Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

year 4 CDM 2 > Case 12: Malaria > Flashcards

Case 12: Malaria Flashcards

1
Q

Malaria transmission

A
  • Caused by Plasmodium protozoa spread by the female Anopheles mosquito (Anopheles gambiae)
  • Four different types: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, Plasmodium malariae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Characteristics of the 4 types of malaria

A
  • Plasmodium falciparum is the most common and severe. Causes fatal and malignant disease
  • Plasmodium vivax is the most common cause of benign malaria
  • P.vivax and Ovale- rarely fatal, causes dormant liver stage
  • P.malarie: can cause chronic infection over years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Protective factors for malaria

A

Sickle cell trait, G26PD deficiency, HLA-B53, absence of Duffy antigen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Life cycle of malaria

A
  • Following inoculation parasites (sporozoites) pass to the liver
  • In the liver they divide asexually over 7 days, maturing into Schizonts which rupture. They emerge from the liver (as Merozoites) and infect red blood cells.
  • Infected RBC’s are Trophozoites. They then divide and rupture infecting more RBC. Cycles of red cell rupture link with fever pattern
  • The infected red blood cells are sequestered by various tissues of the body
  • Gametocytes form from Trophozoites and are taken up by feeding mosquitos to spread
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Malaria liver

A
  • Plasmodium vivax and Plasmodium ovale (but not Plasmodium falciparum) lay down Hypnozoites in the liver
  • these dormant forms are not affected by conventional antimalarial drugs and can reactivate after months or years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Fever by different Plasmodium species

A
  • Plasmodium falciparum: Irregular fever patterns without clear periodicity.
  • Plasmodium vivaxandPlasmodium ovale: Tertian fever pattern (every 48 hours).
  • Plasmodium malariae: Quartan fever pattern (every 72 hours).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Clinical features of malaria

A
  • Prodromal symptoms (7-30 days): malaise, headache, fatigue, myalgia. Precedes fever
  • Fever: Hallmark of malarias, appears as paroxysms- periodic episodes of fevers with chills and rigors
  • GI: N+V, adbo pain, diarrhoea, Hepatomegaly sometimes
  • Splenomegaly: due to clearing erythrocytes can cause splenic rupture. Particularly P.vivax
  • Anaemia and Haemolysis: Haemoglobinuria (blackwater fever) is rare and due to massive intravascular haemolysis and acute renal failure
  • AKI
  • Dermatological: jaundice due to haemolysis or hepatic dysfunction. Rarely urticaria or purpuria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Key symptoms of malaria

A
  • FEVER (or history of fever)- from a malaria endemic region
  • Rigors
  • Headache +/- confusion
  • Myalgia, arthralgia
  • Nausea, vomiting, diarrhoea
  • Dark urine (Haemoglobinuria)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Key signs of malaria

A
  • Fever
  • Jaundice
  • Pallor
  • Splenomegaly and Hepatomegaly
  • Altered consciousness
  • Focal neurological signs
  • Coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Symptoms of P.falciparum

A
  • Respiratory: Cough, dyspnea, chest pain, or pleural effusion with severe P. falciparum infection due to pulmonary oedema or ARDS.
  • Neurological: altered mental state, seizures, ataxia or coma due to Cerebral malaria. Signs include nystagmus, cranial nerve palsies and focal neurological deficit
  • DIC: petechiae, and bleeding from venepuncture sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

P.falciparum pathophysiology

A
  • Sequestration: less flexible, electrical charge, intra-cellular adhesion. More difficult to pass through the micro-circulation. More likely to adhere to each other and vessels
  • Features: Cerebral malaria (reduced GCS, seizures), Renal failure (oliguria), ARD’s (pulmonary oedema), Tissue acidosis (multi-infarct in capillary beds), Coagulopathy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Complications of malaria (indications for IV treatment)

