TOXOPLASMOSIS

Infection with Toxoplasma gondii, causing a spectrum of manifestations ranging from asymptomatic benign lymphadenopathy to life-threatening CNS disease, chorioretinitis, and mental retardation.

Symptomatic infections may present in several ways

Acute toxoplasmosis may mimic infectious mononucleosis with lymphadenopathy, fever, malaise, myalgia, hepatosplenomegaly, and pharyngitis. Atypical lymphocytosis, mild anemia, leukopenia, and slightly abnormal liver function tests are common. The syndrome may persist for weeks or months but is almost always self-limited.

A severe disseminated form characterized by pneumonitis, myocarditis, meningoencephalitis, polymyositis, diffuse maculopapular rash, high fevers, chills, and prostration. Acute fulminating disease is uncommon.

Congenital toxoplasmosis usually results from a primary (and often asymptomatic) acute infection acquired by the mother during pregnancy. The risk of transplacental infection increases from 15% to 30 to 60% for maternal infections acquired in the 1st, 2nd, or 3rd trimester of gestation, respectively

Hepatic failure 
Etiology. Chronic hepatic disease (e.g., chronic active hepatitis or alcoholic cirrhosis) is the most common cause of hepatic failure although acute liver disease may also be responsible.

- Widespread liver necrosis may be seen with carbon tetrachloride and acetaminophen toxicity. Widespread steatosis is seen in Reye's syndrome, a cause of acute liver failure most often seen in children with a recent history of aspirin ingestion for an unrelated viral illness. 
- Massive necrosis may also be seen in acute viral hepatitis, after certain anesthetic agents, and in shock from any cause. 

Clinical features. Hepatic failure causes jaundice, musty odor of breath and urine, encephalopathy, renal failure (either by simultaneous toxicity to the liver and kidneys or the hepatorerial syndrome), palmar erythema, spider angiomas, gynecomastia , testicular atrophy 

INFLUENZA

An acute viral respiratory infection with influenza, a virus causing fever, coryza, cough, headache, malaise, and inflamed respiratory mucous membranes.

Influenza B viruses typically cause mild respiratory disease

Symptoms and Signs

mild cases:

Chills and fever up to 39 to 39.5° C

Prostration and generalized aches and pains, Headache, photophobia and retrobulbar aching

Respiratory tract symptoms may be mild at first, with scratchy sore throat, substernal burning, nonproductive cough, and sometimes coryza. Later, the lower respiratory illness becomes dominant; cough can be persistent and productive.

severe cases

sputum may be bloody. Skin is warm and flushed. Soft palate, posterior hard palate, tonsillar pillars, and posterior pharyngeal wall may be reddened, but no exudate appears. Eyes water easily, and the conjunctiva may be mildly inflamed

Encephalitis, myocarditis, and myoglobinuria are infrequent complications of influenza and, if present, usually occur during convalescence

Coccidioidomycosis (Valley Fever; San Joaquin Fever)

A disease caused by the fungus Coccidioides immitis, usually occurring in a primary form as an acute benign asymptomatic or self-limited respiratory infection, occasionally disseminating to cause focal lesions in skin, subcutaneous tissues, lymph nodes, bones, liver, kidneys, meninges, brain, or other tissues.

Primary coccidioidomycosis is usually asymptomatic, but nonspecific respiratory symptoms resembling influenza or acute bronchitis sometimes occur or, less often, acute pneumonia or pleural effusion. Symptoms, in decreasing order of frequency, include fever, cough, chest pain, chills, sputum production, sore throat, and hemoptysis.

Progressive disseminated coccidioidomycosis may develop a few weeks, months, or occasionally years after primary infections,, is more common in men than women and is more likely to occur in association with HIV infection, immunosuppressive therapy

Symptoms often are nonspecific, including low-grade fever, anorexia, weight loss, and weakness. Extensive pulmonary involvement may cause progressive cyanosis, dyspnea, and discharge of mucopurulent or bloody sputum. Extrapulmonary lesions are usually focal, involving one or more tissue sites in bones, joints, skin, subcutaneous tissues, viscera, brain, or meninges. Draining sinus tracts sometimes connect deeper lesions to the skin. Localized extrapulmonary lesions often become chronic and recur frequently, sometimes long after completion of seemingly successful antifungal therapy.

A dermatofibroma is a benign tumor of the dermis, MC located on the lower extremity, where it has a nodular, pigmented appearance.
 - composed of benign histiocytes.

Growth and spread of tumours

Growth in excess of normal is a feature of all tumours but extension to tissue away from the site of origin is a feature of malignant tumours.

Modes of spread of malignant tumours

- local, invasion. This is a feature of all malignant tumors and  takes place along tissue spaces and facial planes
    o    Lymphatic spread. Most often seen in carcinomas. This can be in the form of 
    o    Lymphatic permeation:  Where the cells extend along the lymphatics as a  solid core 
    o    Lymphatic embolisation: Where a group of tumour cells break off and get carried to the draining mode

-Vascular spread :  This is a common and early mode of spread for sarcomas but certain carcinomas like renal cell carcinoma and chorio carcinoma have a predilection to early vascular spread.

Vascular spread is most often due .to invasion of venous channels and can be by permeation or embolisation.

Lungs, liver, bones and brain are the common sites for vascular metastasis but
different tumours have different organ preference for metastasis, e.g. : Bronchogenic carcinoma often spreads to liver and adrenals.

-Body cavities and natural passages
    o    Gastrointestinal carcinomas spread to ovaries (Krukenberg’s tomour)