Infectious Diseases

Presenting problems in infectious diseases;

1. Fever:

it is the most common and most constant presentation

A. Fever in tropical resident:

Geography and exposure
Mosquito bite ……Malaria
Sand fly bite ……..Leishmaniasis
Infected person contact……Hemorrhagic fever, hepatitis, HIV
Animal contact …..Brucellosis, anthrax
Fresh water swimming… Schistosomiasis

B. Fever in old age :

Oral temperature are unreliable
Frequently associated with confusion
Commonly caused by pneumonia, UTI, soft tissue infection & gateroenteritis

C. Factitious fever:

mainly in female patients with medical or nursing background
The patients looks well with bizarre temperature chart , absence of diurnal variation and changes in pulse rate
Absence f sweating
Normal ESR & CRP
Evidence of self – injection or self – harm.

D. Fever in neutropenic patient:

caused by gram +ve organisms most commonly.
broad spectrum antibiotic should be started.
The most common regimen is pipracillin + gentamicin i.v with the addition of antifungal if the fever not resolved within 48 hours

2. SKIN RASHES

A. Patterns of rash associated with infection

1. Macular: Measeles, Rubella, Typhoid fever, Secondary Syphilis.
2. Haemorrhagic: Meningococcal infection, haemrrhaghaemrrhagic fever, Leptospirosis, Septicaemia with DIC
3. Vesicular: Chickenpox, Poxvirus, herpes simplex, Shingles
4. Erythematous: Scarlet fever, Toxic shock syndrome, human erythrovirus 19, Drug rash.






5. Urticarial; Schistosomiasis, Strongyloidosis6. Nodular: Erythema nodosum ( primary TB, Leprosy, streptococcal infection, mycoplasma)7. Chancres (( ulcerating nodules )): Primary Syphilis, anthrax, Trypanosomiasis

B. Onset of rash

Really
Sick
People
Must
Take
No
Exercise

3. SPLENOMEGALY ( TROPICAL )

Mild: Malaria, toxoplasmosis, Hepatitis, HIV, Typhoid, Brucellosis, Leptospirosis, …..
Moderate: SBE, portal hypertension due to schistosomiasis.
Massive: Visceral Leishmaniasis, tropical splenomegaly syndrome.

4. EOSINOPHILIA

It is associated with parasite infections and any patients with eosinophil count more than 400 cell/ml. should be investigated for possible parasitic infection which include:
Strongyloidosis, Hook warm, Ascariasis, Schistosomiasis, Cysticercosis, hydatid disease,……

5. Bacteraemia & Septicaemia:

Bacteraemia is the presence of living organism in the blood and it can occur in healthy people without symptoms but when it cause a disease it is called as septicaemia.
The organism may originate from any area of the body
Septicaemia can be complicated by metastatic septic lesions in organs or tissues e.g heart valves, liver, brain, bone, joint,….






Circulatory failure ( septic shock syndrome ) is the most dangerous complication of septicaemia with possible organ failure
(( heart failure, renal failure, bone marrow failure, respiratory failure,….)
Blood cultures are the most important
Treatment: Antibiotics according to the result of blood culture and sensitivity.

6. Pyrexia Of Unknown Origin (( PUO )):

It is consistently elevated body temperature more than 37.8 c persisting for more than 2 weeks with no diagnosis after initial investigations.

Aetiology of PUO:

A. Infection:
1. sepsis, abscesses
2. Tuberculosis
3. Endocarditis
4. Enteric fever
5. Brucellosis
6. HIV
7. Toxoplasmosis
8. fungal infection

B. Malignancies

1. Lymphoma
2. Hodgkin s disease
3. Myeloma
4. Hypernephroma
5. Leukemia

C. Connective tissue disorders:

1. Vasculitis
2. SLE
3. Polyarteritis nodosa
4. Still s disease

D. Miscellaneous:

1. inflammatory bowel disease
2. drug fever
3. sarcoidosis
4. FMF
5. Atrial myxoma
E. No diagnosis or resolves spontaneously

Investigations & Management

A. Re take history
B. Repeat the examination
C. Review results of investigations and repeat if indicated
D. consider farther investigations; serological, CT, MRI, tissue biopsies,…
E. Consider therapeutic trial e.g antimalaria

7. Acute Diarrhoea

It is the predominant symptom of acute infective gasteroenteritis
Infectious causes of acute diarrhea:
A. Toxin mediated: Bacillus cereus, Clostridial enterotoxin, staphylococcal enterotoxin.
B. infective food poisoning: caused by Rota virus, Shigella, cholera, E.Coli, Salmonella,….
C. Protozoal; Giardiasis, Amoebiasis,…
D. Systemic illness: sepsis, pneumonia, Malaria, Meningococcal sepsis.

8. Chronic Diarrhoea:

It is defined as Diarrhoea persisting for more than 14 days and its infectious causes include:
a. Giardiasis
b. Strongyloidiasis
c. HIV enteropathy
d. Tropical sprue
e. Enteropathic E. Coli






usually the diarrhoea with pale bulky stools,abdominal symptoms with distension and flatulence, nutritional deficiencies and general ill health.

9. Lymphadenopathy.