A
  • Cerebral involvement - reduced GCS/seizures
  • Anaemia – Hb < 8g/dL
  • Lactic acidosis – pH<7.3
  • Renal Failure: Oliguria <0.4ml/kg/hr, Creatinine > 265 (AKI)
  • Pulmonary Oedema/ARDS
  • Hypoglycaemia – BM <2.2 mmol/L
  • Shock – BP <90/60 (refractory to fluids)
  • Bleeding/DIC
  • Haemoglobinuria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Malaria: classification of severity

A
  • Parasitaemia: determined by looking at percentage of infected cells under thin films
  • UNCOMPLICATED: All of the following: Parasitaemia <2% No schizonts, No clinical complications. Oral treatment
  • POTENTIALLY SEVERE: Any of the following: Parasitaemia >2%, Parasitaemia <2% with schizonts or complications
  • SEVERE: Complications present, regardless of parasitaemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Benign malaria

A
  • P.vivax: Asia, S.America
  • P.ovale: west and central Africa
  • Reduced sequestration in the micro-circulation to P.falciparum
  • Benign disease <2% parasitaemia
  • Hypnozoites: dormant liver stage, relapsing malaria
  • P.malariae: least common, never causes severe disease, may persist for decades, rare cause of nephrotic syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Malaria investigations

A
  • Blood film: gold standard. Thick is more sensitive and thin determines species. Thin film uses Geimsa stain, Thick uses field stain
  • FBC: Thrombocythemia (excess platelet production), neutropoenia, normochromic normocytic anaemia, reticulocytosis
  • FBC which use flow cytometry show fluorescent populations of Malaria DNA/RNA
  • Quantitative Buffy Coats (QBC): Malaria fluoresce under a microscope
  • Immunochromatographic Rapid Diagnostic Tests: cant differentiate between types
  • PCR: sensitive but slow, done if uncertain
  • Antibody detection using immunoassays or fluorescence techniques: used to screen blood donations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Routine malarial diagnosis in newcastle

A
  • FBC
  • Thick and thin film: if suspicious of malaria but negative film repeat 12-24hrs and 48hrs
  • Carestart Combo Rapid Test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pregnancy malaria

A
  • Pregnant women are advised to not travel where malaria is endemic
  • chloroquine can be taken
  • proguanil: folate supplementation (5mg od) should be given
  • Malarone (atovaquone + proguanil): the BNF advises to avoid these drugs unless essential. If taken then folate supplementation should be given
  • mefloquine: caution advised
  • doxycycline is contraindicated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Complications Malaria

A
  • Cerebral malaria
  • Seizures
  • Reduced consciousness
  • Acute kidney injury
  • Pulmonary oedema
  • Disseminated intravascular coagulopathy (DIC)
  • Severe haemolytic anaemia
  • Multi-organ failure and death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

General advise for preventing malaria

A
  • Use mosquito spray (e.g., 50% DEET spray)
  • Use mosquito nets and barriers in sleeping areas
  • Seek medical advice if symptoms develop
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Treatment for severe/complicated malaria

A
  • IV Artesunate, Quinine is 2nd line
  • If delay in treatment can give Quinine till Artesunate is available
  • Manage in HDU or ICU
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Quinine and Artesunate

A
  • Quinine: Can cause Cinchonism (tetanus, blurred vision, vertigo). Cardiac toxicity monitor with ECG. Started IV then continue orally with second agent (Doxycycline, Clindamycin)
  • Artesunate: minimum 24hr IV therapy. Side effects: delayed post treatment haemolysis
22
Q

Uncomplicated malaria treatment

A
  • Artemether-lumefantrine: first line in the UK
  • Atovaquone/proguanil (Malarone): 4 ‘standard’ tablets daily for 3 days.
  • Quinine sulphate for 5 - 7 days plus doxycycline (or clindamycin for pregnant women) for 7 days
23
Q

Malaria- Hypnozoite therapy

A
  • Prevention of relapse in vivax and ovale malaria
  • Primaquine for 2 weeks
  • G6PD deficiency are at rusk of haemoylsis with Primaquine
24
Q

