HSV1 (Herpesvirus)?
Causes oral lesions and some genital lesions.
What is the medical importance of HSV2 (Herpesvirus)?
Causes genital lesions and some oral lesions.
What is the medical importance of Varicella-zoster virus (Herpesvirus)?
Causes chickenpox and shingles.
What diseases are caused by Epstein-Barr virus (Herpesvirus)?
Causes mononucleosis and Burkitt’s lymphoma.
What is the medical importance of Cytomegalovirus (Herpesvirus)?
Causes congenital infections
What disease is caused by HHV6 (Herpesvirus)?
Causes sixth disease (roseola).
What cancer is associated with HHV8 (Herpesvirus)?
Causes Kaposi’s sarcoma.
What is the medical importance of Poxvirus?
Causes smallpox.
What disease is caused by Poliovirus (Picornavirus)?
Causes poliomyelitis.
What is the medical importance of Rhinovirus (Picornavirus)?
Causes the common cold.
What disease is caused by Coxsackievirus (Picornavirus)?
Causes Hand
What disease is caused by Hepatitis A (Picornavirus)?
Causes hepatitis A.
What disease is caused by Hepatitis E (Calicivirus)?
Causes hepatitis E.
What is the medical importance of Norwalk virus (Calicivirus)?
Causes gastroenteritis.
What disease is caused by Rotavirus (Reovirus)?
Causes diarrhea.
What disease is caused by Hepatitis C (Flavivirus)?
Causes hepatitis C.
What disease is caused by Rubella (Togavirus)?
Causes rubella (German measles).
What disease is caused by HIV (Retrovirus)?
Causes HIV/AIDS.
What disease is caused by Influenza (Orthomyxovirus)?
Causes influenza (flu).
What diseases are caused by Measles (Paramyxovirus)?
Causes measles.
What disease is caused by Mumps (Paramyxovirus)?
Causes mumps.
What disease is caused by Parainfluenza (Paramyxovirus)?
Causes croup.
What disease is caused by RSV (Paramyxovirus)?
Causes bronchiolitis.
What disease is caused by Rabies (Rhabdovirus)?
Causes rabies.
What is the medical importance of Ebola/Marburg (Filovirus)?
Causes hemorrhagic fever.
What disease is caused by COVID-19 (Coronavirus)?
Causes COVID-19 and the common cold.
What disease is caused by LCV (Arenavirus)?
Causes lymphocytic choriomeningitis.
What disease is caused by Hantavirus (Bunyavirus)?
Causes hemorrhagic fever.