T15: Congenital and acquired immunodeficiencies Flashcards
1
Q
Introduction
- Immunodeficiencies predispose patients to 3 main complications. List them
- Immunodeficiencies are divided into primary and secondary- describe each
- Secondary immunodeficiency is divided into 4 groups. List these and give examples in each
A
- Predispose to infections, lymphomas, cancers, autoimmune conditions
- Primary- genetics, and hereditary. Secondary- acquitted, more common (reversible)
Secondary immunodeficiencies: Physiological (age, pregnancy), Iatrogenic (chemotherapy, steroids, bone marrow ablation before transplant), Systemic (DM, SLE, HIV, alcohol, protein-losing enteropathy), and prolonged serious illness (long hospitalization, critically ill, organ dysfunction)
2
Q
ASPLENIA
- What is asplenia?
- The spleen’s role is__
- In order to achieve its role, the spleen has red pulp and white pulp- how do these help the spleen to achieve its role?
- List 4 encapsulated bacteria (HINT: These commonly cause meningitis)
A
- Absence of a spleen
- Function: clearance of pathogens and control of infection
- Red pulp is made up of sinusoids (mechanical clearance/filtration e.g. in malaria, unopsonized bacteria) and macrophages (phagocytosis and cytokine production)
- The white pulp is made up of B lymphocytes which produce antibodies against encapsulated bacteria
- S. aureus, H influenza, N meningitidis, and Capnocytophaga canimorsus
3
Q
ASPLENIA
- List the causes of asplenia
- In a patient with asplenia- how can we prevent infection? (5)
A
- Congenital (rare), functional (infarctions in sickle cell anemia), and surgical removal due to trauma or therapeutic reasons (ITP, Hhypersplenia, hemolytic anemia)
- Patient and family education (keep antibiotics at home and take if you have a fever and see a doctor); vaccination against encapsulated bacteria and influenza. travel advice- malaria, animal exposures, consider prophylactic antibiotics in children less than 5 and in immunocompromised people
4
Q
THE ELDERLY
- A 1/3 of deaths in > 65-year-olds are due to infections. Why do they have higher mortality?
- The risks of infections in the elderly increase due to 3 risk factors- list these
- Why is age a risk factor to infection acquisition?
A
The mortality is higher due to underlying illnesses and functional decline
- Co-morbidities, communal living, and age
- With age> there are altered natural barriers, decreased Ab production to vaccines, cellular and humoral immunity changes, impaired immunoglobulin production, and decreased signal transduction after cytokine binding
5
Q
THE ELDERLY
- Clinical presentation of infections in the elderly can be typical or atypical. Explain
- the two main challenges in the elderly are antibiotic dosing, UTIs, and infective endocarditis- how so?
A
- Atypical: cognitive impairment, poor communication
- Typical: signs are often absent. 30-50% are usually afebrile/ They may have pneumonia (fever, coughing, pleuritic chest pain). In a confused, falling, and anorexic patient= investigate.
Antibiotic dosing: renal function decreases with age. Institutionalized patients, especially with indwelling devices have resistance to antibiotics. High risk for C difficile
UTIs: diagnosis is complicated because of a high prevalence of chronic urinary symptoms. asymptomatic bacteriuria, cognitive impairment. ALWAYS TEST THE URINE
Infective endocarditis: High risk due to degenerative disease-> Streptococcus and staphylococcus. Use a transesophageal echo to diagnose.
6
Q
BIOLOGICAL THERAPIES
- What is the major difference between traditional immunosuppressive drugs and biological agents?
- List examples of traditional immunosuppressive drugs
- What are biological agents used for?
- What is the downside of biological therapies
A
- Traditional= global immunosuppression, Biological= does not cause global immunosuppression
- Corticosteroids, metrotrexate, azathioprine, cyclosporine
- Rheumatic, inflammatory, or malignant disease
- The downside is that it has unintended effects such as reactivation of TB, HBV
7
Q
PREGNANCY
Pregnancy predisposes both the mother and the baby to infection. Give examples
A
The mother:
- Malaria (severe malaria)
- HEV (fulminant hepatitis)
- TB
- Varicella (varicella pneumonia)
The infant
- Listeria and Group B streptococcus (sepsis/ meningitis), Zika (microcephaly), HIV/ HBV (MTCT), TB, Congenital infections- toxoplasmosis, CMV, syphilis (TORCHES)
8
Q
DIABETES
- List 4 infections that are strongly linked to diabetes
- List 5 infections common in diabetic patients
- In terms of risk factors to infection in diabetic patients: we divide risk factors into» host factors and pathogen factors. Explain these
A
- Emphysematous pyelonephritis/ cholecystitis, mucormycosis, malignant otitis media
- Mucocutaneous fungal infections (oral, vaginal, nails), bacterial foot infections, non-resolving pneumonia (Nocardia, TB), UTI, deep soft tissue infections (pyomyositis)
Host factors- Hyperglycemia (decreased neutrophils and cytokine release), vascular insufficiency (decreased blood flow), sensory peripheral neuropathy (late presentation), motor neuropathy (foot deformities), autonomic neuropathy (decreased sweat), Skin and mucosal colonization (candida, S. aureus)
Pathogen factors
- Candida (glucose-inducible proteins), Rhizopus species (Ketone reductases, mucormycosis), uropathogenic E.coli (due to accumulation of advanced glycation end-products)
9
Q
MUCORMYCOSIS
- Define this infection
- which 4 groups of patients are at risk?