Treatment of malaria

A
  • Due to P.falciparum if uncomplicated: Riamet (artemether and Lumefantrine)
  • Due to P.malariae, vivax or ovale: chloroquine plus primaquine
25
Q

Chemoprophylaxus malaria: causal

A
  • Directed against hepatic stage (i.e. schizonts, not hypnozoites)
  • Prevents progression to erythrocytic stage
  • Continue for 7 days following last possible exposure
  • Examples – atovaquone/proguanil (Malarone)
26
Q

Chemoprophylaxis malaria suppressive

A
  • Directed against erythrocytic stages
  • Continue for 4 weeks post-exposure
  • Examples – chloroquine (rarely used), doxycycline (can cause skinburns and GI upset), mefloquine (dont give if depressed or seizures)
27
Q

Where do you find the different types of malaria

A
  • P.flaciparum: widespread, tropics and subtropics
  • P.vivax: Tropical and subtropical areas, spreads into Temperate. Rare in Africa
  • P.malarie: Broad but patchy
  • P.ovale: tropical Africa and west Pacific islands, not India
  • P.knowlesi: SE Asia
28
Q

What features may be seen on a blood film in malaria caused by p falciparum

A
  • no red cell enlargement of infected RBCs
  • fine ring trophozoites (some may have two chromatin dots)
  • May have multiple parasites in cell
  • Dont see schizonts in peripheral blood
  • accole/marginal forms
  • Mauers clefts
  • Crescent shaped Gametocytes- take 4 weeks
29
Q

What features may be seen on a blood film in malaria caused by P.malariae

A
  • no red cell enlargement of infected RBCs
  • Squashed ring
  • thick trophozoites which form bands across the cell
  • band forms
  • daisy head schizonts
30
Q

What features may be seen on a blood film in malaria caused by P.ovale

A
  • slight red cell enlargement
  • fimbriation: jagged edge
  • comet forms: oval shaped
  • schizonts with less than 12 merozoites
  • James dots (coarse)
31
Q

What features be seen on a blood film in malaria caused by P.vivax

A
  • enlarged red cells
  • amoeboid trophozoites (large and coarse)
  • schizonts with numerous merozoites 12-24
  • Schuffners dots
  • Round Gametocytes
32
Q

Plasmodium Knowlesi and what do you screen before starting malaria treatment

A

Plasmodium Knowlesi: rare, has an erythrocytic cycle of 24hrs and high parasitaemia which can be fatal. Difficult to distinguish from P.malariae under the microscope.

What do you need to screen for before starting malaria treatment: G6PD deficiency

33
Q

Microfilaria testing

A
  • Take one blood sample at 1pm and another at midnight
  • For low parasitaemias polycarbonate membrane filtration or saponin centrifuged preps can be performed.
  • Antigen testing
34
Q

Loa Loa and Wuchereria bancrofti

A

Loa Loa: African eye worm, body has lots of kinks, nuclei extends to tip of tail. Lunchtime speciemen

Wuchereria bancrofti: causes massively swollen leg. Take sample at midnight. Worms body curves are few and large, fewer nuclei none in the end of the tail.

35
Q

Trypanosomes

A
  • African Trypanosomiasis: T gambiense and T rhodesiense (both types of T brucei). Kineptoplast is larger then American
  • American disease: T cruzi (Chagas disease), T rangoli. Forms C shape
  • African spreads through Tsetse fly, Chagas spread through kissing bug
36
Q

Leishmaniasis

A
  • Spread through Sandfly
  • 3 types: cutaneous, mucocutaneous, visceral
  • Bone marrow Amastigotes
37
Q

Main antimalarial prophylaxis

A
  • Proguanilwithatovaquone(Malarone): less side effects but expensive, Taken 2 days before to 7 days after travel
  • Doxycycline: taken 2 days before to 4 weeks after travel. Can cause sunburns, diarrhoea and thrush
  • Mefloquine(risk of psychiatric side effects i.e. anxiety, depression): Taken two days before until 4 weeks after travel
  • Chloroquinewithproguanil(less often used due to high resistance)
  • After 6 months away you loose natural immunity to a Malaria endemic region
38
Q