- There are 4 classical syndromes of mucormycosis. Name them
- In terms of clinical presentation: where does this infection start? It then moves to which 2 areas? Describe the early and late symptoms
- On examination, what would your findings be? (5)
- How do you treat these patients? (in 3 ways)
A
- This is a rare, invasive, and aggressive fungal infection
- It is found in certain: diabetic, neutropenic. hematological cancers and penetrative trauma patients
- Cutaneous, disseminated, pulmonary, and rhinocerebral involvement (most common, especially in DKA)
- CLINICAL: it all starts in the paranasal sinuses. Then moves to the orbit or brain. Early symptoms: facial pain, headache, nasal stiffness. Late: orbital pain, facial anesthesia, double/ loss of vision. If it moves to the brain- mental changes
- On physical exam: orbital cellulitis/ facial swelling, proptosis/ decreased extraocular movement, necrotic tissue in the nares, a black eschar on the hard palate is the hallmark of mucormycosis.
- Immediately: amphotericin B, aggressive surgical debridement, and control Bp.
10
Q
EMPHYSEMATOUS PYELONEPHRITIS
- Define emphysematous pyelonephritis
- The organisms that cause this disease do so by fermentation of glucose and lactate CO2. List 3 of these organisms
- List the 3 clinical findings and dipstick and blood findings
- What is the imaging modality of choice here?
- Besides DM, list other risk factors for developing emphysematous pyelonephritis
A
- Gas producing necrotizing infection» renal parenchyma and perinephric tissue
- Klebsiella pneumonia, Proteus species, E. coli
- fever, N&V, flank, or abdominal pain. On blood: high WCC, CRP. On dipstick: leucocytes
- CT is the imaging of choice
- Women, urinary obstruction, elderly, very ill/ slow response to antibiotics
11
Q
MALIGNANT OTITIS EXTERNA
- Define this infection
- Name the organism that causes it 90% of the time
- List 2 groups of patients at risk for it
- You do a physical examination of this patient. What will your findings be? (in early and in late infection)
- Describe the clinical presentation in these patients
- The diagnosis of malignant otitis external is dependent on clinical, lab, and radiological findings. Which lab findings will you get
- How are these patients managed?
A
- Infection of the external auditory canal and temporal bone
- Pseudomonas aeuriginosa
- DM and advanced HIV patients
- On physical exam: granulation tissue on infections portion of the external canal. As the infection advances,» osteomyelitis of the skull base and temporal-mandibular jing pain
- Exquisite otalgia and otorrhea, not responsive to measures for a simple external otitis media, nocturnal pain, and pain extending to temporal-mandibular joint (pain on mastication) associated with cranial nerve palsies (6,7,9,10,11,12)
Lab findings: raised ESR, CRP, cultures diagnostic and CT and MRI diagnostic.
- management: There is no place for topical treatment or surgical debridement. Give effective anti-pseudomonal antibiotics (ciprofloxacin, cefepime, piptazo). This infection is malignant due to an aggressive clinical behaviour, poot treatment outcomes and high mortality
12
Q
MALIGNANT OTITIS EXTERNA
- Define this infection
- Name the organism that causes it 90% of the time
- List 2 groups of patients at risk for it
- You do a physical examination of this patient. What will your findings be? (in early and in late infection)
- Describe the clinical presentation in these patients
- The diagnosis of malignant otitis external is dependent on clinical, lab, and radiological findings. Which lab findings will you get
- How are these patients managed?
A
- Infection of the external auditory canal and temporal bone
- Pseudomonas aeuriginosa
- DM and advanced HIV patients
- On physical exam: granulation tissue on infections portion of the external canal. As the infection advances,» osteomyelitis of the skull base and temporal-mandibular jing pain
- Exquisite otalgia and otorrhea, not responsive to measures for a simple external otitis media, nocturnal pain, and pain extending to temporal-mandibular joint (pain on mastication) associated with cranial nerve palsies (6,7,9,10,11,12)
Lab findings: raised ESR, CRP, cultures diagnostic, and CT and MRI diagnostic.
- management: There is no place for topical treatment or surgical debridement. Give effective anti-pseudomonal antibiotics (ciprofloxacin, cefepime, piptazo). This infection is malignant due to aggressive clinical behavior, poot treatment outcomes, and high mortality