Typical malaria prophylaxis if area is sensitive to chloroquine

A
  • chloroquine daily
  • proguanil weekly start 1 week before and continue 4 weeks after
39
Q

Options for malaria prophylaxis if area is not sensitive to chloroquine

A
  • Malarone (atovaquone plus proguanil)
  • doxycyline
  • Lariam (mefloquine)
40
Q

Categories of Osteomyelitis

A
  • acute v chronic. Native bone v associated with osteosynthetic device i.e. metal plates or nails.
  • How infections spread: Haematogenous, direct inoculation, Contiguous spread
41
Q

Osteomyelitis

A

Infection typically bacterial involving the bone. More prevalent in diabetes or PAD.

42
Q

Biofilm

A

A structured community of micro-organisms adhering to a surface and producing an extracellular matrix of polysaccharides. Often occurs with prosthetic material. Difficult to treat with antibiotics

43
Q

Risk factors for osteomyelitis

A
  • Haematogenous: Indwelling vascular catheter or IV drug use, diabetic foot
  • Direct inoculation: trauma, medical procedures, surgery. Difficult to treat create biofilm. Coagulase negative Streptococci
  • Associated conditions: diabetes, PAD, sickle cell disease, open fractures, orthopaedic operations
44
Q

Bone and joint infection presentation

A
  • Septic arthritis: rapid onset of pain, swelling and redness in a single joint
  • Prosthetic joint infection: joint pain & evidence of inflammation at the surgical site
  • Vertebral osteomyelitis: back pain (weeks to months) & may progress to cause neurological signs (numbness, weakness)
  • Chronic osteomyelitis often causes a sinus over the bone (ulcer which discharges material) which does not heal
45
Q

Bone and joint infections investigations

A
  • Fever often absent (except for septic)
  • Blood tests: FBC, U&Es, CRP, blood cultures
  • Microbiological tests: Joint aspiration (culture, PCR), bone biopsy (osteomyelitis), tissue biopsy (vertebral osteomyelitis), sonication of excised prosthetic material to get a culture
  • Radiology: Plain X-rays (osteomyelitis), CT scans, MRI scans
  • Back pain with raised inflammatory markers suggest vertebral osteomyelitis
46
Q

Course of antibiotics in bone and joint infection

A
  • Four weeks for septic arthritis
  • At least six weeks for vertebral osteomyelitis & prosthetic joint infections
  • IV medicines can be given in OPAT clinics
47
Q

Osteomyelitis pathophysiology

A
  • Most common cause: Staph aureus
  • In sickle cell Salmonella is the most common
  • Haematogenous: most common, due to microorganisms from another source in the body. Common in children and causes vertebral osteomyelitis. IV drug users high risk, can be secondary to endocarditis
  • Non-haematogenous: secondary to trauma/surgery often secondary to adjacent soft tissue infection. Peripheral neuropathy (diabetes) increases risk.
48
Q

Acute osteomyelitis

A
  • Symptoms tend to develop gradually over a few days
  • Pain is the most common symptom, with warmth, erythema and swelling of the soft tissue surrounding the affected bone
  • Osteomyelitis of the proximal joints such as the hips or vertebrae may present only with pain
  • Fever, malaise
49
Q

Chronic osteomyelitis

A
  • Tends to present only with local symptoms such as swelling, erythema and pain
  • Fever often absent
  • A draining sinus tract may be seen - pathognomonic of osteomyelitis
  • Patients with diabetes or vascular insufficiency may develop osteomyelitis subsequent to foot ulcers without the classic symptoms (asymptomatic)
  • May also present as non-healing fractures
  • Diabetics with ulcers >2cmare very likely to have osteomyelitis, even if no bone is visible
50
Q

Vertebral osteomyelitis and complications of osteomyelitis

A

Vertebral osteomyelitis: localised spine inflammation, chronic back pain worse at rest/night

Complications of osteomyelitis: septic arthritis, fracture, deformity

year 4 CDM 2 (39 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions